Area Forecast Discussion
Issued by NWS St. Louis, MO

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103
FXUS63 KLSX 261121
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
621 AM CDT MON SEP 26 2016

.SHORT TERM...  (Through Late Tonight)
Issued at 317 AM CDT Mon Sep 26 2016

Northeast to southwest oriented frontogenetical band of rain
currently over the central CWA will push southeast of the area early
this morning as the shortwave trough moves through the region.
Expect clouds to move out of the region this morning because of the
dry air advection.  Today will be much cooler because of the cold
air advection.  Went close to the GFS MOS highs which are in the
lower 70s.

Expect clear skies tonight with light westerly winds.  Clear skies,
a light west wind, and a dry air mass will help temperature fall to
near the agreeable MOS lows.  Can`t rule out some steam fog near the
rivers, though with the dry airmass, think fog will stay close to
the rivers and won`t introduce it into the forecast at this time.

Britt

.LONG TERM...  (Tuesday through Sunday)
Issued at 317 AM CDT Mon Sep 26 2016

Northwest flow aloft will dominate the weather pattern over the Mid-
Mississippi Valley at least through the end of the week and probably
through next weekend as well.  The upper level low over the Great
Lakes on Tuesday morning will meander south into the Ohio Valley by
Wednesday night and further southeast into the Mid Appalachian
region by Thursday afternoon and evening.  This will force the only
"exciting" weather of the week to occur as a strong lobe of
vorticity rotates around the low which will drive a reinforcing
surface cold front south through the area on Wednesday.  There will
be little if any moisture return ahead of this reinforcing shot of
cool air, so current thinking is that the front will go through dry.
A sprawling ridge of high pressure stretching from southern Texas
through south central Canada will dominate the surface pattern for
the rest of the week and into the weekend.  Should make for
spectacular Fall weather with highs mainly in the low to mid 70s and
lows in the upper 40s to mid 50s.

Carney

&&

.AVIATION...  (For the 12z TAFs through 12z Tuesday Morning)
Issued at 621 AM CDT Mon Sep 26 2016

Dry and VFR conditions are expected at the terminals through the
period. Rain has now moved southeast into southern Illinois and
southeast Missouri.  There may be some steam fog development late
tonight and early Tuesday near area rivers, but confidence is too
low at this point that it will affect any of the TAF sites because
of the low humidity.

SPECIFICS FOR KSTL: Dry and VFR conditions are expected over the
next 30 hours.

Britt

&&

.FIRE WEATHER...
Issued at 317 AM CDT Mon Sep 26 2016

12-15 mph wind and minimum relative humidity below 30 percent
will combine with dry fuels to produce elevated fire danger across
parts of northeast Missouri and west central Illinois this
afternoon. Increasing fuel moisture to the south and southeast
should mitigate the fire danger across the rest of the area.

Carney


&&

.PRELIMINARY POINT TEMPS/POPS...
Saint Louis     72  56  75  54 /  10   0   0   0
Quincy          71  50  72  50 /   0   0   0   0
Columbia        71  51  75  52 /   0   0   0   0
Jefferson City  72  51  76  51 /   0   0   0   0
Salem           72  50  74  51 /  20   0   0   5
Farmington      71  49  75  52 /  20   0   0   0

&&

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

$$

WFO LSX



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