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Area forecast discussion...updated aviation 
National Weather Service St Louis MO
1159 am CDT Sat Sep 5 2015

Short term: (through late this afternoon)
issued at 322 am CDT Sat Sep 5 2015

Expect yet another warm day today as high temperatures should climb
once again into the lower-mid 90s under mainly sunny skies. Mixing
should be above 800mb. Mixing down 850mb temperatures around +20c
support high temperatures in the lower-mid 90s. Heat index readings
will be close to 100 degrees given that dewpoints will be well into
the 60s if not 70 degrees at times.

Will also stick with a dry forecast as thunderstorms stayed over
eastern Illinois despite the atmosphere being unstable and uncapped
yesterday afternoon. Conditions will be similar over the area today
with MUCAPES being in the 1000-2000 j/kg range with little cinh and
some of the cams showing some convective development by midday.
However, much like yesterday, there will be the mid-level ridge axis
over the region that should suppress thunderstorm development, so
will leave forecast dry for now.

Britt

Long term: (tonight through friday)
issued at 322 am CDT Sat Sep 5 2015

(tonight through monday)

Will keep forecast dry through late Sunday night as forecast
soundings are showing less instability tomorrow than today as the
ridge axis reorients itself southwest-northeast across the area.
Temperatures and humidity will be similar to today. Chances of
showers and thunderstorms will begin to increase by late Sunday
night as the upper ridge shifts to the south and low level moisture
convergence increases over central and northeast Missouri. Chances
will continue to increase over the area Monday and Monday night as
the upper ridge shifts farther south and the faster, upper flow and
eventually the surface cold front moves into northern Missouri and
central Illinois. Have likely pops on Monday night over parts of
central and northeast Missouri as well as west central Illinois.

(Tuesday through friday)

Cold front will be slow to move through the Missouri and Illinois as
a series of shortwave troughs move through the region during this
period. First front will move through the area on Tuesday into
Wednesday followed by a secondary front that both the GFS and European model (ecmwf)
are showing that will move through late week. Both the series of
shortwave troughs and the fronts will keep a persistent chance of
showers and thunderstorms in the forecast through next week.

Temperatures will begin to fall back to near normal behind the front
by mid to late next week...particularly with clouds and the chance
of rain.

Britt

&&

Aviation: (for the 18z tafs through 18z Sunday afternoon)
issued at 1157 am CDT Sat Sep 5 2015

VFR and dry thru the period except for possible river fog at ksus
and possibly kcps. Otherwise, ssely to sly winds aob 10 kts.

&&

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

$$

Weather forecast office lsx

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