Area Forecast Discussion
Issued by NWS Paducah, KY

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FXUS63 KPAH 152012

308 PM CDT Fri Aug 15 2014

.SHORT TERM...(Tonight through Sunday night)
Issued at 255 PM CDT FRI AUG 15 2014

Changes toward warmer, more humid and unsettled conditions are
likely as we head through the weekend.

High pressure that has given the region an unusually pleasant week
is beginning to pull off to the east. Should remain generally
rainfree for another 24 hours or so, but mid level short wave
energy and a surface low pressure system will be heading into west
central Illinois by Saturday night. Moist, southerly flow ahead of
the system will bring PWATS up to near 2 inches by later Saturday
night. All of this points to a good chc of showers and
thunderstorms coming into the forecast Saturday night and Sunday.
Due to the high PW values, can expect some heavy downpours where
storms do occur. Operational models have come into decent
agreement on timing and path of the system, but still differ on
QPF timing and amounts. Therefore, will not get too cute with
breaking down timing into much less than 12 hr increments, and
broad brush/average QPF as much as possible. Still, would not be
surprised to see some locations pick up over an inch or so by the
time the weekend is over.

The potential for severe convection may depend on the timing of
the surface front with respect to daytime heating Sunday. Right
now, it appears that at least the southeast 2/3 of the forecast
area will remain in the warm sector ahead of the sfc front much of
the day Sunday, where a very very moist and moderately unstable
air mass should be in place. Ongoing morning convection/cloud
debris may make it difficult to destabilize further, but if we get
a period of sunshine during the day, the airmass could become
quite unstable. 0-6 km bulk shear also looks like it will be
adequate for at least semi-organized structures. Re-initiation of
thunderstorms, some quite strong and possibly severe should at
least be considered along and ahead of the sfc low/cold front
Sunday afternoon, esp over se IL, sw IN, wrn KY and the Bootheel
region of se MO.

.LONG TERM...(Monday through Friday)
Issued at 255 PM CDT FRI AUG 15 2014

The long term period looks seasonably hot and humid with mainly
diurnal scattered convection. The main band of upper level
westerlies will remain primarily north of the Ohio Valley.

As far as the daily details...
On Monday...the shortwave trough and associated surface low
responsible for the weekend storms will be to our east. Deep west to
northwest flow will bring slightly cooler and drier air. Pops will
be toned down just a little around 20 percent in se
Missouri/southern Illinois/far west Kentucky and 30 percent

On Tuesday and upper level shortwave trough will
migrate slowly east from the Upper Mississippi Valley to the Great
Lakes region. The surface low and frontal boundary will remain well
to our north...along with the best upper level forcing. However...a
southwest low level flow /around 20 knots at 850 mb/ of very warm
and moist air will provide a favorable environment for convection.
Expect at least scattered convection to break out in a zone of warm
moist advection over the Lower Ohio Valley and se Missouri. Will
keep chance pops going for Tuesday through Wednesday.

On Thursday and upper level ridge over the Gulf Coast
states will build northward into the Ohio Valley. This ridge will
gradually stifle convective chances. Pops will go down to slight
chance Thursday. The forecast for Friday will be dry. Along with the
upper ridge will come heat and humidity levels a little above normal
for August but probably shy of advisory criteria.


Issued at 300 PM CDT FRI AUG 15 2014

VFR conditions through most of the period with ocnl mid and high
clouds, and light winds. However, may be another MVFR to IFR fog
event late tonight at KCGI/KPAH.




LONG TERM...MY is the U.S. government's official web portal to all federal, state and local government web resources and services.