Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 190443
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
1143 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 06Z TAFS through 06Z Wednesday)
Issued at 1143 PM CDT Mon Sep 18 2017

Models continue to show low level moisture advection into eastern
KS overnight with some isentropic lift. Although QPF progs are
mixed whether there will be storms. With the bulk of guidance
keeping dry weather, will not include any mention of precip in the
forecast through the night. Think VFR conditions are likely to
prevail and with no organized forcing progged for tomorrow,
confidence in storm development in the afternoon is to low to
mention TS in the forecast Tuesday afternoon. Models have
continued to prog the low level winds to be weaker. So will
remove the mention of LLWS from TOP and lower the speed of the low
level jet expected to impact MHK.

&&

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

$$

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



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