Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 171124
AFDTOP

Area Forecast Discussion
National Weather Service Topeka KS
624 AM CDT Mon Jul 17 2017

...Update to aviation forecast discussion...

.SHORT TERM...(Today and tonight)
Issued at 355 AM CDT Mon Jul 17 2017

Satellite early this morning shows upper high over eastern Kansas
while a slow moving vorticity lobe was spinning along the northwest
Kansas and northeast Colorado border. The models bring this weak
wave northeast today into southern Nebraska, then move it slowly
east across north central Kansas and south central Nebraska tonight.

Expect temperatures today to be around or slightly higher than
yesterdays readings. Highs will top out in the lower to middle 90s
with heat indices in the mid to upper 90s.

The high resolution models offer differing solutions with the
precipitation associated with the slow moving wave late tonight as
it moves into north central Kansas with the consensus remaining
mainly along and west of U.S. Highway 81. Better inflow looks to
remain to the west of the cwa tonight then shifts a bit to the
northeast as the jet veers to the southwest after 06Z. Therefore in
creased precipitation chances in north central Kansas later tonight
and increased the cloud cover from previous forecast. Lows tonight
will be in the low to mid 70s.

.LONG TERM...(Tuesday through Sunday)
Issued at 355 AM CDT Mon Jul 17 2017

The main focus for mid to late week will be the expected hot and
humid conditions that prompted the issuance of the Excessive Heat
Watch for Tuesday through Saturday.

By Tuesday, a mid-level high will be centered over the region with
the expansive ridge extending across the entire U.S. There is the
potential for some scattered showers and thunderstorms to develop
and skim across far north central to far northeast Kansas on
Tuesday and again early Wednesday morning as models show a couple
weak embedded shortwaves tracking near the area. By mid to late
week, the ridge axis of the broad mid-level ridge will build
further north of the area, resulting in any scattered
precipitation from embedded shortwaves to shift further north of
the CWA. This expansive ridge combined with the presence of
surface high pressure over the central U.S. will keep conditions
dry Wednesday through early Saturday. Steady southerly winds will
support continued weak moisture advection and warm-air advection
into the region, with dewpoints in the upper 60s/low 70s and 850mb
temperatures gradually rising into the 22C to 29C range. Expect
some of this warmer air aloft to mix down to the surface,
resulting in high temperatures soaring into the mid 90s to low
100s, with mild overnight low temperatures in the mid/upper 70s to
around 80 degrees. With these expected temperature/dewpoint
values, afternoon heat indices will likely surge into the 100 to
110 degree range Tuesday afternoon through Saturday. As a result,
the Excessive Heat Watch remains in effect for that period.

On Saturday, models show a stronger embedded shortwave trough
developing over the eastern Rockies and tracking across Kansas
during the weekend. This shortwave will help to push surface low
pressure and an associated cold front into the CWA by mid/late
Saturday afternoon, with the boundary slowly sagging southward
across the CWA on Sunday. As a result, increased cloud cover from
scattered shower and thunderstorm development near the boundary
will allow for a bit of relief from the heat by Sunday with high
temperatures in the low/mid 90s.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 622 AM CDT Mon Jul 17 2017

VFR conditions are expected to continue through the period. Winds
light southerly becoming south around 10 kts by 20Z.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
Excessive Heat Watch from Tuesday afternoon through Saturday
evening for KSZ008>012-020>024-026-034>040-054>056-058-059.

&&

$$

SHORT TERM...53
LONG TERM...Hennecke
AVIATION...53



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