Area Forecast Discussion
Issued by NWS St. Louis, MO
FXUS63 KLSX 310457
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1157 PM CDT Thu Oct 30 2014
Issued at 944 PM CDT Thu Oct 30 2014
The light showers which have been moving through southeast MO and
southwest IL should shift southeast of our forecast area by
midnight. Patchy light rain, mainly sprinkles will move
southeastward through mainly the IL counties of our forecast area
late this evening and overnight. This activity is associated with
another northwest flow shortwave and a secondary cold front. Post
frontal low level cloudiness across the northern Plains will
advect southeastward into our area later tonight. Surface winds
will become northwesterly and strengthen behind the second cold
front, bringing much colder air into our area. This strong cold
air advection late tonight will lead to below normal temperatures
across northeast MO with temperatures dropping to close to
32 degrees in this area by 12z Friday.
.SHORT TERM: (Through Tonight)
Issued at 250 PM CDT Thu Oct 30 2014
Focus this evening will be on PoPs.
Sfc low continues to move thru the CWA with light SHRA ahead of
the low. At the current rate, the SHRA will be out of the CWA
around or by 00z. However, redevelopment will be possible,
especially across ern portions of the CWA as a secondary fnt
pushes swd. The secondary fnt shud bring colder air, but
additional clouds as well. This presents a bit of a forecast
challenge for temps tonight. Overall, trended twd the cooler
guidance across the N where clouds shud clear late tonight, and
warmer further S where clouds shud linger and fnt may not arrive
by sunrise tomorrow. While temps tonight will be around freezing
across the nrn counties, do not anticipate a hard freeze and
strong winds behind the fnt shud prevent any frost from forming.
.LONG TERM: (Friday through Next Thursday)
Issued at 257 PM CDT Thu Oct 30 2014
Sfc ridge builds into the region beginning Fri. With no precip
expected, focus turns to temps thru the weekend.
Mdls are in good agreement thru the weekend with the sfc ridge
settling just NW of the CWA Fri night, then to the SE on Sat
night. This shud allow ample radiational cooling across the region
with a clear sky for nearly the entire night. Have upgraded the
Freeze Watch to a Warning for the entire CWA as confidence
continues to build. Note that if this Warning verifies across the
CWA, this will end the Freeze/Frost headlines for the CWA this
year as the growing season has come to a close.
Mdls remain in fairly good agreement with the next cdfnt to impact
the region. Latest guidance suggests precip develop/enter the CWA
Mon afternoon and persist thru much of the day Tues and into Tues
evening as the slow moving cdfnt pushes thru the area.
Not much in the way of cold air is currently expected behind this
fnt. Some differences exist among mdl guidance regarding temps
behind this fnt. For now, have trended twd a compromise.
.AVIATION: (For the 06z TAFs through 06z Friday Night)
Issued at 1157 PM CDT Thu Oct 30 2014
VFR conditions and dry weather will prevail at the TAF sites thru
much of the valid period. A weak area of low pressure just west of
the STL metro area, resulting in light and variable winds with
strengthening winds in its wake out of the N-NW, will drop
southeast allowing a secondary cold front in later tonight. The
only exception to the VFR looks to be with a period of lower CIGs
following the secondary cold front. Another potential pitfall with
non-VFR is a period early on of fog with weak winds, mostly clear
skies and low dewpoint depressions over the STL metro area, but
increasing winds, drier air, and clouds very soon should nullify
that possibility. There is also some small potential for light
sprinkles with the lower CIGs when they do move in, but left dry
in the TAFs. Otherwise, look for a substantial increase in winds
from the N-NW later tonight with this second front and this should
persist thru Friday with clouds scattering out Friday morning, and
then a diminishing around sunset.
Specifics for KSTL: VFR and dry thru much of the valid period.
Exception will be late tonight with MVFR CIGs expected and perhaps
a few sprinkles as well. Gusty N-NW winds will move in about the
same time as the lower CIGs and should persist thru the day on
Friday--only diminishing toward sunset.
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
MO...FREEZE WARNING from 1 AM to 10 AM CDT Saturday 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 WARNING from 1 AM to 10 AM CDT Saturday 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