Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 210659

Area Forecast Discussion
National Weather Service Saint Louis MO
159 AM CDT SUN AUG 21 2016

.SHORT TERM...  (Through Late Tonight)
Issued at 155 AM CDT Sun Aug 21 2016

High pressure centered over the central Plains will build east
across the Mid Mississippi Valley today and into the Ohio Valley by
early Monday morning.  This is a cool and dry Canadian airmass with
dew point temperatures in the 50s.  Highs in the mid 70s to around
80 today combined with this low humidity will feel more like
September 21 than August 21.  Light wind and clear sky tonight
should make for good radiational cooling conditions.  Like today`s
highs, tonight`s lows will be more like mid September in the 55-60
degree range.


.LONG TERM...  (Sunday through Friday)
Issued at 155 AM CDT Sun Aug 21 2016

Dry weather is still expected Monday and Monday night as subsidence
sets under the shortwave ridge that will move across the area. The
low level moisture will also temporarily shift south of the area
early this week as a large surface high moves across Missouri and

It still looks like Tuesday into Thursday will be unsettled.
Moisture will move into the area by Tuesday as the low level flow
turns out of the southwest in wake of the high moving east toward
the East Coast.  Both the GFS and ECMWF are showing the area setting
up in west southwesterly flow aloft with a series of weak shortwaves
moving across the Mid Mississippi Valley.  The chance of
thunderstorms will increase on Tuesday across Missouri with the
initial surge of moisture convergence that will then spread across
the entire area on Tuesday night as a shortwave trough moves across
the area. Will go with high chance or likely PoPs on Wednesday and
Thursday as a cold front moves southeast across the area.  Drier
weather is expected by Friday as the cold front moves into
Arkansas and the Ohio Valley at the same time a weak upper ridge
works into the area. By Saturday, the GFS and ECMWF are showing
another upper trough moving through the central CONUS that will
bring another chance of showers and thunderstorms.

Still appears that temperatures will be mainly below normal early
this week with 850mb temperatures in the 10-15C range, but there
will be some warm up just ahead of the passage of the cold front on
Wednesday and Thursday.  Temperatures will fall back below normal at
the end of the week behind the cold front.



.AVIATION...  (For the 06z TAFs through 06z Sunday Night)
Issued at 1144 PM CDT Sat Aug 20 2016

VFR conditions to prevail through the period. Cold front has
pushed through all sites, which means mainly clear skies tonight
as high pressure builds in. Just a few diurnal cu are expected on
Sunday with WNW winds around 10 knots. Winds will go light and
variable Sunday night as high pressure shifts across the region.

VFR conditions through the period. Light WNW winds tonight,
picking up to around 10 knots Sunday afternoon. A few diurnal cu
are expected Sunday afternoon before skies clear out once again
Sunday night and winds go light and variable.





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