Area Forecast Discussion
Issued by NWS St. Louis, MO

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000
FXUS63 KLSX 221839
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
139 PM CDT Tue Jul 22 2014

.UPDATE:
Issued at 728 AM CDT Tue Jul 22 2014

Updated forecast for northeast MO and west central IL this morning
as isolated thunderstorms (some quite strong) continue to develop
in southeast IA and drift toward the northern reaches of the CWA.

CVKING

&&

.SHORT TERM:  (Through Late This Afternoon)
Issued at 348 AM CDT Tue Jul 22 2014

During the day today the upper ridge will remain in place with
surface temperatures expected to warm up into the low to mid 90s.
Low level moisture continues to increase as well, so will see heat
indicies between 100 and 105 for central and northeast MO as well as
west central IL.

Byrd

.LONG TERM:  (Tonight through Monday)
Issued at 348 AM CDT Tue Jul 22 2014

In the meantime, cold front associated with next weather system
to move into far northern portions of MO by 00z Wednesday. Short
term models begin to develop complex along frontal boundary around
this time and track it to the south and southeast through forecast
area tonight. Some differences on timing and coverage between the
models, so went with a blend and increased pops to likely late
this evening and into the overnight hours as it moves through.
Despite all of the instability and moisture, some concern about
mid level capping, but confident cap will weaken sufficiently to
allow storm development. With decent capes, moisture and
instability, SPC has placed northern portions of forecast area in
a slight risk for tonight with main threats being large hail and
damaging winds.

System to continue tracking south through southern portions of
forecast area Wednesday morning, before tapering off Wednesday
afternoon. As for highs on Wednesday, will range from the low 80s
far north to around 90 far south.

By Wednesday night, surface ridge begins to build in and bring in
drier and cooler weather for the last half of the work week. Highs
on Thursday will be in the upper 70s to mid 80s.

Surface ridge to move off to the east by Friday with a warm front
developing across region with elevated convection possible for
portions of forecast area Friday and Friday night. Then as main cold
front moves into region on Saturday, will see additional rounds of
storms through Sunday night before system exits region on Monday.
Temperatures to moderate through the weekend once again.

Byrd

&&

.AVIATION:  (For the 18z TAFs through 18z Wednesday Afternoon)
Issued at 131 PM CDT Tue Jul 22 2014

Upper level high retreating some to the west will allow fairly
strong short wave to drop into into the eastern US bringing
northwest flow back to the region. Associated surface cold front
will move through late tonight and Wednesday morning. Forecast
issue is when, where and if thunderstorms develop. Cooling aloft
has to occur before the instability disappears. No model is
convincing enough toexclusively follow. Have blended and followed
previous forecast putting storm at UIN about 00z and gradually
moving south, into STL at 06z. Models and soundings suggest some
mvfr cielings wednesday am.

Specifics for KSTL: Nothing out there has convinced me to change the
previous forecast. CWSU concurs to keep the prevailing
thunderstorms from 06 - 08z...with a couple of hours of mvfr
ceilings Wednesday am.

JPK

&&

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

$$

WFO LSX





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