Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 310835

335 AM CDT Tue Mar 31 2015

.SHORT TERM: (Through Tonight)
Issued at 330 AM CDT Tue Mar 31 2015

NW flow and dry conditions in place today and tonight. An impulse
embedded in the NW flow will drag a weak cold front thru the FA
today but with limited moisture to work with...should be a dry
FROPA. The front settles well south of the area by Wed mrng. There
is an outside chance that this feature may spark off some very isld
convection across sthrn IL/MO late this aftn/evng. Chances look
minimal with slightly better chances just south of the CWA.


.LONG TERM: (Wednesday through Monday)
Issued at 330 AM CDT Tue Mar 31 2015

Upper lvl ridge slides across the region on Wed with a significant
short wave following closely behind along the US/Canadian border
with a weakness in the heights extending SW to a short wave coming
on shore along the west coast Wed night. The lead short wave will
induce a low to dvlp across the nthrn high plains and move east
along the international border Tue night lifting into sthrn Canada
Wed. This feature will drive a cold front into the cntrl CONUS for
the end of the work week. Weak sfc ridge slides east of the CWA by
Wed putting the region in sthrly flow between the retreating high and
the approaching bndry. Winds are expected to become rather gusty by
Wed aftn. Strong WWA and decent bndry layer moisture may be
sufficient to produce a few isld SHRA/TSMs Wed aftn...primarily
across MO where the better moisture and instability should reside.
The better chances of precip on Wed appear to be across SW MO where
the tail end of the weak cold front from Tue attempts to lift back
north. Wed should be the warmest day of the week with the strong
sthrly flow.

The cold front approaches the area Wed night with most guidance in
agreement...timing wise...bringing the bndry into the NE CWA around
12Z Thu. The front makes steady progress south thru the day and
should exit the sthrn FA around 00Z Fri. The bndry slows Thu night
due to an area of low pressure that is fcst to form along the tail
end of the bndry across the sthrn high plains in response to the
trailing short wave. The low is fcst to track from AR to the OH
vly on Fri ending the precip threat by aftn. It still appears that
the nthrn CWA`s best chance for precip will be with FROPA Thu mrng
with the remainder of the precip Thu night and Fri being along and
south of I70. Thunder is expected to accompany the front on Thu but
should be confined closer to the front across the sthrn FA Thu
night and Fri.

Temps on Thu will depend on frontal timing/position and assoc
precip. The slower either are then the warmer temps will be. Fri
will be a cool day with plenty of clouds and precip. Friday will
be a cloudy cool damp day with highs mainly in the 50s.

A low amplitude upper lvl ridge will attempt to build into the
region over the wknd with a sfc ridge moves from the cntrl plains to
the TN vly. It should be a decent wknd with mostly clear skies and
seasonal temps. Upper flow is fcst to transition to a broad SW chance PoPs have been introduced for the beginning of
the week.



.AVIATION:  (For the 06z TAFs through 06z Tuesday Night)
Issued at 1007 PM CDT Mon Mar 30 2015

VFR conditions expected through this TAF period. Weak surface
front will approach KUIN around 10Z and the KSTL metro TAF sites
by around 14Z. LLWS will exist at all sites through the night
until frontal passage. A wind shift to light northerly surface winds
will accompany the front but little else in sensible weather.

Specifics for KSTL: VFR conditions other than LLWS until around
14Z when a weak cold front will pass through. Surface winds will
become light northerly behind the front.





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