295 
FXUS63 KPAH 121709 AAA
AFDPAH

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PADUCAH KY
1209 PM CDT Thu Sep 12 2013

.UPDATE...
ISSUED AT 1203 PM CDT THU SEP 12 2013


Updated the aviation section for the 18Z TAF issuance.

&&

.SHORT TERM...(Today and Tonight)
ISSUED AT 310 AM CDT THU SEP 12 2013

Patchy fog may be around some locations by sunrise where high cloud
cover has not increased too much. This would be most likely in the
southeastern half of the PAH forecast area. Another factor against
dense fog formation will be a slight increase in srly low level
winds ahead of a cold front forecast to arrive today, driven by a
robust mid level shrtwv. 

Short term models indicate that the orientation of flow at 850 mb
will be conducive to wrly winds at that level this morning, which 
will be roughly at the base of deeper moisture. These veered
winds will limit convergence along the front, and therefore
coverage of showers and tstms, to mainly the ern quadrant of the
region. The sfc boundary should bisect the region by mid morning
and be through the region by late afternoon. Due to the elevated
nature of the moisture column, most of the pcpn is expected to be
post-frontal. The initial batch of showers and tstms will be
along the I-64 corridor in the late morning, followed by some
convection mainly in wrn ky in the afternoon. mlcapes of 2000 j/kg
are quite possible in the soupy air mass initially in place over
the PAH forecast area. This combined with moderate winds aloft and
drier air below 850 mb may allow a few strong tstms to develop
over wrn ky an adjacent areas, with marginally severe hail and
wind gusts (downdrafts) a possibility through sunset. Cooler and
much drier high pressure air will surge in behind the front.

As an 850mb shear axis moves into the area Fri morning, nrly winds
are forecast to increase significantly just after sunrise and veer
to the nne. Sustained winds of 13 to 14 kts will be possible,
especially in swrn ind and adjacent areas. bufkit soundings
indicate gusts up to about 21 kts will be possible there in the
late morning, diminishing a bit as the day goes on. This could
challenge operation of smaller craft on area lakes and rivers.

Saturday will have crystal clear skies, lighter winds, the lowest
humidity, and the coolest temps of the 7 day forecast, with lows
in the 40s and highs in the 70s.

.LONG TERM...(Saturday night through Wednesday) 
ISSUED AT 253 AM CDT THU SEP 12 2013

Given both ECMWF and GFS 00z models deflect pcpn outside of pah fa 
Sat Night-Monday, have decided to go ahead and keep the extended dry
until late in the period. Lower 80s for highs, and 50s to near 60 
for lows, will prevail thru Tuesday. 

Starting Tue night, the warming and moistening of the column over 
pah fa will result in area-wide pops thru the remainder of the 
forecast as the upper flow becomes zonal. Temps will start to creep 
up into the mid and upper 80s for highs and mid and upper 60s for 
lows.

All of the aforementioned represents not much change to the going 
forecast, only minor edits and tweeks for the latest data.

&&

.AVIATION...
ISSUED AT 1203 PM CDT THU SEP 12 2013

VFR conditions expected at all sites through the period. Remote
chance of SHRA/TSRA this afternoon but too little to mention in
TAFs. Northerly winds 8-10 kts will drop off to aob 5 kts after
sundown, then pick back up out of the northeast around 10 kts with
gusts up to 15 kts after 14-15Z.

&&

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

$$

SHORT TERM/AVIATION...JP
LONG TERM/FIRE WX...KH