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000
FXUS63 KSGF 020540
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1140 PM CST Sun Dec 1 2013

.SHORT TERM...(This Evening through Tuesday)
Issued at 317 PM CST SUN DEC 1 2013

The main forecast concern for this period will be the potential
for dense fog. Fog was most prevalent last night across west-
central Missouri and southeastern Kansas. The fog was very slow to
burn off with low stratus still persisting this afternoon across
southwestern Missouri and portions of extreme southeastern Kansas.
The setup looks even better for tonight as low level moisture
advection continues. Current thinking is that almost all of the
Missouri Ozarks and southeastern Kansas will get in on at least
some patchy fog action. We suspect that fog may form rather
quickly across west-central Missouri this evening as temperatures
will not have all that far to fall to approach dew points. A Dense
Fog Advisory may again be required for part of the area later
tonight. After morning fog on Monday, the setup again looks good
for fog Monday night as even stronger moisture advection develops.
There is some question on fog coverage Monday night as increasing
southerly winds may promote low stratus over some areas.

Otherwise, above normal temperatures will persist early this week
as the upper level flow backs from northwesterly to westerly.
Even with occasional fog and low clouds, highs on Monday should
have no problem making the upper 50s. Overnight lows will be in
the upper 30s and 40s...which is a solid 10 to 15 degrees above
normal for early December. While most areas are expected to remain
dry through Monday night, some drizzle will be possible across
southern Missouri.

Tuesday will then be even warmer with surface winds becoming gusty
out of the south to southwest. Models are progging 850 mb
temperatures warming into the 10 to 13 Celsius range. This should
result in all areas warming into the 60s Tuesday afternoon.
Unfortunately for us, these mild temperatures will become a distant
memory by next weekend.

.LONG TERM...(Tuesday Night through Sunday)
Issued at 317 PM CST SUN DEC 1 2013

A massive pattern change will commence from mid to late week. The
upper level flow will become southwesterly as strong upper level
energy digs down the west coast. Global models continue to advertise
short wave energy emerging from a long wave trough across the
western United states...with this wave tracking across the northern
and central Plains on Wednesday. This will drive a strong cold front
south across the Ozarks sometime Wednesday night/Thursday morning.
At this time, we prefer a faster frontal passage given that this air
mass will be awfully chilly in nature. As the initial front passes,
we may see a few rain showers develop across the region. At this
time, instability supportive of thunder appears as if it will remain
just southeast of the area.

The bigger concerns then start from late Wednesday night into
Thursday. An Arctic origin air mass will continue to filter into the
area as a 1040+ mb high pressure slides down from the Canadian High
Plains. As this happens, global models remain consistent in phasing
a split upper level jet from the southern Plains into the Great
Lakes. Models then subsequently strengthen and back-build a jet core
into the southern Plains as short wave energy emerges from the
southwestern United States from later Thursday into Friday. This
will promote a substantial increase in large scale lift across the
region and a high likelihood for wintry precipitation late this week.
At this time, it appears that the most likely time period for
widespread wintry precipitation will be from Thursday afternoon
into Friday morning.

Precipitation type is still a big question with this setup. Most, if
not all global models paint primarily a snow picture after a brief
window of freezing rain potential. It must be pointed out that
global models handle both the position and depth of Arctic air
masses poorly. Given that the large scale trough will be positively
tilted, it is possible that the cold dome will not be as deep as
models are currently showing. We have therefore held onto freezing
rain potential into Thursday night across south-central Missouri.
Farther to the north, confidence is higher that primarily snow will
fall from extreme southeastern Kansas up into the Lake of the Ozarks
region. Given that the main core of this storm system is just now
coming onshore across British Columbia, accumulation amounts remain
a big question. Obviously, precipitation type will be key. Liquid to
snow ratio will also come into play as the Arctic air mass filters
in.

Another big story by the end of the week will be bitter cold
temperatures and wind chills. Low temperatures in the single digits
will be quite possible by the weekend...especially if there is snow
on the ground. High temperatures this weekend may struggle to
even reach the lower to middle 20s. With the main core of the
surface high remaining to our north, we will hang onto a
persistent northerly wind. This will drive wind chills down below
zero at times.

Medium range models then show more upper level energy coming across
the region late this weekend. If this indeed occurs, snow would be
the likely precipitation type with the cold air mass entrenched
across the region.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday Night)
Issued at 1130 PM CST SUN DEC 1 2013

For the KSGF/KJLN/KBBG tafs: Low ifr fog and ceilings over the
region will gradually lift and burn off from 15z-19z. A
weak/diffuse front over the area will lift lift back to the north
late in the taf period with light south winds. Some fog
redevelopment may occur again late in the taf period, but should
be more common just after the 03/06z cutoff.

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...DENSE FOG ADVISORY until 10 AM CST Monday FOR MOZ055>057-066>070-
     077>081-088>096-101>105.

KS...DENSE FOG ADVISORY until 10 AM CST Monday FOR KSZ073-097-101.

&&

$$

SHORT TERM...Schaumann
LONG TERM...Schaumann
AVIATION...DSA