Area Forecast Discussion
Issued by NWS Huntsville, AL

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000
FXUS64 KHUN 281122
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
622 AM CDT SUN AUG 28 2016

.UPDATE...
For 12Z TAFs.

&&

.DISCUSSION...
 (Issued 310 AM CDT SUN AUG 28 2016)
The 08z surface analysis indicated that the upper level ridge axis
was remaining across the southeast U.S. with generally clear skies
and temps in the lower 70s. In the short term, the models are
indicating that a weakness in the ridge axis will occur across
Southern Middle Tennessee and into northeast Alabama today. We can
expect isolated to slight chance afternoon shra/tsra pops across
these areas. The shra/tsra development by this afternoon will
primarily be due to orographic effects. Have compromised involving
todays high temps between the cooler GFS and warmer NAM temps.

The same general weather pattern is expected to continue into mid
week. The models are in similar agreement involving keeping the upper
ridge axis across the region, limiting much of shra/tsra development.
By Wednesday, a weakening cold front is expected to shift southeast
out of the midwest into the lower Ohio valley. By Thursday, the GFS
and ECMWF models are in decent agreement in slowly moving the frontal
boundary into and through the forecast area. If this scenario
continues, the frontal boundary will shift south of the forecast area
by later Thursday and will affect the movement of a tropical system
that is progged to develop in the Gulf of Mexico also by Thursday. To
differing degrees, the ECMWF and GFS models develop a tropical system
in the gulf of mexico by Thursday, but there are differences
involving this system placement and its development with each model
run.

If the 00Z model run trending continues, the forecast area will be
on the subsidence side of the system well to the northwest and drier
and slightly cooler air will filter southward into the region for the
upcoming labor day weekend. Due to longer term model inconsistencies,
have opted to compromise between the cooler GFS temp guidance and the
warmer ECMWF temp forecast.

TT

&&

.AVIATION...
For 12Z TAFs: Patchy fog around the KMSL terminal and other portions
of the Tennessee Valley should continue through 13Z before
scattering out. There is some uncertainty in the forecast for
thunderstorms this afternoon. Models drop a weak system W/SW out of
eastern TN into the TN Valley today with isolated to scattered storms
forming out ahead of it. But not confident in how widespread the
coverage of storms the models are advertising. So, have kept VCTS at
both terminals through the afternoon hours. Will keep a close eye on
this and adjustments might be needed if more widespread storms do end
up developing. Otherwise, expect VFR conditions through the 08Z
tonight. After 08Z patchy fog is possible at KMSL through sunrise
Monday morning.

Stumpf

&&

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

$$

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at weather.gov/huntsville.



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