Winter Storm Warning 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
121 PM EST Mon Jan 20 2025

...New AVIATION...

.NEAR TERM...
(Today and tonight)
Issued at 358 AM EST Mon Jan 20 2025

Strong cold air advection will continue today with surface high
pressure settling in to the northwest. Highs today are forecast to
only reach the upper 30s to mid 40s across the area this afternoon
despite mostly sunny skies. Breezy northerly winds will keep the
feels like temperatures even lower, maxing out in the mid 30s to low
40s for most of the area. For tonight, southwesterly flow aloft will
carry moisture and cloud cover from a developing surface low over
the western Gulf overhead. Isentropic lift from this system could
create some light rain showers or even perhaps a few flurries over
the waters and near the FL Big Bend Tuesday morning. This precip may
not reach the ground however, since it has to fall through a much
drier layer at the surface first. Despite the increasing cloud
cover, lows overnight tonight are forecast in the low 20s to low 30s
with wind chills in the teens to mid 20s. Another round of cold
weather advisories is expected area-wide tonight with a freeze
warning for hard freeze conditions for northwest portions of the
area.

&&

.SHORT TERM AND LONG TERM...
(Tuesday through Sunday)
Issued at 358 AM EST Mon Jan 20 2025

KEY MESSAGE:

- A High (80-90%) chance of a Winter Storm impacting the area as
soon as Tuesday afternoon through Tuesday Night.

Looking at the big (synoptic) picture, a sprawling 1040+mb high
oozes out of Canada this morning and will set up shop across the
Ohio Valley into the Central Plains. This is the reason we'll be so
cold through the middle of the week. A longwave H5 trough is
currently over most of the country. An embedded H5 shortwave
currently located over Washington and Oregon will dive down towards
Arizona today before pushing across Texas tonight into Tuesday
morning. An area of low pressure develops in the western Gulf of
Mexico in response to the shortwave moving into Texas; we'll see
precipitation blossom across the Lone Star state Monday night into
Tuesday before it travels along I-10 towards our area Tuesday
afternoon into Tuesday night.

With the wintry precipitation forecast to begin falling as early as
Tuesday afternoon, we have left the Winter Storm Watch in place as
we're still beyond 24 hours out. The latest forecast now has
widespread snow totals of 1-2" expected along and northwest of the
Flint and Apalachicola Rivers with less than 1" of snow expected
south and east. With regards to ice totals, higher amounts are
expected in the Florida Big Bend and south-central Georgia, where
ice totals of 0.1" to 0.25" are forecast with less than 0.1" in the
Florida Panhandle, southeast Alabama and our northern Georgia
counties.

That said, uncertainty remains with regards to precipitation type
and how long each type lasts for parts of our area. As mentioned
earlier, we'll see the precipitation travel east along I-10 during
the day Tuesday. Ample moisture aloft in the dendritic growth zone
(DGZ), or around 20,000-25,000 feet, will allow for the formation of
snowflakes, but very dry air in the lowest 1km of the atmosphere
will preclude a lot of that from reaching the ground at first, or
virga. It'll take a few hours for the lower levels to saturate and
allow the precipitation to reach the ground, cooling the lower-
levels of the atmosphere as it does so, or wet-bulbing, to near or
below freezing for most of the region. This should allow for a quick
burst of snow at the onset for most everyone before transitioning to
a wintry mix of snow, sleet, and/or freezing rain along the southern
edge of the precipitation while remaining predominantly snow on the
northern side.

A closer inspection of the forecast soundings continue to indicate a
the presence of a warm nose, or warmer air 3,000-7,000 feet above
ground level (AGL), along the coast with it not being as much of a
factor farther to the north. However, experience tells me that the
warm nose is typically a little stronger than modeled and makes it
more northwest than currently forecast. This is super important as
it will drive precipitation types across the region. If the warm
nose is more prevalent, then that opens the door for more sleet
and/or freezing rain; if the warm nose isn't as strong then that
means more snow. So if the warm nose is stronger then snow totals
would decrease while ice totals would come up, especially for areas
to the northwest of the Flint/Apalachicola River basins. This is
something we'll monitor over the next 36 hours, and, honestly, may
not be known until the event begins and the precipitation starts
falling.

Precipitation will end from west to east Tuesday night into very
early Wednesday morning. In it's wake is an area of high pressure
that will keep the cold around for at least a few more days. In
fact, Wednesday night's temperatures could be a little tricky
depending on if there is a snowpack (crazy to say for this area!).
If there is, temperatures could freefall into the 10s. Otherwise,
most locations should bottom out in the lower to middle 20s,
snowpack or not.

The rest of the forecast period will see a subtle H5 ridge develop
over the Southeast Friday and this weekend. This combined with a
southerly wind returning to the region means a warming trend
commences Thursday afternoon and will ultimately see temperatures
climb back above normal, or middle 60s, by Sunday while rain chances
remain out of the forecast.

&&

.AVIATION...
(18Z TAFS)
Issued at 108 PM EST Mon Jan 20 2025

Generally VFR conditions are expected through the end of the TAF
period. Temps will be below freezing at all area terminals
throughout the overnight hours. A approaching low pressure system
will begin to bring in BKN cigs from the south tonight and OVC by
tomorrow morning. This complex system is expected to bring nearly
all precip types across the region tomorrow afternoon, from snow
to freezing rain and sleet to rain. Updates with future TAF
issuances will be able to pinpoint which terminals have the best
probabilities to see a specific precip type.

&&

.MARINE...
Issued at 358 AM EST Mon Jan 20 2025

A Small Craft Advisory remains in effect this morning for the
coastal waters in the wake of yesterday's strong cold frontal
passage. Additional Small Craft Advisories will likely be needed
during mid-week as low pressure moves south of the coastal waters.
Brief Gale conditions may materialize for the offshore waters
between the Okaloosa Walton County Line and Apalachicola Tuesday
night as the low passes south of the region, but confidence was not
high enough to issue a Gale Watch or Warning as this time.

&&

.FIRE WEATHER...
Issued at 358 AM EST Mon Jan 20 2025

Very cold and dry conditions are expected today with minimum
relative humidity around 20-35% for most of the area. Rain chances
increase across the area on Tuesday and Tuesday night as a low
pressure system passes to the south of the area. Some snow, sleet,
and freezing rain will also be possible across the area through
Wednesday morning. There are no other fire weather concerns.

&&

.HYDROLOGY...
Issued at 358 AM EST Mon Jan 20 2025

Precipitation returns to the region Tuesday afternoon into Tuesday
night. Overall, less than 1" of precipitation is anticipated with
this event, so flooding is not anticipated.

&&

.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   31  45  28  41 /  10  50  90  20
Panama City   31  44  28  42 /  10  60  90  10
Dothan        26  39  22  40 /   0  70  70  10
Albany        25  41  24  41 /   0  60  80  10
Valdosta      30  45  29  41 /  10  50  90  20
Cross City    33  48  29  46 /  10  50  90  30
Apalachicola  33  45  31  44 /  10  50  90  20

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...Cold Weather Advisory from 7 PM EST /6 PM CST/ this evening to
     11 AM EST /10 AM CST/ Tuesday for FLZ007>019-026>029-034-
     108-112-114-115-118-127-128-134.

     Freeze Warning from 10 PM this evening to 8 AM CST Tuesday for
     FLZ007>009.

     Winter Storm Watch from Tuesday afternoon through late Tuesday
     night for FLZ007>011-108.

     Winter Storm Watch from Tuesday afternoon through Wednesday
     afternoon for FLZ012>019-026>029-034-112-114-115-118-127-
     128-134.

     High Rip Current Risk through late tonight for FLZ112-114-115.

GA...Cold Weather Advisory from 7 PM this evening to 11 AM EST
     Tuesday for GAZ120>131-142>148-155>161.

     Freeze Warning from 11 PM this evening to 9 AM EST Tuesday for
     GAZ120>128-142>144.

     Winter Storm Watch from Tuesday afternoon through Wednesday
     morning for GAZ120>126-142>144-155.

     Winter Storm Watch from Tuesday afternoon through Wednesday
     afternoon for GAZ127>131-145>148-156>161.

AL...Cold Weather Advisory from 6 PM this evening to 10 AM CST
     Tuesday for ALZ065>069.

     Freeze Warning from 10 PM this evening to 8 AM CST Tuesday for
     ALZ065>069.

     Winter Storm Watch from Tuesday afternoon through late Tuesday
     night for ALZ065>069.

GM...None.
&&

NEAR TERM...Merrifield
SHORT TERM...Reese
LONG TERM....Reese
AVIATION...Oliver
MARINE...Reese
FIRE WEATHER...Merrifield
HYDROLOGY...Reese