####018005918#### FXUS66 KPDT 162320 AFDPDT Area Forecast Discussion National Weather Service Pendleton OR 420 PM PDT Fri May 16 2025 .UPDATED AVIATION... && .PREV DISCUSSION... /issued 229 PM PDT Fri May 16 2025/ SHORT TERM...Tonight through Sunday night... Key Messages: 1. Showers and a 10-30% chance of thunderstorms tonight through Sunday. 2. Breezy to windy conditions through the Cascade gaps and across portions of the Columbia Plateau Saturday and Sunday. 3. Light snowfall for mountain passes Saturday night and Sunday morning. Tonight, the first of back-to-back waves is expected to arrive from the northeast Pacific (>90% confidence). This wave is currently visible on water vapor imagery west of Vancouver Island, diving southeast towards the PacNW. The second vorticity maximum located in the Gulf of Alaska, is not advertised by ensemble NWP to arrive until Saturday night through Sunday, and is the main driver of uncertainty in the short-term forecast; its track will have implications on precipitation and wind. Shower chances will increase tonight, with some weak elevated instability facilitating low-end chances (10-15%) of embedded thunderstorms for portions of central and east-central Oregon, mainly in Grant County. Area-wide shower chances will increase Saturday through Saturday night as the first wave provides ample forcing, and as the second wave digs southeast into the PacNW. Have maintained an area-wide slight chance (15-24% probability) to chance (25-35% probability) mention of thunder in the forecast Saturday. Best chances of thunderstorms will be over the Blue Mountains and their foothills as well as portions of the lower Columbia Basin during the afternoon (25-35% probability) . Delving into clusters of ensemble solutions does reveal some uncertainty in the evolution of the system as the two waves interact Saturday night through Sunday; ensemble members are still uncertain whether the second wave will become a slower-moving closed low overhead late Saturday through Saturday night or if it will remain a weaker open wave trough with a quicker exit through Sunday. Westerly winds will increase in magnitude Saturday afternoon through the Cascade gaps as cross-Cascade pressure differences increase and a robust low-level jet (35-45 kts) sets up. NBM probabilities of exceeding advisory-level gusts (45 mph) through the eastern Columbia River Gorge, Kittitas Valley, and wind-prone portions of the Columbia Basin/Blue Mountain foothills are roughly 40-70%. Saturday night through Sunday, the likelihood of reaching advisory criteria is high (60-95% chance) through the Kittitas Valley and eastern Columbia River Gorge. Moreover, a low-medium chance (30-60%) of warning-level wind gusts (58 mph or greater) is advertised by the NBM for the Kittitas Valley. In other wind- prone portions of the Columbia Basin/Blue Mountain foothills, NBM probabilities of reaching advisory criteria are medium-high (40-70%). Due to the aforementioned uncertainty in the precise track of the second wave, have held off issuing any wind highlights with the afternoon forecast package. Lastly, will mention measurable snowfall (0.1" or greater) is more likely than not (50-85% chance) across mountain passes Saturday night through Sunday morning as colder air associated with the trough/closed low spreads over the region. In fact, NBM probabilities place medium (40-60%) chances of 1" of snowfall or more for the higher passes of the Cascades and Blue Mountains. However, snow accumulation on roadways may be limited due to warm antecedent conditions. Plunkett/86 LONG TERM...Monday through Friday...Westerly flow over the area will allow for a weak system to move across the region on Monday. It will bring mainly light rain to the mountains. Lingering moisture in the westerly flow will keep precip chances in the mountains on Tuesday. The rest of the extended period looks to be dry, with some transitory ridging Tuesday into Wednesday and more zonal flow Wednesday into Thursday then more ridging Thursday into Thursday night. Monday and Tuesday will see diurnally breezy winds, with Tuesday possibly breezier. Winds will mainly be in the 25 to 30 mph range in the normally gusty areas such as the Kittitas Valley, Simcoe Highlands, Columbia Basin and Foothills of the Blue Mountains. On Monday, NBM probabilities of wind gusts >= 25 mph is quite high generally 90 percent or greater in these areas. However, the probabilities of wind gusts >= 39 mph is 20 to 50 percent. On Tuesday. NBM probabilities of wind gusts >= 25 mph is about the same as Monday. However, the probabilities of wind gusts >= 39 mph is a bit higher30 to 60 percent and much higher in the Kittitas Valley (80 percent). && .AVIATION...00Z TAFs...VFR conditions expected through the period with the exception of a brief period of MVFR for BDN/RDM near 13Z. DLS will remain windy through 7Z before a brief settle down between 07-17Z before increasing 15-19G20-25kts. Otherwise, winds will remain below 10kts through 18Z. Bennese/90 && .PRELIMINARY POINT TEMPS/POPS... PDT 48 64 43 62 / 20 90 70 30 ALW 49 64 44 61 / 10 80 90 40 PSC 48 69 45 69 / 10 70 60 10 YKM 49 69 41 67 / 30 70 10 0 HRI 49 69 44 67 / 20 80 50 20 ELN 47 65 41 61 / 40 80 20 0 RDM 42 62 34 57 / 30 80 20 10 LGD 42 58 39 54 / 30 90 90 50 GCD 43 56 36 52 / 70 100 80 30 DLS 51 68 46 64 / 30 60 10 10 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. && $$ SHORT TERM...86 LONG TERM....77 AVIATION...90 ####018003792#### FXUS64 KLUB 162320 AFDLUB Area Forecast Discussion National Weather Service Lubbock TX 620 PM CDT Fri May 16 2025 ...New AVIATION... .KEY MESSAGES... - Above normal temperatures are expected through Monday. - There is a slight chance of thunderstorms across the far eastern Rolling Plains Saturday and Sunday. Most areas will remain dry. - Gusty winds expected Sunday and Monday which may lead to some patchy blowing dust on the Caprock. && .SHORT TERM... (This evening through Saturday) Issued at 159 PM CDT Fri May 16 2025 Quiet and warm conditions will continue tonight and tomorrow. Mostly zonal upper flow will give way to more southwesterly upper flow tonight as the upper low currently over Minnesota moves over the Great Lakes. Surface lee troughing will develop through the day tomorrow and will allow for a low end breezy day with winds out of the southwest around 15 to 20 mph. This will help to dry out the low levels with surface dewpoints dropping into the upper 20s to mid 40s. Models are fairly consistent with bringing an upper shortwave trough, currently west of Baja, over the region tomorrow afternoon. While the shortwave will be a much smaller version of its former self, there could be enough lift for some virga showers tomorrow afternoon as mid/upper level moisture over northern Mexico pushes northward. No mention of PoPs is warranted at this time. Expect afternoon highs to reach into the upper 80s to mid 90s. && .LONG TERM... (Saturday night through next Thursday) Issued at 159 PM CDT Fri May 16 2025 Sunday will be characterized by increasing southwesterly flow as a lead shortwave will round a broad upper-level low centered over the Pacific Northwest. The accompanying lee cyclogenesis along the Palmer divide in Colorado and attendant 500mb jet will result in breezier conditions across west Texas. Southwest winds will advect hot Mexican plateau air into the area with highs into the high 80s/low 90s. Blowing dust will be possible during the afternoon. Storm chances on Sunday will be dependent on the placement of the dryline by late afternoon, though current guidance is in good agreement that best storm chances will be east of the CWA. The upper-level low will quickly translate and fill as it pushes over the Rockies and stalls over the central high plains. The surface cyclone will slowly propagate east from Colorado and push towards Nebraska on Monday resulting in an enhanced belt of mid- level westerlies across CWA. The strong jet overhead will usher in another breezy day at the surface with possible blowing dust. Accompanying the westerlies is hot Sonoran Desert air resulting in highs well into the 90s. No storms are anticipated in the CWA as they will be well east of the area. As midweek arrives, there is good model agreement that northwest flow will dominate the forecast as the upper-level low slowly moves through the eastern CONUS. Stable conditions will preside over the area with dry air and milder temperatures. Long range models are in fairly good agreement that by late week into Memorial day weekend, ridging will build in overhead leading to stable conditions and warmer temperatures. KCL && .AVIATION... (00Z TAFS) Issued at 618 PM CDT Fri May 16 2025 VFR conditions will prevail through TAF period for all three sites. Winds will remain light overnight through tomorrow but are expected to ramp up tomorrow afternoon with gusts up to 30 mph possible. && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...51 LONG TERM....26 AVIATION...10 ####018005962#### FXUS65 KFGZ 162320 AFDFGZ Area Forecast Discussion National Weather Service Flagstaff AZ 420 PM MST Fri May 16 2025 .SYNOPSIS...Cooler weather returns this weekend with strong southwest winds. Slight chances for precipitation on late Saturday through Monday. Warmer and drier conditions will return for Tuesday through the rest of the week. && .DISCUSSION...Saturday through Sunday...A trough will drop down through the Great Basin, bringing some cooler air and stronger winds to the region. Temperatures on Saturday will be cooler than they were the past couple of days but will still feel mild. The colder air will arrive on Sunday, with highs 10-15 degrees below average. Did you miss the winds? We didn't think so but here they come anyway. The pressure gradient starts to tighten up across our western areas on Saturday morning, with increasing southwest winds through the day. Winds will be around 15-30 mph with gusts 35-45 mph. Additionally, moisture is lagging behind the trough and we will remain dry with RH values in the single digits to teens. The fuels across the northern and western parts of the state are in slightly better shape than eastern areas. Model guidance has slowed down slightly over the past couple of runs and it looks like any showers will arrive late Saturday into Sunday into our northwestern areas. With a slightly weaker and less deep trough, the moisture will not extend quite as far south as we had anticipated (and hoped for) resulting in the best precipitation chances remaining north of I-40 and mainly closer to the AZ/UT border. The colder air pushing in early Sunday may allow for some snow showers or a mix of rain and snow showers across the Kaibab Plateau. Instability looks pretty marginal so only isolated thunder is expected on Sunday. Taking into account all of this information, we have issued a Wind Advisory for portions of Coconino and Yavapai counties as well as a Red Flag Warning for the Little Colorado River Valley and the White Mountains. Sunday night through Monday...The first trough exits the region on Sunday as the secondary trough starts to push down from the north. This second trough will push into the area Sunday night and exit by Monday evening. This system also appears to be weaker than it has the past couple of model runs and the moisture is looking to be lacking more than it did previously. Best chances for showers will be along and north of the Mogollon Rim, with a few snow showers possible above 7000 feet. Again, instability is marginal but some isolated thunderstorms will remain possible through Monday afternoon. While some areas will benefit from the increase in moisture, not all areas will be so lucky. Portions of the Little Colorado River Valley will remain pretty dry. The winds will remain gusty on Sunday staying our of the southwest around 15-25 mph with gusts 35-45 mph. Winds will drop off on Monday but will remain gusty across eastern portions of the Little Colorado River Valley. With the continued strong winds and dry conditions, we will again see near-critical to critical fire weather conditions. With a little bit more uncertainty to just how much the RH will increase on Sunday, we have have left the Fire Weather Watch in place. Tuesday and beyond...As the second trough exits the region late Monday, we should see a rather quick recovery across the state. Temperatures will warm to near average by midweek and then 5-15 degrees above average for the second half of the week. Winds are expected to become lighter through the week with typical afternoon breezes. && .AVIATION...Saturday 17/00Z through Sunday 18/00Z...VFR conditions are forecast, though smoke could reduce visibility locally near and downwind of Greer (in eastern Arizona) and Blind fire (southeast of KLFG). Winds generally light and variable overnight, then increase after 16Z becoming southwest at 10-20 kts gusting to 30-35 kts. OUTLOOK...Sunday 18/00Z through Tuesday 20/00Z...VFR conditions prevailing, though smoke could reduce visibility near and downwind of wildfires. Isolated to scattered -SHRA and a slight chance of -TSRA after 06Z Sunday mainly north of I-40. Saturday night will see local southwest winds at 10-20 kts gusting to 30 kts downwind of terrain features. Winds on Sunday expand in coverage remaining southwest at 10-20 kts with gusts to 30-35 kts. Northwest winds 10-20 kts developing after 16Z Monday. && .FIRE WEATHER...This afternoon through Sunday...Dry conditions will continue through Saturday with minimum RH values mostly below 15%. Southwest to west afternoon winds 10 to 20 mph today. Southwest winds increase Saturday to 15-25 mph gusting 30-40 mph. A Red Flag Warning is in effect on Saturday for the Little Colorado River Valley and White Mountains. Winds are expected to be stronger on Sunday with increasing humidity and chances for showers moving from west to east. The LCR in Apache County may still see very low RH and a Fire Weather Watch is in effect there for Sunday. Monday through Wednesday...Windy, cooler, and better chances for showers on Monday. West-northwest 10-20 mph on Monday. Much warmer, less wind, and drier on Tuesday and Wednesday. && .FGZ WATCHES/WARNINGS/ADVISORIES... Wind Advisory from 11 AM MST /noon MDT/ to 11 PM MST /midnight MDT/ Saturday for AZZ004-006>008-015. Red Flag Warning from 11 AM MST /noon MDT/ to 7 PM MST /8 PM MDT/ Saturday for AZZ112>114-117-140. Fire Weather Watch from Sunday morning through Sunday evening for AZZ114. && $$ PUBLIC...Meola AVIATION...McCollum FIRE WEATHER...MAS For Northern Arizona weather information visit weather.gov/flagstaff ####018007703#### FXUS62 KMLB 162320 AFDMLB Area Forecast Discussion National Weather Service Melbourne FL 720 PM EDT Fri May 16 2025 ...New AVIATION... .KEY MESSAGES... Issued at 358 PM EDT Fri May 16 2025 - Increasingly hot and dry conditions forecast for east central Florida this weekend and early next week with widespread low to mid 90s and near record high temperatures, as well as fire sensitive conditions - Peak heat indices forecast to reach 100-106 this weekend into early next week. There is a Moderate HeatRisk on Saturday, a Moderate to Major HeatRisk on Monday, and a Moderate to Extreme HeatRisk Tuesday to Wednesday - Mostly dry weather expected through next Wednesday before isolated to widely scattered showers and lightning storms on Thursday with a "cool" front expected to move over east central Florida. Drought conditions will have the potential to worsen/expand before returning rain chances. && .PREVIOUS DISCUSSION... Issued at 358 PM EDT Fri May 16 2025 Currently-Saturday... Local radar imagery shows dry weather over east central Florida and GOES-16 satellite imagery shows mostly clear skies. High pressure (~1018mb) is situated over the eastern Gulf of America and the state of Florida. Temperatures are currently in the upper 80s to mid 90s with heat index values in the 90s to 100F degrees and dew points generally in the 60s to low 70s. Winds are from the east-southeast at 6-12mph with gusts to 20mph along the coast with the east coast sea breeze beginning to move inland and from the west-southwest at 6-12mph to the west of I-95. Dry and hot weather is expected to continue this afternoon with above normal to record high temperatures. Dry and hot weather will continue Saturday afternoon with high pressure over Florida, as well as 500mb heights at around 591dm forecast over east central Florida into Saturday afternoon. ECMWF and NAEFS ensembles indicate afternoon temperatures in the 97.5th to maximum percentile for this time of year over east central Florida. Lows in the mid 60 to mid 70s are forecast. Above normal (~5-10F+) to record high temperatures in the low to mid 90s are forecast. There is a Moderate HeatRisk on Saturday. This level of heat affects most individuals sensitive to heat, especially those without adequate hydration. It is recommended that those who spend extended periods of time outside this afternoon and early evening to drink plenty of water, wear light-colored clothing, reduce time spent outdoors or stay in the shade, and take breaks in an air conditioned facility. Sunday-Tuesday... High pressure over Florida on Sunday is expected to gradually shift east over the southwest Atlantic on Monday and Tuesday. Guidance shows 500mb heights over east central Florida around 588-591dm Sunday to Tuesday. Additionally, ECMWF and NAEFS ensembles indicate afternoon temperatures in the 90th to maximum percentile for this time of year over east central Florida. Dry weather is expected with high temperatures in the low to upper 90s and lows in generally the mid 60s to mid 70s. Heat index values between 98-106F degrees are forecast. There is a Moderate to Major HeatRisk Sunday to Monday, and a Moderate to Extreme HeatRisk Tuesday. A Major to Extreme HeatRisk affects anyone without effective cooling and/or hydration. More information on HeatRisk can be found at wpc.ncep.noaa.gov/heatrisk. Winds are forecast to increase from the east-southeast at 10-15mph with gusts to 20mph into each afternoon with the east coast sea breeze generally to the east of the Orlando metro with winds from the west-southwest at 5-10mph. Wednesday-Thursday... High pressure is expected to weaken and shift southeast over the southwest Atlantic Wednesday and Thursday before a "cool" front is forecast to move east-southeast over east central Florida on Thursday. Global models show PWATs between 1.40-1.70" over east central Florida on Thursday. Isolated showers (PoPs ~20%) and lightning storms are forecast ahead of the "cool" front Wednesday evening and into early Thursday morning generally along and to the north of I-4 as the aforementioned front moves south over northern Florida before moving over east central Florida into Thursday afternoon. Isolated to widely scattered showers (PoPS ~ 20-30%) and lightning are forecast to develop from the northwest to southeast over east central Florida Thursday morning and afternoon before showers and storms are expected to move offshore of the Treasure Coast into Thursday night. West-southwest winds at 10-15mph with gusts to 20-25mph are forecast. Above normal to record afternoon highs in the low to upper 90s are forecast on Wednesday and the upper 80s to mid 90s are forecast on Thursday. Heat index values between 98-106F degrees are forecast on Wednesday. There is a Moderate to Extreme HeatRisk on Wednesday and a Moderate HeatRisk on Thursday. Lows in the upper 60s to mid 70s are forecast. && .MARINE... Issued at 218 PM EDT Fri May 16 2025 Currently-Saturday.... Favorable boating conditions and dry weather are expected with high pressure (~1018mb) over Florida. South-southeast winds at 6-14kts are expected to veer west- southwest tonight and back east-southeast into Saturday afternoon. Seas to 1-3ft are expected. Sunday-Tuesday... Favorable boating conditions and dry weather are expected with high pressure (~1017mb) over Florida expected to gradually shift southeast over the southwest Atlantic through Tuesday. West-southwest winds at 6-14kts are expected to back east-southeast into each afternoon and increase to 10-15kts on Tuesday. Seas to 1-3ft are expected. && .AVIATION... (00Z TAFs) Issued at 720 PM EDT Fri May 16 2025 VFR conditions anticipated tonight through tomorrow, with no rain chances forecast near the terminals. Variable winds tonight pick up out of the west-southwest at 5 to 10 knots tomorrow morning. Along the coast from TIX southward, winds are forecast to become more onshore as the east coast sea breeze develops and moves inland during the afternoon hours. && .FIRE WEATHER... Issued at 358 PM EDT Fri May 16 2025 Sensitive fire weather conditions are expected through mid week next week with soils expected to continue to dry out with no mentionable rain chances in the forecast through Tuesday. Minimum RH values between 30-35% over the interior are expected Saturday; however, winds will be relatively light, so conditions will not reach Red Flag criteria. Minimum RH values near 50% are forecast close to the coast south of Cape Canaveral. Minimum RH values between 35-40% are forecast generally over the interior Sunday and into early next week. Winds will turn onshore each afternoon at 10-15mph with gusts to 20mph behind the sea breeze, mainly east of the Orlando metro. Above normal to near record high temperatures are expected each day. && .PRELIMINARY POINT TEMPS/POPS... DAB 69 96 70 96 / 0 0 0 0 MCO 72 96 73 96 / 0 0 0 10 MLB 72 92 73 92 / 0 0 0 10 VRB 71 93 72 93 / 0 10 0 10 LEE 70 94 71 94 / 0 0 0 0 SFB 70 97 71 97 / 0 0 0 10 ORL 73 96 73 96 / 0 0 0 10 FPR 70 92 71 92 / 0 10 0 10 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. && $$ DISCUSSION...Fehling AVIATION...Tollefsen ####018005605#### FXUS62 KMFL 162320 AAB AFDMFL Area Forecast Discussion...UPDATED National Weather Service Miami FL 720 PM EDT Fri May 16 2025 ...HEAT INDEX READINGS 98 TO 102 SATURDAY... ...HEAT INDEX READINGS 98 TO 105 SUNDAY... .UPDATE... Issued at 713 PM EDT Fri May 16 2025 High pressure will continue to build into the Florida Peninsula tonight into Friday. This will keep the dry weather over South Florida along with hot temperatures on Saturday Lows tonight should fall into the upper 60s to near 70 over the interior areas to lower to mid 70s over the metro areas. Highs on Saturday will be around 90 over the metro areas to mid 90s over the interior areas. Heat indices will be around 100 over the metro areas to lower 100s over the interior areas. Rest of the forecast looks good at this time and no other changes are planned. && .SHORT TERM... (Rest of today through Saturday) Issued at 1201 PM EDT Fri May 16 2025 It may be the start of the climatological wet season in South FL, but it's not going to look that way heading into this weekend. Upper level ridging and surface high pressure will dominate resulting in warm and dry conditions persisting. Temperatures will be several degrees above normal with highs ranging from the upper 80s near the coasts to middle 90s over interior SW FL. Dewpoints in the upper 60s to lower 70s will result in max heat indices in the mid to upper 90s across the east coast metro, and around 100 over the interior. Little relief is expected overnight with lows ranging from the upper 60s over the interior, to middle 70s closer to the coasts. && .LONG TERM... (Saturday night through next Thursday) Issued at 233 PM EDT Fri May 16 2025 Stout deep-layer ridging and anhydrous weather will prevail across South Florida through the weekend and into much of the upcoming work week. The atmospheric column will remain quite dry during this period as dry air rotates anticyclonically around the surface ridge axis situated across the western Atlantic waters. NASA's/GMAO Dust Aerosol Optical Thickness model even hints at the periphery of a saharan dust plume arriving across South Florida during the early to middle portion of next week. However, the main implication of stout ridging directly overhead will be very light mid to upper level flow aloft. The lack of synoptic forcing will default prevailing weather to mesoscale processes such as the diurnal sea-breeze circulations each afternoon. Given the lack of cloud cover and subsidence aloft, temperatures will be on the toasty side with values several degrees above average across the area. Across inland locales, afternoon temperatures will peak into the mid to upper 90s each with temperatures in the upper 80s to low 90s across coastal locations. The foci of hottest afternoon temperatures may pivot during the work week, switching from southwest florida to southeastern florida as surface flow veers ahead of a weak boundary during the mid to late week period. There won't be much respite overnight as temperatures along the coast will still remain on the warmer side with lows in the middle to upper 70s along the east coast of South Florida. With a lack of cloud cover and surface humidity, apparent temperatures (feels-like temperatures) will reach 100-105 degrees each afternoon. While just below lower bounds of heat advisory thresholds, prolonged exposure outdoors could impact vulnerable individuals. Sheltered areas exposed to these temperatures without climate control (parked cars) could become deadly for children and pets. Always look before you lock! By mid week, a mid-level trough propagating across the Ohio River Valley and Great Lakes region will drag an attendant surface low and boundary eastward across the Mid-Atlantic and northeastern United States. This boundary is then forecast to arrive across our region, bringing a deeper pool of low-level boundary moisture. This extra moisture could provide enough instability to spark up higher rain chances during this period. However, as discussed in the previous area forecast discussion, uncertainty remains regarding the evolution of this boundary as well as if any upper level synoptic support (current models show the base of the "parent" mid-level trough remaining well to the north) will be in tandem with this feature. && .AVIATION... (00Z TAFS) Issued at 642 PM EDT Fri May 16 2025 Winds will be light and variable tonight along with dry and VFR conditions. && .MARINE... Issued at 1201 PM EDT Fri May 16 2025 Benign marine conditions persist through the upcoming weekend, with light winds and seas 2 ft or less. && .PRELIMINARY POINT TEMPS/POPS... Miami 75 92 76 90 / 0 0 0 10 West Kendall 73 93 74 92 / 0 0 0 10 Opa-Locka 75 92 76 92 / 0 0 0 10 Homestead 75 92 75 90 / 0 0 0 0 Fort Lauderdale 76 90 76 88 / 0 0 0 10 N Ft Lauderdale 75 91 76 90 / 0 0 0 10 Pembroke Pines 75 92 78 95 / 0 0 0 10 West Palm Beach 74 92 74 91 / 0 0 0 10 Boca Raton 74 91 75 92 / 0 0 0 10 Naples 74 89 74 90 / 0 0 0 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...None. AM...None. GM...None. && $$ SHORT TERM...CMF LONG TERM....Hadi AVIATION...BNB ####018011091#### FXUS61 KBOX 162321 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 721 PM EDT Fri May 16 2025 .SYNOPSIS... Weakening low pressure will bring scattered showers or thunderstorms at times through the end of the week as it reaches New England, but a majority of the time will be dry. A cold front moves through Saturday night behind the storms, drying and cooling the region. Even with mostly dry conditions, scattered showers remain possible Sunday with a cold pool aloft, then the pattern turns unsettled again toward midweek. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Key Messages: Key Messages: * Isolated showers and storms possible late afternoon-early evening, mainly for western MA and CT. * Low clouds and patchy fog develop tonight. Clouds have scattered out in most spots this afternoon which has helped support some marginal instability. SPC mesoanalysis shows around 500 J/kg of MLCAPE across west and central MA. Although lacking in much forcing, this should be enough to support the risk for a isolated shower or storm in those mentioned areas late this afternoon through early evening. Main story for tonight will be low clouds and patchy fog. Similar conditions to last night with a moist airmass and light winds to support the re-development of low stratus and areas of patchy fog. Can't rule out an isolated shower or sprinkle overnight. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY/... Key Messages: * Fog and stratus develop again tonight, and it may linger for quite a while into Saturday. * Possible round of scattered t-storms Saturday morning in most areas. * Better chance at t-storms between 2-8 PM west of Worcester. Some could become strong. Details: An upper level low and trough slowly approaches southern New England from the Great Lakes region. This will generate better synoptic support for ascent across the region. The already moist airmass will provide a primed environment for convective showers and thunderstorms and potentially even a couple strong to severe ones later on in the day. The forecast is (lack of a better word) "messy" for tomorrow. This owes to the very marginally unstable and sufficiently moist airmass that prevails Friday night and Saturday. High resolution guidance has been having difficulty in resolving showers/storms accurately in timing/location over the past few days. Given this marginal airmass, it hasn't taken much to trigger a shower or storm with a little bit of instability and weak lift. The suite of high resolution guidance continues to lack consensus among each other with the details of the convection on Saturday (timing, location). Some models show the potential for some elevated showers and storms in the morning on Saturday over portions of southern New England with lightning and brief heavy downpours as the main threat. The next element to consider will be how well we clear out. Most model guidance shows that the morning low stratus will be slow/gradual to improve with breaks in the clouds developing in the afternoon across west and central southern New England. This means it will take time for instability to build. If we can break the cloud cover enough, models show a favorable environment for thunderstorms and a couple strong to severe storms as well. If clouds stick around too long, we may not destabilize in time for peak heating while ahead of the approaching cold front. This has been signaled pretty consistently among the CSU, NSSL ML guidance. Moisture is plentiful with decent boundary layer moisture as well given dewpoints in the low to mid 60s. As a cold front approaches from the west, this will steepen the mid- level lapse rates and support MLCAPE values in the 500-1100 J/kg range across west and central southern New England. Sufficient shear as well, especially later in the afternoon as a low level just pushes in from the west. This should be enough to support multi cell convection with a few of those storms strong to severe with damaging wind and large hail (~1"). Can't rule out the low risk for a tornado as well with low LCLs, steep low level lapse rates, and sufficient 0-1 helicity. Another element to the "messier" forecast will be the timing of the convection. There isn't a lot of agreement among high resolution guidance on the timing of the convection. Overall, there will be a round or two of thunderstorms that develop across western southern New England mid afternoon through early evening. The second round of storms will likely hold the greater risk for severe with the HREF showing a line developing across western MA early evening moving eastward. So bottom line, the risk for thunderstorms in west and central New England increases in the afternoon with the higher chance for seeing strong to severe storms late afternoon-early evening. It is that time of year where there are plenty of outdoor events, so stay updated on the forecast and stay aware of incoming weather. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Key Messages * Mild day Sunday with a risk for some scattered showers across interior southern New England * Warm/dry day on Monday with seasonable temperature * Trending cooler Tuesday through the end of next week with daily highs/lows in the upper 50s/lows and mid to upper 40s respectively * Mid-week coastal storm may bring substantial precipitation and gusty winds to southern New England. Sunday and Monday An upper-level low moves over southern New England on Sunday. Cold pool aloft and some elevated instability may produce a few scattered showers in the afternoon mainly across the interior of southern New England. Otherwise expecting mild temperatures in the upper 60s-low 70s. The associated upper trough axis shifts east of southern New England Sunday night into Monday supporting height rises and a dry/mild day on Monday with seasonable high temperatures in the upper 60s to low 70s. Tuesday As the aforementioned upper-level low shifts east of southern New England Monday into Tuesday, a deep northwest flow pattern develops over southern New England. This will support cooler/drier conditions on Tuesday with high temperatures likely confined to the low 60s and perhaps mid 60s in the CT River Valley. Wednesday - Friday By Wednesday, short-wave energy digging south over The Great Lakes will likely support the development of a coastal low-pressure system over The Mid-Atlantic states. This system is forecast to travel up the east coast and produce a late spring Nor'Easter for southern New England. This would mean a period of gusty northeast winds and substantial rainfall. Model guidance differs on the timing with some ensemble members supporting a faster solution that would result in a wet Wednesday afternoon. Other members support a late arrival with a mostly dry day Wednesday followed by a wet Wednesday night/Thursday. As the system departs the region toward the end of next week we'll be left with broad cyclonic flow aloft that will support cool/unsettled weather into next weekend. Stay tuned for more details. && .AVIATION /23Z FRIDAY THROUGH WEDNESDAY/... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. 00Z TAF Update Tonight: Moderate confidence. IFR-LIFR ceilings and visibilities return from the coastal waters mainly after 00z. Low chance of an isolated SHRA after 06z. Saturday: Moderate confidence overall, but lower on timing both sub-VFR improvement and on timing SHRA/TS. IFR-LIFR stratus likely to begin Sat. Slow improvement late morning through early afternoon with MVFR, improving over the west terminals first then eastward. West terminals improve toward VFR mid afternoon. Lower confidence in timing of further improvements across the east terminals in the afternoon, likely not until late afternoon if it does scatter out. Convective showers/storms possible in the morning 13-16z, but will be isolated- widely scattered. Another round for western airports after 18z and closer to 00z. Timing lower confidence. Some storms could become strong, with a better chance for strong activity in the 2nd round of storms for BAF- BDL- ORH. Winds mainly SE to S around 5-10 kt. KBOS TAF...Moderate confidence. IFR cigs move in after 03z with lowering visibilities from BR. Slow improvements in ceilings Saturday morning with MVFR cigs. Low chance for convective showers 14-16z around the terminal. SE winds 5-12 kts. KBDL TAF...Moderate confidence. IFR/LIFR overnight. Gradual improvements after 15z toward MVFR and VFR later in afternoon. Few rounds of thunderstorms possible in the afternoon and early evening. Timing lower confidence. Few stronger storms possible, more likely with the early evening round of storms. Outlook /Sunday Night through Wednesday/... Sunday Night: Mainly VFR, with local MVFR possible. Breezy. Slight chance SHRA. Monday: VFR. Breezy. Monday Night: VFR. Breezy. Slight chance SHRA. Tuesday: VFR. Breezy. Tuesday Night: Mainly VFR, with areas MVFR possible. Wednesday: MVFR/IFR conditions possible. Chance SHRA. && .MARINE... Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. High confidence overall. Fog and reduced visibility will be the biggest potential hazard for mariners tonight, with S winds around 10 kt and seas 4 ft or less. Risk for thunderstorms could develop as soon as pre- dawn Saturday over the southern waters, with another round of storms possible into Saturday afternoon. Winds 10-15 kts out of SE Saturday switching to W Saturday night. Waves across southern outer waters increase to 4-5 ft Sunday which will need SCAs as we get closer. Outlook /Sunday Night through Wednesday/... Sunday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers. Monday: Winds less than 25 kt. Areas of seas approaching 5 ft. Monday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain showers. Tuesday through Tuesday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Wednesday: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...None. RI...None. MARINE...None. && $$ SYNOPSIS...Mensch/RM NEAR TERM...Mensch SHORT TERM...Mensch LONG TERM...RM AVIATION...Mensch/RM MARINE...Mensch/RM ####018008594#### FXUS62 KILM 162321 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 721 PM EDT Fri May 16 2025 .SYNOPSIS... Above normal temperatures near record highs are expected again on Saturday. A weak cold front accompanied by isolated showers and storms will track across the area Saturday night. Mainly dry weather with above normal temps are then expected early next week until a storm system likely affects the area toward the middle of next week, bringing better rain chances and cooler weather for the latter half of the week. && .UPDATE... As of 720 PM...No major changes were made to the forecast. Water vapor imagery early this evening shows the mid-level high in place across FL with multiple areas of lift moving by well north of the forecast area in the westerly flow aloft. Very limited chances for rain here tonight given convective inhibition. Will continue to see plenty of high clouds and with SWly surface winds lows tonight will be well above normal. && .NEAR TERM /THROUGH SATURDAY/... Key Messages/Highlights: *Above normal temps w/ record high temps possible Saturday *Isolated damaging wind gusts/large hail possible Saturday aftn/eve Confidence: *Moderate to High Details: The mid-level ridge over the area will flatten as shortwave energy moves through ahead of a surface cold front. Rain chances overall look to remain limited given the overall limited moisture but an isolated shower/storm is possible this evening, mainly in NC, and again Saturday across all of SE NC and NE SC. There looks to be quite a bit of instability/shear for any storms to tap into so can't rule out a few damaging wind gusts and/or some large hail. Temps should be the big story though as they will be well above normal, only falling into the mid 70s tonight for most locales, and then likely into the lower 90s away from the beaches Saturday when record highs could be reached (see Climate section below for details on the record temps). && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... A cold front is expected to settle southeastward through the are over Saturday night as a closed mid-upper low and its associated surface low track across New England. This far south, forcing for ascent will be meager, but surface convergence along the front may be enough to develop isolated strong convection. Prior to midnight, environmental parameters will support severe weather for any storm which manages to develop and grow tall enough to take advantage of 45-55 kts of effective shear amidst waning instability during the evening and early overnight. The Storm Prediction Center has maintained a Marginal risk (threat level 1 out of 5) for severe hail and wind as the anticipated coverage is very low. Otherwise, expect fairly rapid cooling during the evening after another hot day with west- southwesterly winds veering to westerly by the end of the night behind the cold front. Morning lows on Sunday should end up in the upper 60s to low 70s, coolest north, as somewhat drier air nudges in. On Sunday, the front should stall just south of the area as it becomes aligned parallel to the flow aloft. Building ridging west of the forecast area will reinstate northwesterly flow aloft which could bring a cluster of showers or storms to far southern portions of the forecast area nearest to the front, but PoPs remain no higher than slight chance (20%) to account for this threat. Otherwise, mid-level dry air and subsidence should keep the region dry and very warm with highs in the upper 80s to around 90F with passing high cloudiness. The continued increase in ridging west of the forecast area will result in greater subsidence developing through the atmospheric column, allowing for a drier and more capped atmosphere to develop on Sunday night. Thus, outside of a decaying shower scraping our southern areas, the region should stay dry overnight with lows in the mid-upper 60s. && .LONG TERM /MONDAY THROUGH FRIDAY/... Confidence in the long-term forecast is rather low as a substantial western US trough with multiple vort maxes evolves and tracks eastward. This will drag the stalled front back northeastward as a warm front during the first half of the week, along which we may see a round or two of convection tracking southeastward into the forecast area. Otherwise, guidance generally agrees that higher rain chances can be expected around midweek as low pressure drags another cold front towards and through the area from the west. Atmospheric parameters become more supportive of severe thunderstorms on Tuesday and Wednesday, but the outcome of whether severe storms actually develop will depend on finer-scale details related to the mid- upper pattern. Furthermore, whether the cold front clears the area with dry weather in its wake will also depend on the outcome of this pattern, but overall, it appears a solid push of cooler and drier air will be in store at some point by the end of the week. However, until the front arrives, continued very warm weather is expected with highs in the upper 80s to around 90, although lower dew points away from the coast should allow low temps to fall to or below 70F in many locations on Monday night and Tuesday night, and potentially much cooler than that behind the front late in the week. && .AVIATION /23Z FRIDAY THROUGH WEDNESDAY/... High confidence in VFR conditions through 00Z Sun, especially given limited convective chances. Also, LLWS is expected late tonight, primarily for the coastal terminals as a west- southwesterly low-level jet increases across the area. Also, expecting frequent gusts of 20-25 kt with the heating of the day tomorrow. Extended Outlook...Mainly VFR conditions are expected through the period. && .MARINE... Through Saturday... Moderate to high confidence this period. The area will remain between an inland trough and approaching weak cold front and offshore high pressure. Thus, southerly winds will prevail. The combination of the low-level jet and pressure gradient could push winds to near Small Craft Advisory levels Saturday when gusts to near 25 kt are likely, although we don't feel an Advisory is warranted at this time, especially since seas should stay 4 ft or less. Saturday night through Wednesday... Southwesterly winds on Saturday evening of 15-20 kts veer to westerly and subside as a cold front slides through the waters. Winds become light and variable around or below 10 kts for Sunday and Monday as the front stalls just south of the area and wavers (although the sea breeze circulation should yield enhanced nearshore winds around 10-15 kts). The front should lift back northward at some point on Tuesday with winds becoming southerly behind it. Strengthening low pressure northwest of the waters will tighten the pressure gradient and lead to increasing flow on Wednesday ahead of a cold front, with chances for showers and thunderstorms peaking ahead of this front. Seas will relax from their 3-4 ft state Saturday evening into the 2-3 ft range on Sunday as winds ease up behind the front. Seas are expected to hold in the 1-3 ft range for Monday and Tuesday as the flow remains generally light. Seas increase in tandem with the increasing winds on Wednesday, although how high waves reach will depend on the strength of the low pressure system northwest of the waters. Outside of diurnally-driven wind waves, a persistent 1-2 ft southeasterly swell with a period around 9 sec will continue. && .CLIMATE... A new record high was set at Florence, SC today (95F, the old record was 93F set in 2022). High temperature records may be challenged again Saturday as anomalously warm air overspreads the region ahead of a cold front. Record highs for our four climate sites are as follows: Saturday, May 17th... Wilmington, NC: 92F (1960, 1990) Lumberton, NC: 96F (1941) Florence, SC: 93F (1977) N. Myrtle Beach, SC: 92F (1941) && .ILM WATCHES/WARNINGS/ADVISORIES... NC...None. SC...None. MARINE...None. && $$ SYNOPSIS...ILM UPDATE...SRP NEAR TERM...RJB SHORT TERM...ABW LONG TERM...ABW AVIATION...SRP MARINE...RJB/ABW CLIMATE...ILM ####018006029#### FXUS65 KGJT 162321 AFDGJT Area Forecast Discussion National Weather Service Grand Junction CO 521 PM MDT Fri May 16 2025 .KEY MESSAGES... - Warm and dry conditions will continue through Saturday, with isolated afternoon showers limited to the higher terrain north of I-70. - Critical fire weather conditions are expected Saturday afternoon across east-central and southeast Utah where the Fire Weather Watch has been upgraded to a Red Flag Warning. - The next storm will move in Sunday, bringing cooler and wetter conditions through Tuesday, as well as mountain snow. && .SHORT TERM /THROUGH SATURDAY NIGHT/... Issued at 245 PM MDT Fri May 16 2025 Remnant moisture and a weak shortwave moving across the north (more a wiggle in the near zonal flow) will keep isolated to scattered showers with a few thunderstorms in the picture this afternoon across the northern mountains. So far today, not much is happening outside of a few virga showers but a lot less than activity than the last couple days. Temperatures are already about 5 degrees warmer than yesterday and highs are expected to be closer to normal today and about 5 degrees above normal on Saturday as southwest flow increases ahead of an incoming low pressure trough dropping into the Great Basin from the Pacific Northwest. Enough mixing and warm air advection will allow highs to push towards 80 degrees in the Grand Valley with some lower desert valleys in eastern Utah pushing low to mid 80s, while the remaining lower valleys look to see highs well into the 70s. This warm bump is all before the much cooler airmass arrives on Sunday with the incoming low pressure trough. Southwest winds will gust 25 to 35 mph across east-central to southeast Utah and southwest Colorado on Saturday, with relative humidity also dropping into the teens and single digits, resulting in critical fire weather conditions. Decided to upgrade the Fire Weather Watch to a Red Flag Warning on Saturday for the zones where fuels are considered critical at this time, which includes east-central and southeast Utah (Utah Fire Zones 490 and 491). Regardless of fuel status, caution is urged and outdoor burning is not recommended given the drier and breezy to windy conditions. Precipitation may increase across eastern Utah Saturday night but the latest model guidance seems to be coming around to holding off on the majority of widespread precipitation until Sunday. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Issued at 245 PM MDT Fri May 16 2025 A deep upper-level trough will move overhead on Sunday, bringing widespread precipitation across the CWA along with another bout of strong wind gusts upwards of 35 mph. Temperatures behind the associated slow-moving cold front will drop high temperatures on Sunday 10-15 degrees below normal, though there is little clarity on how much this will bolster snow accumulations considering the uncertainty on how quick the front will move. Should frontal passage occur late morning/early afternoon, cooler temperatures may yield lower snow levels and higher accumulations as opposed to a mid-afternoon frontal passage during peak heating. Deterministic models are siding with the latter at the moment, resulting in modest snow accumulations of 2-4" over the San Juans, central Colorado mountains, and the Grand Mesa, and higher accumulations of 6-10" over the eastern Uintas. Uncertainty grows on Monday as a northern closed low descends southwards through the trough. Lacking moisture with this low (PWAT's 90-130% of normal) will result in primarily orographically-driven showers, though the further reduced temperatures associated with the system would favor more mountain snow and valley rain as snow levels drop to around to 7.5-8.5 kft. The rapidly evolving upper-level pattern regarding the slow- moving trough and the southwards-moving closed low leaves the early-week weather difficult to pinpoint. One way or another, widespread precipitation favoring higher terrain where orographics can better support storms is expected to occur. However, timing and intensity remains unclear, and future forecast discussions should provide more clarity on the details as more short-range model guidance becomes available. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 521 PM MDT Fri May 16 2025 A few high based showers or virga will continue to bring a threat of gusty winds to the northern TAF sites through sunset. Otherwise mid to high level cloudiness will be drifting through leaving VFR conditions in place. Once again moisture and winds will combine to bring a threat of more afternoon gustiness to the TAF sites on Saturday with the PROB30 statements places at KHDN and KVEL with this forecast issuance. && .FIRE WEATHER... Issued at 245 PM MDT Fri May 16 2025 Critical fire weather conditions are expected across east- central and southeast Utah as well as west-central and southwest Colorado. The only area that is currently seeing critical fuels though is east-central and southeast Utah (Utah Fire Weather Zones 490 and 491). Therefore, the Fire Weather Watch has been upgraded to a Red Flag Warning for the areas where fuels are critical and conditions look to be met. This Red Flag Warning is in effect Saturday from noon to 8 pm MDT. Critical fire weather concerns lessen Sunday through mid week as we welcome the arrival of a cooler and wetter storm system. However, dry and warmer weather looks to return by late next week which could lead to elevated fire weather concerns. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...Red Flag Warning from noon to 8 PM MDT Saturday for UTZ490-491. && $$ SHORT TERM...MDA LONG TERM...BW AVIATION...TGJT FIRE WEATHER...TGJT ####018004670#### FXUS63 KSGF 162321 AFDSGF Area Forecast Discussion National Weather Service Springfield MO 621 PM CDT Fri May 16 2025 .KEY MESSAGES... - A Moderate (4 of 5) Risk for severe weather this afternoon, mainly along and east of Highway 65 and before sunset. Very large hail to the size of softballs, damaging winds up to 80 mph, and tornadoes will be possible. - 50-70% chance for showers and thunderstorms Saturday night into Sunday morning. A Slight(2 of 5) Risk exists for a few thunderstorms may become capable of producing wind gusts up to 60 mph and hail up to the size of quarters. - The unsettled weather pattern will continue across the area early next week. This includes the potential for strong to severe thunderstorms in addition to localized heavy rainfall and flooding. Uncertainty remains in the exact details. && .SHORT TERM /THROUGH SATURDAY NIGHT/... Issued at 210 PM CDT Fri May 16 2025 This afternoon into early evening: A significant air mass change occurred this morning across this Missouri Ozarks as a warm front lifted back into the area that brought dew points back into to the upper 60s to low 70s and temperatures have risen into the low to mid 80s. This has caused significant instability to develop ahead of a cold front that was pushing west to east into the area. Severe storms quickly developed around midday ahead of the cold front and continue to quickly lift east- northeast into eastern sections of the CWA. The atmosphere is prime for very large hail with the instability and shear combination over the area. Hodographs have supported splitting supercells which is what we've seen so far across the area. While we are not seeing much in the way of backed surface winds, we can't rule out a tornadoes with the strong low level shear. The storms should quickly push east of the area between 21z and 00z and the severe weather risk with this round of storms should come to an end for our CWA. Rest of tonight: We should clear out behind the frontal boundary tonight as drier air moves moves in with dew points in the 40s for most of the area. Overnight lows should dip into the mid 50s. Saturday into Saturday night: Upper level flow remains out of the west-southwest and will bring in another wave of energy by late in the day into Saturday night. Moisture and instability will begin to creep back into the area from the southwest and we'll see the chance for thunderstorms increase (50-70%). Some strong to severe storms will be possible, mainly over the southwest quadrant of the CWA. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Issued at 210 PM CDT Fri May 16 2025 Sunday-Monday: Convection from Saturday night will linger into Sunday morning. Upper level flow will remain out of the southwest ahead of the main trough still to the west of the area. A frontal boundary will be west to east across the area and we should see low level winds increase during the evening with the approach of the upper level wave. Thunderstorm chances will increase again during the evening (70-80%), especially in the northern CWA north of the boundary. Strong to severe storms will be possible along with very heavy rain and possibly flooding with any training of storms. This activity should push east of the area on Monday morning. ADditional development could occur on Monday afternoon if sufficient atmospheric recovery takes place during the day. Monday night - Tuesday: As the main upper wave begins to push into the area, additional thunderstorms are expected to develop Monday night into Tuesday. Severe weather chances will be conditional on how much instability can develop. Heavy rain will again be likely and with several rounds of heavy rain and several inches of rain possible, flooding will be possible. Wednesday - Thursday: We should finally end the thunderstorm and severe weather chances as the upper wave shifts off to the east of the area. High pressure builds into the area along with a drier air mass. Highs behind this main wave should drop back into the 60s. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 619 PM CDT Fri May 16 2025 VFR through the period with westerly winds continuing to diminish through the evening. Winds will remain south/southwesterly through Saturday around 10 knots or less. && .SGF WATCHES/WARNINGS/ADVISORIES... KS...None. MO...None. && $$ SHORT TERM...Lindenberg LONG TERM...Lindenberg AVIATION...Soria ####018004599#### FXUS65 KBOU 162322 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 522 PM MDT Fri May 16 2025 .KEY MESSAGES... - Scattered thunderstorms over the mountains Saturday afternoon, with just a slight chance of storms on the plains. - Threat of severe storms on Sunday afternoon, mainly in the northeast corner of Colorado. There is uncertainty due to the track of the low pressure system and timing. - Near critical fire weather possible south of I-70 Sunday. - Cooler and windy with more showers/storms Monday and possibly Tuesday, but a lower severe threat. && .DISCUSSION /Through Friday/... Issued at 330 PM MDT Fri May 16 2025 It's looking like a pretty quiet late afternoon/evening as we've still got stable air over the mountains, evidenced by the trapped waves in the mid level cloud deck. Winds have finally started to ease a bit and that will continue into the evening. We did update the forecast for more cloud cover through Saturday as we'll have a weak shortwave trough passing and then the edge of the moisture stalling over us ahead of the developing western trough. This will keep temperatures from rising too much on Saturday despite a warming air mass. With the moistening, we'll return to scattered afternoon thunderstorms over the mountains, but the clouds will limit the eastward progression. The combination of lift from the trough and increasing low level moisture could produce a cluster of stronger storms over the northeast corner Saturday evening. There's been a little model convergence for the Sunday through Tuesday time frame, though we'll need a better handle on details before we know what it means. There's clearer agreement on the two jet streaks rotating around the trough, bringing a lead wave kicking out of the trough on Sunday and then the second part of the trough sliding east Monday night or Tuesday. Unfortunately, there's still a lot of disagreement on the relative strength of the jet streaks and their associated troughs. In general, there's a trend towards a bit weaker trough for Sunday, but we don't have a lot of confidence in that. This could result in a northward shift in the position of the QG lift, but it could also mean that there's less southwest flow to push the developing dryline eastward out of Colorado. The main threat for severe weather is with convergence along the developing dryline which may start in northeastern Colorado Sunday afternoon, or it may focus a bit further east or north and be a few hours later. There should be enough ingredients for all kinds of severe weather somewhere in this area. The severe threat is probably greatest in bordering areas of Kansas and Nebraska in the evening, but there may be a better threat of strong isolated storms in our northeast corner at the beginning. There may be critical fire weather conditions on our southern flank, but with green grass for the moment, the threat is diminished. Monday is in between the two pieces of the trough, and while details about any possible lift or the mid level flow have some uncertainty, we will be in a moist and cooler air mass, probably with decent north or northeast winds. If there's not much cooling, this could be a showery/stormy day, though it may be too cool for much of a severe threat. That will depend on how much cooling there is. The current trends towards a more sheared large scale trough point towards either a faster departure or more westerly flow on Tuesday, but again there's not a lot of confidence in that. NBM gradual decrease in PoPs without warming seems fine for now. Then pretty solid warming and drying in westerly flow with weak ridging for Wednesday into the later part of the week. There may be a shortwave passing north of us in the Thursday/Friday time frame, but this would probably just generate a bit of wind. && .AVIATION /00Z TAFS through 00Z Sunday/... Issued at 518 PM MDT Fri May 16 2025 WNW winds will continue for a few more hours with gusts to 20 kts. Winds will then become north by 02z and then light and variable by 04z. Overnight winds will become south by 10Z. On Sat, high based showers will be possible by 19z with gusty and erractic winds thru the aftn. For now have winds going NE by 19z, but directions could be all over the place thru the aftn. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Gimmestad AVIATION...RPK ####018007257#### FXUS61 KBTV 162322 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 722 PM EDT Fri May 16 2025 .SYNOPSIS... Widely scattered showers and thunderstorms will continue through this evening with a lull in activity overnight. Saturday, strong to severe thunderstorms are possible mainly from noon through 8PM. Much cooler conditions arrive on Sunday and will linger into the first half of next week. && .NEAR TERM /THROUGH SATURDAY/... As of 712 PM EDT Friday...Main focus of this update was to tweak PoPs to better match what is occurring across the forecast area as showers linger but trudge eastward. We're seeing a significant downward trend of number of storms with concerns of being severe as instability wanes. Previous discussion...Moderate CAPE profiles are supportive of scattered to numerous showers with isolated to scattered thunderstorms. Coupled with temperatures in the upper 70s/low 80 with dew points in the upper 50s to 60s, and a few thunderstorms could become strong to severe. Best chance of that occurring this afternoon/early evening will be towards the Champlain Valley of New York and across southern Essex County, NY and Addison/northern Rutland Counties of Vermont. An MCV moving through Essex County, NY could be just the forcing edge to kick off a stronger cell, but so far storms have been fairly tame. A few have likely produced brief periods of small hail and some modest wind gusts, but by and large, storm tops have been low lacking a stronger forcing mechanism outside of decent instability and general troughiness aloft. Should something get going, it could become long-lived and feed off unseasonably hot temperatures - BTV has hit 86 - and develop into a broken line. Showers/thunderstorms track east through the evening with chances decreasing overnight as weak forcing exits northeastward. Some pockets of fog will be possible tonight where low clouds are more limited and rainfall occurs this afternoon/evening. Moisture/clouds will likely keep temperatures moderated tonight for most spots, similar to this morning's lows in the upper 50s to 60s. The next series of troughs will roll through the North Country Saturday bringing decent lapse rates aloft and increased shear. Projected hodographs, moderately high CAPE in the 500-1500 J/kg range, and continued warmth will support better chances of severe thunderstorms Saturday afternoon. As such SPC has our region under a SLIGHT RISK of severe thunderstorms. Given tall CAPE profiles and elevated PWATs, localized heavy rainfall with these thunderstorms could produce flash flooding should multiple cells go over the same area. Cloud cover will temper high temperatures tomorrow, but still looking at upper 70s to around 80 degrees. && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... As of 304 PM EDT Friday...An active, but largely unimpactful stretch of weather is then expected for Saturday night into the Sunday night time frame. Our area will lie on the southern flanks of a synoptic- scale polar longwave trough centered across northern Quebec with rather brisk west-northwest flow aloft. Two distinct shortwave features remain on track to cross our area during the period, mainly focused in the Sunday/Sunday night time frame. Seasonably cool boundary layer thermal profiles support mainly snow showers or light snows with these features, though their quick movement and limited moisture support only light accumulations of 1-3" across elevated terrain and perhaps the SLV, and an inch or less in the Champlain/CT River Valleys. Low temperatures range through the teens to around 20 Saturday night with corresponding highs on Sunday in the upper 20s to mid 30s. Then slightly milder Sunday night with generally 20s expected. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 304 PM EDT Friday...The broad theme for Sunday into next week is one of much cooler and unsettled weather as a series of upper lows affect the region. A series of rex blocks, initially across the far North Atlantic and then across south central Canada by the middle of next week will keep flow more bogged down across our region through the period. Sunday into Sunday night looks quite inclement with periodic showers and cool northerly flow, which likely persist across portions of northern VT into Monday. Brief drying occurs by Tuesday into the first part of Wednesday, before the next upper closed low trundles into the area with a widespread showery regime returning for the back half of the work week. Given cooler temperatures and a largely stable boundary layer, the threat for severe weather is essentially nil. Daily highs to largely range through the 50s to lower 60s with overnight lows in the upper 30s through the 40s. && .AVIATION /23Z FRIDAY THROUGH WEDNESDAY/... Through 00Z SUNDAY...Conditions are generally VFR as showers and thunderstorms dodge sites. We'll have a few more hours of potential for vicinity or direct showers and thunderstorms before all precipitation moves east of the forecast area tonight. Best chances for some lightning will be at Plattsburgh, Montpelier, and Newport this evening though about 03Z Saturday. Winds out of the south and southwest will decrease overnight tonight, and as drier, cooler air flows in from the west, some spots might have more clearing and gaps in the clouds than they did today. This may result in patchy mist or fog at various sites, especially in areas that received rainfall from showers and thunderstorms today. Most likely sites to have some restrictions to visibility and low ceilings tonight are SLK, MPV, EFK, and MSS. Models are indicating PBG could also have some low vis/cigs throughout the night tonight associated with the possibility of low stratus developing over Lake Champlain and drifting westward. Winds appear to remain elevated enough to keep VFR conditions at BTV and RUT, though nothing is out of the question. Tomorrow, ceilings are expected to lower again to MVFR levels at all sites as showers and thunderstorms return. Visibilities are likely to decrease in heavy precip, but this will be scattered. Winds will continue out of the southwest and could gust 15-20 knots for some, higher in thunderstorms. Outlook... Saturday Night: Mainly VFR, with local MVFR possible. Chance SHRA, Slight chance TSRA. Sunday: Mainly MVFR, with local IFR possible. Definite SHRA. Sunday Night: Mainly MVFR, with local IFR possible. Chance SHRA. Monday: Mainly MVFR, with areas VFR possible. Chance SHRA. Monday Night: Mainly VFR, with local IFR possible. Slight chance SHRA. Tuesday: Mainly MVFR, with local IFR possible. Slight chance SHRA. Tuesday Night: Mainly MVFR, with local IFR possible. NO SIG WX. Wednesday: Mainly MVFR, with local IFR possible. Chance SHRA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Boyd NEAR TERM...Boyd/Storm SHORT TERM...JMG LONG TERM...JMG AVIATION...Storm ####018004240#### FXUS63 KICT 162323 AFDICT Area Forecast Discussion National Weather Service Wichita KS 623 PM CDT Fri May 16 2025 .KEY MESSAGES... - Mild and dry conditions until Saturday evening - Elevated storms possible Saturday evening to Sunday morning - Severe storms potential increasing Sunday and Monday && .DISCUSSION... Issued at 310 PM CDT Fri May 16 2025 Current water vapor imagery shows an upper-level low over the Upper Mississippi Valley that will continue to move east into the Great Lakes region by Saturday morning, keeping flow aloft westerly/northwesterly in the Central Plains. As another shortwave trough lifts out of the Desert Southwest Saturday morning into the Southern Plains by Saturday evening, flow aloft will shift more southwesterly. At the same time, a more robust upper trough over northern California will dig into the Central Great Basin. Transitioning into Saturday evening to Sunday morning, the mid/upper level trough over the Central Great Basin is progged to dig towards the Desert Southwest. At 850-700mb, low-level moisture advection will increase as the warm front lifts north. Elevated storms are likely to develop by Saturday evening, as WAA and strong instability increases. With mid-level lapse rates increasing, and relatively straight hodographs, splitting supercells are likely. Any storm that develops is likely to have wind gusts up to 60 mph, hail up to ping pong size and heavy rainfall, with the best chances in southern to southeast Kansas. As the axis of the trough becomes more negatively tilted into Sunday afternoon, the base of the upper trough will traverse towards the Central/Southern Rockies. There is decent model agreement that the associated surface low sets up in eastern Colorado/western Kansas Sunday afternoon. However, there is variance on where the warm front and dryline set up. The ECMWF and GFS place the warm front along/north of I-70 whereas the GDPS and NAM position it further south. For the dryline, the GFS is further east than the ECMWF and GDPS with the NAM solution closer to the latter. With dewpoints increasing into the upper 60s/lower 70s combined with surface heating, moderate to strong instability is expected. With the low- level jet increasing Sunday afternoon/evening and veering winds near the surface, hodographs become more elongated and favorable for supercells. All hazards are possible with wind gusts up to 70 mph, hail up to tennis ball size and tornadoes. Given this uncertainty, stay tuned for later updates. For Monday, the upper low is expected to move towards northwest Nebraska/western South Dakota while the base of the trough sits over New Mexico. The associated surface low will likely be positioned near Nebraska/Kansas with the dryline along I-135/I-35. With moderate to strong instability and favorable wind shear, supercells with all hazards are possible Monday afternoon to evening. Once again, uncertainty exists with the placement and timing of various synoptic features, stay tuned as we refine forecast details in the coming days. It is possible for storms to linger into Tuesday morning, but by Tuesday afternoon, precipitation should be east of our area. As the upper trough continues east Wednesday morning, flow aloft will shift back to northwesterly as a ridge begins building over the western CONUS. Quiet and dry conditions are expected Wednesday and Thursday with a surface high in place. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 620 PM CDT Fri May 16 2025 Gusty northwest winds will quickly subside this evening becoming light through the overnight hours. Easterly winds will develop over the area on Sat afternoon with gusts in the 15-20 knot range late in the day. Some cumulus in the 4-5k ft range may develop toward the end of the period with increasing chances for showers and storms. Confidence remains too low this far out to mention in TAFs at this time. && .ICT WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...GC AVIATION...MWM ####018003767#### FXUS64 KOHX 162324 AFDOHX Area Forecast Discussion National Weather Service Nashville TN 624 PM CDT Fri May 16 2025 ...New AVIATION... .KEY MESSAGES... Updated at 616 PM CDT Fri May 16 2025 - A few discrete storms will be possible across areas along and north of I-65 this afternoon. The main weather threat will be large hail and winds. This will be ahead of the front and more widespread severe weather. - A dynamic weather system will bring the potential for all modes of severe weather to Middle Tennessee this evening through 2 am Saturday morning. Damaging winds, large hail and tornadoes will all be possible. - Unsettled weather continues into the weekend, though the severe threat will be low. && .SHORT TERM... (Rest of today through Saturday) Issued at 1135 AM CDT Fri May 16 2025 The earlier severe watch has been allowed to expire. There were a couple of storms that became perky. The CAMS are showing the possibility of a few discrete storms this afternoon. The main threat with these discrete storms will be wind and hail. The stronger storms will be with the line of storms this evening and into the overnight hours. Please see previous AFD for the details. Highlights...the discrete storms will form into a line most likely entering the northwest forecast area between 8 to 10 pm. Nashville Metro entering around 10 to midnight. Exiting the Cumberland Plateau around 2 to 3 am. This will be a fast moving line. All forms of severe weather will be possible from winds to 70 mph...large hail...and tornadoes. Since the storms will be moving so fast flooding is not a first level concern unless there are some training storms. As mentioned previously...now is the time to make sure preparations are in place. Make sure your friends and family are aware too and have multiple ways of receiving warnings. && .LONG TERM... (Saturday Night through next Friday) Issued at 1135 AM CDT Fri May 16 2025 Unsettled weather will still be possible next week. There is a marginal risk (1/5) on Sunday as a warm front moves north across middle TN. A low moves out New Mexico/Colorado with a warm front that will meander around the southeast US Sunday through Wednesday. Being spring time...afternoon and evening strong to marginally severe storms will be possible. Thursday will be "best" weather day with the lowest chance for rain. Temperatures for the long term will be highs in the upper 70s to middle 80s with lows in the 60s. && .AVIATION... (00Z TAFS) Issued at 616 PM CDT Fri May 16 2025 We are still expecting a line of storms to move through the mid- state this evening which will likely cause disruptions as it does. It doesn't look like much of a wind-shift or low CIGS but VIS reduction to IFR can be expected. Amendments might be needed once the storms approach or timing changes. After 07-08Z storms should be out of the area with VFR conditions and southwest winds with gusts to about 20kts tomorrow. && .PRELIMINARY POINT TEMPS/POPS... Nashville 68 88 66 85 / 90 0 20 50 Clarksville 65 84 63 82 / 80 0 20 30 Crossville 62 80 60 79 / 90 0 10 40 Columbia 66 87 65 83 / 80 0 20 60 Cookeville 64 82 61 80 / 90 0 10 40 Jamestown 62 82 58 79 / 90 0 10 30 Lawrenceburg 66 86 64 82 / 80 0 20 60 Murfreesboro 67 87 64 83 / 90 0 20 50 Waverly 64 84 63 82 / 90 0 20 50 && .OHX WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...12 LONG TERM....12 AVIATION.....05 ####018005565#### FXUS65 KPIH 162324 AFDPIH Area Forecast Discussion National Weather Service Pocatello ID 524 PM MDT Fri May 16 2025 .KEY MESSAGES... - Showers and thunderstorms today across northern parts of the area. - Frost Advisory in effect for portions of Eastern Idaho from 2 to 8 AM Saturday. - Another potent low pressure system expected for the weekend bringing more rain/storms and cold temperatures Sunday after milder temperatures on Saturday. - Gradual improvement expected early next week with a warmup likely mid/late next week. && .SHORT TERM /THROUGH SATURDAY NIGHT/... Issued at 205 PM MDT Fri May 16 2025 Showers and thunderstorms are a bit more limited in coverage today, but that doesn't mean everyone is getting a break from the activity as a weak shortwave passes through our area. While we've seen showers moving into the I-15 corridor early this afternoon, the bulk of our thunderstorms this afternoon and evening will be confined to our northeast corner/Island Park area, or generally north and east of Idaho Falls. Temperatures this afternoon will be back into the low 60s in the eastern Magic Valley and lower Snake River Plain and remain a couple of degrees cooler in the upper Snake River Plain thanks to cloud cover and showers. Storms today are expected to remain the "garden variety" as we have little CAPE today (we're talking 100-300 J/kg tops), 0-6 km shear of 25 to 30 kts in the vicinity of Clark and Fremont counties, and modest laps rates of 6.5 deg C/km. So, max wind gusts today with storms would most likely be around 40. In addition, it's just a bit breezy in general today with wind gusts for many around 25 to 30 mph. Temperatures tonight will drop into the 30s and 40s area wide in our lower elevations, so we have a Frost Advisory out for several zones where temperatures are expected to be at or below 36 deg F early Saturday morning. It's a bit tricky, because there's about a 70 to 80 percent chance temperatures will remain above that 36 degree threshold in Pocatello and Idaho Falls, but will drop quickly as you move outside of town. On Saturday, a strong cold front will sweep through Eastern Idaho and bring another round of rain and storms with it. With these storms, we will have better "ingredients" for some stronger to even marginally severe storms. A NAMNest sounding shows around 1000-1500 J/kg of CAPE in the Snake River Plain on Saturday, around 40 kts of 0-6 km shear, and lapse rates around 8.0 deg C/km. These values are plenty sufficient for marginally severe storms with the potential for wind gusts up to 65 mph. We will warm up into the mid and upper 60s Saturday ahead of the cold front, but look for a sharp drop in temperatures by Sunday. In fact, as temperatures drop we will see an increasing chance for accumulating snow Saturday night through Sunday morning. At this point, the bulk of the snow will fall above pass level, but there still remains about a 50 to 60 percent chance of at least 2 inches of snow and a 20 to 30 percent chance of at least 4 inches of snow at Galena Summit. Overall, we're looking at decent QPF across the entire CWA with about a quarter of an inch of liquid in our valley locations by Sunday morning. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Issued at 205 PM MDT Fri May 16 2025 Upper low over East Idaho during the day Sunday for continued wet and cool conditions most of East Idaho. Another day with highs in the 40s/lower 50s is anticipated. Snow levels drop as low as 5500- 6000 ft during the day leading to snow accumulation over higher elevations. The greatest snowfall accumulations likely over the Central Mountains, but the heaviest snowfall should remain confined to high elevations so we are not thinking headlines as this point in time. Areas along/east of I-15 look to be the warmest, and thus most unstable with greatest chance of an afternoon/evening thunderstorm. Beginning Monday, upper low looks to shift far enough east of the region to see a decreasing precipitation trend through the day for most areas. Temperatures warm over the low weekend values Monday and beyond. Weak shortwave activity through the week could be enough for isolated shower/thunderstorm development each afternoon Tuesday through Friday, mainly in the northern portions of the forecast area. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 517 PM MDT Fri May 16 2025 Satellite and radar imagery show a weak shortwave feature moving through KDIJ currently bringing light rain. Have removed Prob30 for thunderstorms for KDIJ. Winds are breezy throughout the Snake Plain currently, strongest at KIDA with gusts approaching 25kts. Expect the showers to decrease around sunset. Winds will back off as well. Expect VFR conditions and overall light winds for all TAF sites overnight. Next shortwave drives showers and thunderstorms into the region during the day Saturday. Added PROB30 TSRA for all TAF sites early to mid afternoon. Should see showers on stations with chance of MVFR conditioins by late morning for KSUN and KBYI and early to mid afternoon for all other TAF sites. && .PIH WATCHES/WARNINGS/ADVISORIES... Frost Advisory from 2 AM to 8 AM MDT Saturday for IDZ051>054. && $$ SHORT TERM...AMM LONG TERM...DMH AVIATION...TW