Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 220144
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
844 PM CDT Mon Apr 21 2014

.UPDATE:
Issued at 842 PM CDT Mon Apr 21 2014

Band of showers along the cold front will continue to weaken as
they move southeast through 06Z.

CVKING

&&

.SHORT TERM:  (Through Late Tonight)
Issued at 311 PM CDT Mon Apr 21 2014

Cold front has moved into Missouri and will continue to track to the
southeast this evening. Showers and some thunderstorms have
developed ahead of cold front, but they will remain scattered in
nature before coming to an end late this evening. As for
temperatures, not a lot of caa behind this front so will have lows
in the mid 40s to mid 50s.

Byrd

.LONG TERM:  (Tuesday through Next Monday)
Issued at 311 PM CDT Mon Apr 21 2014

Skies to clear out by daybreak on Tuesday with north winds
persisting throughout the day. So a bit chillier but highs will be
in the mid 60s to low 70s.

Then surface ridge to move off to the east by Wednesday allowing
southerly winds to return ahead of next weather system. Highs on
Wednesday will be in the upper 60s to mid 70s.

Showers and thunderstorms to develop along frontal boundary late
Wednesday night and spread east. Best chances of precipitation will
be during the day on Thursday. Front to move through during the
afternoon and evening hours with decent instability, i.e.
surface based capes between 500 and 1000 j/kg and deep layer shear
in excess of 40kts.  However, unsure yet what the severe potential
will be. As for highs on Thursday, they will be in the upper 60s to
low 70s.

Beyond that, next chance for precipitation will be Saturday night
through Monday. But extended models have timing and placement
issues, so no major changes at this time.

Byrd

&&

.AVIATION:  (For the 00z TAFs through 00z Tuesday Evening)
Issued at 622 PM CDT Mon Apr 21 2014

Specifics for KCOU, KUIN: Expect variable flight conditions over
the next 6 hours with improvement expected by 9-12 hours at the
latest. An area of SHRA/TSRA was affecting KCOU at TAF issuance
and a second line was located north and west of KUIN. This second
line is associated with a cold front and will probably move
through KUIN, but instability might not be sufficient for it to
reach KCOU. The additional low-level moisture provided by
scattered SHRA/TSRA could help ceilings lower to MVFR for a couple
of hours this evening until the cold front moves through later
tonight. Winds become northwest to north after FROPA.

Specifics for KSTL, KSUS, KCPS: Expect variable flight conditions
over the next 6 hours with improvement expected by 9-12 hours. An
area of SHRA/TSRA stretched roughly from KCOU to KPPQ at TAF
issuance and was moving southeastward. Some spotty showers are
possible at metro area TAF sites before this broader area of
precip reaches the terminals. A second line of SHRA/TSRA was
located farther northwest and was associated with a cold front.
There is some question about whether or not the instability will
be sufficient for this line to hold together long enough to reach
KSTL/KSUS/KCPS. The additional low-level moisture provided by
scattered SHRA/TSRA could help ceilings lower to MVFR for a couple
of hours this evening until the cold front moves through
overnight. Winds become northwest to north after FROPA.

Kanofsky

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX






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