Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 041728

Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1228 PM CDT WED MAY 4 2016

Issued at 1155 AM CDT Wed May 4 2016

Going forecast on track with few changes made. Diurnal CU cloud
field is well underway in forming and will get added bonus of
upper support in the far eastern counties of our forecast area,
around KSLO, where a slight chance for SHRA/TSRA remains this
afternoon. Temperatures will be stunted in their diurnal rise
thanks to CAA behind the cold front, but with a strong sun angle
and somewhat warm start to the day, should still top out in the 65
to 70 degree range.

Skies will clear over much of the area tonight with temps possibly
edging into the upper 30s into parts of northeast MO and valley
areas of the eastern Ozarks of southeast MO, with low-mid 40s
expected elsewhere. Some additional clouds may remain in far
eastern sections of the CWA.

Cooler start, but slightly less clouds with more or less the same
airmass should result in a day that strongly favors persistence
max temps.



.SHORT TERM...  (Through Late This Afternoon)
Issued at 300 AM CDT Wed May 4 2016

Main focus for today will be temps.

At the beginning of the period this morning, 12z, the cdfnt is
expected to be approx half way thru the CWA. As the fnt pushes S,
winds increase and become nnwly behind the fnt. Deep mixing behind
the fnt, and ample insolation, will help offset the CAA and shud
still allow temps to warm into the mid to upper 60s. Going forecast
may in fact still be too cool, especially across the ern half of the
CWA where few if any clouds are expected.

Ongoing SHRA ahead of the fnt continues to quickly push swd early
this morning. These SHRA shud be exiting the sern portions of the
CWA around sunrise. The question then turns to chances this
afternoon. Believe that better chances for SHRA will remain E of the
area, but have kept mention of isod SHRA for early to mid this
afternoon as a vort max rotates around the upper low. Can also not
rule out TS given the steep lapse rates with some CAPE suggested by


.LONG TERM...  (Tonight through Tuesday)
Issued at 300 AM CDT Wed May 4 2016

Surface ridge to slowly build in across region tonight and
remain over the area through Friday. Will see dry and cooler weather
with lows in the 40s and highs in the mid to upper 60s on Thursday,
warming up into the 75 to 80 degree range on Friday.

Surface ridging to begin moving off to the east by Saturday as next
weather system approaches the region. Models are a bit faster with
developing a warm front over northern portions of forecast area on
Saturday with increasing low level moisture and convergence along
the boundary, so could see some elevated convection fireup by
Saturday afternoon and persist through the rest of the forecast
period as front stalls out over region. It will not be a continuous
rain event, but will see several rounds through out the rest of the
forecast period. The warmest day will be Saturday with highs in the
upper 70s to mid 80s, then dip down to near normal temps as frontal
boundary settles a bit further south along the I-70 corridor.



.AVIATION...  (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1227 PM CDT Wed May 4 2016

VFR conditions, dry wx, and N-NW surface winds will prevail at
the TAF sites thru the valid period. Winds will be gusty at times
this afternoon to around 25kts.





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