Area Forecast Discussion
Issued by NWS St. Louis, MO
Issued by NWS St. Louis, MO
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795 FXUS63 KLSX 230441 AFDLSX Area Forecast Discussion...Updated Aviation National Weather Service Saint Louis MO 1041 PM CST Fri Nov 22 2024 .KEY MESSAGES... -Dry weather is expected through the weekend with moderating temperatures. -Temperatures are expected to turn colder for Thanksgiving week. There is chance of rain Wednesday into Thursday with the possibility of snow mixing in. && .SHORT TERM... (Through Late Saturday Night) Issued at 215 PM CST Fri Nov 22 2024 The low clouds have persisted across the area today in the low level cyclonic flow. There have been some breaks showing up in the visible satellite imagery, but areas that don`t clear out late this afternoon could very well stay cloudy tonight because of the long nights this time of year. The HREF is showing the low level flow turning out of the southwest late tonight into tomorrow which will lead to the clouds breaking up from west to east late tonight into tomorrow morning. The HREF probabilities continue to favor dry weather through Sunday as an upper ridge builds into the area. Lows will drop to near normal tonight with the coolest readings over central and southeast Missouri where it is most likely to clear out. Highs on Saturday will be near normal with skies clearing out and winds turning out of the west and then climb back above normal on Sunday with southwesterly low level flow and 850mb temperatures climbing to around +10C. Britt && .LONG TERM... (Sunday through Next Friday) Issued at 215 PM CST Fri Nov 22 2024 We will go into a more active pattern next week leading up to Thanksgiving. There is still agreement in model guidance that a cold front will move through the CWA on Monday and that this front will stay south of the area the rest of the week. This front will bring a chance (20-40%) of rain as it moves across the area Sunday night into Monday. There will be strong cold air advection behind this front with lows falling below normal the rest of the week. It now looks like the Monday night through Tuesday night will be dry before a second upper trough will approach the area from the Rockies. I have kept with the NBM`s precipitation chances Wednesday through Thanksgiving Day has the upper trough moves through the area. This is when some of the operational models are showing good synoptic forcing setting up across Missouri and Illinois including a coupled jet and mid level frontogenesis. NBM and LREF precipitation probabilities are favoring the best chances (50-60%) over southeast Missouri and southern Illinois on Wednesday night, but this system is several days out and may very well shift to north or south as the forecast becomes clearer in the next few days. The LREF does have some members that are producing snowfall with this second system and the latest NBM probabilities showing about 20-30% chance of snowfall Wednesday night into Thursday over parts of the CWA. Britt && .AVIATION... (For the 06z TAFs through 06z Saturday Night) Issued at 1033 PM CST Fri Nov 22 2024 The stratus has cleared eastward this evening and the back edge seems to be holding quasi-steady from near KUIN to southwest of the St. Louis region. The trends overnight are unclear, and I have leaned on the pessimistic side maintaining the stratus at KUIN and KSUS/KSTL/KCPS overnight into Saturday morning. I think KUIN is on the cusp of IFR cigs and I can`t rule out that some of the St. Louis metro terminals may fall at times from MVFR to IFR. Otherwise these clouds should clear to the east with flight conditions becoming VFR between 15-16z. Further west at KCOU and KJEF, there are some high clouds that will impact these terminals overnight but I still think some fog development will occur with visibilities possibly dropping to IFR. The fog should dissipate by 15-16z with VFR thereafter. Glass && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX