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000
FXUS63 KTOP 021742
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1142 AM CST Sun Mar 2 2014

...Update to short term and aviation forecast...

.UPDATE...
Issued at 1128 AM CST SUN MAR 2 2014

The main upper trough is now ejecting into the Plains and the
combination of stronger ascent and increased moisture influx into
the dry layer aloft has allowed a band of moderate to heavy snow
to move into the region. Dry advection in the low levels from the
northeast is still persistent and strong on the northern edge of
the snow band, with a sharp cut off from very light snow to heavy
snow along an Abilene to Topeka line. Cancelled all winter weather
advisories north of this line while maintaining products south of
it. Current indications are that additional snow from 10 AM
through the end of the storm will probably range from 1 to 4
inches with the lowest amounts north, near the aforementioned cut
off line. The warm nose aloft also remains evident in dual pol
radar imagery south of an Emporia to Ottawa line so may see a bit
of sleet still mixing in over these areas. The center of the
filling upper trough will move into southwest Missouri after 6
PM...and may maintain enough forcing to continue some light snow
over east central KS through around 9 PM or so...but with the
continued dry advection expect only light additional accumulation
beyond 4 PM. Wind chill advisory has also been expanded across the
entire area and extended through Monday morning as the wind chill
will range from -10 to -25 across the area through this entire
period.

&&

.SHORT TERM...(Today and Tonight)
Issued at 349 AM CST SUN MAR 2 2014

Bands of frontogenesis continue to bring precipitation to mainly
eastern and southern sections of the CWA. Radar trends suggesting
precip types trending to more snow versus sleet. Latest water vapor
has upper trough still not yet through the Four Corners with 09Z obs
putting axis of surface ridge through central Kansas.

Models continue to differ on just where precip will be today. The
GFS seems to be the strong outlier again, with much stronger and
deeper frontogenesis redeveloping this morning. This seems to be
tied to a very strong and channeled vorticity max it brings through
aloft, backing mid level winds and tightening the thermal gradient.
With its recent runs not panning out too well, and it being the
outlier, have put little weight on it. Still will have some 1.5 PV
pressure advection this morning and increasing 300-700mb Q-vector
convergence across east central Kansas as the wave enters the
Panhandles this afternoon. Non-GFS models are similar with the
middle and lower levels drying throughout the day, helping limit
precip chances north of I-70 to mainly the early day, with southern
areas clearing overnight as the wave passes. Have trended amounts
down, but still somewhat conservatively as RAP and HRRR still
suggest some banded structures continuing northeast into northeast
and east central Kansas. Any significant accumulations for north
central Kansas should be finished and dropped the Advisory there,
while tapering amounts elsewhere for a downgrade from Riley to
Jackson counties and ending the Warning earlier for locations north
of the Turnpike. Mid level winds do back a bit as the wave nears for
a potentially warmer warm nose and perhaps more sleet to return just
north of the Turnpike this morning. Wind chills are the other major
consideration and Advisory levels should persist through around
midday for the entire area, and will likely return this evening as
temps drop to around 0 and winds slowly subside. Just how far the
winds go down is a big challenge with clearing taking place as the
center of the high comes in. With the ongoing situation and
uncertainty tonight, will hold off on a headline for tonight at this
point.

.LONG TERM...(Monday through Saturday)
Issued at 349 AM CST SUN MAR 2 2014

After a very cold start to the day on Monday with wind chills in the
15 to 23 below zero range through late morning. The winds will be
around 5 mph with temperatures of 4 to 8 below zero rising above
zero by noon. Surface high pressure will be located over northeast
Kansas on Monday morning then moving off to the east through the
day. This will allow for winds to come back around to the southeast
from west to east through the day. Highs on Monday with limited
mixing and some snow cover will only warm into the teens.

Tuesday a wave moves through the northwest flow across the Northern
Plains and into the Great Lakes Region. This will push another front
south into the CWA by the end of the day. Highs on Tuesday will warm
back to above freezing ranging from the lower to middle 30s.

Models bring the next trough across the Central Plains in the
northwest flow on Wednesday. There appears to be sufficient moisture
and lift with this system as it moves through for light
precipitation. Forecast soundings from the GFS and ECMWF suggest all
snow generally along and south of Interstate 70 with some light snow
to the north. Highs Wednesday will again be in the 30s.

Warm advection and weak ridging occur Thursday into Friday which
will warm things up for the end of the week. Highs in the 40s
expected on Thursday with 50s on Friday. Friday night and Saturday
will see the next system move through the area. This will bring a
chance of rain and snow to the CWA. There is still model uncertainty
with the timing of the trough late in the week so confidence is low
with regards to the timing as the GFS is much faster and further
north than the ECMWF.

&&

.AVIATION...(For the 18Z TAFs through 18Z Monday Afternoon)
Issued at 1128 AM CST SUN MAR 2 2014

Snow, moderate and perhaps even heavy at times will move across
the region. There is a very sharp cut off on the north edge of
this snow, with VFR conditions expected at MHK, with periods of
VFR, MVFR, and IFR conditions at TOP/FOE. FOE has the best chance
for more persistent IFR through around 21Z. Have fair confidence
in snow end time, and expect VFR conditions to be dominant after
snow comes to an end with winds also tapering off after 00Z.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY until 9 AM CST Monday FOR KSZ008>012-020>024-
026-034>040-054>056-058-059.

WINTER STORM WARNING until 6 PM CST this evening FOR KSZ026-
035>040.

WINTER STORM WARNING until Midnight CST tonight FOR KSZ054>056-
058-059.

&&

$$

UPDATE...Barjenbruch
SHORT TERM...65
LONG TERM...53
AVIATION...Barjenbruch