National Weather Service Weather Forecast Office

Area Forecast Discussion

687
FXUS62 KTAE 031523
AFDTAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
1123 AM EDT Thu Oct 3 2013

...Tropical Storm Karen Has Formed in the Southeast Gulf of
Mexico...

...A Hurricane Watch is in Effect from Grand Isle Louisiana Eastward
to Indian Pass...

...The Hurricane Watch for the Local Area includes from Destin
Eastward to Indian Pass...

.NEAR TERM [Through Tonight]...
The regional longwave pattern is highlighted by an H5 ridge along
the extreme SE Coast and a weak shortwave over the TN Valley and a
developing longwave trough over Wrn Conus. At the surface, high in
Atlc off Carolinas with ridge Wwd to Nrn GA. Main feature is newly
developed TS Karen over SE Gulf of Mex. At 11 am EDT, Karen was
located at 22.2N and 87.9W or about 485 miles south of the mouth of
the MS River. (See short term discussion for details). Locally this
translates to light ELY winds across the area. Any precipitation
will be focused across the Panhandle waters closest to the deeper
layer moisture. Will continue with 10-40% NE-SE POP gradient across
these waters. With increasing high clouds from the tropical storm
well to our south, highs will be in the mid 80s.

By tonight, Ern ridge has been shunted offshore with upper low in
Srn gulf of Mexico. Deeper layer moisture continues to stream Nwd
but remains just south of our marine area. Precipitation will wane
towards sunrise with 20-30% POPs over the water. Expect minimum
temperatures from the mid 60s north to near 70 coast.

&&

.SHORT TERM [Friday Through Sunday]...
The NHC track guidance has TS Karen moving NWD reaching the coast
near Pensacola during the pre-dawn hours of Sunday before racing
rapidly newd overland through Sunday. At that time, Karen is
protected to be a tropical storm with sustained winds at 50 kts and
gusts to 60kts. The local forecast is based on the NHC and thus will
be modified as the track/speed or intensity is modified.

On Friday moisture will start to increase ahead of TS Karen.
However, it is still expected to be far enough south to keep
significant rain chances out of the area with just 30% PoPs across
the western areas.

By Saturday afternoon, outer bands could start affecting the
coastal counties. SE winds will begin to noticeably increase across
the Panhandle waters and counties. By sundown, Tropical storm winds
with gusts to 46 kts from the south are forecast to reach the
extreme Wrn Panhandle waters. However, the possibility of more
significant impacts is currently expected to hold off until night.
60-0% SW-NE POP gradient.

During Saturday night, SLY tropical storm sustained winds will exist
over extreme coastal Wrn Panhandle waters and Walton County with
S/SE winds 15 to 20 kts extending as far east as Jefferson County.
By sunrise, as Karen moves NEWD, strongest winds extend Nwd into SE
AL/inland Panhandle. 70-0% W-E pop gradient.

On Sunday morning, SLY Tropical storm winds will likely still exist
over Walton and Wrn Coffee and Geneva counties with winds above 20
kts extending as far east as Jefferson and Thomas counties. By
sundown, as remnants of Karen race newd, local winds will have
noticeably to 10 to 15 mph. 60-20% NW-SE POP gradient.

&&

.LONG TERM [Sunday Night through Thursday]...
The start of the long range period is a little tricky dependent on
eventual speed, intensity and track of Karen. Based on current
track, by Sunday night, Karen will have raced well northeast of the
forecast area taking deeper moisture with it and with local winds
significantly decreasing to SW 10 to 15 mph range.

For the rest of the period, mainly offshore winds will decrease to
normal levels. POPs will decrease to mid sct on Mon, low sct on Tues
and wdly sct Wed into Thurs.

&&

.AVIATION...
[Through 12 UTC Friday] VFR conditions are forecast through the
period with exception of a period of MVFR visibility expected at VLD
after midnight.

&&

.MARINE...
The forecast will be contingent on future strength, track and
intensity of TS Karen. Expect winds to be on the increase out of the
southeast through this weekend as TS Karen moves into northern Gulf
of Mexico. (see above discussions for more details).

Based on current NHC projection, winds will likely reach SCEC
levels over Wrn waters Fri night rapidly intensifying to SCA
levels before sunrise. Seas will reach 7 feet over Wrn most
waters. On Sat, tropical storm wings/gusts reach extreme mainly
nearshore Wrn waters with SCEC conditions spreading into Wrn
Apalachee Bay. Seas increase rapidly to 7-13 (E-W) feet Panhandle
waters on Sat. On Sat night thru Sun, seas increase up to 6 feet
Apalachee Bay and 11-15 feet Panhandle waters with highest seas
along Walton county coastal waters. Seas remain at 7-12 feet N-S
on Sun decreasing rapidly on Sun night to below SCA levels except
possibly far offshore Apalachee Bay. Winds will decrease to below
SCA levels before sundown Sun. By Mon, seas will begin to rapidly
decrease but remain at SCA levels until Mon morning before slowly
returning to normal heights.

&&

.FIRE WEATHER...
Red Flag conditions are unlikely through at least this early next
week.

&&

.HYDROLOGY...
River flows remain above base levels for early October with area
soils still quite moist from the summer rains. The impacts of TS
Karen this weekend will need to be closely monitored. This could
easily produce enough rainfall to result in a fair amount of areal
and riverine flooding into next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
Tallahassee   86  67  89  71  87 / 10  10  10  10  30
Panama City   86  72  86  73  85 / 10  20  30  20  40
Dothan        86  64  89  68  85 / 10   0  10  10  30
Albany        87  64  89  66  87 /  0   0   0   0  10
Valdosta      85  64  88  66  88 /  0   0  10  10  10
Cross City    87  67  88  68  87 /  0  10  10  10  20
Apalachicola  82  72  84  74  83 / 10  10  30  20  40

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...HURRICANE WATCH for Coastal Bay-Coastal Gulf-South Walton.
GA...None.
AL...None.
GM...HURRICANE WATCH for Coastal waters from Apalachicola to Destin
     FL out 20 NM-Waters from Apalachicola to Destin FL from
     20 to 60 NM.
&&

$$

Near Term/Aviation/Short Term...Block
Marine...Wool
Hydrology...DVD/Block