000
FXUS63 KTOP 260522
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1122 PM CST Wed Feb 25 2015

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Thursday)
Issued at 349 PM CST WED FEB 25 2015

A shortwave trough continued to move across southeast across
Nebraska this afternoon. A surface low and associated cold front
were moving southeast across northwest Missouri into south central
Kansas at 20Z. Frontogenetic forcing along the front from the
surface through 850 mb has keep a band of precipitation together
through the afternoon. Upstream observations show precipitation
initially starts as rain then transitions into light snow within an
hour or two. In addition winds have shifted to the north around
25 mph with gusts of 35-40 mph behind the front with temperatures
falling some 15 to 20 degrees in an hours time after frontal
passage. Radar trends as well as high resolution short term models
move the frontal band of precipitation southeast across northeast
and east central Kansas this evening. Forcing shifts off to the
southeast around midnight. An upstream wave across the northern
plains will move southeast overnight and may even squeeze out a few
flurries. Pressure gradient will remain tight through the night as
arctic high builds south. The winds combined with temperatures
falling into the single digits and teens will produce wind chills in
the 3 to 10 below range Thursday morning.

Temperatures will not recover very much on Thursday with cold
advection continuing through the day. Clouds should start to breakup
later in the morning hours. Highs on Thursday will range from the
teens along the Nebraska border to the lower 20s in east central and
central Kansas.

.LONG TERM...(Thursday Night through Wednesday)
Issued at 349 PM CST WED FEB 25 2015

Shortwave troughs will continue to top the Eastern Pacific ridge and
dive down the west coast into the weekend. The northwest flow will
keep cold air in place across the county warning area through the
end of the week and into the early weekend. The coldest lows should
occur Friday morning with the center of the high and lighter winds
working into the area with lows in the single digits with some below
zero readings possible near the Nebraska border.

As shortwave continue to drop into the southwestern CONUS...the flow
aloft across the central plains will slowly back. Although this will
keep relatively cold air in place across the cwa through the
weekend...it will also produce persistent warm air advection and
isentropic lift across the area beginning Saturday and continuing
into early Sunday before another cold front pushes into the area.
Forecast soundings across the area support all snow during the day
Saturday and Saturday night...although models such as the GFS are
still edging above freezing temps working northward into portions of
the east central counties by Sunday morning with a snow/sleet
potential. As a stronger shortwave trough emerges from the southwest
CONUS and into the plains...this mixture will spread northward
Monday and into Monday night with the potential for a mixture of
freezing rain/sleet and snow across all but the northwest 1/3 of the
cwa. There may be a brief lull or break in the precipitation late
Sunday into early Monday before the stronger wave arrives. As the
warmer air lifts further north with the approach of the
shortwave...have trended to a rain/snow mix potential for Tuesday
with highs in the 30s and lower 40s before precipitation comes to an
end.

At this point...expect snowfall amounts Saturday into Sunday to
range from 4 to 6 inches north to south across the area...although
the mixed precipitation potential into Monday and Tuesday with
milder temperatures makes it a tougher call on accumulations.

Also...at this point expect more on snow and sleet with some light
freezing rain accumulations possible...but this far out...forecaster
confidence is low on ice accumulations and will need to be carefully
monitored with updated forecasts.

&&

.AVIATION...(For the 06Z TAFs through 06Z Thursday Night)
Issued at 1117 PM CST WED FEB 25 2015

Will carry cigs at 2kft for overnight hours as cooling temperatures
and lift may keep them at or below this level. Do however see
some breaks in the clouds to the north, which could lead to this
deck breaking up sooner. Winds remain strong out of the north and
lose gusts later in the morning Thursday.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...53
LONG TERM...63
AVIATION...67