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

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FXUS63 KEAX 280500

1200 AM CDT Sun Jun 28 2015

Issued at 323 PM CDT SAT JUN 27 2015

A widespread cu field and isolated showers have begun developing
across the region in response to diurnal surface heating and cold
air aloft. Showers and cu will dissipate this evening as the
boundary layer cools, and precipitation amounts are expected to be
low due to the isolated and progressive nature of precipitation.

Main focus in the short term is the severe weather potential across
our CWA on Sunday afternoon through the early evening. The longwave
trough responsible for today`s quiet and cooler conditions will push
eastward tonight, and as it does, a shortwave trough will sink south
down the backside of the departing trough. At low-levels, the short-
wave trough will push a slow-moving cold front through the region,
providing low-level focus for convection. Early in the day, most
precipitation will focus across eastern Missouri where upper-level
forcing is strongest, then as moisture arrives and surface heating
increases instability, winds increase and convergence along the
boundary enhances, storms are expected to strengthen and back build
to the southwest along the front. Shear will be more than adequate
for supercells in the 45 to 50 kt range, and low-level turning will
result in 0-3 km helicity approaching 300 m2/s2. The slow-moving
nature of the boundary should prevent undercutting of updrafts with
cold air; thus strong to severe storms appear probable from ~2 PM
through when the front exits the region in the evening. The limiting
factors for strong to severe storms will be warm-air aloft edging
eastward as the long wave trough departs, and the arrival of low-
level moisture before the front passes. Both of these limitations
exist mainly in the western half of the CWA, keeping severe weather
chances and the overall probability of precipitation a little more
conditional west of Hwy 65 and especially west of the state line.

After storms depart the CWA to the southeast Sunday evening, quiet
and just slightly cooler conditions are expected for Monday. Upper
flow begins to flatten Tuesday into Wednesday and a boundary stalls
across the CWA, resulting the return of precipitation chances and
near to slightly below normal temperatures from midweek on. Heavy
rain could be a threat if multiple rounds of convection fire, but
will evaluate the threat for flooding once the position of the
boundary becomes clearer.


.AVIATION...(For the 06Z TAFS through 06Z Sunday Night)
Issued at 1157 PM CDT SAT JUN 27 2015

There could be some isolated to scattered showers moving into
northern Missouri during the overnight hours, but while hi-res models
depict a few showers moving into the northern terminals (KSTJ/KMCI)
forecast soundings are not supportive of rain reaching these
terminals. So kept the mention showers early in the period out of all
terminals. For Sunday afternoon a cold front will move in and kick
off some showers and thunderstorms. Some of these storms could be
severe with hail and strong winds. Models seem consistent in breaking
out storms along and south of I-70, so kept KMCI/KSTJ out of the
thunderstorm mention. Otherwise, the storms could move out rather
quickly to the south. Thereafter expect VFR.




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