Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 110541
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1141 PM CST Sun Dec 10 2017

.SHORT TERM...  (Through Late Monday Afternoon)
Issued at 323 PM CST Sun Dec 10 2017

Skies were mostly sunny across the area this afternoon.  A warm
front has moved east of the area allowing temperatures to warm into
the the upper 40s and lower 50s.  Winds are expected to back
southwesterly tonight ahead of a cold front that will move across
the area during the day on Monday.  There will be some increase in
mid-high clouds late tonight ahead of the next shortwave trough that
is moving southeast in the northwesterly flow aloft. Skies will
turn partly sunny by tomorrow, but expect a mainly dry passage of
the attendant cold front as there will be limited moisture for the
shortwave to work with. Lows tonight will be close to mid
December normals. Highs tomorrow will climb above normal ahead of
the cold front as there will be deep mixing ahead of the front and
850mb temperatures are around +5C.

Britt

.LONG TERM...  (Monday Night through Next Sunday)
Issued at 323 PM CST Sun Dec 10 2017

The upper flow pattern this week will continue to be dominated by
northwesterly flow aloft with weak shortwaves moving across the
area. The first shortwave will be the one that will move through
on Monday. Both the ECMWF and GFS show a second one with an
attendant cold front crossing through MO/IL late Wednesday with
another one late Thursday. By next weekend, the GFS/ECMWF are
showing the eastern CONUS longwave moving off to the east and a
trough setting up in the Plains. This may be enough for just a
slight chance of precipitation over parts of the area on Saturday
night.

With northwesterly flow aloft this week, expect temperatures to be
at or below normal.  850mb temperatures this week will fall to -10C
or lower at times.  May see temperatures to climb back above normal
by next weekend when upper flow turns back out of the southwest.

Britt

&&

.AVIATION...  (For the 06z TAFs through 06z Monday Night)
Issued at 1137 PM CST Sun Dec 10 2017

VFR flight conditions will prevail overnight through early Monday
afternoon with periodic waves of mid-high clouds in the northwest
flow aloft. Surface winds will be light and back to southwesterly
overnight, and then increase and becoming gusty from the west-
southwest on Monday morning as a surface trof moves east. In the
wake of the surface trof, a potent cold front will move
southeastward during the afternoon accompanied by lowering cigs
and gusty northwest winds. The gusty northwest winds will persist
into the evening. MVFR flight conditions/cigs will spread from
northwest to southeast across the area during the later afternoon
and through the evening.

SPECIFICS FOR KSTL:

VFR flight conditions will prevail tonight through Monday afternoon
with periodic waves of mid-high clouds in the northwest flow aloft.
Surface winds will be light and back to southwesterly overnight,
and then increase and becoming gusty from the west-southwest on
Monday morning as a surface trof moves east. In the wake of the
surface trof, a potent cold front will move through the terminal
in the early afternoon accompanied by lowering cigs and gusty
northwest winds. MVFR flight conditions/cigs will move into KSTL
on Monday evening with gusty northwest winds continuing.

Glass

&&

.FIRE WEATHER...
Issued at 323 PM CST Sun Dec 10 2017

There will be an heightened fire danger over parts of central,
east central, and southeast Missouri on Monday afternoon.
Temperatures are expected to climb to around 60 while the minimum
relative humidity falls below 30 percent and sustained winds will
be between 12-15 mph with higher gusts.

Britt


&&

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

$$

WFO LSX



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