Area Forecast Discussion
Issued by NWS St. Louis, MO

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000
FXUS63 KLSX 301139
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
639 AM CDT Thu Oct 30 2014

.SHORT TERM:  (Through Late This Afternoon)
Issued at 343 AM CDT Thu Oct 30 2014

Main focus for today will be clipper-like system coming in from the
mid-Missouri Valley and its associated impacts on the sensible weather.
Models are in fairly good agreement wrt track and timing of this system
with sfc low located just west of KMBY around 1800 UTC to just west of KFAM
around 0000 UTC Friday...quite an unusual track this far southwest
especially given the time of year. Have increased PoPs parallel and to
the ENE of the sfc low track into the low-end likely category which
conceptually matches best with the QPF output from the 0000 UTC
Thursday model run from the ECMWF. Specifically...this paints some likely
PoPs oriented northwest to southeast from near KHAE to NW of KSAR. Amounts
will be fairly light...around a tenth of an inch.

Temperatures will also be problematic today...certainly not atypical of
clippers...with a sharp southwest to northeast gradient. Leaned above
guidance along and especially to the south and west of the consensus sfc
low track...i.e. most of central Missouri including KCOU and KJEF. For
roughly the northeastern half of the CWA leaned a bit cooler than guidance
due to more cloud cover...higher likelihood of rain showers...and a more
easterly component to winds which combined are expected to hold temps in
check.

Gosselin

.LONG TERM:  (Tonight through Wednesday)
Issued at 343 AM CDT Thu Oct 30 2014

Surface low to continue tracking southeast tonight away from
forecast area. Could still see some showers this evening for
southeast Missouri as well as southwestern Illinois. Otherwise, lows
will be in the low 30s to low 40s.

On Friday, more vigorous shortwave to drop south across Illinois on
backside of upper low. Could see some showers develop far east, but
confidence is low so kept this area dry for now. This system will
bring in much colder air as the day progresses as well as gusty
north winds. Temperatures will struggle to rise much, depending on
cloud cover. For now have highs in the mid to upper 40s. Could reach
highs by midday, then see temps remain steady or slowly fall during
the afternoon hours.

Friday night will be the coldest we have seen since mid April. With
the clear skies and winds diminishing, will see lows in the 20s.
Kept freeze watch going for late Friday night/early Saturday
morning.

Temperatures to begin a slow moderation by Sunday as surface ridge
moves off to east and next weather system approaches region. Highs
by Sunday will be in the upper 40s to mid 50s. Models are a bit
slower in bringing in precipitation with next system, so only have
slight chance pops for far northern portions of forecast area Sunday
night. Best chances of precipitation will be Monday afternoon
through Tuesday before tapering off by Wednesday. Some isolated
thunderstorms will be possible with this system, but expect mostly
showers. Highs will be in the mid 50s to low 60s Monday through
Wednesday.

Byrd

&&

.AVIATION:  (For the 12z TAFs through 12z Friday Morning)
Issued at 630 AM CDT Thu Oct 30 2014

Main focus will be on chances of rain showers through late this
afternoon. Scattered showers may impact terminals beginning later
this morning with continued chances of rain through the afternoon.
Believe best chances of rain showers will be St. Louis metro TAF
sites early/mid afternoon and have tempo to account for this. Rain
should be fairly light coming out of a mid cloud deck and probably
will not result in low ceilings and/or visibility restrictions.
Winds will shift to out of the northwest behind the clipper-like
system this evening and become gusty late tonight/early Friday morning.

Specifics for KSTL:

Main focus will be on chances of rain showers through late this
afternoon. Scattered showers may impact site as soon as later
this morning with continued chances of rain through the afternoon.
Believe best chance of rain showers will be early/mid afternoon
and have tempo to account for this. Rain should be fairly light
coming out of a mid cloud deck and probably will not result in low
ceilings and/or visibility restrictions. Winds will shift to the
northwest behind the clipper-like system this evening and become
gusty late tonight/early Friday morning.

Gosselin

&&

.CLIMATE:
Issued at 236 PM CDT Tue Oct 28 2014

Halloween Top News of the Day Article on the NWS St. Louis Website
contains Halloween Climate Statistics for St. Louis, Columbia and
Quincy.  (http://www.crh.noaa.gov/lsx)


&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...FREEZE WATCH from late Friday night through Saturday morning FOR
     Audrain MO-Boone MO-Callaway MO-Cole MO-Crawford MO-
     Franklin MO-Gasconade MO-Iron MO-Jefferson MO-Knox MO-Lewis
     MO-Lincoln MO-Madison MO-Marion MO-Moniteau MO-Monroe MO-
     Montgomery MO-Osage MO-Pike MO-Ralls MO-Reynolds MO-Shelby
     MO-St. Charles MO-St. Francois MO-St. Louis City MO-St.
     Louis MO-Ste. Genevieve MO-Warren MO-Washington MO.

IL...FREEZE WATCH from late Friday night through Saturday morning FOR
     Adams IL-Bond IL-Brown IL-Calhoun IL-Clinton IL-Fayette IL-
     Greene IL-Jersey IL-Macoupin IL-Madison IL-Marion IL-Monroe
     IL-Montgomery IL-Pike IL-Randolph IL-St. Clair IL-
     Washington IL.

&&

$$

WFO LSX






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