Area Forecast Discussion
Issued by NWS Topeka, KS

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FXUS63 KTOP 210446

Area Forecast Discussion
National Weather Service Topeka KS
1146 PM CDT Thu Jul 20 2017

...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Friday)
Issued at 251 PM CDT Thu Jul 20 2017

Expansive upper ridge dominates the southern CONUS this afternoon. A
frontal boundary is draped from central NE through the Midwest
region to our north, bringing scattered cloud cover as far south as
the KS and NE border. Temperatures this afternoon are on track to
reach the upper 90s, to the century mark. Dewpoints are a bit
trickier, especially over eastern KS where lesser mixing of the
boundary layer has resulted in low to mid 70 dewpoints. Heat indices
as a result were between 105 and 110 degrees by noon. Taking note of
this and past trends lead to increasing dewpoints towards the mid
70s on Friday afternoon as well. With the forecast highs again near
100 degrees, heat indices become more widespread in the 107 to 112
degree range. One minor change noted for the tonight period, sfc low
is progged to lift northeast in response to an upper trough entering
the Pacific Northwest. Low level winds are expected to increase from
the south and southwest just off the sfc overnight. A shallow
inversion layer is expected to form, however most of the area should
see winds around 10 mph. Lows were therefore raised a few degrees
around 80 degrees.

.LONG TERM...(Friday night through Thursday)
Issued at 251 PM CDT Thu Jul 20 2017

By Friday night the persistent mid-level ridge over the central US
begins to break down and zonal flow returns over the northern CONUS.
 At the surface, low pressure extends into northern Nebraska into
western Kansas, extending a boundary across central and northeast
Kansas by Saturday afternoon as the main low moves eastward. Showers
and thunderstorms are expected to develop along this front which
will bisect the CWA from east to west by Saturday night.  Some of
these storms have the potential to be strong to severe Saturday late
afternoon and evening with strong winds being the main hazard.  As
for temperatures Saturday, another hot day is in store especially in
areas south of the front where highs will reach into the upper 90s
and low 100s.  Heat indicies will be similar to previous days
ranging from 103-110 degrees and this will be the last day of the
Excessive Heat Warning.

Lingering showers and storms may last into Sunday before shifting
south and out of the area leaving relatively dry conditions through
Monday night.  The upper high builds back into the southwestern US
by Monday and a mid-level shortwave moves across the central plains
bringing more chances for precipitation during the day Tuesday.  The
ECMWF is much more robust with this solution for Tuesday while the
GFS keeps most precipitation with this system south of the area, so
continued with only small PoPs.  The ridge continues to build back
into the central CONUS Tuesday night through the end of the period.
Temperatures Sunday onward look to be in the low 90s and upper 80s,
slowly rising through the end of the period.  Heat indicies will be
back in the 100s by Thursday.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1142 PM CDT Thu Jul 20 2017

Kept forecast similar to previous although added LLWS for the FOE
area for a few hours overnight. Winds become more southwesterly as
atmosphere mixes out and will likely come down toward the end of
this taf cycle.


Excessive Heat Warning until 8 PM CDT Saturday for KSZ008>012-



LONG TERM...Heller
AVIATION...67 is the U.S. government's official web portal to all federal, state and local government web resources and services.