Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 241140

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
640 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 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.


.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.



.AVIATION...  (For the 12z TAFs through 12z Sunday Morning)
Issued at 632 AM CDT Sat Sep 24 2016

Areas of MVFR fog mainly across eastern Missouri and Illinois will
dissipate by 13-14Z this morning. VFR conditions will prevail
thereafter with scattered CU developing by 17Z. A cold front will
dip into northwest Missouri during the pre-dawn hours of Sunday. A
few thunderstorms may be possible ahead of the front in parts of
central and northeast Missouri.


VFR flight conditions are expected to prevail at Lambert through
today and tonight. A cold front will move into central Missouri
Sunday afternoon. A few thunderstorms are possible ahead of the
front in the STL Metro Area.





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