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Area forecast discussion...updated aviation 
National Weather Service St Louis MO
515 PM CDT Wednesday Jul 29 2015

Short term: (through late tonight)
issued at 331 PM CDT Wednesday Jul 29 2015

"cold" front is now almost all the way through the County warning forecast area. Tough to
really pick it out, but even Farmington is reporting northwesterly
winds at this hour. It might be hung up over the far southern
portions of Iron and Reynolds though. Regardless, we're at peak
heating right now, and we can't seem to crack 105 degrees on the
heat index, so will be dropping the excessive heat warning at 400
PM. Widely scattered convection is firing along the front, but in
southeast Missouri and southern Illinois, but a weak cap has
developed over the area according to rap soundings so I don't expect
any convection for the rest of the day and evening hours except
potentially in the vicinity of the front. Any storms that do affect
our southern County warning forecast area should be out of the area or dissipated by early
evening. Slightly cooler, but substantially drier air will filter
south overnight. Stuck close to ensemble guidance for lows tonight
which are actually a little warmer than operational met/mav. Wanted
to be a little more conservative on the "cool down" since it is July
after all, and this isn't exactly an Arctic front.

Carney

Long term: (thursday through next wednesday)
issued at 352 PM CDT Wednesday Jul 29 2015

Air temperatures behind the front on Thursday will not be that much
cooler than today. However, should have dewpoint temperatures as
much as 10-15 degrees cooler so while it will still be hot, it
should feel significantly less bad. Northwest flow aloft will bring
another weak cold front southeast through the bi-state region Friday
night. There appears to be very little if any return flow ahead of
the front, so unless evapotranspiration can raise the dewpoints
significantly ahead of the front, it might go through dry. However,
NAM and GFS are printing out some precipitation along the front Friday
afternoon and Friday night over northern Missouri and west central
Illinois, so have introduced some slight chance probability of precipitation. After the
front GOES through it looks like a dry and continued warm forecast
at least until Monday or Monday night when another cold front dips
south across the Midwest. The strong high north of the front moves
southeast across the Great Lakes into the Ohio Valley Tuesday night
into Wednesday, but we stay on the periphery, and current medium
range solutions keep the front wavering between central Missouri and
the Mississippi River through early Thursday morning. This will
keep a chance of precipitation in the forecast into the latter part of the
week.

Carney

&&

Aviation: (for the 00z tafs through 00z Thursday evening)
issued at 508 PM CDT Wednesday Jul 29 2015

Cold front has m0ved through the area with high pressure settling
in from the northern rocikes to the lower Missouri Valley. Dew
points in the 60s will be a welcome change. Light west to
northwest wind and VFR conditions.

Specifics for kstl: high pressure moving with drier air. Light
west to northwest wind through Thursday. VFR.

Jpk

&&

Preliminary point temperatures/pops:
Saint Louis 71 91 72 91 / 5 0 0 10
Quincy 65 89 66 89 / 0 0 0 20
Columbia 67 89 67 90 / 0 0 0 10
Jefferson City 67 91 66 91 / 0 0 0 10
Salem 67 89 67 89 / 10 0 0 10
Farmington 68 89 65 89 / 10 0 0 5

&&

Lsx watches/warnings/advisories:
MO...none.
Illinois...none.
&&

$$

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