Wind Chill Advisory 1, NWS Tallahassee, FL

Coffee County, AL, Dale County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Bay County, FL, Calhoun County, FL, Dixie County, FL, Franklin County, FL, Gadsden County, FL, Gulf County, FL, Holmes County, FL, Jackson County, FL, Jefferson County, FL, Lafayette County, FL, Leon County, FL, Madison County, FL, Taylor County, FL, Wakulla County, FL, Walton County, FL, Washington County, FL, Baker County, GA, Ben Hill County, GA, Berrien County, GA, Brooks County, GA, Calhoun County, GA, Clay County, GA, Colquitt County, GA, Cook County, GA, Decatur County, GA, Dougherty County, GA, Early County, GA, Grady County, GA, Irwin County, GA, Lanier County, GA, Lee County, GA, Lowndes County, GA, Miller County, GA, Mitchell County, GA, Quitman County, GA, Randolph County, GA, Seminole County, GA, Terrell County, GA, Thomas County, GA, Tift County, GA, Turner County, GA, Worth County, GA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
800 PM EST Tue Jan 6 2015

...Arctic air arriving late Wednesday...

.Near Term [Through Tonight]...

A dry cold front off to our northwest will push through the local
region overnight. Min temps will be similar as last night bottoming
out in the lower to mid 30s by daybreak.

.Short Term [Wednesday Through Thursday Night]...

Arctic air will infiltrate the Deep South on Wednesday, with the
peak of the cold air advection occurring across our forecast area
Wednesday night. Wednesday's high temperatures will be seasonably
cool- in the upper 40s north of Albany and Dothan, to around 60 at
Cross City. It will turn very cold Wednesday night, with a hard
freeze likely across most of our forecast area. The forecast lows
are a little tricky. Normally strong winds during the overnight
hours limit cooling, as adiabatic warming (through turbulent mixing)
offsets radiational cooling. In this case, however, the temperature
at 950 mb (roughly 2,500 ft AGL) will be around -10 C, so vertical
mixing may not save us from a hard freeze.

There are some similarities (in the large scale weather pattern)
with this expected arctic outbreak, and previous 'super'
arctic outbreaks (e.g. Dec 1983, Jan 1985) that sent local low
temperatures into the single digits and lower teens. The
similarities are: the deep 500 mb trough along the U.S. east coast,
and extremely high pressure over much of the eastern half of the
CONUS. However, there are a few differences that may prevent this
from being a 'super' arctic outbreak, at least for our region. All
of the NWP output shows this being a very shallow airmass, with the
deepest cold air (and coldest 850 mb temperatures) well to our
north. Additionally, the forecast 500 mb heights are about 150
meters higher than the composite of the super arctic outbreaks that
affected this part of the country.

Still, it will be plenty cold; and our forecast is a blend of our
the latest MOS and raw model consensus. With gusty north winds of 10
to 15 MPH, wind chills will be in the 10 to 15 deg range. Despite
ample sunshine expected on Thursday, shallow mixing and a cold start
will keep highs only in the upper 30s in GA & AL, and lower 40s in
FL. Surface winds will likely be calm Thursday night, and with very
dry air and cold afternoon temperatures, a hard freeze is possible.
Increasing high level clouds may limit the amount of cooling, and
we're forecasting lows in the mid 20s (away from the beaches and
cities, where it will be a little warmer).

.Long Term [Friday Through Tuesday]...

The large scale 500 mb flow will once again become split across the
CONUS. With a more active subtropical jet stream there will be a
chance of rain on Sunday - Tuesday (20-30% PoP), as weak upper level
disturbances interact with a quasi-stationary frontal system near or
just south of our forecast area. After a light freeze on Saturday
morning, temperatures will return to about average for the remainder
of the period.

&&

.Aviation...

[Through 00z Wednesday] VFR conditions will prevail with just a
scattering of cirrus. Winds will be from the northwest at 5 to 10
knots increasing into the 15 to 20 knot range with higher gusts by
mid to late Thursday afternoon with the passage of the Arctic cold
front.

&&

.Marine...

Relatively light N-NW winds tonight (around 10 KT) will increase
Wednesday, and especially Wednesday night. In fact, a period of
frequent gale-force wind gusts is likely Wednesday night and early
Thursday. Winds and seas will gradually subside Thursday and
Thursday night.

&&

.Fire Weather...

A very dry airmass will filter in behind the Arctic front on
Thursday. Despite high temperatures expected to only reach the upper
30s to lower 40, dew point temps will be in the lower single digits.
This will result in minimum relative humidity values in the upper
teens to the lower 20s. Red Flag criteria may be met across our
southeast Alabama zones. ERC values and the 10-hour fuel moisture
should stay above critical levels for our Florida and Georgia zones.
Also, high transport winds coupled with relatively low daytime
mixing heights will yield high dispersion indices both Wednesday and
Thursday.

&&

.Hydrology...

The Apalachicola River at Blountstown will be at minor flood for
several days. Otherwise, no additional rainfall is expected across
the region until at least the weekend.

&&

.Preliminary Point Temps/PoPs...

Tallahassee   36  57  24  41  24 /   0   0   0   0   0
Panama City   42  56  27  43  31 /   0   0   0   0   0
Dothan        34  51  20  38  24 /   0   0   0   0   0
Albany        34  53  21  38  22 /   0   0   0   0   0
Valdosta      36  58  22  40  26 /   0   0   0   0   0
Cross City    38  60  26  45  30 /   0   0   0   0   0
Apalachicola  41  58  28  42  33 /   0   0   0   0  10

&&

.TAE Watches/Warnings/Advisories...

FL...Hard Freeze Watch from late Wednesday night through Thursday
     morning 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-Inland Walton-Jackson-
     Lafayette-Leon-Liberty-Madison-South Walton-Washington.

GA...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.

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

GM...Gale Watch from Wednesday evening through Thursday 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.

&&

NEAR TERM...BARRY
SHORT TERM...FOURNIER
LONG TERM...FOURNIER
AVIATION...BARRY
MARINE...FOURNIER
FIRE WEATHER...BARRY
HYDROLOGY...FOURNIER