Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 230428

1128 PM CDT Wed Oct 22 2014

.SHORT TERM: (Tonight and Thursday)
Issued at 328 PM CDT Wed Oct 22 2014

The surface ridge which has been controlling our weather for the
past couple of days is drifting east and weakening slightly with
time.  Water vapor imagery is showing an elongated wave extending
from Saskatchewan all the way south into west Texas.  This wave will
continue working slowly eastward overnight and should extend from
south central Iowa southwest through eastern Oklahoma by 12Z
Thursday morning.  Operational guidance is pretty adamant that there
will be little if any precip east-southeast of Kirksville in our
area before 12Z, with precip chances ramping up during the daylight
hours Thursday morning.  Scattered to isolated showers probably
won`t get into east central Missouri, but central and northeast
Missouri and west central Illinois should see some light showers in
the morning.  Rain chances diminish Thursday afternoon as the wave
loses some potency, and drier low level air on the western side of
the stubborn surface ridge cuts into the showers.  MOS guidance
looks reasonable for both highs Thursday afternoon and lows tonight.


.LONG TERM: (Thursday Night through Next Wednesday)
Issued at 402 PM CDT Wed Oct 22 2014

Any lingering showers should be exiting the area along with the
shortwave by 00Z Friday or shortly thereafter.  Another upper level
ridge builds over the Rockies and across the Great Plains Friday
into Saturday.  Northwest flow aloft will prevail both days while a
weak cold front tries to dip into Missouri and Illinois.  The upper
ridge will move over the Midwest on Sunday allowing another high
pressure system to move into the Ohio Valley.  The western edge of
the airmass keeps edging further and further west with each model
run.  Have lowered temperatures a bit from the last couple of
forecasts, tho have tried to keep highs Sunday warmer than guidance,
and retained warmest temperatures over west/southwest sections of
the CWFA.

A full-latitude trof moves into the Great Plains Monday which will
bring broad south-southwest flow to the region and warm temperatures
in the mid to upper 70s.  The surface system associated with the
trof will gain strength and affect the area Tuesday into Wednesday.
Some discrepancies with the medium range models out that far, but
high chance PoPs ahead of the cold front on Tuesday look
reasonable.  Position and speed of the system will determine whether
or not there will be thunderstorms, but a slight chance is not out
of the question.



.AVIATION:  (For the 06z TAFs through 06z Thursday Night)
Issued at 1103 PM CDT Wed Oct 22 2014

Surface ridge extending from MI southwest through southeast MO
will shift slowly southeastward this period. An upper level
disturbance and associated weakening cool front/surface trough
will move eastward through the region on Thursday. Most of the
precipitation associated with this feature will be n-nw of the taf
sites, although UIN may receive a brief shower late Thursday
morning or early afternoon. For now will include mainly mid-high
level cloudiness in the tafs for Thursday. The NAM MOS guidance
appears a little overdone on its low level cloud forecast. Could
not rule out a little fog in SUS and CPS late tonight with only a
little cirrus cloudiness and calm surface wind. E-sely surface
winds will veer around to a sly direction Thursday morning.

Specifics for KSTL: Mid-high level cloudiness will advect into the
STL area on Thursday. Any significant rain should remain n-nw of
STL. A light e-sely surface wind late tonight will gradually veer
around to a sly direction Thursday morning, and eventually to a
swly direction Thursday night.



Saint Louis     45  65  53  73 /   5  20  10   5
Quincy          43  62  50  70 /  10  40  10   5
Columbia        47  67  52  75 /  10  30  10   5
Jefferson City  45  68  50  76 /  10  20  10   5
Salem           39  62  49  69 /   0  10  10   5
Farmington      39  63  48  72 /   5  10  10   5




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