####018004680#### FXUS64 KJAN 171136 AAA AFDJAN Area Forecast Discussion...UPDATED National Weather Service Jackson MS 636 AM CDT Sat May 17 2025 ...New AVIATION... .DISCUSSION... Issued at 440 AM CDT Sat May 17 2025 Today and tonight... The severe potential should come to an end around 5am morning with early morning radar scans showing a line of showers and storms north of Hwy 82 propagating east towards Alabama. Additional shower and thunderstorm development will continue later this morning as the stalling frontal boundary sags into central MS. Rain chances will start to diminish across our CWA later this afternoon as the stalled frontal boundary start to slowly drag south of I-20. Isolated severe storms will redevelop across our forecast area later this evening into tonight with afternoon highs peaking in the upper 80s/lower 90s. Depending how the rain pans out later this afternoon, it is possible that a couple of areas along and south of I-20 could see heat indices around 100 degrees. Regardless, the "Marginal" risk will continue to be advertised for areas along and north of the I-20 corridor. No changes have been made to the severe graphic for tonight and a "Slight" risk will continue to be advertise for portions of the Delta including portions of southeast Arkansas. Some of these storms could produce heavy rainfall at times, with rainfall totals ranging between 0.5-1.25 inches with local higher amounts possible especially for areas along and north of Hwy 82. Given that this system will moving quite fast across our CWA, flash flooding concerns will be low; however, some localized flash flooding cannot be ruled out. Sunday through the Late Week... The chance for marginally severe thunderstorms will continue Sunday through late Monday evening as the frontal boundary stalls just to the north of our CWA. Quiet weather conditions will occur across the area early Tuesday morning as future global guidance continues to show the ridge axis beginning to slowly push east away from our forecast area giving us a small little break from the rain. A significant 1004mb low pressure system hovering over the Central Plains will push east towards the Ohio River Valley region Tuesday afternoon/evening. The associated cold front over southern Texas will track east towards the southeast region late Tuesday evening. This combined with southerly moisture flow from the Gulf, a mid- level jet moving into the area along with an unstable airmass in place will help increase bulk shear. This will allow for organized convection across our whole forecast area. Because of this, SPC has upgraded to a 30% severe weather potential for Tuesday with higher confidence for northern portions of our CWA. There is still alot of uncertainty in regards to both the hazards and timing as this system is still several days away. We will keep you updated on any changes as we get closer. Storm chances will continue heading into early Wednesday morning as the cold pushes southeast across our forecast area. Rain chances will start to diminish across the region looking ahead into Wednesday afternoon/evening with quiet conditions prevailing across our CWA by Thursday as the cold front tracks southeast out of our forecast area towards the Gulf Coast giving us a nice little break from the rain. Weather conditions will remain quiet heading into Friday with mostly to partly sunny skies by the weekend. /CR/ && .AVIATION... (12Z TAFS) Issued at 636 AM CDT Sat May 17 2025 SHRA & TSRA ongoing across the area, drifting south of Hwy 82 corridor. Variable ceilings, visibility & gusts >30mph possible with any TSRA. Chances for impacts from thunder will decrease by 17/15-17Z Saturday. Some lowered ceilings have fallen to MVFR in spots & will lift to VFR by 17/14-16Z Saturday. Additional SHRA & TSRA development is on tap after 18/00Z Sunday, with MVFR/IFR ceiling & vsby reductions from 18/08Z Sunday through the end of the 12Z TAF period. /NF/DC/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 90 72 90 71 / 50 20 10 10 Meridian 89 70 91 70 / 60 30 10 0 Vicksburg 90 72 90 71 / 40 20 10 0 Hattiesburg 93 72 94 71 / 20 10 0 0 Natchez 89 72 90 72 / 20 10 0 0 Greenville 89 72 88 73 / 20 40 30 20 Greenwood 90 72 90 72 / 20 30 40 20 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ CR/NF/DC ####018007527#### FXUS65 KBOU 171136 AFDBOU Area Forecast Discussion National Weather Service Denver/Boulder CO 536 AM MDT Sat May 17 2025 .KEY MESSAGES... - Scattered thunderstorms over the mountains this 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. - Cooler and windy with more showers/storms Monday and possibly Tuesday, but a lower severe threat. && .UPDATE... Issued at 312 AM MDT Sat May 17 2025 A couple of targeted forecast updates to note this morning for the day 1-3 period... 1) Modest surface lee cyclogenesis over southern Colorado this afternoon ahead of the approaching upper-level trough should promote advection of higher dewpoints into the eastern plains in the afternoon. Most CAMs indicate sufficient MLCAPE of 300-700 J/Kg to allow for convective initiation by late afternoon/early evening along a weak surface convergence axis. With pockets of bulk shear above 40 kts, would not be surprising to see one or two strong to severe storms develop, most likely focused over Washington County and into the northeast plains through the evening. Have increased PoPs a good amount in these areas to better message this potential. 2) Sunday's severe weather threat remains in play, although the latest guidance does seem to have nudged the developing dryline and warm front northward slightly. There should be a fairly steep north to south gradient in precipitation/thunderstorm potential as a result, with the best chances of severe thunderstorms focused across our northern and especially northeastern plains. Some question as to whether storm intensity will pick up quickly enough for more than a brief window of severe weather potential before lifting north out of our area, but ingredients do appear to be there for both a hail and tornado threat over a relatively narrow axis. 3) For Monday we'll still retain a potential for precipitation as cyclic shortwaves continue to emerge from the parent trough, but NBM PoPs seemed much too high in general, and rather misplaced. With a cooler and more stable post-frontal airmass, a lack of jet support and QG lift, and favored prevalence of north/northwest surface winds, simply couldn't justify the 70-80% PoPs advertised by the NBM. Thus, shifted the greater precipitation potential southward towards the Palmer Divide (upslope) rather than for our northern areas. && .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 /12Z TAFS through 12Z Sunday/... Issued at 528 AM MDT Sat May 17 2025 VFR conditions are expected to prevail for all terminals through the TAF period. Light drainage winds at the current hour will increasingly battle against a Denver cyclone setup as the morning progresses. Models are struggling to agree in its positioning, but for the most part keep it hovering in the vicinity of KDEN through at least early to mid-afternoon. As a result, there is a high uncertainty in prevailing wind directions for most of the day, and an increased likelihood of VRB directions, especially between 17-20Z (11am-2pm MT). For now, will favor mostly SE flow with cyclone remaining just north of KDEN. After ~20Z (2pm MT), ISO-SCT high-based -SHRA/-TSRA will develop in the area, and may impact Denver area terminals through approximately 01Z this evening, creating the potential for brief outflow gusts. There's a possibility of more organized convection developing in the eastern plains in the evening. If this occurs, easterly outflow winds with gusts 20-30 kts can't be ruled out, especially for KDEN/KAPA. Lastly, an approaching warm front Sun AM will lead to increased potential for lower CIGS 010-015 starting near 10Z (4am MT) Sun. Bases should remain high enough to limit vis restrictions at the terminals. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Rodriguez DISCUSSION...Gimmestad AVIATION...Rodriguez ####018011386#### FXUS62 KJAX 171137 AFDJAX Area Forecast Discussion National Weather Service Jacksonville FL 737 AM EDT Sat May 17 2025 ...New AVIATION... .SYNOPSIS... Issued at 354 AM EDT Sat May 17 2025 Overnight surface analysis depicts Atlantic high pressure extending its axis westward across the FL peninsula and the southeastern Gulf. Meanwhile, pair of cold fronts extend southwestward from strong low pressure (990 millibars) that was migrating across the Great Lakes region, with these boundaries pushing across the Upper Midwest and approaching the Ohio, Tennessee, and lower Mississippi Valleys. Aloft...deep-layered ridging that extends across the Gulf and the FL peninsula was flattening as deep troughing migrates across the Great Lakes states, with a 120 knot jet streak positioned around 250 millibars (around 35,000 feet) migrating across the Ozarks and the Tennessee Valley in between these features that was fueling a severe weather outbreak across the lower Mississippi and Tennessee Valleys. Latest derived Total Precipitable Water imagery indicates that a dry and subsident air mass prevails locally, with PWATs of only around 1 inch at most locations. Brisk northwesterly flow above 500 millibars (around 25,000 feet) located on the periphery of the ridge over the Gulf was advecting thin cirrus into our region, with thicker cirrostratus located upstream across the Deep South. A west-southwesterly breeze was keeping temperatures in the upper 60s and lower 70s at most locations as of 07Z, with dewpoints mostly in the low and middle 60s. && .NEAR TERM... (Today and Tonight) Issued at 354 AM EDT Sat May 17 2025 Cirrus cloud cover will overspread our region briefly this morning, with some thicker cirrostratus at times for locations along and north of Interstate 10. Thinner cirrus south of I-10 may allow for some low stratus ceilings and possibly some patchy fog to develop during the predawn and early morning hours today for inland portions of north central FL. Otherwise, ridging aloft will continue to flatten across the Gulf and FL peninsula as deep troughing migrates slowly eastward across the eastern Great Lakes through tonight. This will allow a frontal boundary to push through the Tennessee Valley and the Carolinas by late tonight. A ribbon of deeper moisture will pool downstream of this frontal boundary across central AL and GA this afternoon, with a jet streak migrating eastward across the Tennessee Valley and the Carolinas helping to develop a squall line of strong to severe thunderstorms that will approach the Altamaha and Ocmulgee Rivers by late afternoon. However, the best forcing and dynamics associated with this jet streak will remain situated just north of our area, likely resulting in the squall line breaking up while weakening towards sunset. Widely scattered showers and possibly and few thunderstorms will migrate across the Ocmulgee and Altamaha Rivers towards sunset, with activity then dissipating before reaching Waycross and points eastward to coastal southeast GA. Our local pressure gradient will remain rather tight across our area today as the storm system passes well to the north of our region. High altitude cloudiness should thin out this afternoon. A hot, dry, and subsident air mass will persist for locations south of Waycross, and the Atlantic sea breeze may remain just east of area beaches until late afternoon, which will allow for another day of record breaking heat to again extend all the way to coastal locations. Increasing afternoon cloudiness will keep highs in the low to mid 90s for locations north of Waycross, while mid to upper 90s continue elsewhere. Dewpoints falling through the low and mid 60s this afternoon will keep maximum heat index values around 100. Any leftover, low-topped convection over inland southeast GA should dissipate during the early to mid-evening hours. Debris clouds from this activity will thin out after midnight, setting the stage for fog and low stratus ceilings to advect eastward off Apalachee Bay and across the Suwannee Valley overnight. This bank of low stratus and fog should continue advecting eastward along the I-10 corridor during the predawn hours, possibly approaching the I-95 corridor towards sunrise. Lows tonight will again only fall to the upper 60s and lower 70s. && .SHORT TERM... (Sunday through Monday night) Issued at 354 AM EDT Sat May 17 2025 A broad high pressure ridge will extend across south FL this period. A front will be stalled across central GA on Sunday, then lift back to the north on Monday. The flow aloft on Sunday will allow weak waves to move east across SE GA. These waves, coupled with convergence associated with frontal boundary, and diurnal heating will lead to potential for a few showers and storms over SE GA Sunday afternoon. Low level moisture will result in patchy fog potential across area Sunday night. Dry weather is expected for Monday. With the west southwest flow, the east coast sea breeze will struggle to move inland Sunday, likely not making it past I95. Highs inland in the middle 90s will be common. With the sea breeze having a harder time pushing inland, highs at the coast should still reach the lower 90s before the sea breeze moves inland. Temperatures will remain above average Sunday night. The sea breeze will once again struggle to push inland against the prevailing flow from the west southwest Monday. So, again the heat will get all the way to the coast before the sea breeze pushes in. Highs Monday will range from the middle 90s inland, to the lower to mid 90s coast. The above average temperatures will continue Monday night. Inland fog potential Monday night due to flow off the Gulf. && .LONG TERM... (Tuesday through Friday) Issued at 354 AM EDT Sat May 17 2025 The high will push further away to the south southeast Tuesday, as a frontal system approaches from the northwest. Tuesday will be a dry day, with temperatures above seasonal averages. After a dry night Tuesday night, the front will move into the southeast Wednesday. The front will then move through the area through Thursday morning. A round of showers and thunderstorms will accompany the front Wednesday through early Thursday. A significant change in temperatures is expected with the front, hinting at the potential for strong to possibly severe storms with the passage. Temperatures will continue above seasonal averages through Wednesday, then near to below Thursday into Friday. && .AVIATION...(12Z TAFS) Issued at 734 AM EDT Sat May 17 2025 Low stratus, at IFR to LIFR levels, will persist as late as 13z at KVQQ & KJAX before lifting. This morning's stratus will be followed by VFR conditions with BKN cirrus at or above 20kft. Westerly winds will increase after the inversion breaks this morning, with peak gusts around 20 kts through the early afternoon. Though most airfields will be dry today, a decaying impulse across central Georgia may bring an isolated shower this afternoon and early evening, between 20z-24z. Westerly winds persist overnight but will trend light by daybreak Sunday as another round of low stratus pushes across NE FL. && .MARINE... Issued at 354 AM EDT Sat May 17 2025 Atlantic high pressure will continue to extend its axis westward across the Florida peninsula and into the eastern Gulf through early next week, creating a prevailing west southwesterly wind flow across our local waters. Seas of 2 to 3 feet will prevail both near shore and offshore through Tuesday night. Meanwhile, a frontal boundary currently pushing across the Ohio and Tennessee Valleys will stall to the north of our area on Sunday, with showers and possibly a few strong thunderstorms possibly impacting the Georgia waters during the late afternoon and evening hours. This front will lift northward early next week in advance of a cold front that will move across our local waters on Wednesday night and early Thursday. Scattered showers and thunderstorms may accompany this frontal passage on Wednesday afternoon and night. Strengthening southwesterly winds will result in seas building slightly to 3-4 feet offshore by midweek. High pressure will then build into the southeastern states late this week and during the beginning of Memorial Day weekend in the wake of this frontal passage. Rip Currents: Prevailing offshore winds and low surf heights will keep a low risk in place at all area beaches today. Afternoon sea breezes may combine with a lingering easterly ocean swell to create a moderate risk at the northeast FL beaches on Sunday and Monday, but we opted to keep the risk low at this time due to expected low surf heights that will persist through at least midweek. && .FIRE WEATHER... Issued at 354 AM EDT Sat May 17 2025 A dry and very hot air mass will continue across our region today, with only isolated late afternoon and evening thunderstorms possible for locations north of Waycross. Minimum humidity values will fall to around 30 percent this afternoon for locations south of Waycross, extending all the way to coastal locations, as the Atlantic sea breeze remains pinned along area beaches. Otherwise, breezy transport winds will combine with elevated mixing heights to create pockets of high daytime dispersion values at inland locations, while good values otherwise prevail. Widely scattered strong to isolated severe thunderstorms will be possible across southeast GA late on Sunday afternoon and evening. Minimum humidity values will fall to the 30-35 percent range for inland locations to the south of Waycross. Breezy westerly transport winds and elevated mixing heights will again create pockets of high daytime dispersion values at inland locations, with good values expected elsewhere. Surface and transport winds will shift to southwesterly on Monday, with elevated mixing heights again resulting in high daytime dispersion values at some inland locations, while good values otherwise prevail across our area. && .CLIMATE... Issued at 354 AM EDT Sat May 17 2025 Daily Record High Temperatures through Wednesday at our designated climate sites: Sat 5/17 Sun 5/18 Mon 5/19 Tues 5/20 Wed 5/21 -------------------------------------------------- Jacksonville 96/1995 96/1899 97/1960 99/1962 99/1938 Gainesville 96/1915 97/1930 99/1899 97/1938 100/1938 Alma, GA 94/2001 95/2001 97/1960 99/1962 97/1962 Craig Airport 93/2001 93/2001 92/2006 97/2006 98/2006 && .PRELIMINARY POINT TEMPS/POPS... AMG 93 71 92 68 / 10 10 50 0 SSI 94 73 90 72 / 0 0 30 20 JAX 97 69 97 68 / 0 0 0 0 SGJ 96 70 94 69 / 0 0 0 0 GNV 96 67 95 65 / 0 0 0 0 OCF 94 67 93 67 / 0 0 0 0 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$ ####018009371#### FXUS62 KMHX 171137 AFDMHX Area Forecast Discussion National Weather Service Newport/Morehead City NC 737 AM EDT Sat May 17 2025 .SYNOPSIS... A cold front will move through the area this evening. High pressure then builds in late in the weekend and into early next week. Another frontal boundary then impacts the area mid to late week. && .NEAR TERM /TODAY/... As of 700 AM Saturday... KEY MESSAGES - Severe weather risk appears to be low for today As expected, thunderstorms from last night have weakened as they have pushed east of the western NC mountains. While a few showers may reach the coastal plain of ENC this morning, the risk of severe thunderstorms with this activity has significantly decreased. Convective outflow from the weakening thunderstorms is currently pushing east through central NC with a northwesterly wind shift and a brief burst of 20-30 mph winds. It's expected that a similar wind shift and bump in winds will move through the coastal plain this morning, with the outflow eventually weakening as it gets to the coast. In the wake of any morning thunderstorms or convective outflow, it's unclear whether or not sufficient destabilization can occur this afternoon. Even if it does become sufficiently unstable, questionable forcing in the wake of the morning outflow calls into question whether thunderstorms can redevelop this afternoon. Short term deterministic and machine learning guidance generally reflect a reduced risk of thunderstorms and severe weather, and the forecast will reflect this expectation. However, very recently, some short term guidance has trended back towards isolated to scattered thunderstorm development this afternoon. It appears this may be tied to a convectively- enhanced MCV, currently moving east out of the TN Valley. This scenario still currently appears unlikely, but is something that we will continue to monitor through the afternoon. Should this scenario play out, the shear/instability combo appears supportive of at least some severe weather potential. Widespread mid and high clouds today may tend to temper how hot it gets, and it's possible highs today won't get as hot as yesterday. Still, with highs near 90 and dewpoints in the upper 60s, the heat risk will be moderate, primarily impacting those more sensitive to heat and/or those without effective cooling. && .SHORT TERM /TONIGHT/... As of 230 AM Saturday... KEY MESSAGES - Quiet weather expected tonight A cold front will push east through ENC this evening, with drier and slightly cooler air moving in behind it. This sets the stage for lows ending up about 10 degrees cooler tonight than last night. With a drier and more stable airmass moving in, no thunderstorms are expected once the front clears the area. && .LONG TERM /SUNDAY THROUGH FRIDAY/... As of 0500 Saturday...MOSTLY quiet end of the weekend with unsettled pattern beginning to unfold middle of upcoming week. Sunday and Monday...Quiet and relatively cool compared to last week with downsloping NWerly flow aloft between the departing low and shortwave ridging briefly amplifying over SECONUS. The front that pushed through Saturday will wiggle its way back Nward over Crystal Coast, but there remains some question with just how far N the front will make it. Mostly clear skies early may provide enough destabilization to allow moisture convergence along the front to lead to a low end SChc of showers SUN afternoon and evening. Front will sink back Sward through the SUN night. Up to Midweek...The next low to impact the area stems from digging trough aloft over central CONUS ultimately leading to stout vertically stacked low traversing the Ohio River Valley and approaching the NECONUS coast early week. Shortwave embedded in the flow aloft leads to cyclogenesis along the meandering boundary. This low will work up the SC and eventually NC coast Tuesday through Wednesday, upping cloudiness and rain chances again. Late week...High pressure builds in at the SFC from the W while low departs to the NE. Trough aloft lingers over NECONUS through the end of the week preventing a completely dry forecast until stronger ridging spills Eward toward the end of the longterm period. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... SHORT TERM /through 12z Sunday/... As of 715 AM Saturday... KEY MESSAGES - LLWS risk decreases this morning, but may briefly return this evening - Low confidence TSRA forecast over the next 12 hours - Gusty southwest to west winds this afternoon and evening TSRA from last night have continued to weaken as they have progressed east of the western NC mountains this morning. This trend is expected to continue. However, an outflow boundary from the weakening TSRA will likely impact KISO and KPGV over the next 1-2 hours with a northwesterly wind shift and a bump up in winds to 20- 25kt. It's unclear how far south and east the outflow will reach, so for now I've opted to only include TEMPO groups at those terminals this morning. A background southwesterly flow should then return across the area by late morning or early afternoon. That southwesterly flow will be gusty at times through around early this evening. A cold front then moves through with more of a westerly wind expected tonight. The TSRA forecast remains a low confidence one through this evening. Any TSRA activity this morning should be isolated in nature. Later this afternoon, a few TSRA may manage to redevelop if sufficient instability and lift can be realized. Guidance remains mixed on this, and I'll continue to keep TSRA out of the TAFs due to the above-mentioned limitations. Early this morning, there will continue to be a westerly LLWS risk through about 13 or 14z. Another brief westerly LLWS risk may develop along the cold front this evening as well. LONG TERM /Sunday through Wednesday/... As of 0430 Saturday...Front that crosses area Saturday night stalls to our S Sunday and will meander for a few days until mid week. Expecting mostly VFR flight cats through MON, low end chance of showers SUN may bring subVFR. Better chances of subVFR flight cats Tues and Wed as wave of low pressure traveling along the front traverses the Carolinas. && .MARINE... SHORT TERM /through tonight/... As of 730 AM Saturday... KEY MESSAGES - Elevated winds and seas through this evening - Small Craft Advisory has been expanded - Thunderstorm risk appears to be decreasing Outflow from weakening thunderstorms is expected to move through the Albemarle Sound/Alligator River/Croatan and Roanoke Sounds vicinity this morning with a northwesterly wind shift and a bump up in winds to 20-25kt. Further south across the central and southern waters, it's unclear whether or not the outflow will survive that far. This outflow will disrupt the gradient for a short time this morning. However, the gradient is expected to strengthen through the day as a cold front approaches from the west. This is still expected to support a period of 15-25kt southwesterly winds. Guidance has trended up some with winds this afternoon, and we have reflected this in the forecast. In light of this change, I've expanded the Small Craft Advisory to include the Albemarle Sound and the Alligator River. Winds will then become more westerly tonight in the wake of a cold front moving through. The thunderstorm risk appears low through this evening, but the risk isn't zero. LONG TERM /Sunday through Wednesday/... As of 0445 Friday... Late weekend through early week...Tonight's front stalls to the S of the FA where it will meander back N and S through early week. Werly winds 10-15kt early SUN become SWerly 15-20kt in afternoon as front lifts back Nward. Winds become Nerly late Sun into early Mon as front sinks back Sward allowing weak high pressure to briefly build in. NEerly winds Tuesday continuing to veer to become Serly WED ahead of the next approaching low. Conditions deteriorate as low approaches with SCA conditions possible and increase in shower/tstorm chances. && .CLIMATE... Record High temps for May 17th, Saturday. LOCATION TEMP/YEAR New Bern 95/1941 (KEWN ASOS) Cape Hatteras 86/1991 (KHSE ASOS) Greenville 95/1915 (COOP - Not KPGV AWOS) Morehead City 85/1991 (COOP - Not KMRH ASOS) Kinston 96/1941 (COOP - Not KISO AWOS) Jacksonville 93/1990 (NCA ASOS) && .MHX WATCHES/WARNINGS/ADVISORIES... NC...Beach Hazards Statement through this evening for NCZ195-196- 199-204-205. MARINE...Small Craft Advisory from noon today to 10 PM EDT this evening for AMZ131-135-230-231. Small Craft Advisory from noon today to 2 AM EDT Sunday for AMZ152-154-156-158. && $$ SYNOPSIS...MHX NEAR TERM...RM SHORT TERM...RM LONG TERM...CEB AVIATION...RM/CEB MARINE...RM/CEB CLIMATE...MHX ####018007921#### FXUS65 KRIW 171138 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 538 AM MDT Sat May 17 2025 .KEY MESSAGES... - An increased chance of showers and thunderstorms today, most numerous in western Wyoming. - Turning much cooler Sunday in the west with mountain snow, thunderstorms possible again East of the Divide. - Much cooler Sunday night and Monday with rain and mountain snow continuing East of the Divide. && .DISCUSSION... Issued at 340 AM MDT Sat May 17 2025 Other than a few sprinkles, things are largely quiet across Western and Central Wyoming as a shortwave ridge exits the area stage east. this will not last though. Our next weather maker will move toward the area today, an upper level low dropping out of British Columbia and moving southeastward toward the Cowboy State over the next few days. Most areas will start dry but increasing moisture will introduce the chance of showers to southern areas starting later this morning with the chance of showers spreading across roughly the western two thirds of the area this afternoon. The best coverage of showers will remain in western Wyoming, with anywhere from 2 in 5 chance to a 7 out of 10 chance at any given location. In areas East of the Divide, the chance drops to 1 in 3 at the most. In addition, in areas East of the Divide a vast majority of the day will be rain free. Southwest flow will warm temperatures as well, with most areas being within a few degrees of normal. As for stronger thunderstorms, the Storm Prediction Center has dropped the marginal risk in southwestern Wyoming this morning. There could be a few stronger storms but this would be the exception rather than the rule. By tonight, showers should end East of the Divide, but continue in the west. And now brings us to Sunday, and we have a few concerns. First, we will address thunderstorms. This day looks like a decent likelihood for them, especially East of the Divide, The next question is, will they be strong? There is a bit more CAPE on this day, especially in our most favored location, Johnson County, where values as high as 750 J/KG may exist. Lifted indices only go to minus 2 as well. There will be a bit of shear though. The big X factor will be cloud cover. If we can get some clearing to destabilize the atmosphere a bit, we could get a few stronger storms in the afternoon, especially in Johnson County and the northern Bighorn Basin. This is far from certain but we will have to watch it. And, with the schizophrenic nature of weather with spring weather in Wyoming, this reminds of an old Monty Python quote, "Now for something completely different." And that is the cold side of the storm and potential for snow. Some of the higher peaks West of the Divide will see some through tonight. However, 700 millibar temperatures should remain around 0 celsius or higher through Saturday night, which would keep snow largely above pass level. Colder air then arrives in earnest on Sunday across the west, spilling East of the Divide Sunday night into Monday. At the same time, the upper level low will be moving across Wyoming. Lee cyclogenesis will be occurring over Colorado Sunday into Sunday night, with the low moving into Nebraska on Monday. Flow will likely turn northeastward and enhance upslope along the eastern slopes East of the Divide. As for snow levels, areas in the west may see 700 millibar temperatures fall as low as minus 4 to minus 5, which could bring some snow even down into the valley floors on Sunday. East of the Divide, the lowest would be minus 3, which would put snow levels at 7000 feet by Sunday night. As for accumulations, NBM ensemble guidance gives at least a 1 in 2 chance of 6 inches or more across the higher elevations of the Tetons, Absarokas, Wind River Range and Bighorns. As for the chance of a foot, the main concern here would be the higher elevations of the Bighorn Range, with a 1 in 2 chance above 9500 feet. As for highlights, none will be issued at this time. The heaviest snow for the Tetons would fall during the day on Sunday, and with borderline temperatures and the strong mid May sun, it would likely have trouble sticking to roads. In the Absarokas, the heaviest snow would fall in areas with few to no people. In addition, the one impacted road, Beartooth Pass, is still seasonally closed. In the Wind River Range, the heaviest would fall in the western peaks away from travel routes. So, that leaves the Bighorn Range. I do have more concerns here. There will be favored upslope flow. The heaviest snow will also likely fall on Sunday night, when there is a better chance for accumulation on roads. We won't issue any highlights right now since impacts wouldn't begin until Sunday night, this would be the most likely location. All areas will see well below normal temperatures Monday, with places like Buffalo likely remaining in the lower 40s. The other concern is heavy rain. There has been decent consistency in showing the heaviest QPF in the western mountains as well as the northern half of the area. The Weather Prediction Center has issued a marginal risk for excessive rainfall for the northeastern half of the area for Sunday. Precipitable waters do rise to around 150 percent of normal for the Bighorn Basin as well as Johnson County on Sunday. As for flooding, there is some risk but not a large one. The air is not very warm ahead of the system and cooler air moving in Sunday night should put an end to any snowpack melting in the mountains. The main threat would be from any convection that develops and puts down heavy rain in a short amount of time. Probabilistic guidance gives at least a 1 in 2 chance of a half an inch of QPF from Sunday through Monday night for the northwestern half of the area. The favored north to northeasterly upslope areas have at least a 2 in 5 chance of 1 inch of QPF or more. This includes the Lander Foothills, near Thermopolis and especially Johnson County where the chance rises to as high as 3 out of 4. Most of the rain will fall west of the Bighorns through Sunday night, with Johnson and Natrona Counties seeing rain and snow continuing through Monday and even Monday night before tapering off. Quieter weather should move in after this. Some lingering moisture may bring a few showers Tuesday or Wednesday but it will be a milder day. Ridging should then build into the area later in the week, bring drier and warmer weather as we head toward the holiday weekend. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 537 AM MDT Sat May 17 2025 VFR conditions with mostly scattered cloud decks are expected through the rest of the morning. Focus then returns to convection as showers and thunderstorms become widespread this afternoon as the leading shortwave from an approaching trough pushes into Wyoming. This activity will move from southwest to northeast through the afternoon, with the main aviation concern of gusty winds to around 40 kts. Brief heavy rainfall is also possible with the strongest cells, which could bring short periods of MVFR conditions to terminals. While shower and thunderstorm coverage will generally decrease late this evening, the arriving trough will bring more persistent precipitation chances to western Wyoming (KJAC) near the end of the period. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts. && .RIW WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Hattings AVIATION...Myers ####018003379#### FXUS64 KMRX 171139 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 739 AM EDT Sat May 17 2025 ...New AVIATION... .SHORT TERM... (Today and tonight) Issued at 151 AM EDT Sat May 17 2025 Key Messages: 1. A line of strong to severe storms will move through the region overnight. A Tornado Watch is in effect for most of the region. 2. Rain and clouds will clear out by mid morning as a cold front moves through. Discussion: Not much has changed in regards to severe storm potential overnight. A line of strong to severe storms will be moving into the region within the next couple of hours. Two discrete supercells have produced tornadoes in Southeast Kentucky. Mesoanalysis shows effective shear around 60 knots and 0-1 km shear 35 knots. Isolated tornadoes will be possible. Damaging straight-line winds will be the main threat. In the upper levels, nearly zonal flow will be over the region as a closed low moves through the Great Lakes Region and a ridge is over the Gulf. At the surface, a cold front will be moving through the region this morning. Winds will become more westerly and dew points will be dropping after noon behind the front. Rain and clouds will clear out by mid morning. Westerly winds will be a bit gusty especially in SW Virginia and NE Tennessee, closer to the upper low. Tonight will be dry and uneventful. && .LONG TERM... (Sunday through Friday) Issued at 151 AM EDT Sat May 17 2025 Key Messages: 1. Mainly diurnal showers and storms Sunday and Monday. 2. The best chance for significant rain and storms will be Tuesday into Wednesday as a strong system moves through. Discussion: By Sunday a ridge begins to build into the Southeast, TN and Ohio Valleys. Sunday and Monday may see some showers and thunderstorms mainly in the afternoon as a boundary over the Southeast lifts northward by Monday. By Tuesday, a closed low moves into the Midwest. A surface low will move through the Ohio Valley Tuesday evening bringing a cold front through the region by Wednesday morning. Increasing chances for showers and storms with this system Tuesday into Wednesday. This will be the best chance for severe storms in the extended forecast period. Beyond Wednesday there is more uncertainty in the guidance. GFS has drier weather and the Euro has a cut-off low over the Great Lakes and Northeast bringing lingering rain chances. && .AVIATION... (12Z TAFS) Issued at 737 AM EDT Sat May 17 2025 Wx and any associated CIG have departed all terminals this morning. VFR will dominate today with clearing conditions and lifting/thinning cloud cover. However, SWly gusts will continue at TYS and TRI for the afternoon before decreasing tonight. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 87 65 84 66 / 20 10 50 30 Knoxville McGhee Tyson Airport, TN 83 62 81 63 / 10 10 30 20 Oak Ridge, TN 85 61 82 62 / 10 0 30 20 Tri Cities Airport, TN 80 57 79 57 / 10 0 10 10 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...McD LONG TERM....McD AVIATION...KS ####018010215#### FXUS63 KSGF 171140 AFDSGF Area Forecast Discussion National Weather Service Springfield MO 640 AM CDT Sat May 17 2025 .KEY MESSAGES... - 50-70% chance for showers and thunderstorms tonight into Sunday morning. A Marginal (1 of 5) to Slight (2 of 5) Risk exists for a few thunderstorms that 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 storm mode and evolution, which will impact main hazards. - Active pattern is forecast to end after Tuesday, with mostly dry and cooler temperatures Wednesday onwards. && .SHORT TERM /THROUGH TONIGHT/... Issued at 345 AM CDT Sat May 17 2025 Current water vapor imagery depicts a hexagonal spinner over MN/WI consistent with a deep vertically stacked low pressure system. South of the low, mid-level dry air is noted within a belt of 80-100 kt westerlies originating from a shortwave over the Baja Peninsula. Extending from the stacked surface low are two cold fronts that are currently draped from MI through MO, and into the southern Plains states. The second cold front will bring northwesterly winds, cooler temperatures this morning (lows in the lower to middle 50s), and drier air. The front is forecast to stall just south of the MO/AR border, so high temperatures will range from the middle 70s in central MO, to the lower 80s along the southern border. Marginal to Slight Risk for severe storms tonight: The stalled cold front boundary is forecast to very slowly lift back north as an effective warm front starting this afternoon as shortwave energy overspreads TX/OK. While the surface front will still be south of the border tonight, the 850 mb front will lift through southern MO. Associated southerly flow will then advect warm and moist air over the surface boundary, bringing 500-1000 J/kg MUCAPE along and south of a Nevada to Eminence line as noted by the 00Z HREF. Warm air advection and isentropic upglide over the front should then force showers and thunderstorms in far southwest MO after 7 PM. These will then spread northeastward along with the lifting warm front, bringing 50-70% chances for rain. Modest 500 mb flow associated with the incoming shortwave should generate 25-40 kts of effective shear, according to RAP forecast soundings. Thus, some thunderstorms may become organized enough to produce wind gusts up to 60 mph, and with mid-level lapse rates at 7-8 C/km and elevated instability, hail up to the size of quarters are also possible. Later overnight, the remnants of storms over southern KS/northern OK may also make it into southern MO. These storms would also pose a wind and hail threat late tonight into early Sunday morning, depending on their longevity. Slight (2 of 5) Risk for severe thunderstorms Sunday: Elevated showers and thunderstorms may continue Sunday morning and into the afternoon along the lifting warm front. Behind the warm front, instability will gradually increase and overspread the area as temperatures warm into the upper 70s and lower 80s and dewpoints in the middle 60s. The HREF mean depicts 1500-2500 J/kg MLCAPE, and RAP/HRRR suggests upwards of 2500-4000 J/kg MUCAPE in extreme SW MO and SE KS. Deep layer shear is also expected to increase to 40-50 kts as stronger southeasterly surface flow undercuts persistent westerly mid- level flow. Therefore, the environment during the day Sunday will be primed for severe weather if storms can continue. Forecast soundings depict 25 to 50 J/kg of capping during the day, though persistent 850 mb warm air advection may promote elevated convection. However, rising heights during the day may suppress the weak synoptic forcing of WAA. Thus, severe thunderstorm development is uncertain during the day Sunday. If storms are able to initiate, supercells will be possible with hail up to golf ball size and wind gusts up to 60 mph. If these happen to be surface-based, a tornado or two cannot be ruled out, especially in the vicinity of the warm front where hodographs will be a bit more curved producing 100-150 m2/s2 0-1 km SRH. Though storm development during the day is uncertain, there will more likely be storms Sunday night. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Issued at 345 AM CDT Sat May 17 2025 Slight (2 of 5) Risk for severe thunderstorms Sunday night: While the airmass over the Ozarks will be deeply unstable and sheared, forcing for ascent and convective initiation along and south of the warm front is weak and uncertain. There is a much higher likelihood for storms to develop along the dryline across central KS/OK during the day. These will then progress eastward into our area during the evening and overnight hours. Storm mode and evolution for these are still uncertain as CAMs are all over the place. Initial mode in KS/OK will likely be intense discrete supercells given the environment and shear vectors directly perpendicular to the dryline. However, the evolution is uncertain. Discrete supercells could be maintained as shear vectors persist westerly across our area. On the flip side, efficient cold pools and an increase low-level jet could produce an MCS. Then there could always be a mixed mode of both. Time will tell how this shakes out, but the storm mode/evolution will dictate our most likely hazards. If supercells can be maintained, all hazards including hail up to tennis balls, a couple tornadoes, and 60 mph wind gusts will be possible. If an MCS is the dominant mode, wind gusts up to 60 mph, a couple tornadoes (as low-level shear vectors will be westerly promoting a QLCS spin-up threat), and quarter-sized hail will be the main hazards. Enhanced (3 of 5) Risk for severe thunderstorms Monday: The same sort of setup as Sunday will exist Monday, except slightly more amplified and the dryline shifting a bit eastward into east-central KS/OK. Medium-range guidance suggests MUCAPE greater than 3000 J/kg as dewpoints increase to the upper 60s, and deep-layer shear greater than 50 kts as the flow aloft increases ahead of a deepening trough. Therefore, again, storm development is a low-end scenario during the day Monday, with higher chances Monday evening/night as they move in from the west. Hazards will once again be determined by storm mode/evolution, however, with the initiating dryline shifting eastward, there is a larger/longer window for discrete all- hazards supercells (potentially significant hail) late Monday afternoon/early evening before any potential change in evolution. This combined with the amplified instability/shear parameters is leading to an Enhanced (3 of 5) Risk for the western 2/3rds of our forecast area. Slight (2 of 5) Risk for severe thunderstorms Tuesday: As the potent system translates eastward, severe thunderstorms will once again be possible Tuesday. Global models seem to be a bit more progressive with the warm sector forecast to be along and east of Highway 65 after 12 PM Tuesday. With a crashing cold front progged to accompany a deepening upper-level low severe weather is possible as it moves through our CWA Tuesday afternoon. Hazards are currently uncertain, but given the strong frontal forcing, damaging wind gusts look to be a main hazard. Compounding showers and storms could lead to localized flooding: Along with the chances for severe weather each day, the compounding effect if multiple rounds of showers and storms (especially from heavy rain within severe convection) could lead to localized flooding. The EFI is highlighting 0.6-0.8 values with a shift of the day every day through Tuesday. Despite this, the location of any flooding is highly uncertain right now, as it will depend on where storms go. Due to smoothing of timing and location from every model, most areas in our CWA are forecast to see between 2 and 4 inches through Wednesday. However, if MCSs become the dominant storm mode each night, and end up riding the warm front at the nose of the nocturnal low-level jet, there could definitely be banded areas that see well over 4 inches of rain. For example, the experimental MPAS ensemble puts a band of 7-12 inches total precipitation Saturday through Wednesday across central Missouri. This is not to be taken literally, but it does highlight the scenario of multiple MCSs riding a relatively stationary warm front each day/night. Trends will continue to be monitored. Cooler and drier weather Wednesday onwards: After the potent trough kicks through the region, cooler and drier weather are forecast Wednesday onwards. Highs Wednesday are forecast to be in the lower 60s with lows in the middle 40s Wednesday night. These cooler temperatures will then gradually warm to highs in the middle 70s and lows in the upper 50s by Memorial weekend. Some rain chances return Friday and Saturday within a northwesterly flow regime, but details are currently uncertain. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 640 AM CDT Sat May 17 2025 VFR conditions will prevail at all TAF sites through at least 00Z. Light northwesterly winds will shift to easterly between 19-23Z. Then, chances increase for showers and thunderstorms after 00Z ahead of a lifting warm front. There is still uncertainty in exact timing, but the best 6 hour window for storms at the TAF sites look to be between 03-10Z with ensemble guidance suggesting a better window between 06-09Z. Have put PROB30s for this time period. && .SGF WATCHES/WARNINGS/ADVISORIES... KS...None. MO...None. && $$ SHORT TERM...Price LONG TERM...Price AVIATION...Price