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000
FXUS63 KEAX 282202
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
402 PM CST Wed Jan 28 2015

.DISCUSSION...
Issued at 341 AM CST WED JAN 28 2015

Today will signal the last day to the extended stretch of winter
warmth that we have experienced. Beyond today, winter-like
temperatures and conditions will return. The main concern during
this period will be the potential for accumulating snow over the
weekend.

A ridge of high pressure is shifting east into the Ohio Valley early
this morning. Back to the west an upper level shortwave is moving
through the Rockies allowing a cold front to strengthen across the
northern and central Plains. This will cause the pressure gradient
to tighten across the area providing for strong southerly winds and
good mixing today. 850mb temperatures will range between 13C-16C
providing for afternoon highs in the upper 50s to the lower 70s
across the southwestern CWA. Tonight the aforementioned upper level
shortwave moves through the Plains and into the local area forcing a
cold front through the area. By Thursday, the upper level trough
will push east of the area leaving the region under northwest flow
aloft. At the surface, strong CAA will be ongoing behind the cold
front. That, accompanied with mostly cloudy skies will provide for a
return to more seasonable highs in the low to mid 40s. High pressure
will move into the area Thursday night and remain over the area
through the day on Friday. A cold start with lows in the low to mid
20s, coupled with weak mixed will only yield highs in the mid 30s to
lower 40s on Friday.

The forecast become challenging over the weekend as an evolving
storm system gets organized and poised to bring precipitation to the
area. The system in question will involve the merging of a deep
trough over the southwestern CONUS on Saturday and an upper level
shortwave diving south out of the Canadian Rockies into the central
Plains. These two system look to merge over the Plains on Saturday.
Precipitation will move into the area on Saturday morning out ahead
of a cold front. P-type on Saturday is still uncertain at this point
however, model sounding suggest that near surface temperatures will
be warm enough to support rain at this time. However, there are ice
crystals in the snow growth zone so precipitation may fall as snow
if the warm layer near the surface is not as deep as represented
however, snow is not expected to accumulate. Saturday night the cold
front will push through the area with CAA behind it. This should
sufficiently cool the entire column below freezing. The question at
this time is there ice crystals in the snow growth zone. Soundings
suggest that there are and that should provide for a period of snow
Saturday night into Sunday. The phased upper level trough will move
through the area on Sunday with snow coming to an end from west to
east during the day. Highs Sunday will only reach into the upper 20s
to mid 30s. Surface high pressure then quickly moves into the
forecast area Sunday night providing for good radiational cooling.
Lows by Monday morning will be the coldest we have seen since the
beginning of January in the single digits and lower teens. Monday
will be dry and cold as surface high pressure remains on the area
with highs in the teens in the upper teens to mid 20s. Models are
suggesting a shortwave will move through the region on Monday
night/Tuesday but spatial and timing difference among the models
preclude more than slight chance POPs for that timeframe.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1116 AM CST WED JAN 28 2015

VFR conditions are expected to persist through the afternoon and
evening as scattered cirrus drifts across the region. Winds will
increase out of the south southwest within the next hour or so, and
should gust between 20 and 25 kts through sunset. Gusts should
briefly drop off between sunset and the arrival of the cold front,
then will veer sharply to the northwest at sustained speeds up to 20
kts with gusts up to 30 kts. Broken MVFR ceilings are expected to
follow behind the front, and could possibly drop below 2 kft after
09z.


&&

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

$$

DISCUSSION...73
AVIATION...Laflin