Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 211125
AFDTOP

AREA FORECAST DISCUSSION
National Weather Service Topeka KS
625 AM CDT THU JUL 21 2016

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 318 AM CDT THU JUL 21 2016

Similar to previous nights across the area, with temperatures still
holding in the low 80s for much of the area at this early hour.  A
bit more wind out west has kept middle 80s there.  Outflow boundary
has made progress across western Kansas from convection on the high
plains, and may make a run at the north central counties but not
expecting much in the way of a sensible weather impact.  Mid level
temps rise 2-4C at 850mb today, and have increased high temps a few
degrees to reflect this. Widespread heat indices around 110F make
for dangerous heat today and the excessive heat warning remains in
place.  Also expecting another night with lows well into the 70s.  A
few models generate convection late to our northeast or west, but do
not think it will impact our forecast area before sunrise on
Friday.

.LONG TERM...(Friday through Wednesday)
Issued at 318 AM CDT THU JUL 21 2016

The forecast remains on track into at least Saturday. Weak front
washes out in central Nebraska Friday with minor convergence
resulting to the northwest and west. Enough potential for convection
to form and move this way for small pops in the northwest counties
Friday night. Upper ridge breaks down somewhat Friday into Friday
night with upper wave passing well north during the weekend.
Continued south to southwest low level flow however keeps hot air in
place. Models continue to show hottest conditions Friday with 850mb
temps mainly in the 25-30C range. There remains to be some variation
in how hot/mixed western areas will be, but overall combination of
heat and humidity keeps afternoon heat index values in the 103-111
range for the entire area Friday and Saturday. Models continue to
trend a bit slower with front`s passage through the area during the
weekend, with the potential for at least southeastern areas to be in
the warm sector for much of Sunday. Questions on specifics of mixing
depths in the weaker flow, dewpoints, cloud cover, and potential
precip however keep confidence too low for an extension of the
Warning. As for precip chances, weak forcing keeps chances low
Saturday night and Sunday, with better potential in subsequent
periods, mainly Sunday night and Tuesday night-Wednesday -- Sunday
night as the low level jet increases over the old front and Tuesday
night into Wednesday as the next upper wave passes across the
Northern Plains and the jet again responds. Extreme heat is not
anticipated to return in these periods, with highs mainly in the 90-
95 range depending on precip timing/persistence.

&&

.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 624 AM CDT THU JUL 21 2016

VFR conditions expected through the period. Late night/early
morning LLWS will need to be monitored, but appears below criteria
at this time.

&&

.TOP Watches/Warnings/Advisories...
Excessive Heat Warning until 7 PM CDT Saturday for KSZ008>012-
020>024-026-034>040-054>056-058-059.

&&

$$

SHORT TERM...67
LONG TERM...65
AVIATION...67


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