Area Forecast Discussion
Issued by NWS St. Louis, MO

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000 FXUS63 KLSX 062338 AFDLSX Area Forecast Discussion...Updated Aviation National Weather Service Saint Louis MO 538 PM CST Sat Mar 6 2021 .SHORT TERM... (Through Late Sunday Night) Issued at 223 PM CST Sat Mar 6 2021 A warming trend will continue through the remainder of the weekend as the surface ridge extending from WI southwest into southeastern MO shifts eastward with strengthening south-southwest winds on Sunday as the surface pressure gradient tightens. Upper level heights will also be rising as the upper level ridge over the Plains moves eastward into MO. Went warmer than NBM for highs on Sunday as it has been consistently under-performing on maximum temperatures this past week. Highs on Sunday will be about 15 to 20 degrees above normal for early March. GKS .LONG TERM... (Monday through Next Saturday) Issued at 223 PM CST Sat Mar 6 2021 The warming trend will continue through Wednesday with an upper level ridge over the central US and persistent south-southwest surface/low level winds. Used the 75th percentile of model certainty for highs Monday through Wednesday. Nighttime lows will also be quite mild with surface dew points on the rise. By Tuesday night lows will be around 25 degrees above normal. A more active weather pattern will commence on Wednesday as low-mid level warm air advection increases ahead of southwest flow shortwaves. This will be coupled with increasing low level moisture and instability as we begin to tap Gulf moisture. The best chance of convection Wednesday night will be across northeast MO and west central IL along a cold front which will be dropping slowly southeastward into our area. The chance of showers and a few storms will increase across southeast MO and southwest IL Thursday and Thursday night as this front shifts slowly southward through our forecast area with the best coverage along and just behind the front. Will start to see a cooling trend across northeast MO and west central IL by Thursday and Thursday night due to low level cold air advection behind the front. There is still plenty of model inconsistency with the progression of this front leading to a large spread in the NBM temperatures by the end of the work week. The trend of cooler temperatures will continue into Saturday for the entire forecast area, but there is low confidence on the precipitation forecast beyond Friday. GKS && .AVIATION... (For the 00z TAFs through 00z Sunday Evening) Issued at 537 PM CST Sat Mar 6 2021 Dry and VFR flight conditions are expected to persist through the TAF period with only scattered mid-level clouds at times, especially during the day Sunday. Otherwise, light and variable winds tonight will increase and become southerly to south-southwesterly by Sunday afternoon with a few gusts approaching 20 kt possible at KCOU and KUIN. Pfahler && .FIRE WEATHER... Issued at 223 PM CST Sat Mar 6 2021 Elevated fire danger can be expected across central and eastern MO Sunday afternoon, and across central and southeast MO...along and south of I-70 Monday afternoon. This is due to winds increasing to around 12 to 15 mph across this area coupled with minimum afternoon relative humidity of 25 to 30 percent, and 10 hour fuel moisture of only 8 to 10 percent. GKS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX

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