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

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864
FXUS63 KEAX 171124
AFDEAX

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
624 AM CDT Mon Jul 17 2017

.Discussion...
Issued at 330 AM CDT MON JUL 17 2017

Surface pattern at 08z characterized by light southerly winds
within a loose pressure gradient between a developing surface low
to the west over the Rocky Mountain region and a surface ridge
over the Mississippi and Ohio River Valleys to the east. Through
the week expect that feature to remain in place with the marginal
surface pressure gradient keeping the southerly winds down around
10 mph through the week. Expect the bulk of the area to remain
deep within the surface warm sector as the warm front associate
with this surface trough pushes well to the north. This boundary
being well north of the area should keep the focus for
precipitation in the near to mid term well north of the forecast
area, keeping most of Missouri dry through the week and into the
weekend. In the mid/upper levels a ridge of high pressure is
currently present over the western Central Plains with light N`ly
flow aloft over Missouri. This ridge will eventually slide east
with time and strengthen as we get into the Tuesday/Wednesday time
frame. GFS/EC still prog H5 pressure heights centered over eastern
Kansas and western Missouri around 595 to 598 dm by mid week. The
result will be a prolonged stretch of daytime temperatures ranging
from 95 to 100 degrees across the region through mid to late week.
While the ridge is still off to the west on Monday and Tuesday
expect hot temperatures to be somewhat mitigated, with day time
highs reaching the mid 90s, with heat indices in the upper 90s to
lower 100s. While that stretch will be plenty hot, the period
starting Wed and lasting through Saturday will be quite a bit
warmer as that ridge slides into place. Expect highs for Wed-Fri
to reach the upper 90s with some locations likely hitting 100+
degrees. High dew points will work with the hot air to create heat
indices nearing 110 degrees in most places Wed-Sat. As such the
Excessive Heat Watch was expanded to cover all of EAX counties,
despite perhaps less certainty of the prolonged heat affecting far
northern Missouri counties. This uncertainty stems from the
chances for convection initiating across northern Nebraska and
northern Iowa dropping into far northern Missouri, either brining
some small chances for rain or at the very least some cloud debris
from the Neb/Iowa convection mid week. Have inserted some low end
Chc PoPs for far northern Missouri for this convective activity.
Despite some uncertainty of far northern Missouri reaching HI
values over 110 degrees and/or 4 straight days of ~105+ HI
readings, enough certain resides to cover the area with the watch
for now and determine which counties will need Advisories/Warnings
in upcoming forecasts.

Sunday will likely offer a nice delineation between the oppressive
heat and more palatable conditions. Mid level flow increases along
the northern periphery of the ridge and should flatten it out a
bit as we go into the early part of next week. Temperatures will
still be warm on Sunday and Monday, but not quite as warm as the
105-110 HI values encountered Wed-Sat. Next appreciable chance for
rain comes early next week as a surface boundary slides into the
area and the mid level ridging pattern breaks down, perhaps
allowing a brief period of shortwave troughing before the next
ridge builds back into the region in the extended.

&&

.Aviation...(For the 12Z TAFS through 12Z Tuesday Morning)
Issued at 623 AM CDT MON JUL 17 2017

VFR conditions expected for the next 24 hours, with steady light
southerly winds and some scattered cumulus clouds around 6kft.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...Excessive Heat Watch from Tuesday afternoon through Saturday
     evening for KSZ025-057-060-102>105.

MO...Excessive Heat Watch from Tuesday afternoon through Saturday
     evening for MOZ001>008-011>017-020>025-028>033-037>040-
     043>046-053-054.

&&

$$

Discussion...Leighton
Aviation...Leighton



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