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Area forecast discussion 
National Weather Service St Louis MO
355 am CDT Tuesday Sep 1 2015

Short term: (through late this afternoon)
issued at 330 am CDT Tuesday Sep 1 2015

Primary concern for today is thunderstorm chances throughout the
day. Short range guidance continues to want to break out isolated
to widely scattered convection this morning along a line from near
West Plains Missouri to Salem Illinois. This is in the vicinity of
a middle-upper level vorticity chain stretching up from East Texas
through Arkansas and southeast Missouri into Indiana. Rap shows
some weak low level warm advection and moisture convergence under
the vorticity chain through middle morning and latest infrared Sat-pics show what
looks like Alto-cumulus breaking out in the vicinity of the
aforementioned line. Indeed...surface observation show developing ceilings
between 8000-10,000 feet and an isolated cell has recently popped up
on radar in central Illinois. Should see this activity continue to
percolate through middle morning before waning. Think there will be
some redevelopment this afternoon in the vicinity of that vorticity chain
where the middle level capping and upper level subsidence will be
weakest. Coverage will likely be widely scattered at best. With
relatively stagnant pattern in place, expect highs to be similar to
yesterday's...perhaps a degree or two warmer.


Long term: (tonight through monday)
issued at 355 am CDT Tuesday Sep 1 2015

Expect any thunderstorms that develop this afternoon to quickly
dissipate early this evening as we lose daytime heating. While the
shear axis/vorticity chain in the middle and upper levels will still be
in the vicinity of the area tonight and Wednesday, it looks like it
will be weakening with time as well as dipping further south across
far southeast Missouri, northeast Arkansas, Tennessee, and Kentucky.
I can't totally rule out an isolated shower or thunderstorm
tonight into wednesay, but think precipitation chances are low enough in
our County warning forecast area to keep probability of precipitation below mentionable levels at this time.

The rest of the forecast at least through the weekend looks pretty
uneventful. Late Summer-like pattern with strong ridging through
the depth of the troposphere should keep the area hot and dry
through the weekend. Highs look to be in the low to middle 90s with
lows generally in the low to middle 70s. Dewpoint temperatures should
stay in the upper 60s to low 70s across the area though the period.
While this will feel warm and humid, current thinking is that heat
headlines will not be needed. A pattern shift with some cooler
temperatures may be in the forecast next week, but GFS and European model (ecmwf)
aren't exactly in good agreement on this. Regardless...the shift
(if it occurs) will likely be toward the middle of the week; so have
kept warm temperatures going through Monday.



Aviation: (for the 06z tafs through 06z Tuesday night)
issued at 1105 PM CDT Monday Aug 31 2015

Weak upper low/shear axis will become centered over Indiana by
midday Tuesday. Suspect that will keep most of the thunderstorms and rain deelopment
east of the terminals. While a isolated storm possible, no reason
to put it in the forecast. Patchy fog overnight, basically a
persistence forecast.

Specifics for kstl: VFR dry forecast continues. High pressure
begins building thus the the isolated afternoon thunderstorms will
become even more isolated. Would not be surprised to see some
morning fog/haze start appearing the next couple of days.



Preliminary point temperatures/pops:
Saint Louis 91 78 92 78 / 10 10 5 5
Quincy 90 70 91 70 / 5 5 5 5
Columbia 90 69 91 69 / 10 10 5 5
Jefferson City 91 69 92 70 / 10 10 5 5
Salem 89 71 90 70 / 20 10 10 5
Farmington 88 68 91 69 / 20 20 10 5


Lsx watches/warnings/advisories:


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