000
FXUS63 KPAH 270437 AAB
AFDPAH

Area Forecast Discussion...UPDATED
National Weather Service Paducah KY
1137 PM CDT MON SEP 26 2016

.UPDATE...
Issued at 1137 PM CDT Mon Sep 26 2016

Updated the AVIATION discussion for the 06Z TAF issuance.

&&

.SHORT TERM...(Tonight through Wednesday night)
Issued at 253 PM CDT Mon Sep 26 2016

With the cold front and associated precipitation southeast of the
region, the primary story for the short term portion of the
forecast will be an upper-level storm system that will wobble its
way southward from the Great Lakes into the Ohio Valley. The 12Z
GFS, NAM and ECMWF all have the closed system right over the
Cincinnati area by 12Z Thursday.

This agreement is a new thing, and we will wait for verification
by subsequent model cycles before fully buying into it. Previous
runs of the ECMWF brought it farther west, more into our forecast
area, which would mean the potential for a non-dry forecast on
Wednesday. For now will settle for a modest increase in clouds,
especially in the eastern half of the area Wednesday and Wednesday
night.

All of the models push a secondary surge of surface high pressure
through the area early Wednesday. This along with the clouds
should lead to somewhat cooler conditions as compared to Tuesday.

Tried to lean toward the cooler side of guidance for lows tonight
with good radiational cooling expected over a dry airmass. With
full sun and decent west winds, we should warm to the warm side of
guidance, or not far from normal levels, for highs on Tuesday. The
winds should stay up Tuesday night, so leaned toward the warm side
of guidance for lows. Stayed close to the consensus for highs
Wednesday and lows Wednesday night with the surface high building
in.

.LONG TERM...(Thursday through Monday)
Issued at 253 PM CDT Mon Sep 26 2016

It seems that many of the long term models and even the GEFS have
locked into a solution of a closed low system over Indiana, southern
Michigan and Ohio by the start of the long term period. Model
consensus is that this upper level low will sag southward Wednesday
night into Thursday. However, the exact position of this upper low
will be crucial to determining cloud cover and chances for showers
as well as temperatures. Unfortunately, we are still too far out in
time to nail down these parameters.

However, the latest GFS/GEFS/Canadian seem to indicate that any
potential precipitation should remain to our east, although our far
eastern counties may have a slight chance of seeing a shower or two
if the Euro is correct. Too close a call to leave those eastern
fringes completely dry. But clouds will be a good bet for most
locations east of the Mississippi River, which will mean cooler
temperatures, likely remaining in the lower 70s for much of the
area, even upper 60s for some locations.

This upper level low sits and churns to our east Thursday afternoon
and evening before lifting back northward on Friday. This will keep
the clouds and cooler temperatures in our region. A small chance for
precipitation will also be possible across our northeastern sections
on Friday. However, if the Euro is correct, more areas may some
shower activity. Will leave more areas dry for now since the ECMWF
is somewhat of an outlier right now.

&&

.AVIATION...
Issued at 1137 PM CDT Mon Sep 26 2016

High pressure in the wake of a frontal passage will provide VFR
conditions for all TAF sites through the period, however there
could be BCFG through 12-14Z. Calm winds for the first half of
the period will pick up out of the west AOB 5 knots after 14Z,
then calm again after 00Z.

&&

.PAH Watches/Warnings/Advisories...
IL...None.
MO...None.
IN...None.
KY...None.
&&

$$

SHORT TERM...DRS
LONG TERM...CW
AVIATION...JP