Area Forecast Discussion
Issued by NWS St. Louis, MO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
000
FXUS63 KLSX 301730
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1230 PM CDT Thu Oct 30 2014

.UPDATE:
Issued at 1132 AM CDT Thu Oct 30 2014

Lift associated with the northwest flow short wave trof currently
centered through northwest MO has been producing a growing area of
light rain/showers, which is presently situated from NE MO into SW
MO. Despite relatively dry low levels, measurable precipitation is
occurring and there have been a few lightning strikes in western MO
associated with steep mid level lapse rates/weak elevated instability.
Trends noted on radar within last few hours are not expected to
change much with precipitation spreading eastward across eastern
MO into southwest IL this afternoon. Light measurable precipitation
to trace amounts expected, and can`t rule out an isolated rumble
of thunder.

Glass

&&

.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 18z TAFs through 18z Friday Afternoon)
Issued at 1222 PM CDT Thu Oct 30 2014

The back edge of a large area of showers currently extends from
KUIN to just west of KCOU at midday. These showers will continue
moving to the east through the afternoon impacting the St. Louis
area terminals with light rain showers and VFR conditions. The
precipitation should be east of all TAF sites by 23z. A cold front
will then pass through the area this evening with a big increase
in northwest winds overnight accompanied by a period of MVFR cigs.
The cigs should clear out on Friday morning with gusty northwest
winds continuing well into the afternoon.

Specifics for KSTL:

Light rain showers accompanied by VFR flight conditions will
impact the terminal this afternoon and should exit to the east by
23z. Thereafter a cold front will move through this evening with a
big increase in northwest winds overnight, accompanied by a period
of MVFR cigs beginning around 11z. The cigs should clear out near
15z Friday morning with gusty northwest winds continuing well into
the afternoon.

Glass

&&

.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






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.