Area Forecast Discussion
Issued by NWS Paducah, KY

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000
FXUS63 KPAH 230433
AFDPAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
1132 PM CDT Mon Sep 22 2014

.UPDATE...
Updated aviation section for 06z taf issuance

&&

.SHORT TERM...(Tonight through Wednesday night)
Issued at 207 PM CDT MON SEP 22 2014

A large area of high pressure extended from the Great Lakes to the
southern Plains, with few to no clouds, and mild NNE breezes across
the our area. The high will slowly move on into New England and
the Mid Atlantic states, with modest return flow trying to setup
though trajectories will maintain an easterly component of some
kind through mid week. Aloft, a narrow ridge will develop over the
area between a departing trof to our SE, and a larger scale mid
level trof across the Plains and eventually Upper Midwest. The net
result will be dry weather. As far as clouds, some upper level
moisture will try to move into the area mainly west of the
ridge...non significant scattered high clouds. May see a little
CU Wednesday into southern portions of the area as low level
moisture increases slightly. Temperatures will be a blend of MOS
and bias corrected output for lows given near calm conditions.
Highs will be given a weighted average of our existing numbers and
better performing guidance of late.

.LONG TERM...(Thursday through Monday)
Issued at 207 PM CDT MON SEP 22 2014

The central theme that continues to define the potential for any
convection across the WFO PAH CWA is the evolution and translation
of the Central U.S. low at the beginning of the extended forecast
period.

Both the deterministic medium range guidance and the GFS Ensembles
translate the trough southward, then eastward into the WFO PAH
forecast area by Sunday evening, as an mid-upper level feature (12z
Monday GFS) or a vertically stacked closed low (12z Monday ECMWF)
embedded in a trough.

Regardless of the sub-synoptic evolution, the WFO PAH forecast area
will be in the middle of the baroclinic forcing associated with this
trough. With this in mind, had to keep a chance of rain in place
over the area From Sunday night through Monday, then shifting the
focus of the PoP/Weather east with time on Tuesday.  The southeast
1/2 of the WFO PAH CWA (mainly West Kentucky) will likely see the
most QPF from the event. There is going to be such a sharp
demarcation of little or no precipitation to moderate precipitation
within the deformation zone, it will be difficult to determine the
best axis for QPF at this time.

The longer range model blend guidance suggests that the highest
pops will be late Sunday night into Monday. Maximum Temperatures
were lowered with the CWA (compared to surrounding NWS offices) to
reflect the persistent character of cloud cover, rain chances, etc.
Differential PoPs were used to reflect the lowered instability for
strong updrafts for thunderstorm coverage during this time period.

&&

.AVIATION...
Issued at 1132 PM CDT MON SEP 22 2014

Shallow ground fog is becoming more likely at KCGI early in the
morning. Some fog has formed at the Carbondale airport as of
04z...which could be an indicator of fog potential at fog-prone
sites like KCGI. The risk of shallow ground fog at the other taf
sites appears too low to mention at this time.

Some high thin cirrus clouds are spilling southeastward over the top
of a high pressure ridge over the Plains. Other than that...no
clouds are anticipated through Tuesday.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&

$$

Aviation...MY







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