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000
FXUS63 KPAH 300532
AFDPAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
1132 PM CST Thu Jan 29 2015

.SHORT TERM...(Tonight through Sunday)
Issued at 301 PM CST THU JAN 29 2015

Nice cold frontal passage this morning; we got everything but cold
air. After falling for several hours, the temperature at KPAH is
just now back down to normal high levels for today. Went very
pessimistic on clearing of the low clouds. It will likely be
sometime tomorrow, hopefully morning, before significant clearing
occurs. Nudged low temperatures up a bit tonight, as cooling will
be achieved solely by advection, and we already stated it just
isn`t that cold an airmass. Also tempered highs a bit on Friday.
If the low clouds prove to be more stubborn, we will not be cold
enough.

Surface high pressure will hold on over the region Friday night
and much of Saturday. This should lead to decent radiational
cooling, especially east, and chilly lows possibly into the upper
teens by Saturday morning. All guidance points to a significant
increase in clouds through the day, as our next winter storm
approaches. Undercut statistical guidance for highs Saturday,
despite light south winds developing through the day.

The models may be finally latching onto a coherent solution for
the winter storm Saturday night through Sunday. The 12Z GFS,
ECMWF and GEM spread light QPF across our north initially Saturday
evening, and slowly try to push it south overnight. Much of west
Kentucky and the Missouri Boot Heel region may not see much
precipitation until after 12Z Sunday. The 12Z models, including
the NAM emphasize Sunday morning for the most widespread
precipitation. The precipitation will come to an end from west to
east through the afternoon.

The GFS and ECMWF are in fairly good agreement in the surface
temperature forecast Saturday night and Sunday, and used them as a
guide for temperatures through the period. It still appears that
the precipitation will fall as snow and will be trying to melt in
the near surface layer which will likely be just above freezing
through the event.

Generally, went with pure snow where the GFS/ECMWF blend had less
than 35 degrees, and a rain snow mix elsewhere. Using Superblend
QPF and a 10:1 snow to liquid ratio, both of which could be
conservative values, snowfall totals of around 5" are common
across the northern half of the area. There is a very sharp
gradient to the south. Even the NAM, which has a sharper surface
low and warmer air into the southern portions of the area, has
snowfall totals of 6-8" in the north.

The bottom line is that there is increasing potential for at least
Advisory level snows over much of the area, and Warning levels are
not out of the question across the north. Confidence is increasing,
but it is still not high enough to consider a headline or even a
Special Weather Statement at this time. Will address it in the HWO.

.LONG TERM...(Sunday Night through Thursday)
Issued at 301 PM * CST THU JAN 29 2015

Models show high pressure building over the central Plains Sunday
night, which will help push our surface low farther east.  Light
snow/flurries will gradually taper off from west to east, with only
minor additional accumulations expected mainly during the evening,
and mainly across just our eastern half of counties. With the breezy
north winds, overnight lows will drop into the teens to around 20
degrees.

High pressure will slide across our region on Monday, and this will
help us see some sunshine, but temperatures will only climb into the
20s to around 30 degrees.  The high will move off to our east Monday
night, and the return of southerly winds will help temperatures
rebound to just a few degrees below seasonal readings.

For Tuesday night into Wednesday, ECMWF, GFS and GEM all bring a
cold front across the middle Mississippi and lower Ohio valleys,
with ECMWF and GFS having very similar placement and timing.  Precip
will likely be snow mainly late Tuesday night, with our southern
counties becoming a rain/snow mix on Wednesday based on surface
temperatures.  So far QPF amounts look pretty minor, but how much
warm air and moisture return occur ahead of the front will be
something to continue to watch.  For now just went with some slight
chance pops due to the low QPF amounts.

Behind the mid week cold front, high pressure will again build
across the central U.S.  This will give us quiet and chilly
conditions for Thursday.

&&

.AVIATION...
Issued at 1132 PM CST THU JAN 29 2015

Quite frustrated with the higher VFR ceilings than forecast, but
the expected ceilings near 3kft agl +/- 500 ft are finally coming
to fruition. Plan to keep these ceilings in place through at least
14z. Shortened the period of ceilings by 3-5 hours, before
clearing out.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&

$$

SHORT TERM...DRS
LONG TERM...RST
AVIATION...Smith