Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 132050
AFDLSX

Area Forecast Discussion
National Weather Service Saint Louis MO
250 PM CST Wed Dec 13 2017

.SHORT TERM...  (Through Late Thursday Afternoon)
Issued at 247 PM CST Wed Dec 13 2017

Main impact for tonight will be gusty winds over the area through
the evening. There have already been observed gusts over 45 mph in
central Missouri and western Illinois this afternoon. A Wind
Advisory has been posted through part of the evening for parts of
northeast Missouri and western Illinois. A cold front located just
north of the Interstate 70 corridor will continue to push southeast
and clear the region by the middle of this evening.  The gusty winds
will continue overnight behind the cold front then decrease around
sunrise over the entire area as the trough moves away from the area
and a ridge of high pressure moves over the region. Temperatures
will be slightly below normal in the upper 30s on Thursday.

Kelly

.LONG TERM...  (Thursday Night through Next Wednesday)
Issued at 247 PM CST Wed Dec 13 2017

A decent shortwave/cold front to slide southeast through region late
Thursday night/Friday morning. Little in the way of moisture
associated with it, but could see some flurries after midnight
Thursday night for portions of northeast MO and west central IL.
Otherwise, another cold night with lows in the low to mid 20s.

By Friday, despite passage of cold front, not a lot of CAA
associated with it and winds will back to the west to southwest as
weak surface ridge builds in. So will see partly sunny skies and
highs in the upper 30s to mid 40s.

Upper ridge to build in Friday night/Saturday, allowing southwest
winds to bring in decent WAA for first half of weekend. Lows
Friday night will be in the mid 20s to low 30s, while highs on
Saturday will be in the upper 40s to upper 50s.

Extended models having major differences on timing and strength of
next system that will affect area beginning late Saturday night
through Sunday. ECMWF remains a bit faster with system than GFS.
Kept initial blend, which backed off on pops after 06z Saturday, but
ramped them up Sunday morning, before tapering off Sunday afternoon.
As for precipitation type, should be mostly rain, though would not
be surprised to see a few flakes mixed in around sunrise on Sunday.

Beyond the weekend, the extended models really diverge in their
solutions for first part of work week. So for now went with the
warmer solution with highs about 10 degrees above normal for this
time of year. Could see another system move through on Tuesday, but
for now kept slight chance pop mention for portions of area.

Byrd
&&

.AVIATION...  (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1128 AM CST Wed Dec 13 2017

Gusty northwest winds will continue to increase with gusts up to
40 knots possible over parts of northeast Missouri and western
Illinois from 18z through 06z. VFR ceilings will give way to MVFR
ceilings with cold front pushing southeast with a wind shift
through the region this afternoon and evening. There is some
uncertainty as to how far south MVFR ceilings will travel south of
the terminals before ceilings lift to VFR around sunrise and
winds will also begin to decrease rapidly.

SPECIFICS FOR KSTL:

Gusty southwest winds will persist over the terminal through 00z
before turning to a more northerly component and decreasing around
04z. Dry and VFR ceilings and conditions will give way to MVFR
ceilings around 04z. MVFR ceilings will likely lift to VFR around
08z with winds continuing to decrease through Thursday afternoon.

Kelly

&&

.PRELIMINARY POINT TEMPS/POPS...
Saint Louis     26  37  26  45 /   0   0   5   5
Quincy          22  34  23  39 /   0   0  10  10
Columbia        25  37  25  43 /   0   0   5   5
Jefferson City  26  38  26  43 /   0   0   5   5
Salem           24  36  24  40 /   0   0   5   5
Farmington      27  37  23  43 /   0   5   5   5

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...Wind Advisory until 9 PM CST this evening for Knox MO-Lewis MO.

IL...Wind Advisory until 9 PM CST this evening for Adams IL-Bond IL-
     Brown IL-Clinton IL-Fayette IL-Greene IL-Macoupin IL-Marion
     IL-Montgomery IL-Pike IL-Washington IL.

&&

$$
WFO LSX


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