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Area forecast discussion 
National Weather Service Paducah Kentucky
853 PM CDT Sat Aug 30 2014

Update...
issued at 847 PM CDT Sat Aug 30 2014

Update short term forecast (tonight) to reduce rain chances to
next to nil through midnight over all locations except the far
southern pennyrile of west KY, where rain and isolated
thunderstorms will likely lift back NE into the region from NW Tennessee.
Will allow rain chance to increase some after midnight, esp over
wrn Kentucky as sfc low and another possible h50 shortwave approach
from the west.

&&

Short term...(tonight through Monday night)
issued at 237 PM CDT Sat Aug 30 2014

Heavy rain producing showers and thunderstorms persisted across
west Kentucky this afternoon, with scattered development seen from semo
into southern Illinois in an axis of slightly greater instability. The
general pop depiction through tonight will be highest across the
southeast 1/2, slightly lower northwest 1/2. Locally heavy rain will remain a
concern with pw's over 2" across much of the area, coupled with a
persistent low level SW jet and mid level flow unidirectional to
the low trop. Once the final wave moves through Sunday morning and
dampens out, convection over mainly west Kentucky into SW in should push
on to the east. Will have lowering pops through the day and early
evening. Later Sunday night through Labor Day looks somewhat
inactive. We lowered pops for Labor Day, and kept just small
chances far north over portions of southern Illinois into SW in. Not
expecting much coverage overall. Chances will ramp up Monday night
when a front moves toward the region and mid level energy moves
across the Midwest toward the Ohio Valley. In terms of temps, used
a blend of existing numbers (persistence) and latest raw model
output.

Long term...(tuesday through saturday)
issued at 237 PM CDT Sat Aug 30 2014

The long term will start out busy as the mid level flow remains
active. Another shortwave will approach from the west on Tuesday,
along with weakening front at the surface. Models generate healthy
quantitative precipitation forecast as the front enters the County Warning Area around 12z Tuesday in parts of
southwest Illinois and southeast MO. Convergence/lift weakens along the
front as it moves east during the morning and especially during
afternoon. However, it still appears convection will be likely in
the western sections early in the day, possibly lessening in
coverage during the afternoon as things progress eastward. The
00z/12z European model (ecmwf) is more robust with quantitative precipitation forecast especially for the afternoon,
as the GFS really drops off quantitative precipitation forecast during that time. Will raise probability of precipitation
though to just shy of the likely category with the best chances in
MO/IL. Instability parameters are off the charts on the GFS so if we
have enough lift, there may be more convection then the quantitative precipitation forecast
indicates.

The front ends up stalling over the southern sections on Tuesday
night, so will linger probability of precipitation with best chances south. The GFS
indicates that the front will start moving northward as a warm front
late Tuesday night into Wednesday. In turn, the GFS indicates
scattered convection during the day and into the night. The flow
aloft remains zonal with the center of the upper high centered over
the deep south. The European model (ecmwf) is not as pronounced with showing much of
a retreat back north, and therefore does not show much in the way of
quantitative precipitation forecast. In fact, it shows the upper ridge building somewhat across our
area, which will tend to keep US dry through Wednesday night. Will
maintain low chance probability of precipitation for now until we can get a better handle on
what this front will end up doing.

By Thursday and through the end of the period, it appears as though
upper level ridging will take over which should end any chances for
decent chances for rain, except for isolated afternoon chances.

Highs will be in the upper 80s translating to the lower 90s by the
end of the period. With dewpoints in the lower 70s, it should
continue to feel like Summer for a while longer.

&&

Aviation...
issued at 623 PM CDT Sat Aug 30 2014

Clusters of showers and storms will continue to move north/northeast
from the lower Mississippi Valley tonight. The kpah and kevv taf
sites will be near the western fringe of this activity...which
should be rather widespread through the night. It appears kowb will
have occasional rain through the night. Kcgi will remain mainly to
the west of the rain. Some rumbles of thunder are possible...but
instability has waned due to widespread rain and clouds this
afternoon.

Second concern is low stratus around sunrise where the ground is
saturated. Will follow computer guidance and go with IFR cigs early
to mid morning where widespread rain has moistened the low levels.
Drier air arriving in the wake of the low pressure system will allow
for partial clearing Sunday afternoon. A few isolated storms could
pop up in the heat of the day...but coverage will be too low to
mention in tafs.



&&

Pah watches/warnings/advisories...
Illinois...none.
MO...none.
In...none.
Kentucky...none.
&&

$$

Update...GM

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