Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 201121

621 AM CDT Mon Apr 20 2015

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 258 AM CDT MON APR 20 2015

Mostly clear skies across the area tonight as surface low continues
to move northeast into the Great Lakes region.  Larger scale upper
trof that has resulted from phasing of the systems across the plains
continues to drop ripples of energy southward through the west side
of the trof.  As they move through, they are expected to enhance
mixing this morning, aiding in bringing down higher winds and
gusts.  Radar profilers already indicating around 35-40 kts at 850
and 925 mb moving into the area.

Winds expected to pick up not long after sunrise and continue
through the middle afternoon, with sustained winds around 20 mph
with gusts around 30-35mph.  Temperatures should rise quickly into
the upper 50s and lower 60s.  Combined with dewpoints in the 20s,
the temperatures and winds will make for very high fire danger today
across much of the northern and western portions of the area.  As
winds diminish through the evening and overnight, and temperatures
fall into the 40s to middle/upper 30s, may need to consider patchy
frost later tonight. At this time most guidance suggests some clouds
moving in later tonight toward early Tuesday morning and may be
enough to keep frost at bay.

.LONG TERM...(Tuesday through Sunday)
Issued at 258 AM CDT MON APR 20 2015

Tuesday morning the region remains under strong NW flow aloft as the
now current surface high retreats eastward through the mid south.
Weak shortwaves within the NW flow aloft will track over the
forecast area on the day Tuesday, and supply some mid level moisture
and lift. There will still be a deep layer of low level dry air,
which may prevent some precip from reaching the ground. Another
high pressure builds southward through the northern plains on
Tuesday. This will push a cold front through the forecast area
either late Tuesday or early Wednesday, but there are some timing
issues with the models as of now. Showers and isolated thunder
will be possible with the front generally along and south of
interstate 70 Tuesday night into Wednesday morning. If the high
pressure moves in quicker then most of Wednesday appears to be
dry. On Thursday isentropic lift increases over portions of
southern KS ahead of the next southern stream shortwave. This wave
is forecast to track over the southern Rockies and into the plains
Friday and Saturday. Although, there are some important
differences among the operations models with regards to how strong
this shortwave will be as it lifts out over the plains, which will
have an impact on timing. Depending on the model either Thursday
through Friday diffluence aloft associated with the wave, a
strengthening low level jet, decent moisture, and lee side
cyclogenesis in SE CO should support better chances for showers
and storms. Steep lapse rates and moisture will overspread the
region allowing the instability to increase, although with such
widespread activity this could inhibit surface instability at the
least. One thing for sure is that the deep layer shear will be in
place and could support elevated hailstorms depending on how much
is actually effective.


.AVIATION...(For the 12Z TAFs through 12Z Tuesday Morning)
Issued at 619 AM CDT MON APR 20 2015

VFR conditions expected through the period. Winds increase from
the northwest today before diminishing this evening.




LONG TERM...Sanders
AVIATION...67 is the U.S. government's official web portal to all federal, state and local government web resources and services.