Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 270744
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
244 AM CDT Wed Aug 27 2014

.SYNOPSIS:
Issued at 237 AM CDT Wed Aug 27 2014

Front is slowly making progress into the CWA early this morning
and is currently stretching from near Kansas City, Missouri to
Quincy, Illinois. Some isolated thunderstorms continue to pop up
here and there on outflow boundaries across eastern Missouri and
west central Illinois, with a better defined cluster of convection
now taking shape across far northwest Missouri. Temperatures
remain mild with all locations still in the 70s this morning.

CVKING

&&

.SHORT TERM:  (Through Tonight)
Issued at 237 AM CDT Wed Aug 27 2014

Elevated convection will continue to develop across northern
Missouri early this morning with scattered thunderstorms forecast
through the lunch hour across the northern counties of the CWA.

Front will make very slow progress south today. Temperatures will
quickly rise into the 90s south of the front and due to pooled
dewpoints in the lower to middle 70s, produce at least a few hours
of heat indices above 100 degrees along and south of I-70. Although
it won`t be as hot as the past few days - feel current heat
headlines are warranted given potential for one more day of heat
indices reaching 105 degrees this afternoon.

The front will also serve as the focus for convective initiation
with scattered thunderstorms expected along and south of I-70 this
afternoon. As was the case yesterday, a few of the storms could
produce some gusty winds to 50 mph and torrential downpours.

Diurnal convection expected to dissipate quickly after sunset with
the focus for more elevated development shifting back north of the
boundary across the northern reaches of the CWA after midnight.

CVKING

.LONG TERM: (Thursday through Tuesday)
Issued at 237 AM CDT Wed Aug 27 2014

Boundary will be slow to lift back north on Thursday and may become
orientated more northwest to southeast across the CWA...paralleling
the Mississippi River. Once again, afternoon convection will be
possible in the vicinity of this front.

The boundary should finally lift north as a warm front Thursday
night with dry and seasonably warm weather expected on Friday
ahead of the shortwave/cold front that approaches from the west.

Have tried to focus likely POPs Friday night and Saturday with this
next system as blended guidance seems to give too long of a period
of POPs when compared to reality. So, after a wet and cooler
beginning to the Labor Day Weekend, it appears chances of
precipitation will decrease for Sunday and Monday (Labor Day), with
temperatures beginning to inch back up above normal in the wake
of this storm system.

CVKING

&&

.AVIATION:  (For the 06z TAFs through 06z Wednesday Night)
Issued at 1054 PM CDT Tue Aug 26 2014

Cluster of storms northeast of the St Louis metro area will
likely slowly dissipate late tonight, although could not rule out
an isolated storm along the outflow boundary moving southwestward
through the St Louis metro. The surface wind will temporarily
switch to a northeast direction and pick up behind the outflow
boundary. A cold front was across northern MO, just south of UIN
this evening. This front will sag slowly southward late tonight
and Wednesday with scattered convection possible along and just
north of this front. Latest HRRR model run keeps UIN dry late
tonight, but there may be at least isolated showers/storms in the
UIN area late tonight into Wednesday morning. Due to uncertainty
in timing and coverage may keep the UIN taf dry for now. With
mostly light surface winds, mainly just high level clouds, and
high surface dew points there will likely be some fog late
tonight/early Wednesday morning mainly in SUS and CPS. The surface
wind will be mainly nely in UIN and COU Wednesday, and becoming
nely Wednesday afternoon in the St Louis metro area after fropa.

Specifics for KSTL: May need to include VCTS in the STL taf around
06-07z late tonight if storms develop along outflow boundary
dropping southwestward through STL. The wind will also briefly
switch to a nely direction and become gusty around 06z behind the
outflow boundary. Should have scattered diurnal cumulus clouds
late Wednesday morning and afternoon as the atmosphere becomes
very unstable along the weakening cold front which will sag
southward through central MO. Will likely be isolated to scattered
thunderstorms Wednesday afternoon, but may leave out of the STL
taf for now. The surface wind will become nely Wednesday
afternoon as the front sags south of STL.

GKS

&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     94  77  92  77 /  40  20  40  20
Quincy          87  71  88  71 /  20  20  40  20
Columbia        92  72  92  72 /  20  20  20  10
Jefferson City  93  72  92  72 /  30  20  10  10
Salem           93  71  89  71 /  30  20  30  20
Farmington      95  71  91  71 /  40  20  20  10

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...HEAT ADVISORY until 8 PM CDT this evening FOR Audrain MO-Boone
     MO-Callaway MO-Cole MO-Crawford MO-Franklin MO-Gasconade MO-
     Iron MO-Madison MO-Moniteau MO-Montgomery MO-Osage MO-
     Reynolds MO-St. Francois MO-Ste. Genevieve MO-Warren MO-
     Washington MO.

     EXCESSIVE HEAT WARNING until 8 PM CDT this evening FOR Jefferson
     MO-Lincoln MO-St. Charles MO-St. Louis City MO-St. Louis MO.

IL...EXCESSIVE HEAT WARNING until 8 PM CDT this evening FOR Bond IL-
     Calhoun IL-Clinton IL-Fayette IL-Greene IL-Jersey IL-
     Macoupin IL-Madison IL-Marion IL-Monroe IL-Montgomery IL-
     Randolph IL-St. Clair IL-Washington IL.

&&

$$

WFO LSX






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