Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 181156
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
656 AM CDT Sun Jun 18 2017

.SHORT TERM...  (Through Late Tonight)
Issued at 250 AM CDT Sun Jun 18 2017

Complex of thunderstorms that moved across much of the area has
pushed southeast of the CWA as the cold front continues to move to
the southeast. Lingering showers and a few thunderstorms will be
possible through midday over the southeast half of the CWA as there
will still be some ascent ahead of mid-level trough that will move
across Missouri and Illinois later in the day.  Clouds will clear
out slowly today and there will be some cold air advection which
will allow for cooler temperatures than yesterday. A blend of MOS
highs look good for today.

Skies will turn mostly clear behind the mid level trough axis
tonight.  With light westerly winds tonight and limited clouds,
temperatures should be able to fall to the agreeable MOS lows
near 60 degrees.

Britt

.LONG TERM...  (Monday through Saturday)
Issued at 250 AM CDT Sun Jun 18 2017

Looks like a period of quieter weather for the area through the
middle of next week.  High pressure at the surface and northwest
flow aloft through Tuesday should keep temperatures near normal with
lower humidity than we`ve had the past few days.  The high will
drift east of the area on Wednesday and southerly flow will bring
higher humidity and warmer temperatures back to the area.  GFS and
ECMWF both develop a low level jet Wednesday night as the next
upstream trof strengthens over the Great Plains and the associated
850mb moisture convergence forces some nocturnal convection over
western and northern portions of the CWFA late Wednesday night.

Medium range models diverge toward the end of the week with the GFS
developing a deeper longwave trof over the central CONUS than the
ECMWF toward the end of the week.  This makes the GFS faster in
shifting a cold front southeast through the Plains into the Midwest
than the ECMWF.  The result is that Friday and Friday night are
wetter on the GFS as the front moves through while the ECMWF is
warmer and wetter on Saturday.  Stuck closer to ensemble forecasts
which lean toward the GFS that far out with likely PoPs Friday night
and a mostly dry and cooler Saturday.

Carney

&&

.AVIATION...  (For the 12z TAFs through 12z Monday Morning)
Issued at 643 AM CDT Sun Jun 18 2017

A cold front will move southeastward through the St Louis metro
area early this morning with the surface wind veering around to a
west-northwest direction after fropa. A few light showers will
move through COU and the St Louis metro area early this morning.
There may also be a brief period of MVFR cig heights. Only VFR
cloudiness is expected this afternoon, then little if any
cloudiness tonight. The wind will become light this evening with
surface ridging centered over southwestern MO.

SPECIFICS FOR KSTL: A cold front will move southeastward through
the STL area early this morning with the surface wind veering
around to a west-northwest direction after fropa. A few light
showers will move through STL early this morning. There may also
be a brief period of MVFR cig heights. Only VFR cloudiness is
expected this afternoon, then little if any cloudiness tonight.
The wind will become light this evening with surface ridging
centered over southwestern MO.

GKS

&&

.PRELIMINARY POINT TEMPS/POPS...
Saint Louis     81  63  83  65 /  30   5   5   5
Quincy          78  59  80  59 /  10   5  20   5
Columbia        80  59  82  61 /  20   5   5   5
Jefferson City  81  58  83  61 /  30   5   5   0
Salem           81  61  82  61 /  50   5   5   5
Farmington      79  59  82  59 /  50  10   0   0

&&

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

$$

WFO LSX



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