Area Forecast Discussion
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FXUS62 KTAE 250104
AFDTAE

Area Forecast Discussion
National Weather Service Tallahassee FL
904 PM EDT Thu May 24 2018

.UPDATE...

Showers and thunderstorms continue across portions of the
Wiregrass region at this hour. A subtle mesolow, evident on DHN
radar near Dothan at this hour is yielding new convection to it`s
east across southwestern Georgia where appreciable instability
remains. Outflow boundaries pushing into the Suwannee Valley from
convection across the northern Florida Peninsula is yielding new
shower and thunderstorm development across these areas. Expect
this activity to persist through the late evening hours before
gradually diminishing around or after midnight. Wet soils from
this afternoon and evening`s rainfall will yield patchy fog across
the Tri-State region late tonight. Mostly cloudy conditions will
keep temperatures steady in the low to mid 70s overnight.


&&

.PREV DISCUSSION [352 PM EDT]...

.NEAR TERM [Through Tonight]...

Scattered showers and thunderstorms have developed from the Florida
Panhandle northeastward across Southwest Georgia early this
afternoon. Ample deep layer moisture remains in place with PW values
near 2" across most of our area, and instability has increased this
afternoon to 2000-3000 J/kg of SBCAPE. Due to the combination of
high instability and moisture along with forcing from outflow
boundaries and the sea breeze, showers/storms are expected to expand
in coverage and drift southeastward later this afternoon through the
evening. Showers and thunderstorms should also fill in across
southeast Alabama early this evening according to latest models.

Despite the high instability, severe weather is unlikely this
afternoon. Little shear or DCAPE will be present, resulting in
mainly pulse-type storms that don`t have a high risk of severe
downbursts. However, isolated strong winds and/or small hail are
possible in the stronger thunderstorms. Drier conditions will return
tonight as the airmass stabilizes after an active day of showers and
thunderstorms; however, isolated showers/storms remain possible
overnight with deep layer moisture still in place along with some
remnant outflow boundaries. Overnight lows should range from the
upper 60s to lower 70s inland, with mid 70s along the Gulf Coast.


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

Model guidance is in good agreement on Friday with the airmass
remaining very moist and with southerly flow, expect a pattern
similar to Thursday, with showers and thunderstorms developing
toward late morning and then being enhanced by the afternoon sea
breeze. Kept rain chances fairly uniform across the inland areas,
in the 60-70 percent range for the afternoon. Daytime highs are
expected to be in the mid to upper 80s.

By Saturday, moisture will continue increasing from the south as
a tropical disturbance moves into the Southern Gulf of Mexico.
There`s some indication in the guidance that extensive cloud cover
in advance of the disturbance may limit destabilization across
the region on Saturday afternoon and limit storm coverage. As a
result, rain chances for Saturday are a good bit lower than those
on Friday. With the anticipated cloud cover, temperatures will be
a little lower, generally in the mid 80s for highs.


.LONG TERM [Sunday Through Thursday]...

The focus through the long term period will be on the eventual
track of the tropical disturbance now over the Yucatan Peninsula.
Model guidance over the last 24 to 36 hours has come into better
agreement that once the system moves into the Southern Gulf of
Mexico that the system will gradually become better organized and
then move toward the North Central Gulf of Mexico coast. Rain
chances will increase considerably on Sunday and through the first
part of the week as the system nears and then moves over the
interior Southeast. It`s possible the system takes on some sub-
tropical characteristics as the system moves near or interacts
with an upper low over the western Gulf of Mexico, which could
adversely impact rainfall totals. Given the uncertainty in the
track and intensity of the system, will keep the PoPs fairly
uniform and high Sunday through Wednesday as it is expected that
the system will move slowly once over inland areas of the
Southeast. Temperatures through the period will remain below
normal with highs generally in the lower 80s.


.AVIATION [Through 18Z Friday]...

Scattered showers and thunderstorms have formed near a line from ECP
to ABY. These will move southeastward and impact TLH and VLD later
in the afternoon/early evening, and scattered showers/storms could
develop over DHN during this time as well. Brief visibility
reductions are possible in any heavier showers or storms. VFR
conditions will likely return to all terminals tonight through
tomorrow morning.


.MARINE...

Winds and seas will remain low through Friday. By Saturday,
conditions will begin to gradually deteriorate with advisory
level winds over the marine area by Saturday evening as a tropical
disturbance approaches. Winds will continue to increase into
Sunday and Monday with the potential for sustained winds to gale
force starting Sunday afternoon. Conditions are expected to slowly
improve by Monday evening after the system moves well inland.


.FIRE WEATHER...

Periods of heavy rainfall continue to be likely for the next several
days. Dispersions will be below 20 today and tomorrow afternoon.
Otherwise, there are no fire weather concerns.


.HYDROLOGY...

Recent rains have brought area rivers above base flow with a few
locations in the smaller creeks/rivers nearing action stages from
routed flows from upstream rains in West Central Georgia.

Over the next 48 hours, rainfall amounts should be in the 1-2 inch
range and fairly isolated and have little or no significant impact
on river levels. Isolated heavier totals could present a flash
flood threat, if occurring over an urbanized area.

Beyond 48 hours (starting Sunday), heavier rainfall amounts of 3
to 5 inches with isolated heavier amounts are possible,
particularly across the western half of the region. It is during
this time frame that the threat for flash flooding would begin to
increase along with more sustained river rises. Ensemble
streamflow guidance suggests most areas can tolerate basin average
rainfall of 4-6 inches without any moderate river flooding
occurring, but amounts greater than 7 inches would increase the
potential for moderate river flooding, especially in the smaller
basin creeks in South Georgia (Kinchafoonee/Muckalee) and in
Southeast Alabama (Pea/Choctawhatchee). Positioning of heaviest
rainfall will ultimately determine any further impacts on the
larger stem rivers down into Florida.

It should be noted that recent heavy rains in West Central
Georgia have caused increased releases down the Chattahoochee
River below Columbus and elevated flows are also progressing
through the Flint River below Carsonville. This will result in
portions of these basins reaching action stage over the next
couple of days, even without the additional rainfall.


.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   70  88  71  84  70 /  30  60  30  50  60
Panama City   73  85  73  83  71 /  40  50  20  40  80
Dothan        70  87  70  84  69 /  60  70  40  40  60
Albany        70  88  70  86  70 /  70  70  50  30  50
Valdosta      70  87  68  84  69 /  70  70  40  40  50
Cross City    69  87  69  82  70 /  60  70  30  60  50
Apalachicola  73  84  74  82  72 /  10  40  30  50  80

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk until 5 AM EDT /4 AM CDT/ Friday for
     Coastal Bay-South Walton.

GA...None.
AL...None.
GM...None.
&&

$$

UPDATE...Pullin
NEAR TERM...Lahr
SHORT TERM...Godsey
LONG TERM...Godsey
AVIATION...Lahr
MARINE...Godsey
FIRE WEATHER...Nguyen
HYDROLOGY...Godsey



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