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000
FXUS63 KEAX 091831
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1231 PM CST Mon Dec 9 2013

.UPDATE...
Issued at 1228 PM CST MON DEC 9 2013

Have lowered afternoon temperatures across areas which have snow
cover. The combination of the fresh snow cover and continued presence
of an arctic airmass is proving difficult to warm. Will be adjusting
overnight temperatures...downward...in the afternoon forecast
package despite winds shifting to the southwest.

&&

.SHORT TERM...(Today through Wednesday)
Issued at 319 AM CST MON DEC 9 2013

There will be several small chances for precipitation on the
southern and northern extremes of the forecast area over the next
few days. The first chance will be this evening as a positively
tilted trough swings through the Central Plains and into the Lower
Missouri Valley. A very strong upper jet is situated along the edge
of the upper PV anomaly and very strong QG forcing will develop this
evening as the wave moves east. This will tighten up the temperature
gradient aloft leading to strong frontogenesis in the 600mb to 500mb
layer. The strong coupled forcing will produce a narrow corridor of
snow from southern Kansas through southern Missouri. Depending on how
narrow (or broad) this band of snow is and where it exactly it sets
up, there could be several inches of snow. Right now, this looks to
be south of our forecast area, but the band may be broad enough to
spread some light snow across the southern half of our southernmost
counties.

The second round will come Tuesday night as a clipper dives down the
western edges of the main longwave trough over central to eastern
sections of the CONUS and Canada. The strongest forcing with this clipper
looks to stay in Iowa and the Upper Midwest but there could be some
snow move into our far northern counties as the wave quickly transits
through the region.

With either of these systems, the chances for anything to accumulate
looks very low and have only mentioned slight chances for snow. We
look to continue the relatively dry pattern from the last few
weeks/month, which has helped to extend the drought that developed
this Summer across northern Missouri.

With regards to temperatures, continued cooler than normal
conditions are expected. The only significant change to the current
temperature trends were to lower temperatures on Wednesday. In the
wake of the Tuesday night clipper system, another very strong and
cold high pressure center will push into the region. Strong cold
advection should mostly offset diurnal warming and temperatures may
be steady or falling through the day, especially across northern
Missouri.

.LONG TERM...(Thursday through Sunday)
Issued at 319 AM CST MON DEC 9 2013

Main concern in the extended period will revolve around a storm
system  that could bring a potential ice/snow storm to area. This
system would affect the area in the Friday/Friday night time frame.
Otherwise the other concern will be the continuation of the below
normal temperatures.

Models are in good agreement at the onset of the the extended
period. Northwest flow aloft and surface high pressure residing over
the area Thursday morning will provide a very cold start to the day.
However, high pressure will shift east during the day and "warm" air
will begin to advect into the region. This will occur ahead of an
upper level system which is progged as a closed low over the extreme
southwestern CONUS on Thursday. This low will move into the Four
Corners region Thursday night becoming an open wave. Friday this
open shortwave will move into the Plains states as moisture spreads
northward into the region out of the Gulf ahead of the system. The
precipitation type with this system is tricky right now as subtle
changes in surface features and timing will dictate whether we will
experience liquid or freezing rain. The 00Z GFS shows precipitation
would hold off until Friday afternoon providing for above freezing
temperatures and a cold rain. The 00Z ECMWF is slightly faster with
the onset of precipitation and a few degrees cooler at the surface
which would provide for a freezing rain scenario during the day
Friday. Both models depict a cold front moving through the area
Friday night which would change precipitation over to freezing rain
or snow. In any case, this system will have to be monitored closely
during the upcoming days. The upper shortwave will move through the
area by early Saturday morning providing for the potential for very
light snow which will shift east of the area by Saturday afternoon.

Saturday, high temperatures will continue to be well below average
with highs in the upper 20s to mid 30s. However, temperatures should
begin to moderate through the second half of the weekend into early
next week with highs in the upper 30s to the lower 40s on Monday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday Afternoon)
Issued at 1114 AM CST MON DEC 9 2013

VFR conditions at TAF sites as well as across northern and west
central MO. Further south a band of snow will move through southern
into southeast MO this afternoon and evening. Light winds will shift
to the southwest overnight.


&&

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

$$

UPDATE...MJ
SHORT TERM...CDB
LONG TERM...73
AVIATION...MJ