Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 101744
AFDTOP

AREA FORECAST DISCUSSION
National Weather Service Topeka KS
1144 AM CST WED FEB 10 2016

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 349 AM CST WED FEB 10 2016

A quick little clipper system, with a surface low currently in
northeast Montana, will dive quickly south across the Plains today
with the surface low into southern Kansas by sunset. This system
will initially increase winds from the SW, with occasional gusts 20
to 25 mph in eastern Kansas where the pressure gradient will be
strongest. Dewpoints start out quite dry in the low to mid teens and
while mixing will be effective today, there is some moisture above
the boundary layer and dewpoints will probably rise a bit through
the day. Questions arise by early afternoon though as the surface
low approaches and winds become more westerly and then
northwesterly. These winds should decrease in strength but will also
bring in some drier advection a the top of the boundary layer, and
could see those dewpoints stabilize or decrease in the afternoon.
Temperatures will also be much warmer today, with highs in the 50s
common amidst strong warm advection and good mixing. Regarding fire
weather, the current MinRH forecast is to approach 25% in the Flint
Hills and slightly higher to the north. The lowest RH seems unlikely
to occur at the same time as the strongest winds, which may gust 20+
mph for a bit late this morning...so while fire danger may be
elevated, red flag conditions seem unlikely.

There is a strong temperature gradient from SW to NE across the
region, and the surface low will act to tighten the gradient and
induce frontogenesis from eastern Kansas east across Missouri. The
frontogenesis will be fairly strong and paired with negative EPV for
CSI and even some convective instability above the frontogenesis.
However, we are under a subsident quadrant of the upper jet streak
and have very weak differential vorticity advection in conjunction
with the strongest frontogenesis...at least over the local forecast
area. Additionally, while there will be some saturation in the
mid/upper levels, low levels will be dry with continued advection of
dry air into northeast Kansas. All of this will be likely to keep
the majority of snow with the clipper east of the forecast area,
although there is a small chance for flurries in far northeast
Kansas mainly between 6-10 AM as the strengthening frontogenesis
interacts with weak DPVA for a few hours.

Clear skies early will become cloudy overnight and cold advection is
expected across the region in the wake of the surface low. Winds
turning out of the north should hold at 5-15 mph through the night,
keeping the boundary layer mixed and low temperatures should hold in
the low to mid 20s.

.LONG TERM...(Thursday through Tuesday)
Issued at 349 AM CST WED FEB 10 2016

Tomorrow cold air will move in behind on the backside of a quickly
moving surface low pressure, which means highs will stay in the mid
to upper 30s. Another clipper system will track through the
northwest flow aloft tomorrow night. Although the precipitation will
be light and should stay east of the forecast area. An expansive
surface high pressure then builds into the center of the country as
an upper ridge moves in from the west. This arctic high pressure
will bring cooler temperatures on Saturday with highs struggling to
reach freezing. Return flow after the surface high retreats will
allow temperatures to rebound through next week. During that
timeframe a shortwave trough moves over the northern Rockies and the
plains Sunday. On Sunday the wave will bring a chance of
precipitation mainly to eastern KS. GFS soundings show a lack of ice
in the cloud and decent lift just below the cloud ice layer. Near
the surface there is a substantial cold layer, which would refreeze
any liquid into some sort of wintry mix. The GFS seems to be a
rather cool solution compared to other models. Model consensus of
the forecasted high temperatures that day is the 40s, which would
support rain as opposed to a wintry mix. The ECMWF with a similar
track and strength doesn`t develop any measurable precipitation over
the area. It appears that amounts if any would be rather light yet
worth keeping an eye out. Beyond that the pattern becomes quasizonal
and therefore pretty dry.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1138 AM CST WED FEB 10 2016

Expecting VFR conditions with winds progressively veering to the
northeast. Any gusts calm near sunset and some clouds are expected
to move in from the northwest. Have put in some low level SCT
clouds in the last half of the period with cooling of the boundary
layer.

&&

.TOP Watches/Warnings/Advisories...
NONE.
&&

$$

SHORT TERM...Barjenbruch
LONG TERM...Sanders
AVIATION...Drake


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