Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 231041

441 AM CST MON NOV 23 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 245 AM CST Mon Nov 23 2015

Winds become SW to W today around the back side of a retreating
high. Mostly clear skies and W to SW winds will help temperatures
warm into the upper 40s to mid 50s today.


.LONG TERM:  (Tonight through Sunday)
Issued at 245 AM CST Mon Nov 23 2015

Warming trend continues over the next few days, especially after
winds turn southerly tonight/tomorrow and an upper ridge
moves over the central CONUS. A lead shortwave trough undercuts
the ridge on Tue/Wed, and lift associated with this feature could
bring a slight chance of rain to the area on Wed. Southerly winds
also begin to draw moisture northward into the region, which will
become important for sensible wx trends over Thanksgiving and
Thanksgiving weekend.

Latest model runs depict a large and complex low pressure system
dropping down the west coast and closing off somewhere between CA
and UT. This feature induces SW flow aloft over MO/IL downstream.
A northern stream shortwave moves across the upper Midwest on
Thu/Fri, and models show a 1040+ hPa high sliding out of Canada
into the plains behind it. This will act to sharpen the
temperature contrast across the cold front associated with the
northern stream shortwave. Baroclinicity, moisture return, broad
and sustained isentropic ascent, and RER jet dynamics all point to
pcpn for Thu/Fri. The arrival of colder air behind the front may
change some of the rain to a wintry mix at times. At some point,
the large cutoff low over the southwestern quadrant of the CONUS
will eject eastward, bringing additional pcpn chances to MO/IL
either over the weekend or early next week.



.AVIATION:  (For the 12z TAFs through 12z Tuesday Morning)
Issued at 436 AM CST Mon Nov 23 2015

VFR conditions expected through this TAF period. Light west to
southwest winds will become variable tonight. Cirrus will begin to
move in late tonight.

Specifics for KSTL: VFR through the period. Light west to
southwest winds will become variable early this evening...then
light southeasterly after around 15Z on Tuesday. Cirrus deck will
move in and thicken Teusday morning.





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