Area Forecast Discussion
Issued by NWS St. Louis, MO
Issued by NWS St. Louis, MO
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914 FXUS63 KLSX 082047 AFDLSX Area Forecast Discussion National Weather Service Saint Louis MO 347 PM CDT Wed May 8 2024 .KEY MESSAGES... - Scattered strong to severe thunderstorms will persist through early this evening. All hazards are expected: large hail, damaging winds, isolated tornadoes, as well as flash flooding. - A period of much needed calmer weather and cooler temperatures is expected to end the week and continue through the weekend. && .SHORT TERM... (Through Late Thursday Night) Issued at 344 PM CDT Wed May 8 2024 (Late This Afternoon Through Tonight) As of 3 pm, outflow from the activity continues to sink south and extends from just north of Springfield, MO to just south of Carbondale, IL. The warm sector along and south of the boundary remains quite unstable with MU CAPEs in excess of 3000 J/kg, ML lapse rates of 7-8C/km and 0-6km bulk shear 50-60kts. Also, the ongoing activity, over far southeastern sections of CWA, has congealed into a line with embedded supercells, while further west, in NWS Springfield`s area, discrete supercells are forming along the outflow boundary. These storms will slide east northeast moving into the southern portions of the CWA by 21z. Therefore, there remains a tornado threat as well as large hail possible. North of the outflow boundary, could see scattered strong to severe storms with the main threat being large hail. Otherwise, as the surface low over NE OK lifts northeastward it will drag a cold front eastward through the forecast area, with the precipitation tapering off from west to east. The front will exit the region by 05z Thursday. Still some concern for isolated flash flooding as some storms may train over the area, especially south of I-70. So will not make any adjustments to the Flash Flood watch at this time. Lows tonight will be in the low 50s to low 60s. (Thursday through Thursday Night) On Thursday, a secondary shortwave/cold front on the backside of the system will slide southeast through the region. So expect increasing clouds, especially north of I-70. Otherwise, there will be enough moisture and weak instability to generate scattered showers and a few thunderstorms over portions of northeast Missouri and west central Illinois late morning through early evening. Otherwise, highs on Thursday will be near normal in the upper 60s to upper 70s. Lows Thursday night will be in the upper 40s to low 50s. Byrd && .LONG TERM... (Friday through Next Wednesday) Issued at 344 PM CDT Wed May 8 2024 Cooler and drier weather through the rest of the work week and into the weekend. Beyond that, upper level trough over the western CONUS will begin to lift out towards the region with chances of showers and storms late on Sunday through mid week. Still a lot of timing, strength and location differences among the ensembles and deterministic models, so stuck with the latest NBM solution. Temperatures will moderate through the period with highs in the mid 70s to low 80s. Byrd && .AVIATION... (For the 18z TAFs through 18z Thursday Afternoon) Issued at 1252 PM CDT Wed May 8 2024 Severe storms staying south of TAF sites at this time, but could see storms move through St. Louis metro area TAFs between 18z and 00z Thursday. For KCOU and KJEF, just kept vicinity shower/storm mention through the afternoon hours. With the stronger storms could see brief periods of MVFR ceilings and visibilities, otherwise VFR flight conditions. By this evening as cold front moves through, winds will veer to the southwest to west by 05z Thursday at KCOU and KJEF and by 07z Thursday at KUIN and St. Louis metro area TAF sites. Also, wrap around MVFR ceilings will move into KUIN by 03z Thursday and persist through the remainder of the forecast period. Winds will pickup by mid morning from the northwest with gusts up to 25 kts at times. Byrd && .LSX WATCHES/WARNINGS/ADVISORIES... MO...Flood Watch until midnight CDT tonight for Cole MO-Crawford MO- Franklin MO-Gasconade MO-Iron MO-Jefferson MO-Madison MO- Moniteau MO-Osage MO-Reynolds MO-Saint Francois MO-Saint Louis City MO-Saint Louis MO-Sainte Genevieve MO-Washington MO. IL...Flood Watch until midnight CDT tonight for Monroe IL-Randolph IL- Saint Clair IL. && $$ WFO LSX