Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 170745
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
345 AM EDT Mon Mar 17 2014
.Near Term [Through Today]...
A complex storm system is in place across the southeast this
morning. At 06 UTC, the surface analysis showed the primary area
of low pressure across northeastern Alabama with a cold front
extending down into the Central Gulf of Mexico. A warm frontal
boundary was located across the South Carolina midstate out into
Western Atlantic. Across our region, a weak frontal zone was
analyzed from Apalachee Bay across the Florida Peninsula,
separating our region from a more tropical airmass to the south.
At upper levels, a strong upper low was digging down into the
Western Gulf of Mexico. As this upper low moves eastward with
time, surface cyclogenesis is expected to occur later this
afternoon off the Northeast Florida coast.
With the primary forcing for rainfall this morning shifting up the
Atlantic seaboard by afternoon, it is anticipated there will be a
lull in the precipitation before the main upper feature catches up
this evening. Thus, while rain chances will be high this morning,
cloudy and cool conditions will persist through the afternoon. The
cloud cover will keep temperatures generally in the low to mid
.Short Term [Tonight Through Wednesday]...
This evening, as the main upper level system approaches the
region, expect a redevelopment of rain across the northeastern Gulf
lifting northeastward across the region. Model guidance is split
on how extensive this rainfall will be, with the NAM having the
greatest coverage. The 17/00z Euro/GFS and hi-res guidance
suggests that the best forcing will converge across our eastern
counties after 00z and thus, have indicated the best chances in
these areas tonight. As the upper low moves across the region
tonight, expect rain chances to come to an end quickly as deep
layer forcing diminishes. There isn`t much in the way of cooler
air coming in behind this system, and with post frontal
cloudiness, temperatures overnight should generally be in the
upper 40s to lower 50s.
Tuesday...As the upper low and attendant surface cyclone move out
into the Western Atlantic, surface ridging will build down the
eastern side of the Appalachians pushing a wedge of cooler air
toward our region from the northeast. Model guidance is
understandably having a difficult time showing how far south this
cooler airmass will get. With a more favorable sun angle in Mid
March, it is anticipated that the southward progress of the cool
wedge will be limited to mainly South Central Georgia, where
cloudy and cool conditions will prevail for Tuesday. Further to
the south, the cloud cover should scatter out by afternoon
allowing for temperatures to warm into the lower 70s.
Wednesday...A northern stream storm system will move through the
Great Lakes and try to push a cold front toward our region.
However, with the bulk of the energy staying well to the north,
expect this front to wash out north of our region. Expect what
remains of the cool wedge to be scoured out by this time, yielding
a mostly sunny day with temperatures inland warming into the mid
to upper 70s.
.Long Term [Wednesday Night Through Monday]...
Shortwave impulses will continue to propagate through the upper
level pattern through the long term period, but will stay too far
north of us to enhance rainfall in the southeast again until the
weekend. Temperatures will be near normal, with highs in the upper
60s to mid 70s and lows in the mid to upper 40s.
Friday night, a Srn stream shortwave impulse will move across Nrn
Mexico with a Nrn stream shortwave impulse over the Great Lakes,
this will enhance divergence aloft enough for a surface low to
develop over the Ohio valley and develop a cold front that extends
SWward to the Arklatex region, crossing our forecast area
.Aviation...[Through 06Z Tuesday]...
Light to moderate rain will continue through
the period however it will decrease in coverage and intensity from
west to east tonight. IFR/LCL LIFR conditions will dominate into the
morning hours. By late morning ceilings will improve to MVFR cigs/
vsbys with vsbys becoming VFR at ECP/DHN/TLH in the afternoon.
After 03z cigs and vsbys will likely return to VFR especially GA
terminals. Winds will be light and variable.
A cold front will move across the marine area this afternoon
shifting winds to offshore. With a relatively weak pressure
gradient in place behind the front, winds should gradually
decrease by Tuesday as high pressure moves over the water. Light
winds will continue throughout the week as a reinforcing area of
high pressure builds near the waters by Thursday.
Widespread rain is expected into this evening before decreasing
tonight then ending from west to east Tuesday morning. Low mixing
heights and transport winds will lead to low dispersions especially
today. Red flag conditions are not expected during the entire work
While the intensity of the rain has diminished early this morning,
widespread moderate rainfall amounts have piled up to around 4 to
6 inches across the Florida Panhandle and Big Bend with lesser
amounts in the 2 to 4 inch range across Southeastern Alabama and
Southwestern Georgia. Additional rainfall today and tonight should
not be of a great enough intensity to cause any flash flooding
concerns. As a result, the flash flood watch will be discontinued
later this morning.
With the bulk of the rainfall occurring across the lower portion
of the river basins, river flooding is not anticipated in our
Alabama and Georgia counties, perhaps with the exception at the
Ochlockonee River near Thomasville.
In North Florida, runoff from widespread 4 to 6 inch rainfall
amounts are producing sharp rises on area river points. The
heaviest rain was concentrated from Bay County eastward into Leon
County. As a result, portions of the Chipola and Ochlockonee
Rivers will move toward flood stage this week. Local runoff seems
to be causing a few points to track higher than previous forecasts
and this may result in the Chipola River at Altha reaching flood
stage sooner than predicted. The Ochlockonee is also climbing
fast at Concord and Havana. Rainfall was a little less further to
the east of Tallahassee, but it is still anticipated for the St
Marks River to reach minor flood stage later today, and possibly
moderate flood stage later this week.
For the latest hydrology information, please visit:
.Preliminary Point Temps/PoPs...
Tallahassee 64 51 71 48 78 / 90 80 10 0 0
Panama City 64 51 69 51 73 / 90 60 10 0 0
Dothan 64 47 70 46 76 / 80 40 10 0 0
Albany 63 49 65 45 77 / 90 60 20 10 10
Valdosta 64 52 68 51 78 / 100 90 30 10 10
Cross City 70 53 75 51 79 / 100 100 20 0 0
Apalachicola 65 51 68 51 71 / 90 70 10 0 0