Area Forecast Discussion
Issued by NWS St. Louis, MO
Issued by NWS St. Louis, MO
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383 FXUS63 KLSX 221118 AFDLSX Area Forecast Discussion...Updated Aviation National Weather Service Saint Louis MO 618 AM CDT Sun Sep 22 2024 .KEY MESSAGES... -There will continue to be chances for showers and thunderstorms through Tuesday. -Isolated severe storms are possible over southeast Missouri and southwest Illinois this afternoon and early this evening. The primary threat with the strongest storms will be damaging winds. -Temperatures will cool down behind a cold front today with below normal highs on Monday and Tuesday. && .SHORT TERM... (Through Late Monday Afternoon) Issued at 403 AM CDT Sun Sep 22 2024 Initial round of showers and thunderstorms is moving through the CWA this morning ahead of the cold front in a band of strong low level moisture convergence. This first round will eventually exit to the east by mid-morning as the low level jet veers and weakens. There will continue to be lesser chances (30-50%) for showers and thunderstorms this afternoon into this evening as the cold front that is currently over southeastern Iowa and northwest Missouri will move southeast across the CWA. There still remains the possibility for one or two storms to produce damaging microbursts over southeast Missouri into southern Illinois this afternoon and early this evening given MLCAPES around 1500 J/kg and deep layer shear around 30 knots. There will be some potential for locally heavy rainfall given that PWATS will be in the 1.6-2" range today, especially where any storms can train for very long. The chance for showers and thunderstorms will begin to increase again late tonight into Monday, particularly over the southern half of the CWA. Lift will increase across Missouri and Illinois as the HREF is showing an upper trough moving into the area from the west. Have kept higher PoPs (60-80%) over the southern half of the CWA where the stronger forcing and the best moisture transport will move into the area late tonight into tomorrow afternoon. There will be quite a range in highs today with the front and rain, ranging from near 70 over the north to the middle 80s in the south. Highs tomorrow will be below normal across the CWA with cold air advection behind the front, the clouds, and rain chances. Britt && .LONG TERM... (Monday Night through Saturday) Issued at 403 AM CDT Sun Sep 22 2024 There is decent agreement amongst the medium range models that upper trough will drop down into the Midwest behind Monday`s trough which will keep showers and thunderstorms going over the area Monday night into Tuesday. Some solutions show an upper low cutting off over the Midwest into late week which would keep a chance (20-30%) of showers going over the CWA Thursday into Saturday. Temperatures will still be below normal on Tuesday, but will climb back to near normal the rest of the week. Britt && .AVIATION... (For the 12z TAFs through 12z Monday Morning) Issued at 611 AM CDT Sun Sep 22 2024 A round of showers and thunderstorms will move through the terminals through 15Z bringing MVFR and some IFR conditions along with occasional moderate to heavy rainfall. These conditions will move out of the area by mid morning leaving most of the rest of the day mainly dry with just of chance (20-40%) of additional showers and thunderstorms. Confidence in timing is too low to include in the TAFs at this time. There is reasonable confidence to include additional thunderstorms at COU/JEF after 06Z tonight. Additional thunderstorms will also be possible after 12Z at STL tomorrow. After conditions will improve to VFR today, ceilings are expected to go back to MVFR tonight. Britt && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX