Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 202029

Area Forecast Discussion
National Weather Service Saint Louis MO
Issued by National Weather Service Kansas City/Pleasant Hill MO
329 PM CDT Thu Oct 20 2016

.SHORT TERM...  (Through Late Friday Afternoon)
Issued at 300 PM CDT Thu Oct 20 2016

Main concern heading into the overnight hours involves falling
temps and renewed possibilities of frost early Friday morning.
Cold front now well clear of the fcst area with breezy northwest
winds prevailing in its wake. VIS satellite imagery showing plenty
of cold advection stratus across the region this
afternoon...however arrival of high pressure during the overnight
hours should quickly erode lingering clouds as the evening and
early overnight hours progress. This should set the stage for
effective radiational cooling with fcst guidance suggesting temps
lowering into the middle to upper 30s north of the Interstate 70
corridor early Friday morning. The only caveat will be a continued
weak northerly pressure gradient with winds expected to stay in
the 4-8 mph range. In any event...have elected to hoist a frost
advisory for the northern CWA based on anticipated early morning

Sfc ridge axis expected to take up residence directly over the
fcst area through the day on Friday. With feature
overhead...return southerly flow will be delayed until late
afternoon evening. As a result...expect another cool day with high
temps reaching into the middle to upper 50s with weak winds
prevailing through the day.


.LONG TERM...  (Friday Night through Next Thursday)
Issued at 300 PM CDT Thu Oct 20 2016

Benign weather pattern continues to take shape for the upcoming
weekend as ridging builds overhead and southerly flow is
re-established over the area. Continued warm air advection will
allow temps to quickly rebound into the upper 60s on
Saturday...with low 70s expected by Sunday. Unseasonably warm
temps to continue right through the beginning portions of next
week with the next chance for organized precip holding until
Tuesday night/Wednesday. GFS and ECMWF appear to be in decent
agreement with their suggestion of a leeside low tracking
northeast from the central High Plains into the upper Miss Rvr
Vly. The arrival of this feature will lead to increased chances
for precip with main cold front expected to pass Wed night/early
Thrus. This should allow for a short cool down towards the
conclusion of the work week.



.AVIATION...  (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1141 AM CDT Thu Oct 20 2016

MVFR conditions currently moving through the area will be short-
lived as drier air begins moving into the area this afternoon.
Meanwhile...a passing shower or two will be possible at COU this
afternoon as an upper-level shortwave moves through the region.
The other main story in the near term will be breezy north winds
with gusts of 20-25 kts possible at times before winds weaken
this evening. VFR conditions expected through the overnight as
northwest winds of 5-10 kts continue under clearing skies aloft.

SPECIFICS FOR KSTL: High-end MVFR cigs should begin to rise
shortly after 18z with BKN-OVC at flight level 070 prevailing
through the afternoon hrs. SCT clouds between 025-030 expected
this afternoon...with sustained NNW winds of 10-15 kts with gusts
to 25 kts possible. Clearing skies expected through the overnight
with NNW winds of 5-10 kts likely.



MO...Frost Advisory from 4 AM to 8 AM CDT Friday for Knox MO-Lewis MO-
     Marion MO-Monroe MO-Ralls MO-Shelby MO.

IL...Frost Advisory from 4 AM to 8 AM CDT Friday for Adams IL-Brown
     IL-Pike IL.



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