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 48 49 50
000
FXUS63 KLSX 260909
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
309 AM CST Thu Feb 26 2015

.SHORT TERM:  (Through Late This Afternoon)
Issued at 308 AM CST Thu Feb 26 2015

Shortwave digging over northeast Missouri and associated cold front
now moving through the I-44 corridor will continue to produce light
snow through the first part of the morning.  Have also had a few
reports of freezing drizzle back in central Missouri, but not sure
how long this will last so have opted not to mention in the forecast
at this time.  Will continue to monitor and update if freezing
drizzle ends up persisting.  Both NAM and GFS show some decent low
level frontogenetical forcing back on the cold side of the front
before 12Z this morning...but the forcing quickly diminishes between
12Z and 15Z.  Mesoscale models do keep light snow going for a few
hours this morning, but really back off the precip by 15Z like the
operational models.  Both NSSL and NCEP 4km WRF models pop up what
look like instability snow showers this afternoon, so have kept
chance PoPs going into the afternoon primarily along and east of the
Mississippi River.  Total accumulations of 1 inch or less look
likely along and south of the I-70 corridor with 1-3 inches north
and northeast of St. Louis...primarily across west central and parts
of southwest Illinois.  Will continue headlines as they are this
morning.  Stuck close to the cold side of guidance for temperatures
today as the cold Arctic high moves in behind the cold front.

Carney

.LONG TERM:  (Thursday through Next Wednesday)
Issued at 302 PM CST Wed Feb 25 2015

The clipper system will be followed by an Arctic high pressure
center which builds across the central CONUS on Thursday/Thursday
night. The coldest temps on Thursday night/early Friday morning
should occur across the northwestern CWA due to proximity to the
ridge axis along with the fresh snow cover. The high pressure
center then shifts eastward on Friday and Saturday. Return flow
begins on Saturday around the back side of the high pressure
center.

Kanofsky

Atmospheric responses to a large low pressure system over the
southwestern CONUS and a trough over the northern plains (strong
WAA and frontogenesis) could bring a wintry mix of all ptypes to
the area on Saturday night and then again for Monday through
Tuesday. but confidence in ptypes, timing, duration, amounts,
transitions, and PoPs remains very low. Kept likely PoPs on days 6
& 7 for collaboration with surrounding offices. Anyone who has
travel plans or other weather-dependent plans early next week are
advised to continue monitoring the forecast over the next few
days.

42

&&

.AVIATION:  (For the 06z TAFs through 06z Thursday Night)
Issued at 1139 PM CST Wed Feb 25 2015

Reduced SN at COU as much of the precip across that region has
dissipated. SN at UIN shud gradually diminish thru the early
morning hours as the system pulls sewd. With cigs beginning to
rise, going TAF may hold on to SN too long. However, with sparse
RADAR coverage across this area, it is difficult to determine how
far SE some of the heavier bands stretch. Otherwise, winds will
remain nly with gusts to around 25 kts into the afternoon hrs.
Believe cigs will be slow to rise and going forecast may break up
clouds too quickly.

Specifics for KSTL/KSUS/KCPS: Believe SN will begin shortly before
sunrise. SN will gradually diminish thru the morning with cigs
slow to rise. Given how cold temps will be, can expect light SHSN
periods of flurries thru the day. Otherwise, winds will remain nly
with gusts to around 25 kts thru the afternoon hrs. Believe cigs
will be slow to rise and going forecast may break up clouds too
quickly.

Tilly

&&

.PRELIMINARY POINT TEMPS/POPS:
Saint Louis     24   3  17   7 /  90  10   0   5
Quincy          14  -6  11   0 /  50   5   0   5
Columbia        18   0  16   7 /  40   5   0   5
Jefferson City  21   2  18   8 /  50   5   0   5
Salem           24   2  14   6 /  70  10   0   5
Farmington      24   4  18   7 /  60  10   0   5

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...WINTER WEATHER ADVISORY until 9 AM CST this morning FOR Knox MO-
     Lewis MO-Marion MO-Monroe MO-Ralls MO-Shelby MO.

IL...WINTER WEATHER ADVISORY until 9 AM CST this morning FOR Adams IL-
     Brown IL-Pike 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.