Area Forecast Discussion
Issued by NWS Huntsville, AL

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FXUS64 KHUN 301107 AAA
AFDHUN

Area Forecast Discussion...UPDATED
National Weather Service Huntsville AL
607 AM CDT TUE AUG 30 2016

.UPDATE...
For 12Z TAFs.

&&

.DISCUSSION...
(Issued 233 AM CDT TUE AUG 30 2016)
As of 0730Z not much has changed when comparing current Water Vapor
imagery to the same time yesterday. The high to our north, the low
off the GA/SC coast and the low off the TX coast have shifted ever so
slightly westward. Regional 00Z soundings and satellite derived PWATs
indicate drier air in place across the southern Appalachians with
PWAT values around 1.2 inches. This region is in an area of
subsidence between the high to our north and the low along the GA/SC
coast. Latest guidance has both the high and the low shifting further
W/SW with time today. As a result the drier air mainly in the
mid-levels will be advected into the TN Valley. Not quite buying into
the upper 50s dewpoints across the eastern half of the area this
afternoon shown by a few of the short-term guidance. But do think
dewpoints will lower an additional 1-3 degrees compared to yesterdays
values.

This should all translate into a dry forecast for today with any
shower/thunderstorm activity remain outside of the TN Valley. A weak
shortwave evident in WV across NE TN may provide just enough lift to
spark an isolated storm over the higher terrain in TN/GA but think
our area will remain storm free. Temperatures this afternoon will
again climb into the low to mid 90s but due to the drier air it
should feel less humid today.

Tonight in Wednesday a low pressure system is forecast to drop SE out
of northern Canada towards the NE US sending a pre-frontal trough
towards the the TN Valley. While this is occurring the dry air in
place today gets shifted back to the east and we will see a slight
increase in low/mid-level moisture. Latest guidance differs to some
degree on the timing of the pre-frontal trough on Wednesday. But
believe that with the slight uptick in moisture, strong diurnal
heating, and lift with the trough, we should see isolated showers and
thunderstorms develop Wednesday afternoon.

The best chances for storms will likely come on Thursday as the main
front rolls through the area. Nudged up PoPs and kept the chance
wording for the eastern half of the area as they will be closer to
the upper level trough axis and better lift. At this point not
expecting other than a few isolated strong storms as shear (20kts)
and CAPE (1200 J/kg) aren`t supportive of anything beyond that.

The remainder of the forecast Friday through the Labor Day weekend is
shaping up nicely. We remain in northerly flow through the period,
which will help to keep dewpoints near the 60 degree mark. Highs are
forecast to range from the mid to upper 80s with overnight lows in
the low to mid 60s! Should be a nice weekend for outdoor activities.

Stumpf

&&

.AVIATION...
For 12Z TAFs: VFR conditions will continue today at HSV, but patchy
fog will result in tempo MVFR fog conditions at MSL until around 13z
this morning. VFR conditions will be the rule at both HSV and MSL
after 13z. Some more patchy fog is expected at the terminals at the
end of the TAF period. Added in a tempo 5sm br at both HSV and MSL
after 10z Wednesday.

TT

&&

.HUN Watches/Warnings/Advisories...
AL...NONE.
TN...NONE.
&&

$$

For more information please visit our website
at weather.gov/huntsville.



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