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000
FXUS64 KOHX 221137
AFDOHX

Area Forecast Discussion
National Weather Service Nashville TN
637 AM CDT Sat Jul 22 2017

.UPDATE...
FOR 12Z AVIATION DISCUSSION.

&&

.DISCUSSION...

Heat and humidity will continue to be the main concern through
this weekend. Today`s conditions look very similar to yesterday,
and tomorrow looks almost as hot. So, the Heat Advisory for much
of Middle Tennessee will be extended until 7 PM CDT Sunday.

The upper level high pressure responsible for the heatwave was
positioned just to the west of Middle Tennessee this morning.
Through the rest of the weekend, this high will gradually weaken
over our area. This will probably not make much difference in
terms of temps and humidity today with models showing slight
building of the low level warm air. But, temps are likely to back
off a degree or 2 on Sunday while still yielding potentially
dangerous heat index levels.

A few isolated thunderstorms will occur today, with a little more
coverage than yesterday. Pops will be 10-20 percent, with the
"best" chance for an isolated storm over the Plateau and far
south where low level moisture will be a little greater. The
approach of a front on Sunday will bring greater thunderstorm
chances, especially over the north half Sunday afternoon and
evening. A few of these storms could become strong to briefly
severe in the high cape environment. Localized wind gusts will be
the main concern.

The diffuse frontal zone will linger over the region through
Monday with scattered thunderstorms, and a few strong storms
possible. Monday will be hot and humid, but heat index values
will be less oppressive, in the mid to upper 90s.

In the extended forecast period, it now looks hot and humid- not
quite as much heat relief as we had advertised in previous
forecasts. But, it does not look like advisory level heat, so
that is good news. Highs most of next week will be in the lower
90s with lows mostly lower 70s. There will be at least slight
thunderstorm chances each day. Thunderstorm chances will increase
late week with models showing the approach of a cold front.

&&

.AVIATION...
12Z TAF DISCUSSION.

Patchy BR and HZ may produce a brief period of MVFR conditions at
area terminals up through 1330z. After that expect VFR conditions,
until the reappearance of patchy late morning and early morning BR
and HZ after 11z/23, along with the possibility for a return to MVFR
conditions. High pressure, extending from the Atlantic across the
Gulf of Mexico, will continue to produce Southwest surface flow
through the forecast.

Looking ahead...a cold front is forecast to drop into the Ohio
River Valley on Sunday and produce scattered showers and
thunderstorms in Middle Tennessee by the mid to late afternoon.


&&

.OHX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 7 PM CDT Sunday FOR Bedford-Cheatham-
Davidson-Dickson-Giles-Hickman-Houston-Humphreys-Lawrence-Lewis-
Macon-Marshall-Maury-Montgomery-Perry-Robertson-Rutherford-Smith-
Stewart-Sumner-Trousdale-Wayne-Williamson-Wilson.

&&

$$

DISCUSSION......13
AVIATION........19