Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 111715
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1215 PM CDT Fri Jul 11 2014

.SHORT TERM:  (Through Late This Afternoon)
Issued at 334 AM CDT Fri Jul 11 2014

A warming trend will be underway today as ridging begins to
develop over the region once again, accompanied by a return to
southerly flow. A stationary front south of the area will drift
north as a warm front, and while showers and thunderstorms are
possible in the warm advection regime, it appears the greatest
chance for development today will be over northeast Missouri and
west central Illinois, nearer to the vicinity of a few shortwaves
that are progged to skirt north of the area. Recent model guidance
keeps measurable precipitation just out of the forecast area, so
for now have only included slight chance pops over far northeast
Missouri and west central Illinois. Otherwise, it should feel much
more summer- like today, with increased humidity and highs
climbing to the mid to upper 80s across the area, with around 90
degrees possible in the St. Louis metro area and in mid Missouri.

JP

.LONG TERM:  (Tonight through Thursday)
Issued at 334 AM CDT Fri Jul 11 2014

Tonight, storms are progged to develop over Nebraska and Iowa as a
series of shortwaves continue to ride over the top of the 500mb
ridge, While much of the energy will remained focused to the
north of the forecast area overnight, storms may follow the
surface boundary southeast, clipping portions of northeast
Missouri and into west central Illinois by early Saturday morning.
Have included some chance pops to account for this possibility.
Otherwise, Warming temperatures and southerly flow will continue
to be the main focus through the weekend across the area. 850mb
temperatures are progged to be in the 20-22C range on Saturday,
which would translate to highs in the low to middle 90s across the
area. On Sunday, the chance for convection across northern
portions of the area will begin to increase as the ridge begins to
break down, thus have highs in the upper 80s Sunday across the
northern tier of the forecast area, and low to mid 90s once again
roughly along and south of Interstate 70.

The chance for showers and thunderstorms will overspread the area
Sunday night and Monday, as the ridge continues to break down in
response to a deepening low over the Great Lakes and accompanying
eastern CONUS trough. A strong cold front will move southward
through the area on Monday and Monday night, which will likely be
accompanied by convection, given the seasonably warm and humid air
mass in place ahead of it. The front will be well south of the
forecast area by Tuesday morning, and with cooler temperatures and
drier air filtering in behind the front, we will get another break
from the summer heat. 850mb temperatures Tuesday and Wednesday are
only in the 8-10C range, and thus highs in the low to middle 70s
Tuesday and Wednesday are not out of the question. Expect cool and
dry conditions to persist through the remainder of the extended,
with temperatures slowly moderating, but remaining below normal.

JP

&&

.AVIATION:  (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 1206 PM CDT Fri Jul 11 2014

Main forecast concern at this time is the probability of any showers
or thunderstorms impacting any of the TAF sites. Any development
this afternoon expected to be quite sparse in coverage. Tonight
the main zone of shower and thunderstorm activity will be focused
in the vicinity of a boundary stretching from Nebraska across Iowa
into northwest Illinois. This is expected to remain north of the
terminals, although we will have to keep a close eye on KUIN
overnight. Otherwise VFR flight conditions are expected to be
prevalent through the forecast period.

Specifics for KSTL:

VFR flight conditions are expected to be prevalent through the
forecast period. At this time it appears the main threat of
showers and thunderstorms will remain well north of KSTL, and
elsewhere coverage will be quite isolated.

Glass

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX





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