Area Forecast Discussion
Issued by NWS St. Louis, MO

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406
FXUS63 KLSX 031227
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
627 AM CST WED FEB 3 2016

.SHORT TERM:  (Through Late This Afternoon)
Issued at 311 AM CST Wed Feb 3 2016

Wrap-around type low level cloudiness will advect southeastward
through the entire forecast area this morning, southwest of
surface low moving northeastward through the Great Lakes region.
Although the radar echoes over western MO were weakening, there
may still be patchy drizzle or a few flurries this morning across
northeast and central MO and west central IL as embedded
shortwaves move through the upper level trough extending from MN
southwest into the Plains. Strong and gusty winds can be expected
today due to the tight surface pressure gradient between the
surface low over the Great Lakes region and the strong surface
ridge building eastward into the Plains. With low level cloudiness
and cold air advection temperatures will be nearly steady today,
much colder than yesterday.

GKS

.LONG TERM:  (Tonight through Tuesday)
Issued at 311 AM CST Wed Feb 3 2016

The low level clouds will shift east of our forecast area
tonight. This along with diminishing winds will lead to colder
lows tonight, although close to normal values for early February.
A warming trend will begin on Friday as the upper level trough
moves east of the region, and the surface ridge shifts southeast
of the area. A southern stream upper level trough may bring a
little patchy light snow to parts of the area late Friday night
and Saturday morning. More significant will be the deepening upper
level trough over the northern Plains on Sunday which will send a
cold front southeastward through our area Sunday night. Much
colder temperatures are expected Monday and Tuesday after a
relatively mild weekend with periods of light snow as the upper
level trough continues to deepen over or just east of our forecast
area. Although both the GFS and ECMWF models are similar with the
pattern, the GFS is deeper with the upper level trough/low over
the Great Lakes and Ohio Valley regions on Tuesday and forecasts
colder 850 mb temperatures down to -20 degrees C or less over
parts of our forecast area.

GKS

&&

.AVIATION:  (For the 12z TAFs through 12z Thursday Morning)
Issued at 601 AM CST Wed Feb 3 2016

Gusty wind will turn to the northwest this morning and MVFR
ceilings will prevail across most of the area today. Ceilings will
range from around 1200 FT to 2000 FT. Should see some improvement
this afternoon...but I`m not sure how much. There may also be some
drop again this evening before the clouds clear from the west.
Wind gusts should gradually diminish through the day.

Specifics for KSTL:

Expect ceiling to fall from VFR to MVFR within the next hour or
so. MVFR ceilings should then prevail through much of the day.
There may be some improvement this afternoon...and then a drop
again this evening before the clouds break up from the west before
06Z. Gusty southwest wind will turn to the northwest by mid to
late morning. Wind should diminish by early evening.

Carney

&&

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

$$

WFO LSX



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