Area Forecast Discussion
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FXUS62 KTAE 162039
AFDTAE

Area Forecast Discussion
National Weather Service Tallahassee FL
339 PM EST Tue Jan 16 2018

...WINTRY PRECIPITATION EXPECTED MAINLY WEST OF THE FLINT AND
APALACHICOLA RIVERS LATE TONIGHT, FOLLOWED BY DANGEROUS COLD...

.SHORT TERM [Through Wednesday]...

***KEY POINTS***

*Greatest impacts are expected across southeastern Alabama overnight
 into Wednesday Morning. Bridges and overpasses will be
 particularly at risk of seeing snow and ice accumulation. Impacts
 will generally remain north and west of the Flint and
 Apalachicola Rivers to the I-10 corridor

*Timing: 2am EST to 10am EST

The upper air pattern consists of a large positively tilted trough
from the Great Lakes southwestward to North Mexico and ridging
across the western US. Arctic frontal boundary is located from
southern Alabama northeastward into northern Georgia. Light snow
was noted well behind the front from central Mississippi through
northern Alabama. Light rain is developing across southern Alabama
into the northern Gulf of Mexico.

This entire system will move through the CWA tonight and
Wednesday. Behind the front, colder air will filter in on
northerly flow. Temperatures will quickly fall through the
overnight hours with lows in the low to mid 20s across SE Alabama
and the western Florida panhandle. Mid 20s to mid 30s east of this
area to north of Tallahassee-Valdosta line and mid 30s south of
this line. The winds will be elevated most of the night with 10-15
mph wind speed common and will continue the wind chill advisory
overnight west and north of Apalachicola to Fitzgerald line.

CONCERNING WINTRY PRECIPITATION: As the mid level trough gets
closer, PV advection increases as well as large scale lift
associated with the upper jet, light rain will begin across SE AL
in the evening hours. As cold air continues to advect in, a switch
to rain/snow mix then all snow will occur in the late evening to
around midnight local time. This area of precipitation will move
south and east overnight to affect the western FL panhandle and
the Flint river area through the overnight hours. By morning
(daybreak and thereafter), areas east of the Flint river will
experience a mix of rain and snow through mid to late morning.
This precipitation may even extend into Tallahassee to Valdosta
corridor where a few wet snowflakes may mix in to mostly light
rain. All precipitation is expected to move out of our CWA by
early afternoon Wednesday.

CONCERNING SNOW AMOUNTS: There are some indications in the model
data for enhancement of snow or a congealing of two bands across
southern and southeast Alabama into south central Georgia
overnight. This would lead to a slight increase in snowfall totals
across SE Alabama and west of the Flint river in Georgia. The
model snowfall amounts and SREF plumes suggest one half up to one
inch in this area. Also, model output suggest near 1.5 inches
along the I-65 and I-85 corridors southward to just north of
Coffee/Dale/Henry counties. I would not be surprised if there is
an isolated report or two of just over an inch across the northern
part of those counties but my confidence is low enough to not
upgrade to a warning. Amounts will gradually lower south and east
of this area to just a dusting. No accumulation if any snow
develops from Tallahassee to Valdosta.


.LONG TERM [Wednesday Night Through Tuesday]...

***KEY POINTS***
*With dangerously cold temperatures expected Wednesday and Thursday
nights, people are encouraged to take proper precautions. Remember
to protect the 4 P`s: People, Pipes, Pets, and Plants.

*Any residual moisture lingering across areas that receive wintry
precipitation on Wednesday may experience refreezing Wednesday night
into Thursday morning. Elevated surfaces will be most at risk.

*Be sure to dress properly each morning: wear layers and limit the
amount of skin exposed to the elements.

*Lows Wednesday night: upper 10`s to low 20`s, wind chill: upper
single digits to mid 10`s.

*Lows Thursday Night: Low to mid 20`s, wind chill: 10`s to near 20.

Dangerous cold temperatures will be left in the wake of the cold
front Wednesday night, as arctic air will continue to advect into
the region and clear skies will allow for rapid cooling after the
sun sets. A hard freeze is expected to occur Wednesday night into
Thursday morning, with low temperatures falling into the upper teens
and low 20s F across the region. A Hard Freeze Watch is currently in
effect across the entire region, excluding the immediate coastline
as a result. Northerly winds of 5 to 10 mph through the night will
yield dangerous wind chills region-wide, with wind chills in the
upper single digits to low 10`s possible across the region. A Wind
Chill Advisory has been issued for the entire region Wednesday night
into Thursday morning. While temperatures will manage to warm into
the upper 40s to near 50 degrees Thursday, another night of
temperatures in the 20s are expected Thursday night into Friday
morning, as skies will remain clear and winds become calm with high
pressure building into the region.

Expect a warming trend to commence on Friday, along with increasing
moisture from the south as the aforementioned low level ridge axis
slides off to the east, yielding southerly flow around the periphery
of the high. This, coupled with a weak mid-level impulse embedded
within the southern region of the jet will yield an increase in
cloud cover over the weekend. Rain chances, however, will remain
scant until the beginning of the work week, when the next upper
level low ejects out of the Rockies and across the eastern half of
the CONUS. Rain chances will likely be confined along the trailing
cold front progged to sweep across the region, yielding another
round of drier and cooler air in it`s wake, beyond the day 7 period.
Expect afternoon highs to warm from the 50s on Friday, to the 60s on
Saturday, and pushing 70 on Sunday and Monday. Overnight lows will
range from the mid 30s, to mid 40s, to the low 50s respectively.

&&

.AVIATION [Through 18Z Wednesday]...

VFR conditions initially this afternoon and evening will degrade
to MVFR after midnight at all sites. As a cold front approaches
from the west expect precip to develop and overspread the area. At
DHN precip may begin as a brief period of -RA then transition to
light FRZAPL by 07z and then change to -SN by 10z. ABY will be
similar with precip starting at 10z and -SN by 13z. At ECP, precip
is likely to transition from -RA only to -FZRAPL by sunrise. At
TLH, light RA may mix with -PL before precip ends at 15z. All
sites except VLD VFR by 17z with gusty NW winds to 20 kt.
&&

.MARINE...

Northerly winds will increase tonight through early Thursday morning
as a cold front passes, resulting in elevated seas. As a result, a
small craft advisory has been issued from late tonight through early
Thursday morning. Winds and seas will decrease on Thursday, and
become light from Thursday night through Saturday.
&&

.FIRE WEATHER...

Fuel moisture and relative humidity criteria may briefly combine
with elevated winds resulting in Red Flag conditions on Wednesday.
However, due to the extremely marginal nature of both fuel moisture
and relative humidity, have decided to cancel the Fire Weather Watch
and not upgrade to a warning. On Thursday, low relative humidity
levels will continue, though winds will be lighter and Red Flag
criteria will not be met.

&&

.HYDROLOGY...

Light snow and mixed precipitation is possible late tonight
through early Wednesday for our northern and western areas, but
QPF amounts will be very light. Dry conditions will then persist
for the following few days. As a result, no flooding is expected
and drought conditions will persist.

&&

.SPOTTER INFORMATION STATEMENT...

Spotter activation is requested for tonight and tomorrow morning.
Spotters should safely report significant weather conditions as
the winter storm moves through the area by calling the office or
tweeting us @NWSTallahassee.

&&

.PRELIMINARY POINT TEMPS/POPS...

Tallahassee   33  42  19  50  24 /  10  20   0   0   0
Panama City   30  41  21  48  30 /  40  10   0   0   0
Dothan        24  36  19  47  24 /  70  10   0   0   0
Albany        29  38  18  47  25 /  50  40   0   0   0
Valdosta      35  42  20  47  25 /  10  20   0   0   0
Cross City    36  49  19  49  24 /  10   0   0   0   0
Apalachicola  35  44  23  48  30 /  10  10   0   0   0

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...Wind Chill Advisory from 1 AM EST /midnight CST/ to 1 PM EST
     /noon CST/ Thursday for Calhoun-Central Walton-Coastal Bay-
     Coastal Dixie-Coastal Franklin-Coastal Gulf-Coastal
     Jefferson-Coastal Taylor-Coastal Wakulla-Gadsden-Holmes-
     Inland Bay-Inland Dixie-Inland Franklin-Inland Gulf-Inland
     Jefferson-Inland Taylor-Inland Wakulla-Jackson-Lafayette-
     Leon-Liberty-Madison-North Walton-South Walton-Washington.

     Winter Weather Advisory from 10 PM EST /9 PM CST/ this evening
     to 1 PM EST /noon CST/ Wednesday for Calhoun-Central Walton-
     Coastal Bay-Holmes-Inland Bay-Jackson-North Walton-South
     Walton-Washington.

     Hard Freeze Watch from late Wednesday night through Thursday
     morning for Calhoun-Central Walton-Gadsden-Holmes-Inland
     Bay-Inland Dixie-Inland Franklin-Inland Gulf-Inland
     Jefferson-Inland Taylor-Inland Wakulla-Jackson-Lafayette-
     Leon-Liberty-Madison-North Walton-Washington.

     Wind Chill Advisory from 1 AM EST /midnight CST/ to 1 PM EST
     /noon CST/ Wednesday for Calhoun-Central Walton-Coastal Bay-
     Coastal Gulf-Gadsden-Holmes-Inland Bay-Inland Gulf-Jackson-
     Liberty-North Walton-South Walton-Washington.

GA...Wind Chill Advisory from 1 AM to 1 PM EST Thursday for Baker-Ben
     Hill-Berrien-Brooks-Calhoun-Clay-Colquitt-Cook-Decatur-
     Dougherty-Early-Grady-Irwin-Lanier-Lee-Lowndes-Miller-
     Mitchell-Quitman-Randolph-Seminole-Terrell-Thomas-Tift-
     Turner-Worth.

     Winter Weather Advisory from 10 PM this evening to 1 PM EST
     Wednesday for Baker-Ben Hill-Berrien-Calhoun-Clay-Colquitt-
     Cook-Decatur-Dougherty-Early-Grady-Irwin-Lee-Miller-
     Mitchell-Quitman-Randolph-Seminole-Terrell-Thomas-Tift-
     Turner-Worth.

     Hard Freeze Watch from late Wednesday night through Thursday
     morning for Baker-Ben Hill-Berrien-Brooks-Calhoun-Clay-
     Colquitt-Cook-Decatur-Dougherty-Early-Grady-Irwin-Lanier-
     Lee-Lowndes-Miller-Mitchell-Quitman-Randolph-Seminole-
     Terrell-Thomas-Tift-Turner-Worth.

     Wind Chill Advisory from 1 AM to 1 PM EST Wednesday for Baker-
     Ben Hill-Calhoun-Clay-Colquitt-Decatur-Dougherty-Early-
     Grady-Irwin-Lee-Miller-Mitchell-Quitman-Randolph-Seminole-
     Terrell-Thomas-Tift-Turner-Worth.

AL...Wind Chill Advisory from midnight Wednesday night to noon CST
     Thursday for Coffee-Dale-Geneva-Henry-Houston.

     Winter Weather Advisory from 9 PM this evening to noon CST
     Wednesday for Coffee-Dale-Geneva-Henry-Houston.

     Hard Freeze Watch from late Wednesday night through Thursday
     morning for Coffee-Dale-Geneva-Henry-Houston.

     Wind Chill Advisory from midnight tonight to noon CST Wednesday
     for Coffee-Dale-Geneva-Henry-Houston.

GM...Small Craft Advisory from 1 AM Wednesday to 7 AM EST Thursday
     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.

&&

$$

SHORT TERM...Scholl
LONG TERM...Pullin
AVIATION...Scholl
MARINE...Pullin
FIRE WEATHER...Harrigan
HYDROLOGY...DVD


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