Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 280819

Area Forecast Discussion
National Weather Service Saint Louis MO
319 AM CDT Sun May 28 2017

.SHORT TERM...  (Through Late Tonight)
Issued at 316 AM CDT Sun May 28 2017

Much quieter weather expected across the area today.  High pressure
will begin building across the area behind a cold front which will
move through the area this morning.  The upper level shortwave is
lagging the front back over southeast Nebraska this morning,
and it will move overhead this afternoon.  Models still show some
lingering instability behind the front this afternoon, and most
guidance prints out a few hundredths of QPF ahead of the shortwave
primarily east of the Mississippi River.  Have therefore kept some
slight chance PoPs going for the afternoon hours as the wave moves
through.  The airmass behind the cold front is drier more than it is
cooler.  Afternoon highs will be pretty close to yesterday`s some cases it might actually be a little warmer where
there`s more insolation than yesterday.  With a clear sky and a
relatively light wind tonight we should see some decent
radiational cooling with temperatures falling into the mid and upper


.LONG TERM...  (Monday through Saturday)
Issued at 316 AM CDT Sun May 28 2017

Will continue to keep a slight chance of showers and thunderstorms
on Monday afternoon and evening as a cold front moves southeast
across the area.  The atmosphere will become modestly unstable along
and ahead of the front as a weak shortwave rotates around the
southside of the upper that will be over the northern Great Lakes.
Another weak shortwave trough will bring another chance of showers
to the area late Tuesday and Tuesday night.  The upper level low
will move east of the Great Lakes on Wednesday and high pressure
will move across Missouri and Illinois bringing mainly dry weather.

By late in the week, low level winds will turn out of the southwest
advecting moisture from the Gulf.  With instability increasing over
the area, will keep a chance of showers and thunderstorms over the
area Thursday through Saturday, particularly on Saturday when a
cold front will be dropping south into the area.

Highs will vary from the middle 70s to lower 80s this week which
is supported by the GEFS ensemble guidance.



.AVIATION...  (For the 06z TAFs through 06z Sunday Night)
Issued at 1142 PM CDT Sat May 27 2017

Threat of thunderstorms overnight have pushed well off to the
south of the terminals. Will have to watch for fog potential
overnight but thinking thick mid/upper level cloud cover will help
prevent fog formation, though cannot rule out some MVFR
visibilities were it to occur. Cold front should move through from
west to east late Sunday morning through early afternoon. Will be
isolated thunderstorms possible along/ahead of front though
probability too low to mention in TAF. Winds behind the front will
become predominantly northwesterly.


VFR conditions likely overnight. Slight chance at some MVFR visbys
in fog but probability too low. Isolated showers/storms possible
along cold front late Sunday morning through early afternoon.
Winds become northwesterly behind the front.





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