000
FXUS63 KTOP 101729
AFDTOP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1129 AM CST Tue Dec 10 2013

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 330 AM CST TUE DEC 10 2013

Surface high pressure continues to push southward behind the
departing shortwave that brought snow to far SE KS and SW MO last
evening. Winds have therefore shifted the SW and increased from
earlier in the evening. Expect that boundary layer mixing will
prevent the temperatures from dropping any lower and rather
remaining steady through the early morning hours. Later today a
shortwave will approach the plains from the northern Rockies which
will support the development of a lee side trough and another cold
front set to arrive later tonight. As the trough develops low level
winds shift to the SW allowing temperatures to warm considerably
from yesterday. Today with mostly sunny skies across the region high
temperatures reach the mid 30s for areas along and south of
interstate 70. The deeper snow cover across the northern forecast
area keeps highs there in the upper 20s and low 30s.

Later this afternoon the approaching shortwave digs eastward into
the upper Midwest after exiting the Rockies pushing the cold front
through the region. The front arrives in north central KS tomorrow
around 03Z and south central KS by 09Z shifting the winds to the
north northwest. There is decent lift associated with the front
although there is no available moisture for precipitation. Also the
stronger forcing associated with the passing wave remains north of
the area. Wednesday morning surface winds slightly increase after a
calm frontal passage, but generally remain below 10 mph, with low
temperatures in the upper 0s to low 10s.

.LONG TERM...(Wednesday through Monday)
Issued at 330 AM CST TUE DEC 10 2013

Wednesday and Wednesday Night, an amplified upper trough across the
eastern US will provide eastern KS with northwest flow aloft and
another surge of arctic air on Wednesday. Low-level CAA through the
day will only allow high temperatures on Wednesday to reach the mid
to upper teens across the northern counties of the CWA with lower
20s along the I-70 corridor and mid 20s across the extreme southern
counties.

The center of the surface ridge will build southward across the CWA
Wednesday evening then shift southeast of the CWA by 12Z THU. Clear
skies and light winds will allow for good radiation cooling and
allow temperatures north of I-70 to drop into the single digits.
Areas of Northeast KS with snow cover may approach 0 degrees. As
winds shift to the south across north central KS, temperatures may
slowly rise through the early morning hours of Thursday.

Thursday, high temperatures will warm as winds become southwesterly
at 10 to 20 MPH on the west side of the surface ridge axis the
central and lower MS river valley. Expect highs to reach the mid to
upper 30s across much of the CWA. Areas of north central and east
central KS with snow cover may only reach the lower 30s.

Friday through Saturday, A closed low off the southern CA coast,
embedded within the southern branch of the jet stream will be kicked
east across the desert southwest by an upper level trough moving
onshore across the pacific northwest. The southern branch H5 trough
will lift northeast across OK into MO by Friday night. The ECMWF and
GEM both show enough WAA ahead of the H5 trough that precipitation
on Friday may start out as a mix of freezing rain and rain, then
possibly rain by Friday afternoon. As the H5 trough approaches the
warm layer aloft should cool causing the rain to switch back to snow
through the evening hours. Both the ECMWF and GEM show the potential
for a TROWAL to develop across south central and southeast KS and
lifting northeast across the southeast counties of the CWA Friday
night. This could bring the potential for accumulating snowfall
south of the KS turnpike through Friday night into early Saturday
morning. The GFS model tracks the southern stream H5 trough farther
south across OK into AR and keeps the heavier precip south of the
CWA. Highs Friday afternoon will reach the mid 30s to around 40
degrees. Overnight lows will drop into the 20s.

The second H5 that moved onshore across the pacific northwest and
served as the upstream kicker will dig southeast into Texas and keep
all the stronger ascent will south the southeast of the CWA through
the day Saturday. A surface ridge will build south bringing slightly
cooler temperatures with highs in the upper 20s to lower 30s.

Sunday and Monday. An upper level trough digging southeast out of
central Canada will move across the Great Lakes States. This will
bring an Arctic airmass southward across the Midwest and Great Lakes
states. The coldest air should remain northeast of the CWA. Highs
on Sunday will range from the mid 20s across the extreme northeast
counties to the mid 30s across the southwest counties. Light west
winds will moderate Highs into the mid and upper 30s on Monday.

Another Arctic front may move southwest across the CWA Tuesday night
and Wednesday. Highs Wednesday may only reach the teens.

&&

.AVIATION...(For the 18Z TAFs through 18Z Wednesday Afternoon)
Issued at 1117 AM CST TUE DEC 10 2013

VFR conditions expected at KTOP/KFOE/KMHK through forecast period.
Southwest winds back to the south at KTOP/KFOE aft 21Z remaining
below 10 kts. Another strong fropa is expected to enter KMHK aft
08z and KTOP/KFOE aft 09z. Do not expect precipitation along the
boundary with only a developing scattered cloud deck near 8 kft.
Winds however increase as they veer to the northwest at or above
10 kts sustained through 18z.

&&

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

$$

SHORT TERM...Sanders
LONG TERM...Gargan
AVIATION...Bowen