Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 200354
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1054 PM CDT Sat Jul 19 2014

.UPDATE:
Issued at 923 PM CDT Sat Jul 19 2014

Going forecast looks good as sfc ridge axis maintains its control
over the region. With the exception of some high-level cirrus
spilling over the northeastern periphery of the upper-level ridge
axis...skies are expected to be clear or mostly clear with
light/variable winds. Only real minor change made to previous
forecast was to adjust hourly temps down a bit faster over most
areas late this evening...especially eastern Ozarks and southwest
Illinois... as observations have shown a faster drop in temps due
to ideal radiational cooling conditions. Did not deviate however
yet from previous minimum temperature forecast as some
aforementioned cirrus is expected to advect southeastward along
with weak sfc return flow beginning overnight.

Gosselin

&&

.SHORT TERM: (Tonight through Sunday)
Issued at 246 PM CDT Sat Jul 19 2014

The large surface high centered in the northeastern U.S. continues
to influence conditions across the region producing yet another
day of below average temperatures. This system will gradually
weaken and retreat eastward over the next 24-36 hours as the eastern
trof departs and the four corners ridge builds eastward. We should
see at least one more seasonably "cool" night tonight, and then
more pronounced southerly flow gets underway on Sunday leading to
warming temperatures and increasing moisture/humidity.

Glass

.LONG TERM:  (Sunday Night through Next Saturday)
Issued at 246 PM CDT Sat Jul 19 2014

The upper ridge will continue to strenghthen and build through the
Nation`s midsection Monday into Tuesday leading to progressively
warmer temperatures and low-level moistening. Tuesday looks like
the hottest day of the upcoming week with conditions more typical
for later July. A pronounced low-level thermal ridge centered
through the northern half of the CWA featuring H85 temps of +20 to
+24 degC, warm mid levels and high heights aloft all favor max
temperatures well into the 90s. The pattern aloft will change once
again beginning Tuesday night with higher latitude amplification
and more progressive flow aloft in the vicinity of the U.S./Canadian
border, leading to upper troffing in the eastern U.S. and flattening
and retrogression of the upper high into the the southwestern U.S.
A cold front will push through the area in the late Tuesday night/Wednesday
time frame as a result of this pattern transition/change, bringing
a chance of showers and thunderstorms and then cooler temperatures
during the later half of the week. This front will then make a
northward return bringing a return of thunderstorm chances heading
into the next weekend.

Glass

&&

.AVIATION:  (For the 06z TAFs through 06z Sunday Night)
Issued at 1051 PM CDT Sat Jul 19 2014

VFR flight conditions and light east-southeast flow will continue
across the area for the remainder of the night. Wind will turn to
a more southerly direction by late morning/early afternoon. Expect
another round of afternoon cumulus around 5000-6000FT Sunday as
well. This should dissipate quickly again Sunday evening.

Specifics for KSTL:

VFR flight conditions and light east-southeast flow will continue
at Lambert for the remainder of the night. Wind will turn to a
more southerly direction by late morning/early afternoon. Expect
another round of afternoon cumulus around 5000-6000FT Sunday as
well. This should dissipate quickly again Sunday evening.

Carney

&&

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

$$

WFO LSX






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