####018006208#### FXUS63 KLSX 161955 AFDLSX Area Forecast Discussion National Weather Service Saint Louis MO 255 PM CDT Fri May 16 2025 .KEY MESSAGES... - Severe thunderstorms are expected to continue until storms exit between 6 and 7 PM this evening. - After a brief period of dry weather tonight - Saturday evening, the chance for rain showers and thunderstorms returns Saturday night into next week, with the highest chances on Monday night and Tuesday. && .SHORT TERM... (Through Late Saturday Night) Issued at 248 PM CDT Fri May 16 2025 Isolated to widely scattered supercells have developed fairly rapidly over the past couple of hours in our area along a fast- moving cold front. This boundary is located just west of a KVIH>>KUIN axis and should clear the southeastern CWA by or just before 2300 UTC. Large hail, potentially very large (2.75+") still looks like the main threat given very steep midlevel lapse rates and associated hail CAPE. The tornadic potential increases with southerly extent, with the latest SPC mesoanalysis showing 0-1km SRH around 150-175 m^2/sec^2. LCL values are also a bit lower down in southeast Missouri and southwest Illinois compared to east- central Missouri and south-central Illinois. However, a strong RFD surge very recently just helped spin up a tornado further north, so the threat continues across the entire tornado watch. Much cooler and drier air will filter into the area behind this cold front. Therefore, look for dry weather the remainder of tonight into Saturday evening along with temperatures much closer to seasonal normals. Gosselin && .LONG TERM... (Sunday through Next Friday) Issued at 248 PM CDT Fri May 16 2025 (Saturday Night - Tuesday Night) Today's cold front is expected to stall out across the mid south and then begin to move back northward as a warm front late this weekend into early next week. Multiple rounds of showers and thunderstorms are expected mainly along/north of this retreating boundary through early next week. There still appears to be 2 MCSs that may impact the region, one Sunday night/Monday morning and another Monday night/Tuesday morning. The latter should be further north than its predecessor, but how far north is a question mark. Sometimes antecedent convection really hampers the poleward progress of retreating warm fronts. There is some modest lesside cyclogenesis in the central Plains, which would argue for continued northward movement, but again, this could be offset by the aforementioned convection. The main focus through Tuesday morning likely will be on heavy rain potential and flash flooding. Convection through that time likely is to be focused along/north of the boundary and elevated in nature (hail could be a threat though). In terms of rainfall potential, the probabilities have trickled up about 10% for 2+" of total rainfall through Tuesday night. Chances are now in the 50-70% range across the bi-state area. For at least 4", chances are in the 10-15% range, still quite low but a bit higher than yesterday by about 5% on average. The overall concern for any significant flash flood threat or river flood threat is still fairly low, but we will have to keep an eye on this period for hydrologic impacts. As talked about yesterday, a lot of the area is now running a slight deficit in the rainfall department since May 1st. Parts of northeast Missouri and west-central Illinois have fairly widespread abnormal dryness/moderate drought conditions and could really use 2-3+" of rain. At least a conditional severe threat is still on the table for Tuesday ahead of the midlevel synoptic trough and associated cold frontal passage. Major caveats continue including a lot of spread with the track/strength/timing of the trough itself and on instability. The amount of instability remains a big question mark due to antecedent convection primarily. Temperatures during this time period still are tricky, especially daytime highs. The track of each nocturnal MCS will have ramifications on daytime highs both Monday and Tuesday. Not surprisingly, the inter-quartile range from the NBM each of these days is large, mainly on the order of 8-12 degrees in most locations. (Wednesday - Next Friday) The mid/late week period continues to look increasingly chilly for late May standards as an anomalous mid/upper level low slowly slides across the Great Lakes. Temperature anomalies at 850 hPa peak out at around 6 to 8C below normal Wednesday night across the area. While those type of values wouldn't be noteworthy in the middle of winter, it is for late May (closer to 2 sigma below normal). The coolest day is likely to be on Wednesday, as highs in the 60s are forecast. If clouds and/or rain continues across portions of the area, cannot rule out some locations staying in the 50s. Lows late week are dependent on the timing of the surface ridge and sky cover, but widespread lows in the 40s are certainly on the table. Gosselin && .AVIATION... (For the 18z TAFs through 18z Saturday Afternoon) Issued at 1210 PM CDT Fri May 16 2025 Isolated to scattered thunderstorms will develop along a cold front over the next couple of hours. The metro terminals still have the best chance, but coverage is too low to be confident enough to introduce a prevailing or a TEMPO. Any thunderstorm that does directly impact a terminal would have the capability of producing low visibilities in heavy downpours and large hail with some wind threat as well. Storms will move off to the east quickly, with dry weather and VFR conditions favored thereafter. Winds are expected to veer through this evening, with west/northwest winds behind the front. Gusts may diminish or at least weaken this evening before picking back up again by mid morning on Saturday. Gosselin && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX ####018006820#### FXUS61 KGYX 161955 AFDGYX Area Forecast Discussion National Weather Service Gray ME 355 PM EDT Fri May 16 2025 .SYNOPSIS... A slow moving low pressure system will bring rounds of showers and thunderstorms tonight and through the weekend. Storms through tonight may be slow-moving, potentially leading to localized flash flooding north of the mountains. Saturday, storms may be more organized, leading to some stronger storms across NH as well as a potential flash flooding threat again north of the mountains. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Radar imagery currently shows numerous pulse thunderstorms across the interior. These storms are producing heavy downpours, and may have the potential to produce some gusty winds and small hail as well. Storms may be slow moving and end up training across this area too, so localized flash flooding may occur with some heavier storms. Coastal areas should stay mostly dry this evening, as the sea breeze should keep more stable air over the coast. After the frontal passage late tonight, marine fog builds back into the coastal plain. Scattered showers and developing fog overnight should allow for mild low temperatures tonight, with lows in the 50s and 60s. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... Key Points: -Rounds of storms tomorrow may bring damaging winds and localized flash flooding to New Hampshire and western ME. The damaging wind threat looks to be across southwestern New Hampshire, while the flooding threat tomorrow is highest north of the mountains. -The SPC has issued a Slight Risk for Severe Weather in Southwest NH -The WPC has issued a Slight Risk for a 15% chance of excessive rainfall over locations north of the mountains. Details: Visibility reductions will be possible through most of the day tomorrow as very light onshore winds continue to advect fog into much of western Maine. Fog will keep high temperatures across Maine lower, and keep the environment more stable. Over western and southern NH, there should be thinner clouds with more breaks in them. This will allow for warmer high temperatures and allow for the environment to destabilize, becoming more conducive for severe weather. The environment tomorrow afternoon features 1000-1500J/kg of CAPE, some wind shear and 100m^2/s^2 of low-level helicity. These parameters suggest that damaging winds and hail are possible with thunderstorms across southwestern NH. In addition, multiple rounds of showers and storms across the north tomorrow may produce some localized flash flooding as well. The strongest storms move across western NH in the mid-afternoon, with another round of storms possible later on in the evening. Fog over Maine will allow for the marine layer to advect all the way to the mountains, with most storms weakening as they enter these areas of fog. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... The surface low will exit into Downeast Maine Sunday morning while the 500 mb crosses overhead through the day. There could be fog and low stratus lingering in the morning, especially over eastern areas, but otherwise the upper low will bring another day of high shower coverage during the day and into Sunday night, especially inland and toward the mountains with activity more scattered farther south and closer to the coast. I don't think there's enough instability to include thunderstorms in the forecast at this point as models are mostly showing on the order of a couple hundred J/kg of CAPE. The upper low shifts east of the area early next week to around Nova Scotia, but broad troughing across the NE and enough residual moisture will still be sufficient enough for isolated to scattered showers to develop (lower coverage than Sunday), mainly during the daytime hours. Temperatures will be in the mid 50s to lower 60s for the most part on Monday and then a touch cooler on Tuesday. Another slow-moving, upper low then enters the picture for the second half of next week with models in good agreement a 500-mb low closing off near the Great Lakes that will slowly head toward New England. Shower chances will ramp back up as a result with cloudier conditions and temperatures staying on the cooler side. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... Short Term... Thunderstorms and fog will keep restrictions mostly down this evening, likely continuing through Saturday and Saturday nightas fog and multiple rounds of showers and storms move across NH and ME. Long Term...LIFR to IFR fog and/or stratus may stick around 12-15Z Sunday, mainly in the RKD-AUG corridor...otherwise showers will again be likely during the day Sunday into Sunday and could produce IFR to MVFR conditions. For Monday and Tuesday...MVFR ceilings possible during the first part of Monday, but coverage of showers will be lower and mostly during the daytime hours these days. Chances for showers and and flight restrictions then increase toward the middle of next week. && .MARINE... Short Term... 2-4ft seas expected this evening through Sunday morning. This afternoon, winds will be southerly at 6-11kts. Winds strengthen to 8- 13kts Saturday morning ahead of a frontal boundary. The frontal boundary crosses the waters tomorrow night, with winds shifting to westerlies at 6-11kts by Sunday morning. Long Term...Winds become westerly Sunday and then northwesterly Monday into Tuesday as surface low pressure moves east of the waters. Gusts to 20-25 kt may occur from time to time during this period, but in general things look to remain under SCA levels through Wednesday. Winds become east to northeast toward the second half of next week with developing low pressure to the south. It's uncertain what track the low will take, but SCA conditions are possible toward late week. && .HYDROLOGY... Torrential downpours with rain rates as high as 1-3" per hour from slow-moving showers and storms will pose a risk of flash flooding through this evening, mainly from the mountains northward. Multiple rounds of showers and storms are again possible during the day Saturday and could pose another threat of flash flooding. The threat is highest again in and north of the mountains on Saturday where WPC has highlighted a Slight Risk of Excessive Rainfall. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Palmer SHORT TERM...Palmer LONG TERM...Combs HYDROLOGY...Combs ####018006541#### FXUS64 KHUN 161957 AFDHUN Area Forecast Discussion National Weather Service Huntsville AL 257 PM CDT Fri May 16 2025 ...New NEAR TERM, SHORT TERM, LONG TERM... .NEAR TERM... (Tonight) Issued at 157 PM CDT Fri May 16 2025 Both low and mid cloud cover has thinned significantly over the last few hours east of the I-65 corridor. Further west, thicker mid/high cloud cover has redeveloped. Most locations have reached the lower to mid 80s across northern Alabama and southern middle Tennessee. Still could see an upper 80 degree high near the I-65 corridor and mid 80s further east. A very humid and unstable airmass (3000 to 4000 J/KG) is in place. However, The good news is that there have been very little signs of convective development a few models were hinting could happen around 4 PM. The cap in place aloft and the drier air between 850 mb and 700 mb seen in 7 AM Birmingham sounding, looks like they will hold off any convection this afternoon. Both satellite and radar trends seem to support this as well. Models still show the main upper level forcing sagging southeast into southern middle Tennessee and NW Alabama between 10 PM and 1 AM ahead of an approaching cold front. Enough MUCAPE or SBCAPE (1000 - 2000 J/KG) lingers ahead of the front into the overnight hours. However, strong shear continues to be shown ahead of the front and 0-3 km helicity climbs to between 200 and 350 m2/s2 as the best forcing moves into the area ahead of and with the front. Expect there could be some embedded supercells (producing large hail initially) that move into the area. Still thinking this will form into a more widespread damaging wind threat with a few tornadoes possible. The high low level moisture and cloudy conditions tonight should keep lows very warm, only dropping into the 65 to 70 degree range in most areas. Overall timing of convective initiation hasn't changed much. 1. Franklin (AL) NW Lincoln County (TN) - 10 PM to 2 AM 2. SW Lawrence County (AL) to Sewanee (TN) - Midnight to 3 AM 3. SE Cullman County (AL) to Fort Payne (AL) - 2 AM to 5 AM If some convection does eventually form 4 PM to 8 PM (as those few models were hinting), supercells and a larger hail/stronger tornado threat could exist during that period. At this time, that is not expected to occur. && .SHORT TERM... (Saturday through Monday) Issued at 157 PM CDT Fri May 16 2025 Much drier air moves southeast into the area just after daybreak on Saturday between 8 or 9 AM. The front should be far enough south to keep rain chances out of the forecast by then. Highs should reach the mid to upper 80s again across northern Alabama and southern middle Tennessee on Saturday. Most guidance places the front somewhere through central Alabama when it stalls. However, during the late afternoon/early evening hours, several models move this front northward into northwestern Alabama and then further northeast overnight. Scattered showers and thunderstorms in the evening should give way to more widespread activity overnight. Strong shear pushes back into the area and with very moist low level moisture moving back into the area behind the front, instability will increase enough to warrant at least a low severe threat. Main threats would be damaging winds and up to one inch hail. High dewpoints and cloudy conditions tonight should keep lows very warm, only dropping into the 65 to 70 degree range in most areas. As the front stalls near the southern portion of the forecast area, cloud conditions and additional showers and thunderstorms are expected on and off through the day into the early evening hours on Sunday. Expect cooler conditions as well with highs only climbing into the upper 70s to lower 80s. Again with strong shear over the area and enough instability in place, a few strong to marginally severe storms could occur. && .LONG TERM... (Sunday night through Friday) Issued at 157 PM CDT Fri May 16 2025 Luckily, it looks like we see a break in high rain/thunder chances Sunday night into Monday, as the front really pushes to the north as a stronger warm front. At the same time, upper level ridging builds over the area. Locations north of the Tennessee River could still see scattered showers and thunderstorms, possibly a few again strong to marginally severe. Highs will likely be similar (though current guidance may be a tad too low), reaching the mid to upper 80s. Monday night will still be very humid with lows dropping into the mid to upper 60s. A stronger storm system over the Rockies develops and moves slowly east Monday night into Tuesday. The strength of the upper level ridging and the northward placement of its associated warm front should keep any shower or thunderstorm activity north of the area Monday night. However, on Tuesday into Tuesday night, it looks like higher rain and thunderstorm chances move back into the region. Strong shear and instability will return ahead of that system. A bit more helicity is hinted at with model guidance. So tornadoes may be more of a threat with this system. However, it is still several days out, so alot can change. Again colder air moves into behind this system, towards the end of next week. && .AVIATION... (18Z TAFS) Issued at 124 PM CDT Fri May 16 2025 VFR conditions are expected at both terminals through 04Z at KMSL and 06Z at KHSV. Expect LLWS to pick up to around 40 knots around 00Z at KMSL and 01Z at KHSV from 220 degrees. Around 04Z at KMSL and 06Z at KHSV, expected -TSRA to impact the terminals at times as convection develops and moves into the terminals. This will likely produce MVFR conditions primarily. However, included a tempo group for TSRA and IFR VSBYS or CIGS. LLWS should pick up as well to between 45 and 50 knots between roughly 06Z and 09Z. Some scattered (30 percent) -TSRA could linger from 09Z through 12Z at times, but only included a PROB30 due to the limited coverage of convection expected. MVFR CIGS will likely continue during that time and IFR CIGs/VSBYS could occur if that activity moves directly over either terminal. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...None. TN...None. && $$ NEAR TERM...KTW SHORT TERM....KTW LONG TERM....KTW AVIATION...KTW ####018004310#### FXUS64 KJAN 161958 AFDJAN Area Forecast Discussion National Weather Service Jackson MS 258 PM CDT Fri May 16 2025 ...New DISCUSSION... .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... (18Z TAFS) Issued at 1241 PM CDT Fri May 16 2025 VFR conditions along with a gusty 20-25kt sw-s wind WL prevail areawide this aftn. The gusty wind will gradually subside after 23Z and VFR conditions wl continue to prevail until after 08Z Sat when MVFR cigs wl redevelop. There is a low chance of VCTS across the north 10z-14Z and IFR cigs are psbl in the south by 10Z. Conditions wl begin to improve after 15Z and VFR conditions are expected areawide by 17Z. /22/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 73 90 71 90 / 30 40 20 10 Meridian 72 90 70 91 / 20 40 20 20 Vicksburg 73 90 72 91 / 30 30 20 0 Hattiesburg 74 93 72 93 / 0 20 10 0 Natchez 74 90 71 90 / 10 20 10 0 Greenville 71 89 72 89 / 70 20 40 20 Greenwood 71 90 71 90 / 70 20 40 30 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ 22/SW/22