Area Forecast Discussion
Issued by NWS Paducah, KY

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FXUS63 KPAH 152023
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
323 PM CDT Fri Sep 15 2017

.SHORT TERM...(Tonight through Sunday night)
Issued at 117 PM CDT Fri Sep 15 2017

Visible Imagery shows cu field extensively across FA, perhaps
slightly more agitated across northeast 1/3 FA, where gridded
time/height cross sections reveal 850 mb condensation pressure
deficit values some 10-20 mb lower there. The gfs actually thinks
that is pcpn, so we take that fwd realizing it may be overdoing
some short term pcpn modeling.

Anticipate a clear sky/light wind scenario again tonight, and
while this may be conducive to some late night/early Sat am fog
again, it may not be headline material, at least that is what MOS
suggests.

Saturday-Sunday looks mostly dry/mild. The gfs again appears to
slightly overdo its QPF, with the NAM perhaps modeling the near
term environ better, keeping us pcpn free. We think that is the
way to go, or at least silent with Pops, until better forcing can
come in during the next week.

.LONG TERM...(Monday through Thursday)
Issued at 323 PM CDT Fri Sep 15 2017

The medium range models were in generally good agreement in the
extended period of the forecast regarding the amplified longwave
pattern over the CONUS. Finer details were harder to pin down,
especially Days 6 and 7. We will be in a warm, moist, and unstable
airmass during this time. Thus, there will be PoPs in at least part
of the PAH forecast area in almost every 12 hour period.

On Mon, a mid level ridge over the southern CONUS will be suppressed
somewhat by shortwave energy in the west-southwesterly flow across
the Midwest. At the same time, a weak cold frontal boundary will
approach the northernmost counties before weakening further and
moving back north by Mon night. This will be the first one of the
more certain pcpn signals for everyone except perhaps the Pennyrile
region of KY (scattered showers/tstms).

A period where just about every part of our region will have
scattered showers and tstms around will be Wed (the 2nd signal).
This will be when shortwave energy on the periphery of a large and
expanding mid level western CONUS trof swings through. PoPs should
generally decrease Wed night with the diurnal stabilization, as
another lobe of energy digs into the trof out west, causing heights
over us to rise. Still, the models suggest some possibility of some
scattered deep moist convection, perhaps triggered by subtle
shortwave energy, developing in the heat of the day Thu and Fri as
the lower trop continues to moisten up.

Expect above average temperatures through the extended period. It`s
going to feel like summer all the way up to the end.

&&

.AVIATION...
Issued at 117 PM CDT Fri Sep 15 2017

Scattered to marginally broken diurnally driven VFR bases in the
4.5-6K FT AGL range this pm, will be repeated tmrw pm, according
to gridded time/height analysis. A moclear/light wind overnight
regime may be conducive to fog, patches locally dense, but MOS
suggests perhaps not as extensive as the previous night or two.
Have included inherited mentions and will run with, adjusting with
time as threat emerges in more detail.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.

&&

$$

LONG TERM...DB



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