Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 152322

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
522 PM CST Wed Feb 15 2017

.SHORT TERM...  (Through Late Thursday Afternoon)
Issued at 255 PM CST Wed Feb 15 2017

Sfc ridge axis is expected to move thru the CWA tonight. As it does,
winds will become light and SW as the ridge passes. A clear sky will
allow temps to drop. With swly winds returning to the area, expect
temps to become steady or even rise slightly. Still, with very low
dewpoints, have trended aob the cooler guidance for tonight.

For Thurs, a wrmfnt is expected to lift nwd thru the area bringing
much warmer temps and gusty SW winds. With deeper mixing expected,
just above 900mb, have trended aoa the warmer guidance. However,
this also presents other concerns. While some moisture return is
expected, this will be somewhat offset by the deeper mixing.
Overall, believe much of the 2m dewpoints from mdls are too high and
have trended aob the cooler guidance.

These conditions combined are borderline Red Flag Warning conditions
for the CWA. Since the CWA has received little if any precip for the
entire month of Feb, dry fuels are a given. While there is some
question regarding wind speeds and amount of moisture return for
Thurs, have issued a Red Flag Watch for wrn and central portions of
the CWA.


.LONG TERM...  (Thursday Night through Next Wednesday)
Issued at 255 PM CST Wed Feb 15 2017

Even though surface ridge is off to the east Thursday night, upper
ridge to build into region. So warm and dry conditions to persist
with southwest winds. Lows will be in the upper 30s to low 40s.

Above normal temps to continue through the weekend with highs in the
mid 60s to low 70s. Models are still showing an upper level
shortwave over the panhandle of Texas becoming cutoff and slowly
lifting to the east northeast, just south of forecast area. So will
just see increasing clouds beginning Friday night, along and south
of I70, but rain chances to stay south of region through the

Then upper ridge to build back in for last half of weekend and allow
temps to remain well above normal through beginning of work week.
Extended models still showing a wet pattern to setup for Monday
through Wednesday, but remain stingy with the qpf.



.AVIATION...  (For the 00z TAFs through 00z Thursday Evening)
Issued at 522 PM CST Wed Feb 15 2017

VFR conditions and dry wx will prevail at the TAF sites thru the
valid period. NW surface winds will become light and variable
overnight as a RIDGE passes thru, but already will become
southerly by late tonight and strengthen some during the day on
Thursday in response to a tightening gradient. Marginal LLWS
exists for Thursday night and will take another look at it with
the next issuance, but for now, left out of the 30-hour KSTL TAF.



Issued at 255 PM CST Wed Feb 15 2017

Conditions are looking better for a Red Flag Warning on Thursday
afternoon, so after coordination have issued a Red Flag Watch for
portions of the area. Will see sustained winds of 15-20 mph with
gusts up to 25 mph, relative humidities around 20 to 25 percent,
and dry fuels. Watch area is along Missouri River basin from
Lincoln, Warren and Franklin counties and areas to the west.



Issued at 318 AM CST Wed Feb 15 2017

Record Highs

     2/17  2/18  2/19  2/20
STL: 77    74    77    78
COU: 74    71    76    76
UIN: 70    68    71    72


MO...Fire Weather Watch from Thursday morning through Thursday
     afternoon for Audrain MO-Boone MO-Callaway MO-Cole MO-
     Franklin MO-Gasconade MO-Lincoln MO-Moniteau MO-Montgomery
     MO-Osage MO-Warren MO.



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