Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 271139

539 AM CST Sat Dec 27 2014

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 413 AM CST SAT DEC 27 2014

Early this morning a shortwave upper level trough was lifting
northeast across eastern NE. A positive tilt longer wave length
trough was located from the upper Midwest, southwest into extreme
southeast AZ.

The longer wave length upper level trough will continue to shear out
and fill as it shifts southeast across the plains. An area of light
rain mixed with snow across south central KS will move
east-northeast through the early morning hours and may clip the
extreme southeast counties of the the CWA during the early to mid
morning hours, southeast of I-35. Temperatures will drop into the
20s across the CWA by sunrise, thus any moist road surfaces may
freeze causing patchy ice. Motorist should watch for slick spots on
area roadways through the morning hours. Skies will begin to clear
from west to east across the CWA this afternoon. Northwest winds of
10 to 20 MPH will continue the low-level CAA, thus highs will only
reach the lower to mid 30s.

Tonight, clear skies and light winds will allow over night lows to
drop into the mid to upper teens across much of the CWA. Forecast
soundings show the low-levels will be dry but I cannot rule out some
patchy ground fog towards sunrise in low-lying areas and along
rivers and lakes.

.LONG TERM...(Sunday through Friday)
Issued at 413 AM CST SAT DEC 27 2014

Backing low level flow ahead of the next digging western trough will
aid warm air advection. The combination of warm air advection and
sunshine should push highs through the upper 30s to around 40.
As the upper trough over the western CONUS and deepens...the cold
Canadian airmass to the north will advance southward through the
central plains bringing much colder air to the area. The front is
still expected to advance southward into the far northwest portions
of the cwa early Monday morning then slowly traverse the cwa through
the day. This will likely result in most highs in the north central
early in the day with high elsewhere towards midday with temps
slowly falling most areas through much of the afternoon. Highs
should range from the middle 20s far north central to the upper 30s
south of I 35.

Moisture is lacking and and lift weak...but still cannot totally
rule out a period of light snow/flurries in the wake of the front
Monday and Monday night..but again...feel the better potential for
light snow will remain to the west of the county warning area.
Either way...any snow fall amounts would be very light if at all.
The main weather effects with the front will still be the cold air
and resulting wind chills as lows Tuesday in the 5 to 15 degree
range combine with sustained 10 to 20 mph winds to commonly produce
W.C. indices of zero to 10 below. Highs on Tuesday will still
generally be in the teens with a few low 20s south of i 35. Although
windspeeds will decrease below 10 mph Tuesday night...lows in the
single digits will still result in W.C. indices of -2 to -12
Wednesday morning.

Models are not in good agreement on the timing and track of the
upper trough approaching the area by Thursday and Friday. There
is agreement however that the Canadian high pressure center does
slide off to the south and east with winds becoming more west and
southwesterly leading to warmer air by Wednesday...continuing
through Friday. Have therefore continued a moderation trend in highs
from the 20s on Wednesday into the 30s for New Years Day and Friday.
With various model solutions on the track of the system and
resulting precip type or even precip at all...did not make any
significant changes this far out and left a rain/snow chance across
the entire area by Friday.


.AVIATION...(For the 12Z TAFs through 12Z Sunday Morning)
Issued at 530 AM CST SAT DEC 27 2014

Stratus with MVFR ceilings (1100-1800 FT) will gradually shift east
of the terminals through the mid and late morning hours. Broken
stratocu with MVFR to VFR (2500-3500 FT) ceilings may redevelop
across the terminals this afternoon. Close to sunset the skies
will clear and remain so through the night.




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