Area Forecast Discussion
Issued by NWS St. Louis, MO

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS63 KLSX 011148

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
548 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

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.


.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.



.AVIATION...  (For the 12z TAFs through 12z Friday Morning)
Issued at 529 AM CST Thu Dec 1 2016

Area of MVFR clouds is expected to move ely to esely today.
There is some uncertainty regarding arrival times due to diurnal
CU development along the periphery of the cloud deck. As for
KCOU, currently do not expect clouds to become bkn, however, can
not rule out due to CU development.

Winds will remain wly today with gusts to around 20 kts thru much
of the afternoon. Winds will diminish quickly with sunset this
afternoon and remain light overnight.





WFO LSX is the U.S. government's official web portal to all federal, state and local government web resources and services.