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

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000
FXUS63 KEAX 221744
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1244 PM CDT Tue Jul 22 2014

.DISCUSSION...
Issued at 309 AM CDT TUE JUL 22 2014

Today - Tonight:

Temperatures today will likely be about 5 degrees warmer than
yesterday with similar humidity values. This is going to result in
oppressive heat across the area with heat indices approaching 110
across northwestern Missouri and northeastern Kansas. No significant
changes were made to the temperature forecast and the heat advisory
will obviously remain as is.

The main challenge with the forecast is the potential for storms to
develop along a front that will be moving into the area from the
north. Instability will be extreme with MLCAPE values around 5000
J/kg. Shear will initially be very weak but may increase and become
more favorable overnight as a weak upper shortwave moves into the
area. The very warm temperatures aloft should inhibit convection
during the afternoon. But there may be enough lift along the front
the overcome this so have maintained a very slight chance of storms
in far northwestern Missouri and extreme northeastern Kansas as a
result. If a storm can develop during the heat of the afternoon,
there will be a good chance for damaging downburst winds. The
probability of storms increases during the late evening and
overnight hours. The weak shortwave, in conjunction with the frontal
forcing, may provide enough lift for more widespread storms to form.
There will remain ample instability into the overnight but it will
really depend on if and how quickly stronger shear can move into the
area. With the strong instability and weak shear, the likelihood of
storms primarily being wind producers is high as there will be in
imbalance in the CAPE/Shear combination. Very high freezing levels
approaching 16K feet and wetbulb zero heights of around 13.5K feet
suggest large hail is less likely due to very warm temperatures
aloft. Short-range models are in decent agreement developing storms
across northern Missouri and then tracking them southeast through the
overnight. Have increased PoPs to account for this higher
probability.

Wednesday - Friday:

Cooler weather is expected these days as Canadian high pressure
tracks into the Midwest giving us northeasterly winds. The upper
ridge will have shifted and built in the western states and this may
leave the area on the edge of the cap within northwest flow. A weak
mid-level impulse may then track through the flow and bring another
chance of precipitation to the area Thursday night into Friday.

Saturday - Monday:

Another front is expected to move through the area Saturday which
may lead to additional precipitation chances through the weekend.
But overall have kept chances low as there is a fair amount of
uncertainty in the timing of any upper-level support in the
northwest flow pattern. By the start of next week, models begin to
amplify the flow across the CONUS with the western ridge building
and an eastern trough deepening. At the surface, cooler high
pressure should settle right over the Missouri Valley and into the
Midwest leading to what looks like another period of cooler than
normal weather in the region.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1244 PM CDT TUE JUL 22 2014

Main concern heading into the fcst period remains focused on
convection as weak cold front sinks south across the area. Latest
model trends show the best potential east of all terminal sites but
given the amount of uncertainty with the fcst...VCTS mention was
maintained for all locations after 00z this evening. After 6z...any
convection that does form should be south with weak northeast flow
expected through the remainder of the overnight. Some potential for
developing VSBY restrictions at STJ after 09z as front fails to scour
out abundant low-level moisture.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...HEAT ADVISORY until 7 PM CDT this evening FOR KSZ025-057-060-
     102>105.

MO...HEAT ADVISORY until 7 PM CDT this evening FOR MOZ001>008-011>017-
     020>025-028>033-037>040-043>046-053-054.

&&

$$

DISCUSSION...CDB
AVIATION...32






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