Area Forecast Discussion
Issued by NWS St. Louis, MO

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000
FXUS63 KLSX 231136
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
636 AM CDT Sat May 23 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 331 AM CDT Sat May 23 2015

Will continue to keep today mainly dry for parts of central and
southeast Missouri where the NAM shows some low level moisture
convergence developing in theses areas, especially later this
morning and this afternoon. The NCEP NMM WRF shows a few showers
developing over the area this afternoon. However, do not expect
widespread showers and thunderstorm development as the NAM also
shows an upper level ridge will build over the Midwest with the
NAM/ECMWF showing either neutral or subsidence over the area.
Temperatures will be slightly warmer today with 850mb temperatures
around +10C.

Britt

.LONG TERM:  (Tonight through Friday)
Issued at 331 AM CDT Sat May 23 2015

(Saturday Night through Monday Night)

NAM and ECMWF have shown better continuity than the GFS which also
shows gridscale feedback issues, so will use a blend of these two
models for the forecast solution.  Overall trends are pretty much
the same as going forecast. Upper ridge begins to move east tonight
which allows additional low level moisture convergence to move
into the area. Still expect a series of weak shortwave troughs to
move through the area in the southwest flow aloft with pockets of
low level moisture convergence. Will keep likely and categorical
PoPs going through this period. Will also go with a relatively small
diurnal swing given the clouds and rain. A blend of MOS guidance
looks reasonable given 850mb temperatures around +15C.

(Tuesday through Friday)

Will keep scattered thunderstorms in the forecast as upper flow
stays southwesterly with surface front staying nearby in a unstable
airmass.  ECMWF shows surface front moving just north of the area
which should allow temperatures to climb above normal by Thursday
and Friday.

Britt

&&

.AVIATION:  (For the 12z TAFs through 12z Sunday Morning)
Issued at 627 AM CDT Sat May 23 2015

VFR TAF for now with widely sct sprinkles early in the period.
Winds will be sely, become ssely this morning before backing this
eve to sely, all below 10 kts. Cigs will remain in the 7 kft to 12
kft thru the period. Have added VCTS at COU late tonight as an
area of precip is expected to approach the area.

Specifics for KSTL: VFR and dry except for widely sct sprinkles
early in the period. Winds will remain sely to ssely thru the
period and expected to remain below 10 kts. Chance for TSRA
increases Sun near 18z. Have left out of TAF for now until
confidence in timing builds.

Tilly

&&

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

$$

WFO LSX





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