Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 211955

Area Forecast Discussion
National Weather Service Saint Louis MO
255 PM CDT Fri Oct 21 2016

.SHORT TERM...  (Through Late Saturday Afternoon)
Issued at 255 PM CDT Fri Oct 21 2016

Ridge of high pressure extends from southwest Texas northeast
through central Missouri and continuing northeast into the upper
Midwest. This ridge will drift southeast tonight and Saturday.
Should be another seasonably chilly night tonight under a clear sky
and light wind.  Good radiational cooling conditions should allow us
to hit lows near or a few degrees below normal.  Chilly conditions
and relatively moist air will likely produce patchy frost across
parts of the eastern Ozarks and southwest Illinois where coolest air
will reside tonight.  Remainder of the area will probably be a bit
warmer due to the passage of the ridge axis and subsequent warmer
return flow from the south.

Wind will turn to the south-southwest across the entire area by mid
morning Saturday so expect temperatures to warm up a bit over
today`s highs.  Coolest temperatures in the mid 60s should be over
the Ozarks and southwest/south central Illinois with highs near 70
over central Missouri.


.LONG TERM...  (Saturday Night through Next Friday)
Issued at 255 PM CDT Fri Oct 21 2016

For the most part we are expecting rather tranquil weather until
midweek. Weak ridging aloft with slide into the region Sunday night
with low level WAA becoming established. A cold front will then move
into and through the CWA on Sunday and Sunday evening.  Good low
level WAA will persist ahead of the front and any clouds will be
limited to some thin high clouds. This looks to be the warmest day
of the next week or so, with above average high temps well into the
70s. Present indications are the fropa will be dry with a little
available moisture progged. High pressure will then dominate the low
levels on Monday with near average temperatures, with high pressure
retreating and WAA commencing on Tuesday. A progressive upper trof
and attendant cold front will then move into and through the region
from late Tuesday night into Wednesday night accompanied by a chance
of showers and thunderstorms. Any cool down with this later cold
front looks brief at this time and limited to Thursday. While there
are some model differences with the mass fields aloft by Friday,
there is general consensus that low level WAA will once again get



.AVIATION...  (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 1228 PM CDT Fri Oct 21 2016

VFR flight conditions will prevail across the area through
Saturday. High pressure ridge axis over central Missouri will
shift southeast tonight into Saturday morning. This will cause the
wind to shift from the north-northwest this afternoon to the
south-southwest Saturday morning. Think some steam fog along the
major rivers is likely late tonight as well which will locally
bring the visibility down to IFR. Any river fog that develops
should dissipate quickly after sunrise.


VFR flight conditions will continue to prevail at Lambert through
Saturday. Wind will shift from the north-northwest to the south by
Saturday morning as the ridge axis moves east of the area.





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