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000
FXUS63 KSGF 131704
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1104 AM CST Fri Dec 13 2013

.SHORT TERM...(Today and Tonight)
Issued at 349 AM CST FRI DEC 13 2013

Precipitation has begun to spread across northeastern Oklahoma
already this morning. This is quicker than models had the
precipitation in the previous runs yesterday. As a result we have
expanded the winter weather advisory to the west to cover all our
CWA. The upper level trough is in the process of crossing the
Rockies and moving into the plains. In response, the surface low
was strengthening and sliding south across northern Texas and
western Oklahoma.

The concern continues to be with the speed of the precipitation,
the cold air in place and how far north the expected warm nose
will make it into the region. All the models from the NAM, GFS to
the ECMWF and Canadian have backed off on the strength of the warm
nose and lag the speed of the precipitation we are seeing now.

As a result of the quicker onset of the precipitation and the
weakening of the warm nose by the models, have increased the snow
accumulations across the eastern Ozarks to the 2-4 inch range,
with lesser amounts to the west. The potential for significant
freezing rain seems to be lower at this time but will again depend
on the mid level warm nose, and are thinking that a glaze to a
tenth of an inch is possible across the Ozarks.

In addition to the weaker trend in the warm air in the mid levels,
the nose of a low level jet this morning, will combined with the
left exit region of an upper level jet that moves over the region
this afternoon into tonight. As a result, deep lift will be in
place over the region and allow for more efficiency in the
precipitation. Models are also showing some instability in the
25-100j/kg range between 21-06z this evening. This would bring the
potential fro some isolated convection and a rumble of thunder
would not be out of the question across extreme southwestern
Missouri and extreme southeastern Kansas.

Will continue to monitor the speed of the system this morning and
provide updates as needed.

.LONG TERM...(Saturday through Thursday)
Issued at 349 AM CST FRI DEC 13 2013

The winter storm system will shift to the east early Saturday with
snow ongoing into the morning. After sunrise, the models indicate
a loss of cloud ice with a transition to freezing drizzle before
the precipitation would end from west to east through early
afternoon. A cold air mass will filter into the region behind the
system with temperatures only climbing to around the freezing mark
in the afternoon and falling into the teens for Sunday morning.

In the wake of this system, a warming trend looks to begin for the
Ozarks to begin next week with no expectation of precipitation
until late next week into next weekend. Temperatures by mid week
are expected to climb to around 50 degrees for highs which will
be welcome after the week of temperatures at or below freezing.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 1055 AM CST FRI DEC 13 2013

Messy forecast with critical temperatures holding close to the
freezing line. We have started to see the transition over to
rainfall this morning as the surface temperatures warm to above
freezing and this trend will continue to spread east throughout
the afternoon. An upper level trough and jet max will approach the
region this evening and should see enhanced precipitation develop
during the evening and overnight hours with upper level lift
increasing significantly. Should start to see the ceilings come
down into IFR/LIFR as we hit the late afternoon and early evening.
Heading into the mid to late evening...thermal profiles will begin
to cool and could start to see a transition from rain to snow
which will continue into a good portion of the overnight hours.
Heading into the early morning, we will lose the cloud ice aloft
and will be left with freezing drizzle for a good portion of
Saturday morning. IFR/LIFR conditions will persist from late
afternoon through the remainder of the forecast period Saturday.

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...WINTER WEATHER ADVISORY until 6 AM CST Saturday FOR MOZ055>058-
     066>071-077>083-088>098-101>106.

KS...WINTER WEATHER ADVISORY until 6 AM CST Saturday FOR KSZ073-097-
     101.

&&

$$

SHORT TERM...Hatch
LONG TERM...Hatch
AVIATION...Lindenberg