Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 202351

Area Forecast Discussion
National Weather Service Topeka KS
551 PM CST Mon Nov 20 2017

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Tuesday)
Issued at 343 PM CST Mon Nov 20 2017

For the 24-36 forecast period, quasi zonal flow will transition to
more amplified western CONUS ridge and eastern CONUS trough set up.
Currently, southerly flow regime remains in place ahead of an
encroaching frontal system associated with an Alberta clipper system
undergoing frontogenesis over the Canadian Prairies region.  Due to
the zonal to slightly northwest flow over the Rockies, a lee trough
has become more active and intensified allowing for the stronger
surface to upper level winds to set up over the region.  Stronger
winds have been mixing to the surface today and thus have held onto
a wind advisory for areas surrounding the Emporia area along the I-
335 corridor.  Most areas in the advisory have had sustained winds
of over 30 mph this afternoon.  Areas, with stronger mixing have
adiabatically warmed to the mid 60s over the area.

Overnight, the aforementioned Alberta clipper system will deepen and
dig into the Northern Plains and western Great Lakes region as a
compact upper wave traverses the area.  This will help push a cold
front into the area after midnight and pushing through much of the
forecast areas of northeast and east central KS by sunrise.  Right
now, saturation appears to be in the mid levels and adequate for
broken to overcast skies, but dry low levels probably inhibit any
light flurries from making it to the ground.  Therefore have only
gone with very slight chance POPs over northern counties.  If a
flurry or two can fall, this may be a change that needs to be added
in the next forecast cycle.  Overnight lows should be around 40. See
Fire Weather discussion for details on Fire Weather

.LONG TERM...(Tuesday night through Monday)
Issued at 343 PM CST Mon Nov 20 2017

The medium to long term continues to look dry for the next week.
Northwest mid and upper level flow is forecast to continue across
the central Plains for much of the period. Wednesday mornings lows
will be cold with readings in the upper teens to lower 20s which
will be the coldest of the upcoming week. Temperatures begin to
moderate after Wednesdays highs in the 40s to lower 50s back into
the 60s for Thanksgiving Day. Temperatures on Friday are expected to
be 15 to 20 degrees above seasonal normals in the upper 60s to lower
70s ahead of another cold front which is forecast to move through
during the day on Friday which will cool temperatures back to around
seasonal normals for the weekend into next Monday.


.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 541 PM CST Mon Nov 20 2017

For the 00z TAFs, VFR conditions are expected with winds veering
from southwest to north overnight as a weak cold front quickly
tracks southeastward across the area. The LLJ looks to quickly
increase early this evening to around 45-50kts, so expect some
LLWS concerns into the early overnight hours.


Issued at 343 PM CST Mon Nov 20 2017

This afternoon, fire weather concerns are high to very
high across the region.  Min RH values remain in the mid 20 percent
range. Southwest winds will continue until 6 pm CST around 20 mph
and gusts around 30 mph.  Concern late tonight will be a cold front
entering the area by sunrise Tuesday morning.  This will shift winds
back to the NNW.  While fire danger will be somewhat lower on
Tuesday, winds will be strong again this time out of the NW.  Gusts
could approach 30 mph once again late morning into the afternoon.




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