Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 182326
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
626 PM CDT Mon Sep 18 2017

...AVIATION UPDATE...

.SHORT TERM...(This evening through Tuesday)
Issued at 316 PM CDT Mon Sep 18 2017

Clouds are breaking out from west to east across the area as a
leading shortwave trof makes it exit eastward. Another weaker
wave is moving over western Kansas at this hour, and its axis
will likely be just to our east after midnight. A few models
suggesting an isolated shower or storm possible with this wave,
although the HRRR keeps much of it over central and southern
Kansas. Warmer temperatures already seen mixing down over western
and south central Kansas, and will be the main story for tomorrow
as those temps move eastward. Turning of the LLJ winds over this
front may generate a few storms toward morning over the eastern
counties, but again chances are low and have only carried a low
PoP at this time for that area. Biggest change will be the
temperatures tomorrow as the western areas hit middle 90s with
dewpoints in the 60s, and even in the east we rise to upper 80s
with dewpoints near 70, so it will feel quite warm and muggy
tomorrow as heat indicies near upper 90s to 100. One factor that
may help will be increasing winds, as breezy southwest winds of 15
to 20 with gusts to 30 develop tomorrow. Lows tonight fall into
the mid 60s.

.LONG TERM...(Tuesday night through Monday)
Issued at 316 PM CDT Mon Sep 18 2017

Wednesday time frame a weak boundary (hard to call it a cold
front) will likely push into the area during the day as an upper
level shortwave pivots through the Northern Plains around the main
low in Western Canada. Therefore, forcing for ascent resides
mainly to the north of the area. Also, per forecast soundings,
quality of moisture is likely not great in western portions of the
forecast area, but with higher dewpoints pooling along the
boundary as it slowly pushes southeast may come into play by late
in the day into early evening increasing MLCAPE values based on
some guidance up above 4,000 J/kg. Lack of deep layer shear along
with weak mid level lapse rates may be an inhibiting factor into
severe potential and coverage. So, probably just isolated to
scattered storms may form but with increasing isentropic lift into
the overnight time frame, associated with a weak LLJ, will keep
some showers going for the overnight period focused mainly into
the northern MO region extending back into very eastern portions
of the forecast area.

Quiet weather should prevail into the day Thursday until Saturday
late morning/afternoon time frame as a deep western CONUS trough
becomes more established and slowly shifts east drawing up gulf
moisture along a quasi-stationary/cold boundary on the eastern flank
of the trough.  Dynamics and Kinematic forcing don`t look impressive
over the area, so any hazardous weather potential seems low, but
could be a wetter weekend overall.

Temps for the period will be upper 80s and low 90s for the week
before cooling back into the lower 80s over the weekend in
association with cloud cover and precipitation.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday)
Issued at 626 PM CDT Mon Sep 18 2017

There is some potential for elevated storms overnight, but models
seem to focus the better isentropic lift and moisture advection to
the southwest of the terminals. So chances do not look to be good
enough to include a mention in the forecast just yet. Chances for
LLWS also look to be weakening as the magnitude of the low level
jet is progged to be weaker than before. Opted to maintain a
mention at TOP where winds may be backed more and at MHK where low
level winds could still be a little stronger. Outside of any
thunderstorms impacting the terminals, conditions should be VFR
through the period.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...67
LONG TERM...Drake
AVIATION...Wolters


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