Scientific Forecaster Discussion
fxus62 kjax 120717
Area forecast discussion
National Weather Service Jacksonville Florida
217 am EST Thu Dec 12 2019
Near term [through tonight]...
A shortwave was moving across southern Georgia early this morning,
and this was responsible for the light radar returns over
southeast Georgia and the Suwannee Valley. This feature is
forecast to remain rather persistent through the day while slowly
dampening, and rainfall amounts up to 1 inch are possible across
the Suwannee Valley and along I-10 through Baker County today. A
frontal boundary was across central Florida early this morning,
and strong high pressure was pushing to the coast of the mid
Atlantic states. A local Nor'easter has setup with the tight
pressure gradient, resulting in breezy to windy conditions. A
Wind Advisory remains in place through the afternoon hours, with
the strongest winds this morning. A coastal trough will develop
this afternoon, and this will weaken the pressure gradient.
The frontal boundary over central Florida will lift back northward
today and tonight, and be located near the Florida/Georgia border by Friday
morning. An area of low pressure is forecast to develop along the
boundary near the coast of northeast Florida late tonight as well.
Rain chances will increase from south to north along the coast,
with steady light rain expected across at least the coastal areas
this afternoon. Rainfall amounts for the coastal counties are
forecast to be around 0.25-0.5" this afternoon. Another shortwave
will move across the eastern Gulf late this afternoon and move
across northeast Florida overnight as the frontal boundary moves
northward towards the Florida/Georgia border. Coastal convergence and the
additional lift is forecast to lead to another 0.5-1" along the
coast, with locally higher amounts. Across interior southeast
Georgia and the Suwannee Valley, isentropic lift will increase
along and north of the front, with rainfall amounts of 0.5-1" also
possible. A few thunderstorms cannot be ruled out over northeast
Florida as well, but most of the storms will remain over the
High temperatures will range from the mid to upper 50s across
southeast Georgia to the lower 70s across north central Florida.
Lows tonight will be in the upper 40s to low 50s across interior
southeast Georgia and the upper 50s to lower 60s elsewhere.
Short term [friday through saturday]...
Showers along with a slight chance for thunderstorms will cross
the region on Friday, occurring in conjunction with a short wave
trough crossing over southeastern Georgia and northeastern
Florida. Rainfall amounts are expected to range between about 0.50
inches for the southernmost counties and around 1 inch for inland
southeast Georgia, along with areas near the Suwannee River basin
and along the coastline. Showers will clear out through Saturday
morning and then be followed by drier conditions and cooler air.
Temperatures for the beginning of the weekend are expected to be
near climatological normals, with Max temps ranging within the 60s
and 70s. Overnight low temperatures from out of the 50s on Friday
and reach down into the 40s on Saturday.
Long term [sunday through thursday]...
High pressure will continue to build over the region on Sunday
and then drift off to the west on Monday. Convection and warming
temps are expected on Tuesday as a warm southwesterly flow
strengthens in advance of a cold front, which is expected to bring
convection over the area into Wednesday, with cold temperatures
and clearing skies. Daily high temperatures will rise on Monday
and Tuesday in association with the southwesterly flow with temps
rising into the mid 70s and then cooling down into the 50s and
lower 60s on Wednesday, following the frontal passage. Min temps
will similarly peak in the 50s on Tuesday before cooling to
potentially freezing temps on Wednesday night.
[through 06z friday]
A frontal boundary will lift northward as a warm front today and
tonight, and be located near the Florida/Georgia border by Friday morning.
MVFR cigs at ksgj and kgnv will push northward into the Duval
County taf sites this morning, and then to kssi in the early
afternoon. Ceilings will then continue to lower in the late
afternoon and early evening, with IFR cigs prevailing overnight.
Rain chances will also increase from south to north along the
coast through the period, with rain expected at the coastal taf
sites beginning late this afternoon through the end of the period.
An isolated thunderstorm is also possible at the coastal northeast
Florida taf sites, but the probability remains too low to mention
at this time. Strong high pressure building over the northeast
will lead to northeast winds around 15 knots with gusts around 25
knots through the day, with winds diminishing to around 10 knots
Gale Warning remains in effect through this morning for the waters
out to 20 nm and through this afternoon for the regional waters
from 20-60 nm offshore. Winds will diminish late this afternoon
as a coastal trough develops. An area of low pressure will develop
along the trough over the coastal waters late tonight and then
lift northward. Another area of low pressure will develop along
the boundary over the Florida Panhandle and move off to the
northeast on Saturday, pushing a weak front through the area. Weak
high pressure will then build over the waters on Sunday. High
pressure will then shift east of the area, and a strong cold front
will move through the waters on Wednesday.
Rip currents and surf: high risk of rip currents at all the
beaches today. Moderate risk of rip currents on Friday. High surf
advisory at the northeast Florida beaches today due to breakers of
Coastal impacts: a coastal flood statement has been issued for the
northeast Florida coast due to elevated water levels leading to
action stage for the high tide cycle this morning.
Storm total amounts through Friday of 1-2 inches and locally
higher amounts across interior southeast Georgia, the Suwannee
Valley and coastal areas. Storm total amounts around 0.5 inches
across interior northeast Florida.
Preliminary point temps/pops...
Amg 56 49 62 54 67 / 50 100 80 60 30
ssi 58 56 66 58 68 / 50 100 90 40 40
jax 64 58 70 58 72 / 60 80 80 50 40
sgj 68 60 72 59 73 / 70 80 50 40 40
gnv 69 60 72 60 72 / 40 50 60 50 40
ocf 74 60 75 60 75 / 30 40 40 50 40
Florida...high rip current risk through this evening for coastal Duval-
coastal Flagler-coastal Nassau-coastal St. Johns.
High surf advisory until 10 PM EST this evening for coastal
Duval-coastal Flagler-coastal Nassau-coastal St. Johns.
Wind Advisory until 3 PM EST this afternoon for coastal Duval-
coastal Flagler-coastal Nassau-coastal St. Johns.
Georgia...high rip current risk through this evening for coastal Camden-
Am...Small Craft Advisory from 3 PM this afternoon to 3 PM EST Friday
for waters from Altamaha Sound Georgia to Fernandina Beach Florida
from 20 to 60 nm-waters from Fernandina Beach to St.
Augustine Florida from 20 to 60 nm-waters from St. Augustine to
Flagler Beach Florida from 20 to 60 nm.
Gale Warning until 3 PM EST this afternoon for waters from
Altamaha Sound Georgia to Fernandina Beach Florida from 20 to 60 nm-
waters from Fernandina Beach to St. Augustine Florida from 20 to
60 nm-waters from St. Augustine to Flagler Beach Florida from 20
to 60 nm.
Small Craft Advisory from 11 am this morning to 8 am EST Friday
for coastal waters from Altamaha Sound to Fernandina Beach
Florida out 20 nm-coastal waters from Fernandina Beach to St.
Augustine Florida out 20 nm-coastal waters from St. Augustine to
Flagler Beach Florida out 20 nm.
Gale Warning until 11 am EST this morning for coastal waters
from Altamaha Sound to Fernandina Beach Florida out 20 nm-
coastal waters from Fernandina Beach to St. Augustine Florida