Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 150438
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1138 PM CDT Mon Apr 14 2014

.UPDATE:
Issued at 830 PM CDT Mon Apr 14 2014

Band of snow has effectively left our CWA leaving behind a region
of drizzle in its wake, now primarily confined to parts of
southwest IL. The clearing line has made it almost to
Jacksonville, IL, just passed thru Bowling Green, MO and near
Rolla, MO. At its current rate, the skies are expected to clear
for nearly the entire CWA by 06z, just in time for the start of a
total lunar eclipse. Diurnal cloudiness driving southeast from IA
is expected to further break up and dissipate over the next few
hours.

Temps continue to be on track with current forecast, supporting
continuation of Freeze Warnings with widespread mins in the mid to
upper 20s. Note that our forecast will either set or approach
current record low temps. See CLIMATE section below.

TES
&&

.SHORT TERM:  (Through Late Tonight)
Issued at 324 PM CDT Mon Apr 14 2014

Main concerns deal with the band of snow currently extending from
near Pittsfield to Rolla as well as the going freeze warning. The
band has been reducing visibilities to as low as 1/2 mile with
some reports of accumulation on grassy surfaces. It is being
caused by mid level frontogenesis ahead of the 500mb trough that
will move through the area tonight. The RAP and HRRR does show the
frotogenesis weakening as it moves acrosss the CWA, but do think
that it will likely maintain itself the next few hours before it
weakens by early evening. Have extrapolated the band through CWA
through early evening, with little or no accumulation of snow
expected given the warm low level and surface temperatures.

The precipitation and clouds will clear out quick as subsidence
moves in behind the passage of the upper trough.  With cold air
advection and dry dewpoints, expect temperatures to drop quickly to
near MOS temperatures.  Going freeze warning looks good and plan no
changes to it.

Britt

.LONG TERM:  (Tuesday through Next Monday)
Issued at 324 PM CDT Mon Apr 14 2014

(Tuesday through Thursday)

Have kept Tuesday into Thursday dry as the area will remain cut off
from any notable moisture from the Gulf and the active storm track
stays north of the area.  While Tuesday night will not be as cold as
tonight, most areas will still be in the lower to mid 30s for
lows.

(Thursday Night-Next Monday)

The ECMWF and GFS are now similar with the amplitude and timing of
the mid level trough and attendant cold front that will move across
the area on Friday. Will continue with the chance of showers on
Thursday night and Friday before subsidence works in behind the
trough keeping Friday night and Saturday dry.  Then confidence
begins to wane late in the weekend as they both develop QPF over the
area.  The GFS is placing more emphasis on an northern stream upper
over the Upper Midwest while ECMWF is placing it`s emphasis on a
shortwave coming out of the southwest CONUS.  Either way, will
continue the chance of showers we have going Saturday night into
Sunday night.  Temperatures during the period look to be near or
slightly below normal.

Britt
&&

.AVIATION:  (For the 06z TAFs through 06z Tuesday Night)
Issued at 1136 PM CDT Mon Apr 14 2014

Skies have cleared out of taf sites, so clear skies and northwest
winds to persist overnight. Will see some diurnal cu develop by
midday on Tuesday with winds gradually backing to the southwest
then south as surface ridge moves to the east.

Specifics for KSTL:
Skies have cleared out of taf sites, so clear skies and northwest
winds to persist overnight. Will see some diurnal cu develop by
18z Tuesday with winds gradually backing to the southwest then
south by 01z Wednesday as surface ridge moves to the east.

Byrd
&&

.CLIMATE:

RECORD LOWS FOR 4/15:

STL - 27 IN 1928
COU - 25 IN 1928
UIN - 24 IN 1928
FAM - 24 IN 1928

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...FREEZE WARNING until 9 AM CDT Tuesday 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 until 9 AM CDT Tuesday 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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