Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 061947
Area Forecast Discussion
National Weather Service Tallahassee FL
247 PM EST Tue Dec 6 2016
.NEAR TERM [Through Tonight]...
The mid-upper level shortwave trough that`s been driving our weather
for the last several days is now over the southern Appalachians and
will continue to swing eastward, rolling through the upper level
ridge over the Atlantic. Meanwhile, a broad, upper level trough
covers almost all of the CONUS, leaving us under deep layer west-
southwest flow. This flow will prevent humidity from dropping too
much in the wake of this morning`s cold front package. We`ve also
been fortunate to get a brief break in cloud cover between this
morning`s front and the next approaching front (which is currently
laid out along the Mississippi valley and into south TX), which is
keeping temperatures warm today. As the front to our west pushes
eastward tonight, expect an increase in cloud cover over the area
again. Minimum temperatures will only dip into the upper 40s to low
.SHORT TERM [Wednesday Through Thursday Night]...
The region will be between systems at the start of the short term
period. The next (generally dry) cold front will be approaching
by Thursday bringing another blast of chilly arctic air to the
region by Thursday. With little moisture to work with, as this
front comes through the area on Thursday, only a few clouds are
expected and rain chances are less than 10 percent. The front
should clear to the south of the region by Thursday night with
strong cold advection bringing in a very dry and chilly airmass
for the remainder of the week.
Temperatures on Wednesday will generally be near to just above
normal in the upper 60s to lower 70s. A big change begins on
Thursday when high temperatures will only be in the mid to upper
60s. Overnight lows into Friday will drop into the 30s and
possibly even below freezing across our northwestern zones.
Interestingly, the strong winds behind the cold front may be
sufficient to push wind chills on Friday morning into the lower
20s across Southeast Alabama and portions of the inland Florida
Panhandle. Note that local wind chill advisory criteria is 20
.LONG TERM [Friday Through Tuesday]...
A generally dry first few days of the long term period is
expected. Model guidance shows that the cold high pressure area
behind the frontal system will move quickly east across the Mid
South and into the Blue Ridge Mountains by Saturday morning. This
positioning isn`t especially favorable for a widespread freeze
across our region. However, the incoming arctic airmass is
especially chilly. Guidance generally ranges from mid 20s to lower
30s across the area by Saturday morning. Given the unfavorable
high position, will trend the forecast closer to the operational
MEX guidance which is on the warmer side of the envelope and show
borderline light freeze conditions across the area on Saturday
After Saturday evening, the airmass will begin to modify quickly
as the northern stream pattern remains fast. The high pressure
area will reach the Western Atlantic by daybreak on Sunday. With
easterly and eventually southeasterly flow starting by Sunday
afternoon, temperatures and moisture levels will rebound to near
The next frontal system is progged to approach the area on Monday
night into Tuesday. Both the 06/12z Euro and GFS show this to be a
relatively weak system with limited rainfall. Though some cooler
air will be arriving behind this system, it certainly won`t be as
chilly as the initial front from early in the weekend.
.AVIATION [Through 18Z Wednesday]...
Sandwiched between two fronts, our area is seeing a temporary break
in cloud cover with mostly clear skies and scattered low-mid level
(2500-4000 ft) cloud bases. As the second front approaches, however,
more low level clouds will be advected into the area, with most
sites dropping to MVFR overnight, possibly even IFR in some spots.
Some guidance suggests visibility restrictions as well, but the
winds are expected to remain too high overnight to allow fog to
Winds and seas at advisory levels will diminish this evening as
the low pressure area across Western North Carolina moves further
to the northeast. Winds and seas will then remain relatively low
until a dry cold front moves across the marine area on Thursday
evening. Advisory winds and seas are likely behind this front
through at least Saturday morning. Thereafter, winds should be
around 15 knots into Sunday.
After much needed widespread rains, there are no fire weather
concerns at least for the next few days.
Widespread moderate to heavy rainfall across the region over the
last 48 hours has resulted in some sharp rises on area rivers,
particularly on the western side of the forecast area. Analysis of
radar-derived and measured totals showed that storm total rainfall
of 8 to 12 inches was common from the Eastern Florida Panhandle
northeastward across far Southeastern Alabama and into
As a result, the sharpest rises are occurring on the lower
Choctawhatchee River, Chipola River, and within the Flint River
system below Albany. Given that these rivers were all running
very low with the ongoing drought, rises generally to action or
just barely above minor flood stage are expected in the next 2-4
days on these rivers.
Releases out of Woodruff are planned to peak in the 30-35 kcfs
range in the next 2 to 3 days (based on a pool target of 77.5 ft
in Lake Seminole). This should result in a downstream reading on
the Apalachicola River at Blountstown in the 13.5 to 14.5 ft range
in the next 3-4 days, safely below the 17 ft flood stage.
Though some modest rises are expected on the Ochlockonee River
above Lake Talquin and in the upper Withlacoochee River system,
the bulk of the heaviest rain missed the headwater portion of
these basins, thus all sites should end up cresting below action
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 51 71 49 67 35 / 0 0 0 10 0
Panama City 53 68 52 64 37 / 0 0 0 10 0
Dothan 48 65 47 61 30 / 0 0 0 10 0
Albany 49 66 47 63 31 / 0 0 0 10 0
Valdosta 51 71 48 66 33 / 0 0 0 10 0
Cross City 51 73 49 70 36 / 0 0 0 10 0
Apalachicola 53 69 52 67 39 / 0 0 0 10 0
FL...High Rip Current Risk until 7 PM EST /6 PM CST/ this evening for
Coastal Bay-Coastal Franklin-Coastal Gulf-South Walton.
GM...Small Craft Advisory until 7 PM EST this evening for Coastal
waters from Apalachicola to Destin FL out 20 NM-Waters from
Apalachicola to Destin FL from 20 to 60 NM.