FXUS63 KTOP 171129

Area Forecast Discussion
National Weather Service Topeka KS
629 AM CDT Wed Jul 17 2019

...Update to aviation forecast discussion...

.SHORT TERM...(Today and tonight)
Issued at 345 AM CDT Wed Jul 17 2019

Shortwave ridge axis was pushing east over the central Plains early
this morning with veering lower and middle tropospheric flow
leading to weak to moderate warm air advection. Enough mid-level
moisture was in place (700 mb dewpoints around 7 C) to produce
isolated convection across central and eastern portions of Kansas
early this morning, with many observation sites reporting mid cloud
well away from the convection. Recent RAP (and to a lesser extent
HRRR) runs suggesting an uptick in coverage over the next few-
several hours and will keep a small PoP for the entire area into the
mid-morning. 850 mb temps remain on track to rise 3-4 C from Tuesday
afternoon with surface dewpoints able to remain in the mid 60s to
mid 70s in a moist boundary layer. A moderate pressure gradient over
the region east of a deepening lee trough and weak cold front should
be adequate to promote sufficient mixing despite any lingering
convection to bring afternoon temps in the mid 90s to around 100 and
apparent temps into the 105 to 110 range. Have kept some mention of
thunderstorms in portions of north central Kansas where convection
off the stalling front may approach though drier antecedent
conditions compared to this morning should limit this progression.

.LONG TERM...(Thursday through Tuesday)
Issued at 345 AM CDT Wed Jul 17 2019

The persistent high levels of heat and humidity remain to be the
main concern with little opportunity for significant changes to
conditions until late in the weekend as a broad upper ridge lingers
over the southern states. Heat index values should continue to peak
in the 103 to 112 range with a moderate low-level jet keeping
overnight temps in the mid 70s to around 80. A pattern change takes
place during the weekend and allows for the passage of a cold front
around Sunday. There should be at least a small opportunity for
convection associated with the front as well though have limited
mention to nighttime periods given the very warm low levels keeping
some capping in place. Temps early next week should return to near
normal values.


.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 629 AM CDT Wed Jul 17 2019

Isolated elevated convection in MHK area at this time but
coverage and persistence with low-level jet weakening and cloud
tops warming. Only enough confidence for VCTS at MHK and will
watch trends. Surface wind gusts should be common by 17Z with
diurnal trend to LLWS around 02Z.


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



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