000
FXUS63 KSGF 121753
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1153 AM CST Thu Dec 12 2013

.SHORT TERM...(Today and Tonight)
Issued at 238 AM CST THU DEC 12 2013

High pressure over the area will shift southeast with milder s-sw
sfc winds developing today. Dry low levels should keep precip at
bay through tonight.

.LONG TERM...(Friday through Wednesday)
Issued at 238 AM CST THU DEC 12 2013

Precip will develop and/or spread northeast into the region Friday
morning ahead of a vigorous shortwave now beginning to open up
and move onshore over northern Baja. The main concern will be
precip types and amounts, and frankly, a small shift from progged
low level temperature profiles and moisture depth will have a
large affect on precip type Friday and Friday night.

Friday Morning: Precip will develop quickly in response to rapid
moisture advection coupled with lift near the left exit region of
an approaching jet max. Temperatures may be steady and in some
cases slowly rising late (Thu) tonight, especially over the
western cwfa. While some dry air in place early will have to be
overcome, it won`t take too long, especially over the western cwfa
just after daybreak with precip spreading rapidly north and east
during the morning. Vertical temperature profiles from 0-3km will
be a battle of warm air advection and a warm nose at around 800mb
versus evaporative cooling. Ultimately, think that showery precip
will start as some freezing rain and maybe some sleet here and
there with the best chances for some ice accumulation from the
Springfield areas and points north and east. The coldest sfc
temperatures look to be at higher terrain/elevations of the
southern MO Ozarks where some light icing may occur, even on some
elevated road surfaces late Fri morning and early Fri afternoon.
Most other areas should see a transition to rain, and even most
areas just east of Springfield along Hwy 60 should finally get to
32-33 deg F by mid/late afternoon. Overall ice accumulation will
be on the light side, less than a tenth of an inch, but given the
potential showery nature of the precip, there may be pockets of
somewhat higher amounts.

Fri Night: Will see a transition back to a light wintry mix from
north to south over most of the area with some snow or light
freezing rain/drizzle. Precip type will be more dependent on
moisture depth by this time, but overall it looks like we
gradually lose ice crystal growth potential after midnight with
some freezing drizzle possible. Sfc temperatures during this time
do not drop off a great deal, but some accumulation of snow and a
glaze of ice will be possible with the best chances over central
and south central MO.

Overall predicted snow/ice amounts do not support a Winter Storm
Watch right now, but ultimately a Winter Weather Advisory will
likely be required. The main worry will be how fast the first wave
of precipitation comes in Friday morning and how quickly it can
spread east while temperatures remain cold enough for
freezing/frozen precip.

Saturday: Lingering clouds and blustery conditions are expected as
winds shift around to the nnw as low pressure moves through the
southern MS River Vly region early in the day. Some light precip
may linger early, but amounts look trace to minor measurable
amounts at best.

Sunday and beyond: Looks quiet for the most part with a warming
trend early in the week as the cold air mass shifts to the east.
Models differ a bit during the midweek period with the GFS brushing
by with another cold frontal passage, but the brunt of the cold
air will stay off to the northeast. The ECMWF keeps us relatively
mild through midweek.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1149 AM CST THU DEC 12 2013

Pilots can expect VFR conditions today and tonight then
deteriorating flight conditions Friday.

A steady southerly wind at the surface will continue into tonight.
Low level wind shear will also develop as the low level jet strengthens.

Moisture will rapidly increase late tonight and Friday as a storm
system approaches. A mix of precipitation will overspread the
region Friday morning. Freezing rain will impact the terminal
sites before transitioning to rain by Friday afternoon.

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

SHORT TERM...DSA
LONG TERM...DSA
AVIATION...Foster