Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 062338

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.


.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.



.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



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.





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