Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 251125
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
625 AM CDT Mon May 25 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 338 AM CDT Mon May 25 2015

Area of showers currently over west central Missouri will move
northeast and will affect some of the northeast Missouri counties
before 9 am ahead of the mid level shortwave that will move out of
the area by mid-morning. Otherwise, expect a drier day today as
area will lie under subsidence in the wake of the shortwave
trough. Only exception will be over parts of central and southeast
Missouri into southern Illinois where the atmosphere will become
unstable which could still lead to a few showers and thunderstorms
developing during the afternoon hours. High temperatures this
afternoon will be close to what they were on Sunday, which were in
the lower-mid 80s.

Britt

.LONG TERM:  (Tonight through Sunday)
Issued at 338 AM CDT Mon May 25 2015

(Tonight through Wednesday)

Will continue to follow the NAM/ECMWF which has had the best
continuity as of late.  Have kept with current trends on PoPs
tonight into Tuesday.  A shortwave ridge will move off to the east
of the area tonight which will allow for a rapid increase in ascent
after 06Z caused by the approach the next mid-level trough and
increasing low-level moisture convergence.  Will keep likely PoPs
over much of the southern half of the CWA of the area after midnight
tonight, and continue them into Tuesday morning as the mid-
level trough moves through before the showers and thunderstorms
become scattered during the afternoon.  The chance of thunderstorms
will continue Tuesday night into Wednesday as another weak shortwave
moves across the area.

(Thursday through next Sunday)

Rain chances will continue into the extended part of the forecast as
upper trough over western CONUS moves into the Great Plains and
eventually through Middle Mississippi Valley by next Sunday.  ECMWF
shows a series of shortwave troughs with attendant low level
moisture convergence moving through the area ahead of this main
trough.  This is worth keeping a chance of showers and thunderstorms
in each day with the best chance on Saturday when ECMWF currently
shows a cold front moving through.  Temperatures will stay close to
normal with 850mb temperatures in the 10-15C range.

Britt

&&

.AVIATION:  (For the 12z TAFs through 12z Tuesday Morning)
Issued at 615 AM CDT Mon May 25 2015

Conditions expected to improve at terminals this morning,
eventually becoming mostly clear today. Can not rule out isod to
sct TSRA this afternoon into the evening with peak heating.
However, believe main focus for precip will be late tonight into
Tues morning. MVFR cigs are expected to accompany this precip.
Otherwise, winds are expected to be swly to sly thru this evening.

Specifics for KSTL: Pockets of MVFR cigs shud gradually become
more sct with dry conditions expected thru this eve. Can not rule
out isod to sct TSRA this afternoon, but any threat shud be
primarily W of the terminal. Expect precip to move into the area
late tonight into Tues morning with MVFR cigs.

Tilly

&&

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

$$

WFO LSX





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