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Area forecast discussion 
National Weather Service Birmingham Alabama
604 PM CDT Wednesday Aug 31 2016

Update...
for 00z aviation.

&&

Short term...
through Thursday.

Guidance continues to converge on now Tropical Storm Hermine moving
northward and transitioning to the northeast tonight into Thursday
as the upper ridge is expected to break down allowing the weak
gradients to allow Hermine to be pulled toward the Gulf Coast.
The latest data does show a slight change in the track a little to
the west as opposed to previous runs, still including The Big Bend
area of Florida, but she could also affect a tad more of the Florida
Panhandle. By Thursday, we should see a little better rain chances
for the southeast as Hermine inches closer toward the Florida coast
and across the rest of the area thanks to an upper trough that will
swing and dig across eastern conus allowing for shortwaves to
traverse the base and generate some diurnal convection across
central Alabama. Winds from Hermine should not be an issue during
the day Thursday with only a few afternoon minor gusts expected (12-
20kts) generally across the southeast and should remain below
advisory criteria.

08

Long term...
Thursday night through Tuesday.

Hermine is currently forecast to make landfall as a strong
tropical storm or weak hurricane near Apalachicola Florida Thursday
night and move northeastward across southern Georgia through
Friday. Model guidance has shifted a bit westward and slower with
the track. Rainfall and winds are still expected to be asymmetric
with the greatest impacts on the east side of the track, east and
southeast of the forecast area. However, given the westward
shift, rain chances and quantitative precipitation forecast were adjusted westward, and increased
in the extreme far southeastern counties. Highest rain chances in
the far southeast will be after midnight Thursday night into
Friday morning. There will probably a sharp cutoff on the
northwest side of the rain shield due to the presence of dry air,
so rain chances will have to continue to be adjusted. Excessive
rainfall is still not expected. Winds in the far southeastern
counties will be breezy especially on the back side of the system
on Friday, with sustained winds currently forecast to be 10-15 kts
with gusts of 20-25 kts. This remains below Wind Advisory criteria
(sustained 20 kts and/or gusts of 30 kts). Confidence is too low
to mention any wind hazards in the severe weather potential statement but trends will continue to
be monitored, especially if there are any more westward shifts in
the track. Lightning will probably remain isolated due to limited
instability.

Elsewhere across the forecast area, some models do
keep some shower and thunderstorm activity going into Thursday evening
along a frontal boundary and mid-level moisture axis moving in
from the northwest ahead of an approaching upper-level trough. If
these trends continue then low rain chances may need to be
expanded northwestward Thursday night. On Friday, subsidence will
be moving in as Hermine moves in from the east, but an upper-level
trough axis moving through and remnant moisture may at least
squeeze out scattered showers across the east behind Hermine's
rain shield. A gradient in high temperatures is expected with
highs ranging from the mid 80s east to low 90s west. Dry
conditions should quickly build in Friday evening. With drier air
moving in the typically cooler locations in the north and east
lows will fall into the 60s.

Looking at the extended period, a strong mid-level ridge will
build across the southeast with highs in the 90s continuing. Only
small chances of isolated afternoon convection are expected mainly
in the far south given sufficient moisture.

32/Davis



&&

Aviation...
00z taf discussion.

As of 23z, fair weather was in place at all terminals, though a
batch of spotty showers is trying approach toi from the east along
a cumulus band. I've included vcsh for toi through early-evening,
dry elsewhere. VFR conditions are expected through tonight, with
calm to light northeasterly/easterly breezes.

On Thursday, Tropical Storm Hermine will continue its approach
toward the Florida Panhandle, as a surface front moves further
into northern Alabama. Hot/moist conditions and surface
convergence will favor budding cumulus and eventual showers and
thunderstorms. I've gone with early approximations of prob30 or
thunderstorms in the vicinity at some terminals during the afternoon. It's very likely that
additions and adjustments to timing and magnitude will be had as
we approach and step through Thursday afternoon. Surface winds
will average northeasterly around 10-knots, with some higher
gusts.

89/gsatterwhite

&&

Fire weather...

Generally dry conditions are expected for today with slightly
better chances on Thursday, but still low. No impacts are expected
from tropical depression 9. Critical fire weather conditions are
not expected. Dry conditions will be in place after Saturday
afternoon.

&&

Preliminary point temps/pops...
Gadsden 71 92 70 86 66 / 20 30 20 20 10
Anniston 71 91 71 84 68 / 20 30 20 30 10
Birmingham 74 93 72 88 70 / 20 20 20 10 10
Tuscaloosa 73 95 73 92 70 / 10 20 10 10 10
Calera 73 94 72 88 70 / 10 20 20 10 10
Auburn 73 92 72 84 70 / 10 30 30 40 20
Montgomery 74 96 74 91 73 / 10 20 20 30 10
Troy 72 92 73 89 70 / 20 40 30 30 20

&&

Bmx watches/warnings/advisories...
none.

&&

$$

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