Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 231647
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1047 AM CST Mon Feb 23 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 330 AM CST Mon Feb 23 2015

Temperatures this morning not quite as cold as originally
forecast, so wind chill numbers barely reaching criteria. But for
now will keep Wind Chill advisory going til expiration at 15z.
Otherwise, ridge will remain over region today with winds becoming
light and variable. Despite quite a bit of sunshine, especially
over north half of forecast area, highs will only be in the teens.

Byrd

.LONG TERM:  (Tonight through Sunday)
Issued at 330 AM CST Mon Feb 23 2015

Tonight surface ridge begins to move off to the south allowing
southerly winds to return once again. So will see temperatures
drop off rather quickly after sunset, then as winds pickup from
the south, temperatures to remain steady or rise overnight.

Temperatures to moderate on Tuesday ahead of cold front that will
move through Tuesday night. Highs will range from the low 30s far
east to the upper 30s along and west of Mississippi River. Cold
frontal passage will be a dry one with lows in the upper teens to
low 20s.

Then on Wednesday, models continue to show an upper level shortwave
approaching the region on the northwest flow. Clouds will be on the
increase with some light snow moving into northern portions of
forecast area by Wednesday afternoon and spread southeast across
rest of forecast area Wednesday night before exiting by daybreak on
Thursday. Moisture will be marginal with this system, so any
snowfall will be on the light side an inch or less with highest
amounts over northeast/central Missouri.

Surface ridge to build in on Thursday with another shot of colder
air. Highs Thursday and Friday will only be in the upper teens to
upper 20s both days.

Beyond that the extended models still have timing and placement
differences with system that will affect the area for the weekend.
For now precipitation will begin to move in on Saturday and spread
east across forecast area. It will initially start off as snow or a
mix of snow and rain, then as temperatures warm up through the rest
of the weekend, will see the snow mix with and change over to rain
at times.

Byrd

&&

.AVIATION:  (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 1017 AM CST Mon Feb 23 2015

Nly surface winds will become light later this afternoon in COU
and the St Louis metro area like they already have in UIN as the
surface high centered over north central MO moves southeastward.
The light wind will become s-swly later tonight and gradually
strengthen as the surface ridge shifts southeast of the taf sites.
A swly surface wind will continue to increase Tuesday morning as
the surface pressure gradient tightens with a weak cold front
approaching. Mainly just high level clouds this afternoon and
this evening. There may be some low level clouds in UIN around
18Z Tuesday along the weak cold front.

Specifics for KSTL: Nly surface wind will become light late this
afternoon. The light wind will become sly late tonight, albeit
still quite weak, then strengthen Tuesday morning from a swly
direction. Mainly just high level cloudiness this afternoon and
this evening. There may be some low level cloudiness Tuesday
afternoon as a weak cold front moves through with the wind veering
around to a wly direction.

GKS

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX





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