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

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FXUS63 KEAX 300833

333 AM CDT Sat Aug 30 2014

.SHORT TERM...(Today through Monday)
Issued at 333 AM CDT SAT AUG 30 2014

Isolated storms associated with an eastward moving shortwave trough
are beginning to diminish across portions of northern Missouri, and
should gradually become confined to areas of central MO this morning
where a broad region of accas is currently evident. These storms
should also diminish after sunrise, and any potential redevelopment
this afternoon should be confined to our extreme southeast, along
and just north of the northern Ozarks.

As last evening`s shortwave trough departs to the northeast, another
more robust system will follow on its heels this weekend. Ahead of
the approaching trough, the thermal axis will shift into the central
and Plains, bringing 850 hPa temperatures into the 18 to 19 degree
range today and the 20 to 22 C range on Sunday. Enhanced southerly
flow on Sunday ahead of the approaching cold front will also help
temperatures rise, resulting in highs in the mid to upper 80s for
this afternoon and the upper 80s to lower 90s for Sunday.

The main focus in the short term will be storm chances from late
Sunday evening through Monday as the cold front slides southeastward
across the CWA. Timing has not changed significantly from earlier
model runs, and still indicates frontal passage around midnight in
far NW Missouri, and then a gradual slowing of the surface front
during the daylight hours Monday. Currently, the most likely
scenario is that fairly robust storms will develop along the cold
front in southeast NE and southwest IA, in an environment
characterized by 1500-2000 J/kg MUCAPE and 40-45 kts deep layer
shear. These storms will likely form some sort of convective complex
with shear vectors oriented nearly parallel to the surface front,
and cold pool dynamics will then send the complex out ahead of the
surface front after midnight. Storms may initially be strong to
possibly severe, but should eventually move into a less supportive
environment during the early morning hours Monday. Additional storms
may redevelop along the cold front behind the convective complex, but
should be less widespread and weaker in the worked-over environment.
Have generally decreased PoPs southeast of the KC metro area to
account for this scenario, but have kept up to 50 PoPs for Monday,
especially if some clearing occurs in central MO ahead of the front
and allows some instability to build before frontal passage occurs.
The main severe threat both days will be damaging wind, especially
from late evening Sunday through ~3-4 AM Monday across northwest MO
and far northeast KS, and possibly again late Monday afternoon in
central MO, although the shear is less impressive in these areas.

.LONG TERM...(Tuesday through Friday)
Issued at 333 AM CDT SAT AUG 30 2014

The upper trough begins to lift northeast away from the forecast
area at the start of the extended period Tuesday. At the surface, a
cold front is projected to have cleared much of the CWA by Tuesday
morning, but slowing or stalling over the northern Ozarks as the
upper trough departs. The frontal position will dictate best chances
for precipitation, which at this time should be largely confined to
the southern portions of the forecast area Tuesday and Tuesday
night. The surface boundary is expected to retreat northward as a
warm front on Wednesday as heights begin to rise across the region
in response to the upper pattern flattening. Only a slight chance of
thunderstorms is anticipated on Wednesday, with mainly dry
conditions through Thursday. Likewise, temperatures Wednesday and
Thursday will return to above normal readings in part to slightly
warming H85 temperatures as weak upper ridging moves into the
region, with afternoon highs in the upper 80s to lower 90s expected.
Models have decent agreement in the overall synoptic pattern by the
end of the work week, featuring an elongated positively-tilted
trough over the Intermountain West, but deviate with the placement
of a surface cold front over the Northern/Central Plains states. The
southernmost solutions take the frontal boundary as far south as
Northwest Missouri by Friday night, with others no further than
Interstate 80. With the uncertainty of frontal position and the
potential for some upstream convective development to approach the
CWA, will carry a chance of thunderstorms over northern Missouri
beginning late Thursday night into the weekend.


.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
Issued at 1206 AM CDT SAT AUG 30 2014

Thunderstorms continue to percolate around the Kansas City terminals
late tonight, but this activity is not expected to last much longer.
By the time the TAF is valid expectations are that the thunderstorms
activity will have moved to the east or dissipated. Therefore, only
issue in the TAF is the potential for MVFR to IFR fog as skies clear
in the wake of the storms. Winds this morning will be light and
variable which will likely result in at least some haze. Have kept IFR
conditions in for the KSTJ terminal. Otherwise, Light winds will
remain rather variable through the day Saturday, with speeds under `10
knots expected through the day.




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