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Area Forecast Discussion (AFD)

Issued by Topeka, KS (TOP)

FXUS63 KTOP 162041

Area Forecast Discussion
National Weather Service Topeka KS
341 PM CDT Tue Jul 16 2019

.SHORT TERM...(This evening through tonight) 
Issued at 338 PM CDT Tue Jul 16 2019

As of this afternoon, the isolated convection from this morning in 
north central KS has diminished. Furthermore, there is currently 
a cluster of storms near Wichita, a general weakening trend is 
favored as it moves east into an environment with more inhibition,
which would keep us dry through the afternoon and evening. A 
ridge sits over the Southern Plains with the ridge axis expected 
to shift eastward as we head through the overnight hours as a lee 
trough strengthens to the west of our CWA. This will allow the 
pressure gradient to strengthen somewhat and maintain 
southwesterly flow through the short-term forecast period, with 
morning lows expected to fall back to around the mid 70s.

The best forcing for convection overnight into early Wednesday 
morning appears to be associated with an embedded shortwave moving 
through the Dakotas, keeping the highest precip chances well north 
of the CWA. However, RAP/HRRR soundings from north central KS 
show WAA in the 850-700mb layer, which could provide lift 
sufficient enough to develop a few elevated storms on an isolated 
basis near sunrise, given CAPE within 500-1000 J/kg above 700mb. 
As a result, have added slight chance PoPs in north central KS 
after 06Z and lasting until around sunrise.

.LONG TERM...(Wednesday through Tuesday) 
Issued at 338 PM CDT Tue Jul 16 2019

Transitioning into Wednesday, the multi-day excessive heat event 
looks to begin by afternoon...

A few showers and/or isolated storms may persist through the morning 
hours with WAA near 700 mb. Otherwise, any thin layer of cloud cover 
near 700 mb should scatter by late morning and allow for rapid 
warming to occur. Afternoon temperatures are progged to reach the 
mid 90s to near 100. Dew points are expected to remain quite 
uncomfortable in the upper 60s and low 70s resulting in heat index 
values in the 105 to 110 degree range. With this persist heat 
expected through at least Saturday, have opted to upgrade the area 
to an Excessive Heat Warning from Wednesday afternoon through 
Saturday evening. An embedded midlevel shortwave trough is progged 
traverse the High Plains Wednesday afternoon, developing 
thunderstorms across eastern CO/western NE along the lee trough. 
There is the potential for these to grow upscale and reach the 
western counties Wednesday evening. As the shortwave lifts 
northeastward and away from the convection and an overall 
unfavorable environment for MCS maintenance, thunderstorms will 
likely dissipate near/prior to entering central/north central KS.

Otherwise, the hot and dry pattern looks to continue through the end 
of the week as the midlevel ridge remains across the southeastern 
half of the CONUS. Afternoon temperatures in the mid 90s to low 100s 
combined with humid conditions will yield heat index values from 105 
to 110. Furthermore, little relief will be felt overnight with 
temperatures only reaching the upper 70s to near 80. The pattern 
looks to finally break down as a midlevel trough across the Pacific 
Northwest ejects across Northern Rockies Saturday into Sunday, 
shunting a cool front through the area late Sunday into Monday. This 
will provide some relief from the heat with temperatures in the 80s 
by Monday. In addition, the frontal passage could provide some 
rainfall as well. Beyond Monday, the stout midlevel ridge looks to 
remain west of the area with more-comfortable conditions remaining 
across the area through the middle of next week. 


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1241 PM CDT Tue Jul 16 2019

VFR conditions are expected through the TAF period. Winds should
remain light and variable through today before increasing during
the mid-morning hours Wednesday to 10-15 kts. There is a small
chance for thunderstorms near the terminals after sunrise, but
confidence is too low to mention in the TAFs at this time.


Excessive Heat Warning from 1 PM Wednesday to 8 PM CDT Saturday 
for KSZ008>012-020>024-026-034>040-054>056-058-059.



SHORT TERM...Baerg/Picha