Area Forecast Discussion
Issued by NWS St. Louis, MO

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541
FXUS63 KLSX 090348
AFDLSX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
948 PM CST MON FEB 8 2016

.UPDATE:
Issued at 936 PM CST Mon Feb 8 2016

Very light snow and flurries currently continue to affect much of
the CWA late this evening. Next weak upper-level disturbance will
swing through the area late tonight and bring another round of
more widespread light snow along and east of the Mississippi
River. Additional accumulations of up to a half inch of new snow
are possible.

Gosselin

&&

.SHORT TERM:  (Through Late Tonight)
Issued at 345 PM CST Mon Feb 8 2016

Large trof remains centered over the Great Lakes region thru the OH
Valley. This trof continues to send s/w swd over the area. As each
vort max drops thru the area, areas under these shud see a brief
SHSN that reduces visbys to around a mile or so. Have kept likely
PoPs for the ern half of the CWA to account for this. Still do not
anticipate accumulations with the showers due to them being very
brief.

As for temps, with continuing CAA across the region, have trended
twd the coolest guidance thru tonight.

Tilly

.LONG TERM:  (Tuesday through Next Monday)
Issued at 345 PM CST Mon Feb 8 2016

Deep cyclonic flow and additional, yet sheared, disturbances will
result in a slow, measured retreat of the stratocumulus cloud field
to the east thru Tuesday, and until the deck breaks, the lingering
threat for at least flurries will persist.

Model guidance has come into somewhat better focus on a clipper
system late Wednesday into early Thursday--enough to finally include
a mention of snow in the forecast for most areas, especially east of
the MS river.  This is a system that they had been advertising with
some consistency, yet quite varied on strength and track, to not
really include a mention of until now.  If some of the stronger
solutions verify, a stripe of 2-4" of snow may be realized out of
this, while the weaker faster versions would result in a dusting of
snow instead.  Something to watch over the next day or two.

Otherwise, a prolonged period of below average temps is forecast
from now thru the upcoming weekend, with temps possibly moderating
towards average during early next week.  The slower retreat of our
current cold airmass being pushed back to late this week and the
still anticipated arrival of a reinforcing Arctic blast on Friday
will result in little to no moderating period between the two.  The
first shot of cold looks like it will culminate late Tuesday night
into Wednesday morning, where wind chills may bottom out approaching
-15F (wind chill advisory criteria) for some areas in northern MO and
central IL.

A well advertised reinforcing Arctic blast continues to look set for
Friday, preceded by another clipper system which could drop
additional snow accums.  This cold blast looks to peak on Saturday
and Saturday night, with a slow recovery thereafter.  The recovery
may not be as great as the MOS guidance suggests, however, with the
western CONUS RIDGE persisting and allowing for slower movement on
these cold highs as well as keeping the door open for additional
reinforcing shots.

It is this uncertainty with temps late in the forecast that will
continue to plague how to handle what could be a better organized
system for early next week to affect our region.  Maintained PoPs
for Sun-Mon timeframe, but large model splits continue to be seen
with the GFS weaker and more progressive (and less QPF and cold)
than the stronger, more digging system depicted by the EC.  This
system continues to show good potential on having a widespread
wintry impact if it can also hold on to the cold and will be watched
closely over the next several days.

TES

&&

.AVIATION:  (For the 00z TAFs through 00z Tuesday Evening)
Issued at 528 PM CST Mon Feb 8 2016

Widespread stratus deck with ceilings around 3000 feet AGL and
occasional flurries/snow showers will be the rule through the
night. Lower ceilings/visibilities down into IFR will remain
possible tonight in any heavier snow shower activity. Very light
snow or flurries will likely continue along as the stratus deck
remains anchored across the region beneath cyclone flow aloft. By
late Tuesday afternoon/evening however...may finally begin to see
some improvement as ceilings either lift to VFR and/or scatter
out.


Specifics for KSTL:

Borderline MVFR/VFR ceilings along with periodic light snow
through tonight and into early tomorrow. Heavier snow showers will
still be capable of dropping visbys into IFR. Do expect some
improvement by late Tuesday afternoon as ceilings lift and/or
scatter out. Gusty NW winds to continue through the period.


Gosselin

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX



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