Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 200733
AFDLSX

Area Forecast Discussion
National Weather Service Saint Louis MO
133 AM CST Fri Jan 20 2017

.SYNOPSIS...
Issued at 1253 AM CST Fri Jan 20 2017

Unseasonably warm temperatures overnight with lows only falling
into the lower and middle 40s. This is 20 to 25 degrees above
normal! If you go by climatology, this should be the coldest time
of the year with average HIGH temperatures in the upper 30s to
around 40 degrees. Another week and our average highs start
climbing back into the lower 40s!

CVKING

&&

.SHORT TERM... (Through Saturday)
Issued at 1253 AM CST Fri Jan 20 2017

Widespread dense fog blankets the region this morning and much of
the short term model guidance along with climatology suggest that
visibility will not improve until 16Z, so have extended the Dense
Fog Advisory through 10 a.m.

Fog and stratus will try to lift this afternoon, with perhaps a
few peaks of sunshine appearing across the eastern Ozarks by
sunset. This will once again severly limit our diurnal temperature
rise. Have adjusted high temperatures down a couple categories
for today.

Skies will try to clear on Saturday and this forecast assumes that
they do with sunshine for most of the afternoon. With this in mind
have kept high temperatures ridiculously warm for the third
Saturday in January with most locals reaching into the 60s. It
doesn`t appear that any records are obtainable, but certainly the
pick day of the weekend (see climate section below).

CVKING

.LONG TERM... (Saturday Night through Thursday)
Issued at 1253 AM CST Fri Jan 20 2017

Next piece of energy expected to develop into a cutoff low and
move south-southeast from the southern Plains to the Gulf Coast
the second half of the weekend. Have maintained a chance of rain
and isolated thunderstorms for the southern half of the CWA
Saturday night and Sunday given the proximity of the storm system.
Increasing cloud cover Saturday night and lingering through Sunday
night should once again but a cap on the diurnal temperature curve
while temperatures remain above normal.

Upper level ridging in the wake of that storm system should bring
a quiet period of weather to the region Monday and Tuesday with
above normal temperatures.

A pattern shift appears to be in the offing for the middle to end
of next week as the main trough of low pressure that has been
anchored across the west coast will shift east across the Midwest
and allow a new trof of low pressure to setup across the eastern
CONUS by next weekend. With this pattern change there will be a
chance of some light precipitation, more clouds (yay) and
temperatures returning to readings more typical for winter.

CVKING

&&

.AVIATION...  (For the 06z TAFs through 06z Friday Night)
Issued at 1017 PM CST Thu Jan 19 2017

Main issue late tonight and Friday morning will be stratus cloud
deck below 500 feet in height along with low visibilities in fog.
An area of showers and a few thunderstorms moving through the St
Louis metro area this evening have caused some improvement in the
visibilities and ceiling heights, but this should be short lived
with visibilities expected to drop back down to one quarter of a
mile overnight. Patchy drizzle can also be expected for the rest
of the night. Will see gradual improvement of ceilings and
visibilities late Friday morning and afternoon to MVFR conditions
with a southeast surface wind increasing to around 7-9 kts.

SPECIFICS FOR KSTL: Main issue late tonight and Friday morning
will be stratus cloud deck below 500 feet in height along with
low visibilities in fog. An area of showers and a few thunderstorms
moving through the St Louis metro area this evening have caused
some improvement in the visibilities and ceiling heights, but this
should be short lived with visibilities expected to drop back down
to one quarter of a mile overnight. Patchy drizzle can also be
expected for the rest of the night. Will see gradual improvement
of ceilings and visibilities late Friday morning and afternoon to
MVFR conditions with a southeast surface wind increasing to around
7-9 kts.

GKS

&&

.CLIMATE...
Issued at 1253 AM CST Fri Jan 20 2017

January 21st Record High Information

St. Louis, Missouri  STL  75  (1986)
Columbia, Missouri   COU  73  (1957)
Quincy, Illinois     UIN  69  (1957)

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...Dense Fog Advisory until 10 AM CST this 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-Saint Charles MO-
     Saint Francois MO-Saint Louis City MO-Saint Louis MO-Sainte
     Genevieve MO-Shelby MO-Warren MO-Washington MO.

IL...Dense Fog Advisory until 10 AM CST this 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-Saint Clair IL-Washington
     IL.

&&

$$

WFO LSX



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