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Area forecast discussion 
National Weather Service Louisville Kentucky
733 PM EDT sun Jul 5 2015

..updated aviation discussion...

Short term (now through Monday night)...
issued at 257 PM EDT sun Jul 5 2015

Water vapor imagery this afternoon shows a well defined circulation
in the upper level flow over eastern Kentucky. At the surface low
pressure is centered near the Kentucky/Virginia border. The majority of the
showers this afternoon will be across east central Kentucky where
light to moderate rains continue. There could be a few stronger
showers around the Lake Cumberland area. However, for the most part
these should only produce brief heavy rainfall and are not expected
to cause any additional flooding issues. Therefore have decided to
cancel the Flash Flood Watch this afternoon. Short term models also
have isolated to scattered showers developing across southwestern
portions of south central Kentucky this afternoon. These should wane by
late afternoon.

All of the rain should move out of the area by early evening. The
overnight hours are expected to be dry with light to calm winds and
partly to mostly cloudy skies. With plenty of low level moisture,
some patchy fog may develop across the region, so have added that in
to the forecast.

Southwesterly flow will set up tomorrow ahead of a cold front which
will begin to approach the region tomorrow night. There will be
little in the way of large scale forcing tomorrow. However,
relatively unstable soundings and a very weak upper level
disturbance moving through the flow could spark isolated showers
and/or thunderstorms. Rain chances will be on the increase late
Monday night as the cold front nears from the northwest.

Temperatures Monday are expected to be on the warm side with highs
in the mid to upper 80s. Lows tonight and tomorrow night will be in
the upper 60s to lower 70s.

Long term (tuesday through sunday)...
issued at 300 PM EDT sun Jul 5 2015

Tuesday still looks to be the wettest day in the long term period as
a front drops southeast into the Ohio Valley. Although the
strongest mid to upper level flow should remain to our north, there
may be enough 0-6 km bulk shear to produce some strong storms with
gusty winds. Storm strength will also depend on available
instability. While models are showing some, it may be difficult to
build much if we start the day cloudy with an initial round of
showers/storms. Will need to watch the evolution/timing of this
weather system in coming days.

For mid week, the front looks to stall over our region initially
with uncertainty still in how quickly a southeast Continental U.S. Ridge will work
into the Ohio Valley and just how strong it will get. Most mid
range models continue to support shortwaves riding along the
boundary producing multiple rounds of showers/storms tues night/Wed.
By Wed night/thurs, most models indicate that the boundary will be
far enough north, to result in lesser pops. Even the recent, wetter
outlier (the euro) has trended drier on its 12z run. However, the
door is still open for diurnally based convection peaking during the
afternoon/evening hours. This pattern looks to potentially hold
through the weekend with daily pops. If the recent drier
model consensus holds, at least some dry periods during the
overnight hours might be added to the forecast beyond mid week.

Temperatures will generally range through the 80s for highs for
tues-thurs with lows in the upper 60s/lower 70s. As the ridge
builds into the Ohio Valley, it will bring a warmer airmass
resulting in high temps in the mid 80s to lower 90s for Fri-sun with
lows in the lower 70s.

&&

Aviation (00z taf update)...
issued at 730 PM EDT sun Jul 5 2015

Have some slightly reduced visibilities, just under 10 miles, this
hour at klex and ksdf. The latter site however had a dewpoint drop
down to near 60 in the last hour though. This dry air mixing down
should help to keep ksdf from dropping below VFR toward daybreak,
but klex and even kbwg should see at least MVFR after midnight,
given low level moisture in place there. IFR conditions cannot be
ruled out toward daybreak as well, given light winds and relatively
clear skies.

&&

Lmk watches/warnings/advisories...
Kentucky...none.
In...none.
&&

$$

Short term........eer
long term.........Ams
aviation..........rjs

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