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FXUS62 KTAE 252335
AFDTAE

Area Forecast Discussion
National Weather Service Tallahassee FL
735 PM EDT Fri May 25 2018

...SUBTROPICAL STORM ALBERTO TO BRING IMPACTS TO THE GULF COAST AS
EARLY AS SUNDAY MORNING...

.AVIATION [Through 00Z Sunday]...

Generally VFR conditions through the period with scattered showers
and thunderstorms diminishing this evening. Some -SHRA/-TSRA
activity may linger a bit longer causing a brief drop in
conditions as the more persistent showers drift through. Some
patchy fog could also lower visibilities in the early morning
hours to IFR/MVFR, improving quickly after daybreak. Scattered
afternoon showers and thunderstorms are expected again Tomorrow.

&&

.PREV DISCUSSION [346 PM EDT]...

.NEAR TERM [Through Tonight]...

An upper level ridge remains in place over our area, with ample deep
layer moisture prevailing this afternoon as PW values range from
1.5" - 2". At the surface, Subtropical Storm Alberto has developed
well to our south near the Yucatan Peninsula, but light and variable
winds will remain in place over our area through tonight. However,
as the ample moisture interacts with the sea breeze and other
outflow boundaries later this afternoon through the evening, high
coverage of scattered showers and thunderstorms is expected across
our inland areas. Showers and thunderstorms will decrease in
coverage after sunset with the loss of heating/instability, but some
isolated/widely scattered showers and thunderstorms remain possible
along any remnant outflow boundaries with decent moisture still in
place. Overnight lows will range from the upper 60s to lower 70s
across our area.


.SHORT TERM [Saturday Through Monday Night]...

Subtropical storm Alberto will move north into the eastern Gulf by
Saturday morning. The path to landfall remains complicated due to
interactions with an upper-level trough. Model`s are specifically
having a difficult time resolving just how much Alberto will be
pulled under the shortwave, and subsequently how sharp the
westward turn near land fall will be. This shortwave also has
significant implications on the rainfall forecast locally as dry
air is forecast to be entrained into the eastern side of Alberto
as it moves closer to land. Due surface/upper-level interaction
uncertainty, we haven`t changed our previous forecast too much.
Thus, expect 3-6" of rain through Tuesday (highest west of the
Apalachicola River), keeping in mind these numbers have the
potential to go down. Regarding wind impacts, tropical storm
conditions appear to be most likely across Gulf waters west of
Apalachicola and in the Panhandle of Florida west of the
Apalachicola river. Again the uncertainty of the track at this
time could mean no impacts, or an increase in the expected impacts
in these areas. Expect the worst conditions through the day on
Sunday, though rain is expected each day. Eventually the remnants
of Alberto will get swept back eastward across the Southeast as it
gets absorbed by the northern stream, so rain will stick with us
for a while.


.LONG TERM [Tuesday Through Friday]...

The NHC currently predicts subtropical storm Alberto to make
landfall between late Monday night and early Tuesday somewhere along
the north-central Gulf Coast. Regardless of the exact track, our
area can expect rainy conditions throughout the period, with heavy
rain being the primary impact from this system. As such, rain
chances will remain elevated, decreasing slightly late in the week.
The stronger offshore winds will also decrease over the period as
the system passes. High temperatures will stay in the 80s, warming
to the upper 80s by late week and lows will be the low-mid 70s.


.MARINE...

Marine conditions will begin to deteriorate tomorrow as Alberto
enters the Gulf of Mexico. Tropical storm conditions will be
possible as early as tomorrow night. Mariners should remain in
safe harbor until the storm passes early next week.


.FIRE WEATHER...

A continuing wet pattern will prevent any fire weather concerns into
next week.


.HYDROLOGY...

As mentioned above 3-6" of widespread rain is currently forecast
across the region. The highest amounts are forecast to be west of
the Apalachicola and Chattahoochee rivers. Isolated higher
amounts are possible in these areas as well. There is the
potential for these numbers to come down depending upon the
eventual positioning of a ribbon of dry air aloft. This remains
quite uncertain for now, so folks should plan for the widespread
3-6".

Coastal flooding will be a possibility as Alberto moves north into
the Gulf. The greatest threat will be across Franklin and Wakulla
counties, and in the Sunday time frame. Current forecasts call for
the potential for 3 ft above MHHW (approx inundation) in these
areas, and 1-2 ft above elsewhere across the Big Bend and
Panhandle. These values are subject to change with the evolution
of the track and intensity of Alberto.

At this time, advertised rain amounts will be capable of causing
flash flooding, especially if occurring over a short period of
time. Additionally, the greatest potential for river flooding in
this event is across river basins already running above normal,
which include the Flint River, Chattahoochee River, Apalachicola
River, Choctawhatchee River, and Pea River.

The latest rainfall forecasts suggest that minor flooding is
possible on these rivers as early as Monday. Should heavier
rainfall amounts occur, more significant river flooding would be
possible.


.SPOTTER INFORMATION STATEMENT...

Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur by calling the office or tweeting us @NWSTallahassee.

&&

.PRELIMINARY POINT TEMPS/POPS...

Tallahassee   72  84  72  79  74 /  20  60  40  80  60
Panama City   73  82  73  80  76 /  30  50  60  80  60
Dothan        70  83  70  77  72 /  40  50  30  80  70
Albany        70  85  72  80  72 /  50  40  20  80  80
Valdosta      69  87  72  80  73 /  40  40  30  80  60
Cross City    70  85  72  79  74 /  30  60  50  80  50
Apalachicola  74  81  74  79  76 /  30  50  70  80  50

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...Tropical Storm Watch for Coastal Bay-Coastal Gulf-South Walton.

     High Rip Current Risk until 5 AM EDT /4 AM CDT/ Saturday for
     Coastal Bay-South Walton.

GA...None.
AL...None.
GM...Tropical Storm Watch for Coastal Waters From Ochlockonee River
     to Apalachicola Fl out to 20 Nm-Coastal waters from Mexico
     Beach to Apalachicola FL out 20 NM-Coastal waters from
     Mexico Beach to Okaloosa Walton County Line FL out 20 NM-
     Waters from Suwannee River to Apalachicola FL from 20 to 60
     NM-Waters from Apalachicola to Mexico Beach FL from 20 to
     60 NM-Waters from Mexico Beach to Okaloosa Walton County
     Line FL from 20 to 60 NM.

&&

$$

NEAR TERM...Lahr
SHORT TERM...Harrigan
LONG TERM...Harrigan
AVIATION...Humphreys
MARINE...Harrigan
FIRE WEATHER...Humphreys
HYDROLOGY...Harrigan



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