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

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FXUS63 KEAX 272023

323 PM CDT Sat Jun 27 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 longwave 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 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1221 PM CDT SAT JUN 27 2015

A few isolated showers possible this afternoon...however, much of the
activity will be east of the terminals. Convection will dissipate
near sunset before clearing over night. Winds will become more
southerly by tomorrow morning.




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