Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 161226

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
626 AM CST Fri Feb 16 2018

.SHORT TERM...  (Through Late Tonight)
Issued at 342 AM CST Fri Feb 16 2018

A cold front was moving southward early this morning and will
likely have moved through the rest of the CWA before sunrise.
Today`s gusty northwest winds with highs in the 30s-40s will provide
a sharp contrast to yesterday`s record and near-record warmth.
Overnight lows should be in the 20s across the area.

Ongoing rain in the vicinity of the front will taper off through the
morning hours, and most areas should be dry by afternoon. There may
be some isolated pockets of a rain/snow mix at times this morning
due to the arrival of the colder air. Gusty northwest winds will
decrease this evening and then become southeasterly to southerly
very late tonight in response to a surface high pressure center
moving across MO/IA/IL.


.LONG TERM...  (Saturday through Thursday)
Issued at 342 AM CST Fri Feb 16 2018

The sfc ridge in control of the region Fri night quickly builds east
with sly flow returning to the area by Sat morning. Expect two areas
of precip on Sat. One along a weak cdfnt impacting nrn portions of
the CWA and the second associated with a leading s/w and WAA
impacting the srn portions of the CWA. P-type across the south shud
begin as snow as any WAA is countered with wetbulb effects. However,
this will gradually transition to rain as the low levels warm thru
the morning. Expect the ground to still be fairly warm and with
precip intensity expected to be fairly light, have kept snow accums
lower. Precip chances diminish fairly quickly during the afternoon
hours as the trof passes to the east.

With sly to swly flow at low levels on Sat and even more so on Sun,
have trended twd the warmer guidance, especially on Sun.

Warm trends continue on Mon with deep swly flow. Mdls suggest a slow
moving cdfnt pushing into the CWA late Mon night into Tues. This
front is expected to very slowly move south until the upper trof
finally pushes it south of the CWA by Wed morning. A number of
questions remain regarding this front. Among them, how much rain the
region will receive, chance for severe weather tho have continued
chance for thunder. After a clearly warm day on Mon, more
uncertainty exists for Tues and potentially even Wed. For now, have
trended twd a compromise for Tues, then twd cooler guidance for Wed.



.AVIATION...  (For the 12z TAFs through 12z Saturday Morning)
Issued at 556 AM CST Fri Feb 16 2018

SPECIFICS FOR KCOU, KUIN: MVFR cigs will persist for the next few
hours based on satellite and METAR trends. Widely scattered light
flurries are possible through approximately 15z. Initially gusty
northwest winds will diminish and become southeasterly by end of
the valid TAF period.

SPECIFICS FOR KSTL, KSUS, KCPS: MVFR cigs will persist during the
first 0-6 hours of the valid TAF period. VFR conditions are
expected after 18z. Initially gusty northwest winds will diminish
and become southeasterly by the end of the valid TAF period.





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