Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 280542

National Weather Service Topeka KS
1142 PM CST FRI NOV 27 2015

...Update to aviation forecast discussion...

.SHORT TERM...(This Evening through Saturday)
Issued at 259 PM CST FRI NOV 27 2015

Scattered freezing rain and sleet showers are now beginning to exit
the forecast area as that forcing mechanism moves eastward. The
thermo profile indicated by the models suggest a warm nose present
over most of the area through Saturday. For tonight and early
tomorrow morning temps within this melting layer will result in
freezing rain across portions of east central KS, while the rest of
the area should see more of a snow sleet mix. Lower in the profile
temps in the sub freezing layer are cold and deep enough to refreeze
some of this liquid into sleet. So expect the freezing rain and
sleet mix to be the predominate precip type. During periods of no
precip there is a very slight chance for freezing drizzle with the
decrease in mid level lift.

There should be a lull in the precip this evening before another
weak shortwave lifts out over the plains during the morning hours.
The precip amounts appear to be light during this period similar to
today so do not expect much additional accumulations of ice or
sleet. There will probably be enough though to make travel hazardous
since most places have remained below freezing for a decent amount
of time. The best chances for light ice accumulations will be
locations along a south of I-35 through late morning with up to a
tenth of an inch possible. Temperatures are then forecasted to
gradually warm tomorrow, which will allow far east central KS to
warm near or above freezing. Elsewhere locations stay below freezing
through out the day tomorrow. The mid level lift should diminish
along with saturation in the cloud growth layer mid day. Therefore
the predominate precip type becomes drizzle or freezing drizzle
depending on surface temp. There is a slight chance for enough lift
in the warm nose for light rain or freezing rain. Again, there may
be enough frozen precip to cause travel problems therefore the
advisory my need to be extending through tomorrow. Will let the next
shifts evaluate the potential for this period of freezing drizzle.

.LONG TERM...(Saturday Night through Friday)
Issued at 259 PM CST FRI NOV 27 2015

Winter weather could possibly impact the forecast area for
Saturday night through Monday as temps remain around freezing and
the cutoff upper low meanders out west. Models prog the southwest
flow to remain over the forecast area through Sunday. Within this
pattern, models dry out mid levels of the atmosphere and forecast
soundings suggest a loss of any ice within the cloud. Also there
is little sign of large scale forcing within the southwest flow
aloft. So forcing for precip Saturday night and Sunday shifts to
isentropic surfaces which show weak lift at best. It is difficult
to rule out precip chances all together since a weak perturbation
within the pattern could generate some light precip. But at this
time with the loss of ice and the low level cold air moderating
somewhat, the most likely precip type looks to be drizzle or
freezing drizzle depending on what the temp at the surface is. Any
accumulations should be very light since deep layer vertical
motion is progged to generally be neutral.

By Sunday night, there is a consensus for energy to swing around
the base of the cut off low and lift out across central and
eastern KS. With the expectation for some reasonable dynamics to
affect the weather, the best chances for accumulations of a wintry
mix should be Sunday night. The thermal profile will again be
a complicating factor as the GFS and NAM forecast soundings
indicate good low level warm air advection with surface temps
hovering around or just above the freezing mark across northeast
and east central KS. Because of this, the forecast has only rain
mentioned for eastern counties with a mix possible west of Topeka
and Emporia. The only place where mid level temps appear to go
below freezing for some possible snow is over north central KS
from Minneapolis to Washington and points west. The upper low is
progged to finally move out into the central plains on Monday.
This should lift the best forcing north of the forecast area
bringing an end to precip as dry air advects in from the west.

Except for some low level warm air advection on Monday as a
surface low develops in response to the upper dynamics, the
airmass is not expected to change much. Therefore there is not a
lot of change in temps. Overcast skies and weak cold air advection
should keep highs in the 30s on Sunday with temps across eastern
KS trending warmer due to the warm air advection into the lower
and mid 40s. Lows should see a slight trend warmer from Sunday
to Monday with readings generally in the upper 20s and lower 30s.

For Monday night through Friday, the forecast calms down as the
forecast area remains on the back side of the upper cut off low
and eventually transitions to general ridging over the plains by
mid week. Did not stray from the model consensus on temps which
show a gradual warming trend through next week. Although there
does not appear to be much warm air advection until late in the
forecast period.


.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
Issued at 1139 PM CST FRI NOV 27 2015

The low MVFR to IFR stratus ceilings will continue through the
TAF period at all terminals. A mix of sleet and freezing rain will
move across the terminals this morning. Then expect the heavier
precip to end during the afternoon with occasional freezing
drizzle into the evening. Visibilities will lower to 3 SM in
areas of heavier sleet and freezing rain.


.TOP Watches/Warnings/Advisories...
Winter Weather Advisory until 6 AM CST Saturday for KSZ010>012-



SHORT TERM...Sanders
AVIATION...Gargan is the U.S. government's official web portal to all federal, state and local government web resources and services.