Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 271947

247 PM CDT Sat Sep 27 2014

.SHORT TERM:  (Through Late Tonight)
Issued at 236 PM CDT Sat Sep 27 2014

The expansive high pressure system centered in the Great Lakes
will continue to dominate the lower troposphere maintain dry
conditions and light winds. Lows tonight will be comparable to
those of early this morning, perhaps even a degree or so cooler.


.LONG TERM:  (Sunday through Next Saturday)
Issued at 236 PM CDT Sat Sep 27 2014


The blocky upper air pattern that has been in place across the
eastern 2/3rds of the Nation since the middle of last week will
gradually break down through early next week with more progression
noted. In the short term, the upper low presently meandering
across northern Iowa will weaken and become absorbed into an upper
trof evolving from southeast Canada into the Ohio Valley Sunday
into Monday. This will allow the low level anticyclone/high to
maintain its dominance and control of the sensible weather through
Monday. Temperatures during this period should remain above normal
and be similar (within a few degrees) to those experience over the
last few days. The high begins to lose its westward influence on
Tuesday but conditions are expected to remain dry and tranquil and
temperatures above normal.


The deep longwave trof evolving over the western U.S. the next
few days will progress into the Mississippi Valley Wednesday into
Thursday. The extended models have come into much better agreement
with the speed of the system and movement of the associated cold
front across the area Thursday/Thursday night. The chance of pre-
frontal showers and thunderstorms will gradually ramp up west to
east as early as Wednesday with the highest probability of storms
with the cold frontal passage. We will have to keep an eye on this
system and the instability available as shear will be seasonably
strong to promote organized thunderstorms. This front will also
usher a much cooler air mass into the region for the weekend, much
more typical of fall.



.AVIATION:  (For the 18z TAFs through 18z Sunday Afternoon)
Issued at 1154 AM CDT Sat Sep 27 2014

VFR conditions expected through this TAF period. Upper level low
over Iowa with trough extending south into eastern Kansas will
track southeastward Sunday, but atmosphere will remain relatively
dry so any showers will remain isolated. At the surface, winds
will remain light from the east and southeast.

Specifics for KSTL: VFR conditions through this TAF period. Winds
will remain light from the southeast.





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