Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 241158
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
658 AM CDT Fri Apr 24 2015

.SHORT TERM: (Through Sunday)
Issued at 235 AM CDT Fri Apr 24 2015

Heights continue to rise across the central CONUS as the deep
cyclone that brought a period of cool weather to the eastern half
of the country spins across New England. Meanwhile, a shortwave
located across southern California and Arizona is expected to move
toward and across the region over the next 48 hours.

Warm advection ahead of the system is well underway with a marked
increase in cloud cover over the last 6 hours.  Guidance in good
agreement that at least a few showers will develop this morning, but
confidence in coverage and how far east they will traverse in
question with dry low level air mass still entrenched across the
CWA. Have kept PoPs less than 30 percent today with the highest
values across central Missouri and the eastern Ozarks.  Otherwise,
believe temperatures will be a touch cooler than yesterday due to
the cloud cover with highs in the lower to middle 60s.

Chances of showers and thunderstorms really ramp up tonight as the
storm system approaches. Believe the best time for rapid development
and increase in coverage of preciptiation across the eastern half of
the CWA will occur between 05Z and 09Z. Then a dry slot punches
northeast through the CWA and quickly shifts the focus for rainfall
north and east of the CWA after 10Z. Highest threat of severe
weather has been pushed west across Kansas where best moisture
return will occur along with dry-line interaction.

The shortwave is forecast to become sheared as it moves in an
easterly direction across northern Missouri with the surface low
tracking east-southeast along Interstate 70 on Saturday. Along and
north of the low track, showers and clouds will help keep
temperatures cooler, while in the warm sector the threat of severe
thunderstorms may be realized across parts of southeast Missouri as
temperatures rise into the 70s. Not your typical setup for severe
weather in April, but can`t rule out a few severe storms mainly
south of St. Louis Saturday afternoon.

Cold front sweeps across the remaining CWA Saturday night with rain
ending from north to south. Should see some sunshine on Sunday, but
temperatures will once again struggle to climb back into the 60s
with cold advection taking place.

CVKING

.LONG TERM: (Monday through Thursday)
Issued at 235 AM CDT Fri Apr 24 2015

Temperatures to moderate next week with a dry forecast. Cutoff low
appears to remain south of the CWA Monday through Wednesday with a
large ridge developing across the Rockies by midweek.

CVKING

&&

.AVIATION:  (For the 12z TAFs through 12z Saturday Morning)
Issued at 631 AM CDT Fri Apr 24 2015

Specifics for KUIN, KCOU: Cannot rule out isolated to scattered
SHRA/TSRA this morning/afternoon at KCOU but precip chances at
both KCOU/KUIN certainly look much higher after 24/21z when a low
pressure system will be approaching the region. Winds will remain
southeasterly to southerly through the TAF period. Expect cigs to
lower to MVFR and possibly to IFR after 25/03z.

Specifics for KSTL, KSUS, KCPS: VFR for the first 0-6 hours with
increasing mid-level clouds. A period of prevailing SHRA/TSRA
looks more probable after 25/00z however isolated to scattered
SHRA/TSRA are possible during the afternoon hours. Winds will
remain southeasterly to southerly through the TAF period. Expect
cigs to lower to MVFR and possibly to IFR after 25/03z.

Kanofsky

&&

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

$$

WFO LSX





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