Area Forecast Discussion
Issued by NWS Topeka, KS

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000
FXUS63 KTOP 210449
AFDTOP

AREA FORECAST DISCUSSION
National Weather Service Topeka KS
1149 PM CDT TUE SEP 20 2016

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Wednesday)
Issued at 317 PM CDT Tue Sep 20 2016

Upper ridge has settled over the southern CONUS this afternoon while
westerlies centered across the northern plains. Low level Gulf
moisture has lifted as far north as eastern Nebraska with dewpoints
averaging in the lower to middle 70s in northeast KS. Combined with
highs in the low 90s this afternoon, heat indices in the 100 to 104
degrees are expected for the next few hours.

Upper level moisture streaming across the northern periphary of
the ridge will increase high clouds this evening with overall
quiet and mild conditions. Trended a few degrees higher based on
previous morning`s trends in temps with lows around 70 degrees.

Mid level flow backs to the southwest as an incoming shortwave
trough reaches western Nebraska by the afternoon. Tightening
pressure gradient downstream of the sfc trough axis will increase
south winds at 15 to 20 mph. 60s dewpoints approach the north
central areas while much of northeast KS will hover near 70 degrees
once again. Highs are still on track with consistent guidance of
upper 80s to lower 90s. Heat indices are slightly lower than
previous` days between 94 and 98 degrees.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 317 PM CDT Tue Sep 20 2016

The approach and eventually stalling of a front in Nebraska
coincides with increasing mid and upper level moisture for some
increasing precipitation chances Wednesday night. Precip should be
limited to mainly northern areas where modest isentropic lift and a
decent low level jet will exist, with the best chances after
midnight into the early morning of Thursday. The remainder of the
work week looks dry as an upper low slides east into the Rockies.
Low to mid level flow becomes more meridional, with drier air
working its way in and a slight cooling trend.

The models are in good agreement with the energy splitting northeast
and southeast into the weekend, but do diverge into the early next
week periods. PW values ramp up again as the remnants of the
tropical system come northeast. Will likely see at least a few
periods of scattered showers and thunderstorms from Saturday through
Sunday night. Ground conditions will have dried considerably since
the last bought of widespread rains and there is a lack of a
stationary low level focusing mechanism to bring an obvious heavy
rain threat, but the ample moisture will at least bring some quick
downpours. The models diverge more considerably into the early week
with how this upper low moves, but at least somewhat drier air
should filter in behind the northern wave. At this point will keep
small precip chances into Tuesday. Temperatures will drop back
through the weekend with highs in the 70s likely Sunday into
Tuesday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1147 PM CDT Tue Sep 20 2016

VFR conditions are expected through the TAF period with high
clouds. Winds will gust late morning through early evening but
generally less than 20 kts before tapering after 00Z.

&&

.TOP Watches/Warnings/Advisories...
NONE.
&&

$$

SHORT TERM...Prieto
LONG TERM...65
AVIATION...Barjenbruch



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