Area Forecast Discussion
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909
FXUS62 KTAE 170324
AFDTAE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
1024 PM EST Sun Nov 16 2014

.Near Term [Through Tonight]...

Much of the active weather associated with the cold front will
occur after 12Z Monday, and is detailed in the previous "short
term" discussion below. The overall forecast reasoning has changed
little since this afternoon. The main changes made to the forecast
were to add more precise timing based on an average of the
convection-allowing models (CAM), which are actually in fairly
good agreement on the arrival of the main line of storms. The CAMs
place the primary convective line near our western zones right
around 12Z, advance it to ABY-PAM by 15-16Z, and push it through
most of the rest of our forecast area by 20Z. Some isolated to
scattered showers and storms cannot be ruled out later tonight -
mainly after 08Z - but the bulk of the convective activity should
hold off until after 12Z.

As of 03Z this evening, temperatures have likely reached close to
the minimum for tonight, and increasing low-level WAA should allow
for a steady temperature increase for the rest of the night. By
daybreak, most areas should see temperatures 65-70 degrees.

Looking at convection upstream, supercells have developed in a
broken line from S LA into S MS with a few tornado and wind damage
reports thus far. The storms have been developing in an
environment characterized by MLCAPE around 500 j/kg with around 50
knots of effective deep-layer shear and 25-30 knots of 0-1km
shear. That is relatively similar to the environment forecast by
most models across our area tomorrow, so the outlook for a Slight
Risk of severe storms still seems to be on track, particularly
over the southern half of the area.

&&

.Aviation...

[Through 00Z Tuesday] CIGS should gradually lower into the IFR
range overnight with some patchy MVFR visibility restrictions in
fog possible as well. +TSRA should arrive from the west tomorrow
in the form of a broken line of storms, arriving first at DHN
around 13Z, eventually reaching TLH around 17Z and VLD around 19Z.
Some storms could produce gusty winds. During the day, the flight
categories will likely fluctuate, but the forecast calls for MVFR-
IFR improving to VFR after the storms exit a particular terminal.

&&

.Prev Discussion [349 PM EST]...

.Short Term [Monday Through Tuesday Night]...
Showers and thunderstorms spread across the forecast area from
west to east Monday morning ahead of the approaching cold front.
Guidance continues to indicate a rapid recovery to the low-level
air mass, with dewpoints reaching the upper 60s over the southern
half of the area. These dewpoints will help to support surface-
based CAPE approaching 1000 j/kg during the morning and early
afternoon hours ahead of the front. With deep-layer shear AOA 50
knots and 0-1km shear around 30 knots, expect to see a few strong
to possibly severe cells develop either just ahead of, or embedded
within the main line of showers and storms. Isolated tornadoes and
damaging straight-line winds appear to be the primary threats,
with the area highlighted in the Slight Risk area of the SPC Day 2
Outlook.

The front should move into the western zones shortly after 12z,
reach the Tallahassee area by 18z, and be exiting the southeastern
Big Bend by late in the afternoon. Very strong cold air advection
will commence immediately following the frontal passage, with
temperatures falling for much of the day over the western half of
the forecast area. Roughly the northwestern half of the CWA will
likely fall below freezing by sunrise on Tuesday, and a Freeze
Watch has been issued for these counties. With the expected winds,
may see Wind Chill reading briefly fall below 20 degrees in
southeast Alabama.

With the continuing cold air advection on Wednesday, temperatures
will struggle into the 40s, with only the immediate coast and
southeastern Big Bend having a shot at getting above 50 degrees.
The coldest night will be Tuesday night as the surface high
settles in over central/south Georgia, creating ideal radiational
cooling conditions. A widespread hard freeze is likely with low
temperatures reaching the lower 20 away from the immediate coast.
There may even be a few upper teens in SE Alabama and the inland
Florida Panhandle. This will likely be record breaking cold for
the date.


.Long Term [Wednesday Through Sunday]...
A slow and gradual warming trend will begin on Wednesday. However,
highs will still only reach the lower 50s by afternoon, and
another solid freeze is expected Wednesday night. Highs through
the remainder of the week should make it into the 60s, but even
this will be a few degrees below normal. More substantial warming
will likely have to wait until late in the weekend ahead of the
next significant front and chance of rain.


.Marine...
Conditions over the coastal waters will deteriorate tonight ahead
of an approaching cold front. Onshore winds will reach Small Craft
Advisory conditions late tonight, with winds becoming offshore
during the day behind the front. Frequent gusts to Gale Force will
be possible over the offshore legs Monday night, with Small Craft
Advisory conditions elsewhere. Winds and seas will finally
diminish Tuesday night as high pressure builds into the area.


.Fire Weather...
Conditions will be very wet and humid with wet flags posted for
Monday, before much colder and drier air moves in for Tuesday and
Wednesday. Depending on how cold and dry it ultimately gets
(providing the cold air does not cancel out the dry air), Red Flag
conditions could be a distinct possibility by the middle of next
week.


.Hydrology...
Rainfall totals associated with the approaching cold front are
forecast to remain generally below 1 inch. These amounts may lead
to minor rises on area rivers and streams, but have little overall
impact.

&&

.Preliminary Point Temps/PoPs...

Tallahassee   62  74  33  49  22 /  50  90  10   0   0
Panama City   63  71  34  50  30 /  50  90   0   0   0
Dothan        58  68  27  44  23 /  60  90   0   0   0
Albany        59  70  28  47  22 /  40  90   0   0   0
Valdosta      60  74  33  49  23 /  20  90  30   0   0
Cross City    60  74  40  52  23 /  20  90  60   0   0
Apalachicola  64  73  37  51  29 /  50  90  10   0   0

&&

.TAE Watches/Warnings/Advisories...

FL...Freeze Watch from late Monday night through Tuesday morning for
     Calhoun-Central Walton-Holmes-Inland Bay-Inland Walton-
     Jackson-South Walton-Washington.

GA...Freeze Watch from late Monday night through Tuesday morning for
     Baker-Ben Hill-Calhoun-Clay-Decatur-Dougherty-Early-Irwin-
     Lee-Miller-Mitchell-Quitman-Randolph-Seminole-Terrell-Tift-
     Turner-Worth.

AL...Freeze Watch from late Monday night through Tuesday morning for
     Coffee-Dale-Geneva-Henry-Houston.

GM...Small Craft Advisory from 5 AM Monday to 7 AM EST Wednesday for
     Coastal waters From Ochlockonee River to Apalachicola FL
     out to 20 NM-Coastal waters from Apalachicola to Destin FL
     out 20 NM.

     Gale Watch from Monday afternoon through Tuesday morning for
     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 5 AM to 4 PM EST Monday for 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 10 AM Tuesday to 7 AM EST Wednesday
     for 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...LAMERS
SHORT TERM...CAMP
LONG TERM...CAMP
AVIATION...LAMERS
MARINE...CAMP
FIRE WEATHER...GOULD
HYDROLOGY...CAMP






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