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

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000
FXUS63 KEAX 280447
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1147 PM CDT MON JUL 27 2015

.DISCUSSION...
Issued at 416 PM CDT MON JUL 27 2015

Tonight - Wednesday:

Most likely the most active portion of the next 7 days spanning
oppressive heat and humidity with active convection.

For the late afternoon into the early evening hours will focus on
convection developing along a weak warm front best seen in visible
satellite imagery. This boundary extends from the intersection of an
outflow boundary from the IA thunderstorm complex along the MO/IA
border northwest of IRK southeast through northeast Macon county.
Expect convection to develop/roll southeast along this boundary for
the next few hours. Gusty winds to 50 mph and very heavy rainfall.

The rest of the CWA can expect a quiet but sultry night which will
transition to oppressive heat and humidity on Tuesday. No change is
expected in the airmass for tomorrow...and likely even a tad hotter
as 925mb temperatures increase by 1-2C due to a more westerly
component to the boundary layer winds. Given a 4th day of these
conditions for a handful of additional counties have expanded the
Excessive Heat Warning eastward and extended the current advisory
for all but the far northwest CWA through 02z Wednesday.

The weather will become active again beginning late Tuesday
afternoon and continuing through the night. As noted yesterday a
fairly stout mid/upper level shortwave will track east across the
Northern Plains/Upper MS Valley flattening the upper level ridge
axis in the process. Falling heights will allow an associated cold
front to press southeast, reaching far northwest MO by late
afternoon. Operational models have slowed the advancement of the
front a tad but are in good agreement on timing through Tuesday
night. Expect at least a broken convective line to form in response
to MUCAPES in excess of 3000J/kg and modest low level convergence.
While the 0-6km bulk shear of 20-30kt is marginal for supporting
rotating updrafts believe the high instability may be sufficient for
a few severe cells. After peaking by late evening expect the
activity to gradually weaken as it slides southeast overnight. So
highest PoPs will be across the northern 1/2 of the CWA.

Will leave low chance PoPs across the southern CWA Wednesday morning
as the cold front exits the region. Cooler temperatures, i.e. read
seasonal, and drier air will be ushered in by weak high pressure.

Thursday - Monday:

The Central/Southern Plains dome of high pressure will retrograde
westward with general troughing from Hudson Bay through the OH
Valley. This will leave northwest flow from the Northern Rockies
through the Mid MO Valley. Operational models are pretty clear on
this overall flow pattern. What isn`t clear or at least they can`t
agree on timing and location are the weak/embedded
shortwaves/vorticity maxima which typically accompany this type of
pattern. Also don`t see any discernible frontal boundaries. With
that in mind will stick with a blended model approach with any rain
chances more likely across the northern CWA which will be closest to
the stronger upper flow. Expect seasonal temperatures during this
period.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday Night)
Issued at 1144 PM CDT MON JUL 27 2015

VFR conditions are expected through the forecast. A front will move
into the area late in the forecast period, likely between 00Z and
06Z, with times closer to 06Z for the Kansas City area terminals.
There is still a fair amount of uncertainty withhow far southwest
convection can develop along the front given that it looks like the
cap will remain in place.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...EXCESSIVE HEAT WARNING until 9 PM CDT Tuesday for KSZ057-060-
     103>105.

     HEAT ADVISORY until 9 PM CDT Tuesday for KSZ025-102.

MO...EXCESSIVE HEAT WARNING until 9 PM CDT Tuesday for MOZ028-029-
     037>040-043>046-053-054.

     HEAT ADVISORY until 9 PM CDT Tuesday for MOZ005>008-013>017-
     020>025-030>033.

&&

$$

DISCUSSION...MJ
AVIATION...CDB


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