Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO

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FXUS63 KEAX 201714
AFDEAX

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
1214 PM CDT Thu Jul 20 2017

.Discussion...
Issued at 231 AM CDT THU JUL 20 2017

Excessive heat and humidity will be the story for the next 72 hours
as an upper level ridge moves overhead stacking down to low level
high pressure over the southern Mississippi Valley area.  This will
keep an open fetch of gulf moisture flowing up through TX and OK
into northern Missouri.  The result will be temperatures in the
upper 90s to near 100 degrees and dewpoints in the lower to mid 70s
which will allow heat index value to range from 105 to 115F over the
region.  The highest dewpoints will occur today for this event
leading to the hottest day for heat index values especially north of
the Missouri River, with 110-115F values over Atchison and Holt
Counties.  These extremely high heat index values will lead to the
excessive heat warning remaining in place through Saturday
afternoon.  As this ridge breaks down allowing shortwaves to move
through the northern plains a backdoor cold front will finally break
this heat starting Saturday night into Sunday.

The initial push of convection looks to occur late Saturday evening
into Sunday morning as this boundary nears the MO/IA border, perhaps
providing some relief to the northern border counties Saturday
evening.  The main bulk of precipitation will occur after sunset
along and near HWY 36 and slowly move south with the frontal
boundary.  Strong to possibly severe storms will be possible with
the initial convection as 2000+J/kg of MUCAPE and 30kts of effective
bulk shear will be available. The severe threat will decrease
quickly and turn into more of a localized flooding concern as
conditions will be right for training thunderstorms with very
efficient rainfall as PWAT values will be over 2 inches.  By Sunday
morning this boundary is expected to be mostly south of our CWA as
higher pressure builds into the area from the north brining a cool
drier air into the region with Sunday highs in the upper 80s to
lower 90s.

A persistent NE wind direction Monday will bring one of the
nicest days of the month with high temperatures below normal and
dewpoints in the low to mid 60s and plenty of sunshine. This nice
weather will extend into Tuesday with similar conditions expected.
Upper level ridging will start to build back over the Rockies
Wednesday shifting winds to a more southerly direction and
elevating temperatures into the 90s once again with heat index
values climbing back up into the mid to upper 90s as moisture
feeds back into the area.

&&

.Aviation...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1213 PM CDT THU JUL 20 2017

VFR conditions expected through the period.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...Excessive Heat Warning until 8 PM CDT Saturday for KSZ025-057-
     060-102>105.

MO...Excessive Heat Warning until 8 PM CDT Saturday for MOZ001>008-
     011>017-020>025-028>033-037>040-043>046-053-054.

&&

$$

Discussion...Barham
Aviation...Blair



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