Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 031157

657 AM CDT SAT OCT 3 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 345 AM CDT Sat Oct 3 2015

A closed low over the southeastern CONUS will continue to spread
clouds and moisture back to the northwest today. The increased
cloudiness over the southeastern half of the CWA will lead to
slightly lower afternoon high temperatures there compared to
yesterday. Sprinkles are also possible over southwestern IL.


.LONG TERM:  (Tonight through Friday)
Issued at 345 AM CDT Sat Oct 3 2015

Going forecast trends are being supported by 00z model runs and
still look very reasonable. Low level moisture (aob 800MB) will
continue to be advected into the area as the persistent easterly
flow transports moisture from the eastern seaboard. This
additional moisture should allow the clouds to thicken and
continue their westward expansion tonight and into early Sunday,
but solutions also continue to suggest some thinning of the cloud
cover on Sunday afternoon over eastern sections of the CWA as the
easterly flow and moisture transport begins to weaken a bit.

NAM/GFS 00z MOS appear to be too generous with their coverage of low
PoPs in this regime.  Have expanded slight chance PoPs in going
forecast just a bit for tonight and Sunday, but have maintained
the idea that the main threat of any light QPF will be over our IL

By Monday night, cutoff low over the southeast U.S. begins to open
up and move east, which will once again allow weather features to
begin a slow migration across the CONUS. With the breakdown of the
surface ridge that has been parked over the area since last week,
temperatures should begin a rebound to above average early October
levels, as zone of westerlies along the US-Canadian border will
keep the chilly air locked to our north. Medium range solutions of
GFS and ECMWF remain in fairly good agreement that remnants of
cutoff low that forms over the southwest U.S. this weekend should
reach the central CONUS in the Thursday-Friday time frame,
bringing the CWA a chance of showers and thunderstorms.



.AVIATION:  (For the 12z TAFs through 12z Sunday Morning)
Issued at 636 AM CDT Sat Oct 3 2015

MVFR to VFR cloud deck will continue spreading westward with
time this morning. The onset of diurnal mixing should quickly
lead to rising ceilings, and it is possible that cigs will be VFR
by the time they reach KSTL/KSUS/KCPS this morning. Stronger
winds mixing down to the surface should produce wind gusts of
20-25 kts through the day at all TAF sites. BUFKIT profiles
depict cigs falling back to MVFR overnight at KSTL/KSUS/KCPS.
Winds will remain northeasterly through the period. Sprinkles are
possible but isolated coverage precludes a mention in the TAF





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