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000
FXUS63 KEAX 151124
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
624 AM CDT Sat Jun 15 2013

.SHORT TERM...(Today through Sunday)
Issued at 344 AM CDT SAT JUN 15 2013

In the short term, the main forecast challenge will be the timing
and placement of convection associated with a series of shortwave
troughs pushing through the area today through Monday. Ongoing
convection fueled by a departing shortwave trough in eastern
Missouri has pushed several outflow boundaries south and southwest,
which could spark additional convection this morning; however, the
more likely scenario is for the convection across central Missouri to
continue pushing southward and eventually weaken as the shortwave
trough departs and warmer temperatures aloft build in from the west.
A few light echoes have also begun to show up across eastern Kansas
and southwest Missouri ahead of the next system, which could produce
a few very light showers in our west or southwest between sunrise and
mid-morning.

By early afternoon, a second and slightly stronger shortwave trough
will lift into eastern Kansas and portions of southeast Nebraska,
possibly sparking early thunderstorm initiation in these areas.
Storms could push into the northwest corner of the forecast area as
early as 2-3 PM, while additional thunderstorms continue to form
further to the west and northwest along an approaching surface cold
front. Thunderstorms will be most likely during the late afternoon
to overnight period as the front passes slowly through the forecast
area, beginning in far northwest Missouri and spreading southeast as
night falls. Severe weather will be possible from late this
afternoon through the evening hours, with most unstable CAPE in the
2500-3000 J/kg range and 0-6 km bulk shear values ahead of the
surface front in excess of 40 kts. Storm motion will generally be
along the frontal boundary, except for any isolated supercells that
can develop along the boundary and turn southeast, which will also
support a localized flash flood threat this evening and tonight. The
tornado threat appears fairly limited unless a storm can get rooted
along the cold front without being undercut by stable air behind the
boundary; thus, the main concern will be large hail in any robust
updrafts that develop and straight-line winds in linear segments,
especially in the evening.

The boundary will continue to sink southward on Sunday morning, then
another shortwave trough is expected to brush at least the southwest
corner of the forecast area by late Sunday morning or afternoon.
Precipitation chances with this more subtle feature are a bit lower
than Saturday`s chances, and the severe weather threat also looks
lower in a northwest flow regime with lower instability and low-
level moisture. Showers and storms may continue into Sunday night,
but should begin tapering off by Monday morning.

.LONG TERM...(Monday through Friday)
Issued at 344 AM CDT SAT JUN 15 2013

Precipitation chances on Monday are largely dependent on the
evolution of thunderstorms that may organize over the central High
Plains Sunday night. Several models are suggesting a
convectively-enhanced wave, possibly an MCV, tracking into central
or southern MO through the day. Where/if such a wave tracks into the
region will determine the best thunderstorm chances on Monday, which
for now appear to be across the southern portions of the forecast
area into the MO Ozarks. Wind fields do not appear supportive for
organized severe storms with this activity.

The weather pattern will quiet down by Tuesday and Wednesday with
broad height rises over the central U.S. Precipitation chances will
then increase by Thursday as the upper-level ridge axis passes
overhead and weak warm air advection brings a return to warm and
humid conditions. Better precip chances will remain well to the
north in closer proximity to the upper level storm track.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
Issued at 624 AM CDT SAT JUN 15 2013

VFR conditions are expected to persist through mid afternoon, after
which thunderstorms will become increasingly likely. Broken cumulus
with bases between 5,000-6,000 ft will also develop during the late
afternoon, and will lower slightly as storms become more widespread
during the evening and early overnight hours. Visibilities could drop
as low as 1-2 SM in the heaviest thunderstorms, and wind gusts up to
50 kts could be possible with any severe storms. The best chance for
thunderstorms will be between 22z-06z, then storms should gradually
weaken and begin to drop southeast out of the region.

&&

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

$$

SHORT TERM...Laflin
LONG TERM...Hawblitzel
AVIATION...Laflin