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000
FXUS63 KEAX 150455
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1155 PM CDT Tue May 14 2013

.SHORT TERM...(This Evening through Wednesday Night)
Issued at 403 PM CDT TUE MAY 14 2013

Summer made a quick appearance today across the region as
temperatures passed 90 degrees in many locations. Full sun and
southwest winds helped us attain the near to record breaking heat
today, though the real culprit is the thermal ridge. High amplitude
ridging to our west Monday allowed a lot of hot dry air to develop up
the front range of the Rockies and western Plains, but a shortwave
trough, zipping east through the Canadian Plains and Dakotas, forced
the ridge to lean to the east, allowing these exceptionally hot and
dry conditions to prevail as far east as Missouri today --afternoon
highs in Kansas City and St Joseph have already equaled record values
as of this writing, 91 and 93 respectively--.

Surface front, associated with the shortwave trough moving through
the Dakotas, will continue to press slowly south overnight, but
likely wont make it much farther south than far northern Missouri
Wednesday morning owing to the developing local zonal flow and lack
of forcing behind the front as the parent trough scoots by. This
should take a few degrees off the high for Wednesday as elevated
temperatures will take a hit as the thermal ridge retreats to the
west overnight.

Complicating the forecast for Wednesday will be a little vorticity
maximum that will eject up and through the Southern and Central
Plains ahead of a larger trough that is opening up across northern
Mexico. Timing of this vort max indicates that it should take much
of Wednesday morning for it to arrive in our region, limiting its
effect on our forecast to the afternoon and evening hours. Hot and
humid airmass out there will provide a lot of CAPE for storms to
work with --MUCAPE values > 4000 J/KG Wednesday afternoon--, but
surface convergence along the stalled front is poor, and upper level
support even from the vort max doesn`t provide enough shear -- 0 to
6KM values less than 20 knots -- to make anyone think that more than
garden verity pop-up thunderstorms may occur. Better chance for
storms will wait till Wednesday night when the nocturnal jet cranks
up ahead of the open northern Mexico trough, forcing some isentropic
assent up and over the stalled front across northern Missouri. The
potential for severe storms with any of this activity also looks low
as available shear across the region remains low.

.LONG TERM...(Thursday through Tuesday)
Issued at 403 PM CDT TUE MAY 14 2013

More of a late spring type weather pattern will set up across the
region with temperatures hovering just slightly above normal and
thunderstorm chances continuing through the end of the week.
Shortwave ridging will build across the Plains behind a shortwave
trough that will be moving off towards the Northeast. The remnants
of the southerly shortwave trough, that ejected out of the
Southwest, will continue to move eastwards and gradually merge with
the northerly trough across the eastern CONUS. A stationary front
progged to be positioned across northern Missouri will gradually
lift northward towards the Great Lakes as a warm front Thursday
evening and into Friday. By Friday evening...thunderstorm chances
will decrease as warm front moves well north of the region and
shortwave ridging develops ahead of another trough that will be moving
across the intermountain west. This will be the system to watch as
it begins to mature across the Plains.

The models continue to differ on the timing and placement of this
trough as is moves across the Rockies. The EC tends to bring it out
more quickly and obtains a negative tilt as it swings onto the
High Plains region, while the GFS continues to dig the trough into
the Great Basin before swinging it out onto the plains. The GFS
deepens the trough into a closed low by Sunday night with the EC
waiting to close it off until Tuesday night. Both models bring a
cold front across the CWA Sunday night and into Monday. Given that
an upper level jet streak will be nosing into the region combined
with increasing LLJ ahead of the front, and diffluent flow pattern
setting up across the region; wouldn`t be surprised to see some
severe weather Sunday evening and into Monday morning depending on
when the cold frontal passage occurs. Precipitation chances will
decrease significantly by Tuesday morning as the upper level low
moves up into the Great Lakes region and northwest flow aloft
develops once again over the Central Plains.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday Night)
Issued at 1151 PM CDT TUE MAY 14 2013

VFR conditions are expected through the period. Surface wind gusts
have relaxed and still a slight decrease of speed will be possible
during the forecast. Convection is not expected to develop until
after 21Z, and at that the best chances should be north of the KC
metro area, and TAF reflects the spatial and temporal expectations of
convection with inherent uncertainty.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&

$$

SHORT TERM...Cutter
LONG TERM...PMM
AVIATION...Blair