Area Forecast Discussion
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139
FXUS62 KTAE 222116
AFDTAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
416 PM EST Sat Nov 22 2014

.Near Term [Through Tonight]...

A strong northern stream +PV anomaly is merging in with a southern
stream anomaly over the northwest Gulf coast this afternoon. In
the low-levels, flow is veering as high pressure is forced eastward
by the advancing low pressure system. This morning, the veering
flow forced a warm and very moist airmass across the eastern Gulf
and Florida Peninsula, over a cooler airmass in place locally.
This resulted in light to moderate isentropic rain across the
entire Tri-State region that continues at this hour. Expect waves
of light to moderate rain to continue for the remainder of the
afternoon.

Further south in the eastern Gulf, a surface trough is forming
where the nose of the southern stream anomaly is spreading away
from the northern stream flow, resulting in enhanced diffluence
aloft. Since midday, convection has steadily increased in this
region. Through the night, convection in the Gulf is expected to
become more robust and move north in the increasingly southerly
flow regime. This will force the trough/warm front north to the
northeast Gulf coast very early on Sunday morning. Thus, through
the night expect showers and embedded thunderstorms to continue to
move north across the region with rainfall becoming much heavier.
At this time, severe weather is not expected overnight as storms
are unlikely to be rooted at the surface.


.Short Term [Sunday Through Monday Night]...

By dawn on Sunday, the aforementioned area of heavy rain and
isolated thunderstorms will be steadily moving north through the
region. At the same time, the aforementioned northern stream
anomaly will be quickly approaching. The core of this system will
likely pass just northwest of us, through central MS & AL, into
TN. However, due to the strength and size of this system 40-50kts
of deep layer shear will still be able to reach the Tri- State
region, coincident with with a recovering boundary layer yielding
around 1000 J/kg of SBCAPE and a strong LLJ. While there may be
some discrete convection ahead of the main squall line, the
greatest threat for more widespread severe coverage will occur
along along the expected squall line forecast to enter our
Panhandle and Alabama counties around mid afternoon. Both damaging
thunderstorm winds and tornadoes should be expected with any
discrete development and along the squall. The severe threat will
gradually diminish through the late afternoon and evening as the
squall progresses east; with a much lower threat for severe
weather east of a line from Tallahassee to Albany as both wind
shear and instability wane.

A weak front will bisect the region through the day on Monday as
deep layer southerly flow impedes the forward progress of the
system. Showers and isolated thunderstorms should be expected
Sunday night through Monday, especially along and east of a line
from Panama City through Albany. However, these storms are not
expected to become severe.


.Long Term [Tuesday Through Saturday]...

The amplifying northern stream longwave trough will finally push
the surface front and any moisture out of the region by Wednesday
evening. In its wake, dry conditions with highs in the lower to
middle 60s and lows in the middle to upper 30s are anticipated
through the remainder of the week.

&&

.Aviation...
[Through 18Z Sunday]

MVFR to IFR conditions will spread north from the coast through the
remainder of the afternoon, reaching KABY and KDHN by sunset. Cigs
will remain low through Sunday morning. Cigs may rise by late
morning or early afternoon. However, thunderstorms will be likely
thereafter.

&&

.Marine...

A very strong low pressure system will yield solid advisory
conditions through Sunday night. On Sunday, frequent gusts to Gale
force are expected. Thus have kept the Gale warning in place.
Strong to severe storms will also be possible across the northeast
Gulf late tonight, but more likely on Sunday. While advisory
conditions will come to an end on Monday, expect cautionary
conditions to continue until another front increases winds again
Tuesday into Wednesday.

&&

.Fire Weather...

Wet weather will minimize any fire weather risk through Sunday. By
Monday, a drier airmass will move into the region but humidity
values are forecast to remain above critical levels.

&&

.Hydrology...

Periods of heavy rain will move through the region tonight through
Sunday night, resulting in total rainfall amounts of 2-3 inches with
local amounts up to 4 inches possible. This will cause rises on
smaller creeks and rivers next week. Since rivers are all very low
at this time, the only river that we are expecting to get to minor
flood stage is the Kinchafoonee River at Dawson, possibly by mid
week.

&&

.Preliminary Point Temps/PoPs...

Tallahassee   63  76  64  79  49 / 100 100  50  40  20
Panama City   63  74  64  75  51 / 100 100  50  30  10
Dothan        59  74  59  73  44 / 100 100  40  20  10
Albany        60  74  61  75  46 / 100 100  50  30  10
Valdosta      60  77  67  78  50 / 100  80  70  50  20
Cross City    63  78  67  78  53 / 100  60  60  50  20
Apalachicola  66  74  66  76  53 / 100 100  50  50  20

&&

.TAE Watches/Warnings/Advisories...

FL...High Rip Current Risk through late Sunday night for Coastal Bay-
     Coastal Franklin-Coastal Gulf-South Walton.

     High Surf Advisory from 9 AM Sunday to Midnight CST Sunday Night
     for Coastal Bay-South Walton.

GA...None.
AL...None.
GM...Small Craft Advisory from 1 AM to 7 PM EST Sunday for Apalachee
     Bay-Coastal waters from Suwannee River to Keaton Beach FL
     out 20 NM.

     Small Craft Advisory until 1 AM EST Sunday for Coastal waters
     From Ochlockonee River to Apalachicola FL out to 20 NM-
     Coastal waters from Apalachicola to Destin FL out 20 NM-
     Waters from Suwannee River to Apalachicola FL from 20 to 60
     NM-Waters from Apalachicola to Destin FL from 20 to 60 NM.

     Small Craft Advisory from 7 PM Sunday to 7 AM EST Monday for
     Coastal waters From Ochlockonee River to Apalachicola FL
     out to 20 NM-Coastal waters from Apalachicola to Destin FL
     out 20 NM-Waters from Suwannee River to Apalachicola FL
     from 20 to 60 NM-Waters from Apalachicola to Destin FL from
     20 to 60 NM.

     Gale Warning from 1 AM to 7 PM EST Sunday for Coastal waters
     From Ochlockonee River to Apalachicola FL out to 20 NM-
     Coastal waters from Apalachicola to Destin FL out 20 NM-
     Waters from Suwannee River to Apalachicola FL from 20 to 60
     NM-Waters from Apalachicola to Destin FL from 20 to 60 NM.


&&

$$

NEAR TERM...HARRIGAN
SHORT TERM...HARRIGAN
LONG TERM...HARRIGAN
AVIATION...CAMP
MARINE...HARRIGAN
FIRE WEATHER...CAMP
HYDROLOGY...HOLLINGSWORTH






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