Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 011726
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1126 AM CST Thu Dec 1 2016

.SHORT TERM...  (Through Late Tonight)
Issued at 300 AM CST Thu Dec 1 2016

Clouds, and resultant temps, will again be the focus for today and
tonight.

Area of stratus trapped under cyclonic flow of the stacked low over
Great Lakes region will continue to spread esewd this morning.
Expect diurnal CU to develop along the periphery of the cloud deck
which shud be slow to burn off this evening. This area of clouds is
expected to slowly move nwd tonight. Additionally, expect an area of
mid clouds to develop over the KS/OK region and spread into the srn
portions of the CWA tonight.

Otherwise, winds will remain wly with gusts to around 20 kts today.
With a much more relaxed pressure gradient tonight, expect winds to
diminish shortly after sunset as the low system pulls out of the
region and a sfc ridge builds into the area.

Have therefore trended twd the cooler guidance today across the
region. There is a fair amount of uncertainty for temps tonight as a
brief period of a clear sky with light winds will allow temps to
drop quickly. Despite increasing cloud cover expected, have trended
twd cooler guidance overnight.

Tilly

.LONG TERM...  (Friday through Wednesday)
Issued at 300 AM CST Thu Dec 1 2016

Surface ridge to remain over region on Friday with dry and partly
sunny conditions expected. Highs will be near normal in the low 40s
to low 50s.

In the meantime, system over the southwestern US continues to
strengthen. First in a series of shortwaves to lift northeastward
towards forecast area by Friday night/Saturday morning, trying to
phase with northern stream system. Clouds and moisture will be on
the increase. Light rain to develop and spread northward across the
region by Saturday night. Surface temperatures look to be a bit
warmer than previously forecast, so precipitation will mainly be in
the form of rain with some snow mixed in at times late Saturday
night/early Sunday morning. So no accumulation expected. Rain to
taper off by Sunday afternoon.

Dry and near normal temperatures to persist on Monday, as main
system lifts out towards forecast area, phasing with another
northern stream system. Precipitation chances will be on the
increase once again by Monday afternoon, with best chances Monday
night. Lows will be in the mid to upper 30s, so could see a few
flakes mixed in, before tapering off Monday morning.

Beyond that, active pattern to continue as next system strengthens
on lee side of Rockies and moves in by Wednesday.

Byrd

&&

.AVIATION...  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1105 AM CST Thu Dec 1 2016

MVFR conditions for the start of the period trending toward VFR
this evening. KUIN and KSTL remain MVFR through late this
afternoon into this evening with VFR conditions after. Westerly
wind with gusts near 20kts during the early part of the period.
VFR conditions tomorrow with increasing mid to high level clouds
with westerly winds around 5 to 10kts.

SPECIFICS FOR KSTL:
MVFR ceilings scatter out around 19z. VFR conditions through the
rest of the forecast period. Westerly winds with gusts around
20kts this afternoon. Increasing mid to high clouds tonight into
tomorrow.

Walsh

&&

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

$$

WFO LSX


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