Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 192023
AFDLSX

Area Forecast Discussion
National Weather Service Saint Louis MO
323 PM CDT Fri Apr 19 2019

.SHORT TERM...  (Through Late Saturday Night)
Issued at 316 PM CDT Fri Apr 19 2019

The clouds have already cleared out parts of central and
northeast Missouri and west central Illinois as drier air is
advecting into the area at mid afternoon. Latest radar and surface
reports indicate that any light showers are confined to the far
southeastern part of the CWA at this hour as the upper trough axis
has shifted to into southeast Missouri and southwest Illinois.
This trough will continue to move east this evening which will
allow the low level clouds to clear the CWA by midnight.

Dry weather is still expected this weekend as the GFS/NAM continue
to show the upper low currently over the Mid South slowly moving
into the Mid Atlantic by Sunday at the same time a upper ridge
builds over the Midwest. This will allow large scale subsidence to
set up over the area at the same time a surface ridge axis moves
into the CWA on Saturday night. Northwest winds will remain
relatively brisk through midday Saturday before the pressure
gradient begins to relax by late in the day. Winds will turn out
of the south of on Sunday behind the ridge axis.

With clearing skies and the cold air advection, temperatures will
fall over into the upper 30s and lower 40s tonight.  There may be
some areas of frost over northeast Missouri where the winds will be
the lightest tonight.  Temperatures will begin to rebound tomorrow
as forecast sounding are showing deep mixing and 850mb temperatures
in the 5-8C range.  Lows on Saturday night will be warmer with most
locations only dropping into the mid-upper 40s.

Britt

.LONG TERM...  (Sunday through Next Friday)
Issued at 316 PM CDT Fri Apr 19 2019

Deterministic global models and GEFS mean are still in fairly good
agreement that surface front will be north of the area on Monday,
but then become stalled across Missouri and Illinois on Tuesday and
Wednesday.  Will keep with a chance of showers and thunderstorms
along the front Monday into Wednesday, with the best chance on
Tuesday into Wednesday. The front will then push south of the area
by Thursday before another front moves south into the area by
Friday. There is disparity between the ECMWF and the GFS/Canadian
solutions which lowers overall confidence in the forecast late in
the week. Will keep with just slight chances for showers and
thunderstorms late in the week.

Ensemble forecasts and low level model temperature forecasts favor
above normal temperatures Sunday and Monday ahead of the front and
then closer to normal Tuesday and Wednesday as the front moves into
the area with the chance of rain.  Temperatures are expected to
climb back above normal late in the week as the models are depicting
warm air advection.

Britt

&&

.AVIATION...  (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 1222 PM CDT Fri Apr 19 2019

Mainly dry and VFR conditions are expected through the period.
Clouds will clear out of the terminals this afternoon into the
early evening. Sustained northerly winds will decrease tonight and
gusts will diminish as high pressure builds into the area.

SPECIFICS FOR KSTL:

Dry and VFR conditions are expected through the period. Clouds will
clear out of the terminal by 00Z. Sustained northerly winds will
decrease overnight and gusts will diminish as high pressure
builds into the area.

Britt

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&

$$

WFO LSX


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