####018008629#### FXUS65 KRIW 170206 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 806 PM MDT Fri May 16 2025 .KEY MESSAGES... - Isolated showers linger mostly across northern WY this evening, gradually dissipating by the early morning hours Saturday. - A better chance of showers and storms Saturday (30 to 50%), with strong storms possible over southwestern Wyoming. - Turning much cooler Sunday and Monday with rain and mountain snow across much of the area. && .UPDATE... Issued at 235 PM MDT Fri May 16 2025 The forecast remains on track for the next 24 to 48 hours. The HRRR, along with several other CAMs have been tracking well with weak convection developing this afternoon. Convection has already begun to develop along the Cody Foothills, but as expected is very weak, generally just virga. By 1600-1900L there will be slightly better instability, though still <100 J/kg SB CAPE. Thus, during that time frame, there could be an isolated stronger storm with gusty winds to 30 to 40 mph and up to pea size hail being the primary threats. Best chances for these stronger storms (10 to 20%) will be along the Cody Foothills and eastern Bighorn Basin, as well as Yellowstone NP. Any lingering convection will taper off and end quickly after sunset and things should remain fairly quiet overnight. Saturday morning, models remain on track with timing showers and thunderstorms pushing into southwest WY then spreading east through the day. Isolated stronger storms will be possible (30% to 40% chance) across southwest WY, with gusty winds being the main threat but small hail could also be a concern. SPC continues with a marginal risk for Severe for that area as well, which aligns well with local thoughts and model guidance. && .DISCUSSION... Issued at 317 AM MDT Fri May 16 2025 Active weather will continue as we head through the next several days. We do have signs summer is coming though. The first sign is the predawn light when I go out to prepare the weather balloon for launch. This is around 4:45 am. Another sign is twilight still in the sky when I drive to work around 9:45 pm for my favorite shift, the midnight shift. (Yes, I am one of those weird people who prefers working at night). It will not feel like summer the next several days though, and some locations will feel like winter at times, especially early next week. Today looks like one of the least active days of the next several. Shortwave ridging will move across Wyoming and bring a lull in the persistent showers and storms. There will be a weak trailing shortwave that could being some showers this afternoon and evening, but these would be restricted to northern Wyoming and most of the population centers should stay mainly dry. Temperatures will also be somewhat warmer, but still only around 5 degrees below normal for most. And the shortwave will bring gusty wind to Johnson County for another day, but there should not be 60 mph gusts like yesterday. Ensemble guidance only gives a 1 in 3 chance of gusts past 40 mph for most at this time. Things start getting more active on Saturday, as an upper level low moves onshore in the Pacific Northwest and increases moisture across the area once again. Saturday should start dry for most, but coverage of showers and thunderstorms will increase as the low approaches. And things may get a little interesting. There will be decent upper level divergence across the area, and some morning sunshine may destabilize the atmosphere somewhat. Lifted indices will be negative and CAPE values will increase to 500 J/kg at times across southwestern Wyoming. The Storm Prediction Center has put this portion of Wyoming under a Marginal risk, with the main threat being strong wind gusts. The most numerous storms will be across western Wyoming. In areas east of the Divide, southwesterly flow will raise some high temperatures to around 70 degrees. It is also likely to keep most areas dry most of the time, with the average chance of a shower or thunderstorm around 1 out of 4 in this area. The aforementioned upper level low will then dive southeastward through the weekend and into Monday, with lee cyclogenesis likely occurring Sunday night into Monday in eastern Colorado and lifting into the Plains, with another upper level low developing over the western states. As a result showers will become more numerous across the area on Sunday, with another chance of afternoon thunderstorms, this time with thunder mainly east of the Divide where the best instability will be. And this will be the day we may make a transition back into winter for some locations. As flow turns northerly behind the low, much colder air will move in. Some model guidance drops 700 millibar temperatures as low as minus 5C across western Wyoming Sunday night, and this could lead to snow levels falling as low as 6000 to 6500 feet, possibly bring a coating of snow to the western valleys. The colder air then spreads east of the Divide Sunday night and especially Monday. And this is where the bulk of the precipitation will be that day. The air won't be quite as cold here, with 700 millibar temperatures generally bottoming out at around minus 7C, which would put snow levels around 5000 feet. And, given the position of the low and north-northeasterly flow, the Bighorns would be the most impacted area. Some probabilities for over 6 inches of snow include around 3 out of 4 in the higher elevations of the Bighorns and Wind River Range, with about a 3 out of 5 chance in the Tetons and Absarokas through Monday night. Chances of a foot are generally only 1 out of 2 at the very highest elevations so if highlights are needed it would likely be Advisories. This also looks to be a wet storm, with most locations east of the Divide and the northern mountains having at least a 1 out of 2 chance of a half an inch or more of QPF and favored north- northeast upslope locations like Buffalo, Thermopolis and Lander having a 1 in 2 chance of an inch of QPF or more. As for flooding, areas northeast of a Casper to Cody line have a marginal risk of excessive rainfall on Sunday and areas along and east of Interstate 25 have one for Monday. The rain will fall over a fairly long period though. In addition, with the colder air moving in, rain on snow is not likely as the higher elevations would see mainly snow. We will watch it though. Monday will be the coldest day of the week, with many locations having highs in the 40s. We should begin to dry out as the low moves away on Tuesday, although some lingering moisture will keep a few showers around, especially in eastern Wyoming. Flat ridging should then hold for the rest of the period, bringing more seasonal temperatures. Another shortwave may bring some showers and storms by midweek, but timing is all over the place this far out. && .AVIATION /00Z TAFS THROUGH 00Z SATURDAY/... Issued at 349 PM MDT Fri May 16 2025 VFR flight conditions are expected this TAF period at all terminals. Low chances (30%) of showers continue at KCOD and KJAC through 02Z Saturday morning. At KWRL, isolated light rain cannot be ruled out (30% chance) through 06Z. Shower activity is isolated so confidence in direct impacts is low at the aforementioned terminals and this is reflected in the PROB30 groups. Confidence is high (80%) that conditions should remain VFR with any light rain. Shower and thunderstorm chances increase again on Saturday after 15Z at KRKS followed by KJAC, KPNA, KBPI, and then KCOD. There is uncertainty in timing of convection this far out and this uncertainty is communicated as a PROB30 group. Confidence in shower and thunderstorm activity at KRIW, KLND, KWRL, and KCPR is less than 20% after 20Z so opted to keep out of TAF at this time. Otherwise, expect gusty winds to diminish at the west of the Divide terminals and KCPR by sunset tonight. Winds increase with gusts around 20kts at KCPR and KBPI around 17Z Saturday. 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. && $$ UPDATE...Hensley DISCUSSION...Hattings AVIATION...Gerhardt ####018004602#### FXUS64 KJAN 170208 AAA AFDJAN Area Forecast Discussion...UPDATED National Weather Service Jackson MS 908 PM CDT Fri May 16 2025 ...New MESOSCALE UPDATE, AVIATION... .MESOSCALE UPDATE... Issued at 846 PM CDT Fri May 16 2025 Thunderstorms have been developing to the west of our forecast area this evening but are slower to shift eastward than some earlier model guidance suggested. Still appears that storms may move into our forecast area between about midnight to 6 AM tomorrow. No adjustments needed to the severe weather outlook at this time. /NF/ && .DISCUSSION... Issued at 253 PM CDT Fri May 16 2025 Tonight and Saturday: Ridging surface and aloft will hang tough to our south while a nearly stacked low tracks east across the Great Lakes region and pushes an associated cold front into our CWA. Convection developing along and ahead of the cold front this afternoon and evening is progged to move into our northwest zones later this evening. Severe storms capable of damaging wind gusts, hail to golf ball size and perhaps a brief tornado or two will be possible generally along and north of a line from Bastrop, Louisiana to Eupora, Mississippi. Just southeast of this line isolated severe storms will be possible. Although the severe storm potential should end by 5am, additional shower and thunderstorm development will continue Saturday morning as the stalling frontal boundary sags into central Mississippi. During the heat of the day the frontal boundary is expected to drift back to the north. More vigorous convection is expected including the potential for a strong and/or isolated severe storm to develop in close proximity of the boundary but the main severe threat looks to hold off until the evening. Temperatures tonight and Saturday will continue above normal. /22/ Saturday night through Thursday night: As the frontal boundary continues to progress southward, additional shortwave disturbances is expected to keep rain/storm chances throughout the evening. Northwest area of the CWA remains under a 'Slight' risk (2 out of 5) for severe weather. Damaging wind gust up to 60-70 mph and hail up to golf ball size and a brief spin up tornado will be the main concerns within the "Slight" risk. Another chance for severe weather will be possible on Sunday as a frontal boundary stall to the north of the CWA. Depending on how much instability remains in the atmosphere from Saturday's storms, isolated severe storms will be possible on Sunday Sunday afternoon and evening. 'Marginal' risk (1 out of 5) for severe weather continues with the hazards of concerns being damaging wind gusts and hail up to quarter-size. Decreasing rain chances are expected to begin Sunday evening as a mid/sfc ridging pattern will begin to builds over the southeast CONUS. High (lower 90s)/ low (lower 70s) temperatures will continue to be above seasonal averages. Rain/storm chances return on Tuesday as the next system approaches. Upper-lvl trough with a low centered near the Upper Rockies/Mid West is expected to push a cold front towards the region. As the boundary approaches, an unstable airmass will be in place and a mid-lvl jet moving into the area, will help to increase bulk shear. With possible organized convection, SPC highlighted severe weather potential for Tuesday. At this time, uncertainty in hazards and timing and is subject to change over the next few days. Post frontal passage Wednesday, northwest flow will bring in below seasonal temperatures and quiet conditions through the end of the week. /SW/ && .AVIATION... (00Z TAFS) Issued at 846 PM CDT Fri May 16 2025 VFR conditions to start the period, with an expected line of showers and thunderstorms to develop and move into the forecast area after 06Z Saturday. Variable ceilings and visibility possible with any TSRA. Chances for impacts from thunder will decrease by 12Z-18Z. /NF/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 73 90 71 90 / 40 50 30 10 Meridian 73 90 70 91 / 30 50 30 20 Vicksburg 74 90 72 91 / 50 40 20 0 Hattiesburg 73 94 72 93 / 0 20 20 0 Natchez 73 90 71 90 / 10 20 10 0 Greenville 71 88 72 89 / 80 20 20 20 Greenwood 71 89 71 90 / 80 20 20 30 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ 22/SW/NF ####018004666#### FXUS64 KOHX 170208 AFDOHX Area Forecast Discussion National Weather Service Nashville TN 908 PM CDT Fri May 16 2025 ...New UPDATE... .KEY MESSAGES... Updated at 902 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. && .UPDATE... Issued at 902 PM CDT Fri May 16 2025 The forecast is on track. There are no appreciable changes to our messaging. All of Middle Tennessee is now under a Tornado Watch until 08Z, and the leading edge of the incoming line of storms is closing in on Land-between-the-Lakes. Instability across that portion of Middle Tennessee is still off-the-charts, with CAPE values of 3,500 to 4,000 J/kg and lifted indices of -12 to -13. Helicity values have dropped off some (generally 175 to 200). Of note, the 00Z sounding from OHX does show that the elevated inversion that has persisted for several days now has strengthened so that we might find ourselves capped off at some point later on tonight after the boundary layer has cooled some. But for now, we're preparing for severe storms to enter the county warning area shortly. && .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. && $$ UPDATE.......Rose SHORT TERM...12 LONG TERM....12 AVIATION.....05 ####018002714#### FXUS61 KILN 170208 AFDILN Area Forecast Discussion National Weather Service Wilmington OH 1008 PM EDT Fri May 16 2025 .SYNOPSIS... Low pressure over the upper Midwest state and a trailing cold front will bring thunderstorms this evening. High pressure will offer breezy and mild conditions heading into the weekend. An upper level low will bring cloudy and cooler weather early next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Scattered showers and thunderstorms will continue to push east across the region over the next few hours. We have seen an overall weakening trend in the intensity and coverage with the storms and expect this trend to continue as we head into the overnight hours and further stabilize. Lows tonight will generally be in the lower 60s. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... Trailing surface cold front will push through the region Saturday morning. In its wake, westerly winds will gust to 25-35 mph at times. Mostly sunny skies will allow high temperatures to rise to the upper 60s in the northwest to lower-middle 70s in the southeast. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Mid level ridge will translate into the area early in the period, but there are a number of models that show a weak short wave moving through the ridge which could result in some showers making into the Tri-State on Monday. The ridge will get pinched off as a low tracks east out of the central Plains on Tuesday. This low will get absorbed into another low retrograding across southeast Canada on Wednesday. The large merged low will then pivot eastward Thursday night into Friday. This evolution will lead to several days of wet weather, with some improvement late in the week. In addition, temperatures will be below normal with Thursday looking to be the coolest day with readings 10 degrees or more below normal. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... Scattered thunderstorms will continue to push off to the east over the next few hours. We should then be dry through the remainder of the night with mainly VFR conditions persisting. IN developing CAA on the back side of the cold front, expect gusty west winds in the 25 to 30 knot range during the day on Saturday and allow for sct-bkn VFR cu through the day. Th winds and cu will dissipate as we head into Saturday evening. OUTLOOK...No significant weather expected. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS... NEAR TERM...JGL SHORT TERM... LONG TERM... AVIATION...JGL ####018008762#### FXUS62 KGSP 170209 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 1009 PM EDT Fri May 16 2025 .SYNOPSIS... Very warm and humid conditions remain in place through tonight as a cold front sends a line of showers and thunderstorms across the area late tonight into Saturday morning. The front stalls in the vicinity of the area Saturday through early next week, keeping a relatively active pattern in place. && .NEAR TERM /THROUGH SATURDAY/... Key Messages: 1) A line of strong-to-severe thunderstorms is expected to impact the mountains late tonight into Saturday morning, with the threat decreasing eastward. 2) Confidence remains low, but there's potential for severe weather east of the mountains leading up to dawn. 3) Temps around 10 degrees above normal. As of 953 PM EDT Friday: Only major change to the forecast this round was to bump dewpoints up, as they've been consistently a couple degrees higher than forecast all evening. All quiet across the forecast area tonight as we watch and wait for upstream convection to evolve. Multiple bands of organized convection are visible on regional radar imagery over the Cumberland Plateau and central Kentucky. 00z soundings over the Tennessee Valley depict an impressive EML, which should advect into the Carolinas and Mid-Atlantic over the next few hours ahead of a robust shortwave visible on water vapor imagery. Hi-res guidance consensus continues to be that convection will struggle to hold together as it crosses the complex terrain of the Appalachians...owing in large part to the upstream capping advecting into the Carolinas, and the disruptive nature of shear of the ragtag line. Nevertheless, there's more than enough uncertainty to advertise chance PoPs east of the mountains. While the main severe wx threat overnight will be from damaging wind gusts...low level shear will be adequate for brief spin-ups, mainly across the TN border counties. Somewhat concerningly, the 00z HRRR has come in with increasingly impressive redevelopment of embedded thunder within the line, especially over the Upstate and Charlotte-Metro area...likely in response to marginally better lapse rates in this most-recent run, as well as somewhat higher forecast surface dewpoints. The cold pool will effectively push a frontal boundary through the CWA Saturday morning, leaving behind lower theta-E air (mainly manifest as lower surface dewpoints). As such, forecast soundings during the daylight hours feature much weaker instability, and CAMs develop little in the way of diurnal convection. Therefore, after some lingering token small morning PoPs, chances drop to less than 20% across most of the area during the afternoon. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... As of 130 PM EDT Friday: Most of the model guidance are in agreement with the synoptic frontal boundary completing a full fropa across the CFWA and stalling south of the I-20 corridor by Saturday evening as the vertically stacked parent low sets up shop over the northeastern CONUS. The frontal boundary will be draped from the Southern Plains through the Lower MS Valley and Deep South Saturday night as the cold front becomes reactivated when convection initiates over the Southern Plains and Ozarks Saturday evening before becoming clustered and translating east. The flow aloft becomes more progressive Sunday into Monday as a digging upper low over the western CONUS carves out a ridge over the central CONUS, while orientating the flow from the northwest to southeast across the CFWA. Early Sunday morning, the flow aloft won't be fully established, but a potential decaying MCS could make a run at the southwest mountains and Savannah River Valley. Model guidance differ with the overall evolution, with the ECMWF/CMC indicating very little SBCAPE, while the NAM/GFS show a couple hundred J/kg of SBCAPE as it slips towards the area. Kept some mentionable PoPs in this region of the CFWA as a result, while any convective debris could alter afternoon highs on Sunday, but warm thicknesses and slightly lower dewpoints (upper 50s-lower 60s) will help afternoon highs top out ~5 degrees above normal. Deep layer northwesterly flow becomes better established later Sunday as the upper ridge axis gradually shifts over the MS Valley, while an upper low churns over the western CONUS and the other upper low meanders over New England, creating an Omega-like blocking pattern. In this case, drier air will filter into the area, but convective initiation on the leeside of the western upper low and dryline across the Plains will create an assembly line for the activity to grow upscale and make a couple of MCS runs towards the CFWA during the early part of next week with the first MCS possibly tracking towards the area sometime on Monday. Confidence is low on the exact timing and placement of the MCS, but the synoptic setup is favorable and will likely throw a monkey wrench into the temperature and PoP forecast with the associated QPF response and convective debris. However, higher heights build into the area by early next week and should keep temperatures on track to rise a category or so above normal outside of the monkey wrench. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 230 PM EDT Friday: The upper ridge gradually shifts further east towards the eastern-third of the CONUS, while breaking down as the upper low over the western CONUS gets pushed from behind as a Pacific Northwest jet punches in. This will disorientate the northwesterly regime, but guidance try to send one more MCS towards the region late Monday into Tuesday, but will likely hit the northern tier of the CFWA this time around or miss to the north altogether. Diffluent flow aloft becomes better establish later Tuesday into Wednesday as the ridge continues to slide eastward and the upper low deepens into a closed low, which eventually becomes established across the Great Lakes region. Expect an increase in deep layer shear as a result, which will coincide with daily diurnal instability to help instigate strong to severe storms ahead of an encroaching frontal boundary. Model guidance also show a potent shortwave rounding the base of the closed low Wednesday into early Thursday to help the frontal boundary advance eastward and complete a fropa sometime during the first half of Thursday. Drier air is expected behind the front as broad cyclonic flow aloft remains in place and low-level CAA filters in with weak high pressure, setting the stage for a post-frontal regime by the latter half of the forecast period. Northwesterly flow will commence and could produce a few orographically enhanced showers along the TN border. Continued northwesterly flow pattern remains in place through the end of the forecast period and could make the area vulnerable to another favorable MCS pattern, but likely to become more set and stone after D7. Temperatures will be at or slightly above normal Tuesday and Wednesday, before the post-frontal regime allows temperatures to fall a category or so below normal Thursday and Friday. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... At KCLT and elsewhere: Still expect VFR through the period, except for brief restrictions during active convection. A line of organized thunderstorms currently located over Kentucky will arrive from the Tennessee Valley around or after midnight. It remains unclear how well this system will hold together, but confidence is improving that it'll at least affect KAVL, before deteriorating as it exits the NC mountains. PROB30s for TSRA are still advertised at some sites, and gusty winds remain advertised for all the TAF sites during and after the passage of the system. Those gusts will persist through Saturday afternoon, before quieting Saturday evening. Little more than a widely scattered and capped cu field is expected during the daylight hours Saturday. Outlook: The potential for mainly diurnal convection increases again Sunday, with chances continuing through the middle of next week. Early morning fog/low stratus will be possible, especially in the mountain valleys and in locations where appreciable rain fell the previous afternoon/evening. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...CAC NEAR TERM...JDL/MPR SHORT TERM...CAC LONG TERM...CAC AVIATION...MPR