Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 081143

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
543 AM CST Fri Dec 8 2017

.SHORT TERM...  (Through Late Tonight)
Issued at 236 AM CST Fri Dec 8 2017

Not a lot of changes thru tonight. Large upper trof over the
region moves south of the area this afternoon as another upper
trof and associated sfc cdfnt approaches the area. Widespread
clouds are expected to move into the area ahead of this trof.

With mid and high clouds, do not anticipate precip until late
tonight as the main trof digs into the area with lower clouds.
Still believe the accumulating snow will remain east of the CWA.
However, flurries will be possible across much of the CWA late
tonight into Sat morning.

Despite the extensive cloud cover today, expect strong WAA with
swly to wly winds thru lower levels. Have therefore still trended
twd the warmer guidance for today. With the cdfnt pushing thru the
area tonight, have trended cooler across nrn half of the CWA, but
kept twd the warmer guidance elsewhere with front arriving shortly
before sunrise.


.LONG TERM...  (Saturday through Thursday)
Issued at 236 AM CST Fri Dec 8 2017

Upper pattern doesn`t change much overall with NW flow remaining
over the region thru the end of the forecast period. This is
thanks to a blocking event over the wrn U.S. However, a number of
embedded s/w will continue to drop south across the region.
Confidence in any given s/w beyond about 48 hrs is low as small
changes in timing can have large impacts on temps on either side
of the front.

Have expanded the mention of flurries further west Sat morning
with cold temps aloft and anticipated cloud cover given the
cyclonic flow. Clouds shud move out of the area fairly quickly Sat
afternoon leaving a clear sky by Sat night.

Focus then turns to the warm up on Sun and especially Mon. Mdls
are still depicting two separate shortwaves. While the more
wrn s/w will drop into the area, much of the moisture available is
expected to be depleted before reaching the area. Mdls continue
to show another s/w around Wed and another still Thurs and into
Thurs night. Have continued a dry forecast thru the period.

As for temps, have trended warmer for Sun and Mon with good
agreement of SW flow and strong WAA across the region. With lower
confidence in timing beyond Mon, have trended twd a compromise
thru the end of the period.



.AVIATION...  (For the 12z TAFs through 12z Saturday Morning)
Issued at 528 AM CST Fri Dec 8 2017

VFR and dry thru this evening. High and mid clouds will move into
the region today. A strong cold front will push through the region
late tonight. Winds will become nwly with this front. The front
will also bring MVFR cigs as well as a chance of flurries.



Saint Louis     43  27  34  23 /   0  10  10   0
Quincy          38  22  30  20 /   5  10  10   0
Columbia        40  24  35  22 /   5   5   5   0
Jefferson City  42  25  36  22 /   5   5   5   0
Salem           38  24  34  20 /   0  10  10   0
Farmington      40  25  35  20 /   0  10  10   0




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