Area Forecast Discussion
Issued by NWS St. Louis, MO

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781
FXUS63 KLSX 241627
AFDLSX

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1127 AM CDT SAT SEP 24 2016

.SHORT TERM...  (Through Late Tonight)
Issued at 344 AM CDT Sat Sep 24 2016

Today will be dry again with well above normal temps.  The pattern
hasn`t change appreciably from yesterday...in fact there may be a
bit more mixing this afternoon as opposed to Friday.  Guidance
numbers look a little low for this reason so have bumped up a couple
of degrees into the upper 80s and low 90s to better match what
occurred yesterday.

The closed low over Wyoming will lift with increasing speed across
the northern Plains into south central Canada this afternoon and
tonight.  The attendant surface low will also move up into Canada
this evening and the resulting cold front will move through the
Great Plains into northwest Missouri during the pre-dawn hours of
early Sunday morning.  Models are pretty consistent in keeping the
bulk of the precip west of our CWFA tonight.  We`ll be on the
western edge of the weakening upper level ridge over the Tennessee
Valley which should keep some synoptic scale subsidence over at
least the southeastern half of the CWFA.  Additionally, the focus of
the low level jet will be over western and north central Missouri.
Think there could be some isolated to scattered storms between 06-
12Z...but the more widespread precip should stay over west central
and northwest Missouri.

Carney

.LONG TERM...  (Sunday through Friday)
Issued at 344 AM CDT Sat Sep 24 2016

Forecast looks pretty much on track as the chance of showers and
thunderstorms will spread southeast across the area on Sunday. This
will happen as low level moisture convergence sets up ahead of a
deep upper trough moving across the northern CONUS.  Still appears
that rain chances will end from northwest to southeast late Sunday
and Sunday night as a cold front moves through the area and dry air
advection sets up behind it.

Should be one more day of above normal temperatures on Sunday ahead
of the cold front.  Should see highs reach the mid to upper 80s over
the southeastern two thirds of the CWA.

Still looks like Monday through Friday will be dry as the upper
trough moves slowly off to the east and an large upper ridge builds
in over the central CONUS.  While the coolest temperatures will be
on Monday and Tuesday just after the cold front moves through, highs
are expected to remain in the 70s most of the week.

Britt

&&

.AVIATION...  (For the 18z TAFs through 18z Sunday Afternoon)
Issued at 1109 AM CDT Sat Sep 24 2016

Just scattered diurnal cumulus clouds this afternoon along with
some patchy mid level clouds. Mainly southeast surface winds this
afternoon and tonight with surface ridge extending from MI
southwest into southeastern MO and a cold front approaching from
the Plains. Mid-high level cloudiness will be increasing tonight
ahead of an upper level distubance. Showers and storms may move
into UIN and COU Sunday morning just ahead of the approaching cold
front and into STL Sunday afternoon. For now will just include
VCTS in the tafs during these time periods. The surface wind will
veer around to a southwest direction Sunday morning.

SPECIFICS FOR KSTL: Just scattered diurnal cumulus clouds this
afternoon along with some patchy mid level clouds. Mainly
southeast surface winds this afternoon and tonight with surface
ridge extending from MI southwest into southeastern MO and a cold
front approaching from the Plains. Mid-high level cloudiness will
be increasing late tonight and Sunday morning ahead of an upper
level distubance. Showers and storms may move into STL Sunday
afternoon just ahead of the approaching cold front. For now will
just include VCTS in the STL taf Sunday afternoon. The surface
wind will veer around to a southwest direction Sunday.

GKS

&&

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

$$

WFO LSX



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