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000
FXUS63 KEAX 142052
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
352 PM CDT Fri Jun 14 2013

.SHORT TERM...(This Evening through Saturday Night)
Issued at 400 PM CDT FRI JUN 14 2013

Main concerns for the next 24 to 36 hours deals with convective
chances and potential for severe weather this evening and possibly
again tomorrow afternoon/evening.

The northern to northeastern portions of the forecast area is on the
edge of the cap and storms have persisted all day in this area. This
cluster of storms may have layed out an outflow boundary, which is
indistinct, but may run from northeastern MO through central MO. A
warm front should also be in the vicinity which will aid in
convergence and possible initiation as well as provide for extreme
instability with 70 degree dewpoints working northward in eastern
Kansas and western Missouri. The focus for all of this should be
across northwestern MO as several earlier short-range model runs as
well as the NAM initiate convection eastern Nebraska later this
afternoon and shifts it southward this evening and overnight.
Given the instability that has been able to build, which should be
on the order of 2000 to 3000 J/kg and possibly as high as 3000 to
4000 J/kg, and enough shear to lead to storm organization, if storms
can develop, they should become severe. All hazards are possible if
convection can initiate but should mainly be large hail and damaging
winds by this evening and overnight. There is also intensifying
isentropic lift in the 310K to 315K layer after 00Z across
northwestern MO and northeastern KS. This adds confidence to the
model precipitation forecast.

The focus will then shift to a weak upper disturbance lifting
northward from the Southern Plains. Much will depend on how
convection tonight and tomorrow morning plays out and given that part
of the forecast is uncertain, tomorrow`s forecast is very uncertain.
There is the potential for an extremely unstable airmass to be in
place across the forecast area, with CAPE values approaching 4000
J/kg possible. Modest westerly flow should support 0-6 KM shear
around 40 kts. This combination would be more than enough to produce
severe storms if we can get them to develop in the afternoon.
Supercell structures would also be possible but veered surface winds
should tend to limit helicity values and resultant tornado chances.
But very large hail and damaging winds would be possible in the
strongest storms.

Any convection that does form should drift southeastward and impact
the southern zones, mainly south of Interstate 70, through the rest
of the evening and overnight. The threat of severe weather would
diminish overnight but we could still large hail and damaging winds
as well as locally heavy rainfall that could lead to isolated
flooding.

.LONG TERM...(Sunday through Friday)
Issued at 400 PM CDT FRI JUN 14 2013

Sunday-Monday: While the weekend continues to offer the likelihood
of several rounds of organized convection via MCS
development/propagation the details in timing/location will be
lacking owing to mesoscale processes and where any left over
convective boundaries set up. Current model solutions suggest
Saturday nights MCS may be exiting the southern portion of the CWA
Sunday morning and given latest model trends this seems reasonable
so will adjust highest PoPs to Sunday morning. With a tropical type
of airmass in place and any residual boundary(ies) best to leave low
chance PoPs for the afternoon for the possibility of convection
redeveloping within a moderate instability/low shear environment.

A better bet for organized convection will enter the picture Sunday
night although the entire CWA may not be affected. A rather robust
shortwave is progged to strengthen and dive southeast through the
Northern Plains and Upper MS Valley Sunday/Sunday night. The zonal
flow from the Central Rockies through MO will veer in response with
any convective system tracking more nw-se as it exits the Central
High Plains. This makes placement/timing of Sunday nights convection
a bit more difficult. For now will focus the likely PoPs across our
southwestern counties. Convection is expected to exit the CWA from
northwest to southeast as a cold front sweeps the tropical airmass
out.

Temperatures on Sunday will be a challenge owing to convective cloud
debris and any lingering convection. Monday should see readings
closer to seasonal averages.

Tuesday-Wednesday: Canadian high pressure will build into the region
the northerly winds will bring in a welcomed drier and cooler
airmass with seasonal afternoon temperatures and pleasant overnight
readings.

Wednesday night-Friday: A large closed upper system pressing east
through the Northern and Central Rockies will initially bulge an
upper level ridge eastward. This will allow the next chance for
elevated warm advection generated convection to move into the region
Wednesday night. Low chance PoPs will remain through Thursday as a
more humid airmass arrives and allows the airmass to destabilize.
Temperatures will likely warm well into the 80s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 1232 PM CDT FRI JUN 14 2013

VFR conditions should persist at the terminals through the entire
forecast. There is some concern that storms may move into the
terminals late this evening and tonight. The ongoing convection
across northern Missouri my send an outflow boundary that lays down
from southeastern Nebraska through central Missouri. A strengthening
low level jet may then aid in convective development across far
northwestern Missouri with storms then building and/or propagating
southeast into the vicinity of the terminals. Confidence in this
outcome is still fairly low so for now have just a VCTS mention.


&&

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

$$

SHORT TERM...CDB
LONG TERM...MJ
AVIATION...CDB