Scientific Forecaster Discussion
fxus62 kjax 140116
Area forecast discussion
National Weather Service Jacksonville Florida
816 PM EST Wed Nov 13 2019
A coastal trough will begin to take shape over the nearshore
Florida waters tonight, resulting in increasing coverage of
stratocumulus clouds. Mid and high altitude cloud cover will also
thicken after midnight as the cutoff low over Mexico pivots
eastward towards deep south Texas, which will cause the frontal
boundary over the Florida Straits to stall. Strengthening
isentropic lift due to the presence of the coastal trough will
result in a few showers moving onshore along the I-95 corridor
overnight. A period of radiational cooling already this evening
has allowed temperatures to fall into the upper 30s to mid 40s
across the interior from the I-10 corridor northward, while
temperatures at the northeast Florida beaches ranged from the
upper 50s to upper 60s due to the northeasterly onshore flow.
Temperatures will slowly rise during the predawn hours across the
interior as cloudiness increases.
[through 00z friday]
Stratus clouds were streaming inland along the coast from Duval
County northward with MVFR cigs at kssi and kcrg. A coastal trough
developing tonight may lead to a few coastal showers. MVFR cigs
are forecast to move across the rest of the taf sites overnight,
with IFR cigs possible. North to northeast winds 5-10 knots will
prevail overnight, except higher at ksgj. Northeast winds around
10 knots will prevail on Thursday. Rain chances will increase
towards the end of the taf period as trough over the Gulf moves
closer to the area.
Previous discussion [501 PM est]...
Near term [through tonight]...
The strong mid level shortwave over northern New England that
carved a deep trough down the East Coast of the US this morning
will move east towards Halifax as mid level ridging temporarily
moves over the mid Atlantic region to our north. Strong high
pressure at the surface located north of the area continues
supplying onshore NE flow. Meanwhile, the cold front the brought
chilly temperatures this morning is now stationary over South
Florida. A coastal trough will develop later tonight over the
Florida coastal waters, increasing rain chances along the
immediate coastline as dawn approaches. Lows tonight will not be
as cold as this morning with upper 30s to low 40s in interior southeast
GA, upper 40s to low 50s for the southeast Georgia coast and for areas along
I-10 while the NE Florida coast and north central Florida areas drop
only into the mid to upper 50s.
Short term [thursday through Friday night]...
On Thursday, high pressure will slowly move NE of the area while
an area of low pressure will form over the NE Gulf of Mexico and
move east over the area bringing likely rain chances for NE Florida and
southeast Georgia with a chance for thunderstorms by the afternoon. This low
will be over the area on Friday and continue rain chances with an
isolated thunderstorm potential through the early afternoon
before moving east of the area by the evening. An upper level low
associated with a strong mid level shortwave will allow moisture
to wrap around the surface low pressure by late in the day Friday.
Rain chances will be highest over southeast Georgia into Friday evening.
Temperatures will be below normal as northeasterly flow at the
surface continues between the high pressure to our northeast as
the low moves through our area this period.
Long term [saturday through wednesday]...
The upper level shortwave feeding friday's low pressure system
will lift northeastward toward the mid-Atlantic coastline on
Saturday. A weak deep layer ridge will briefly move over the
southeastern U.S. In its wake, but another upper level shortwave
trough will move into the Southern Plains Sunday night. This
shortwave will develop a low pressure system that will sweep
across the Gomex. Additionally, downstream of this feature, there
will be enhanced upper level divergence over the Florida Peninsula that
will help develop a weak low pressure system just off our
coastline Monday night and Tuesday. The Gulf low is forecast to
move south of our local area, keeping US dry after the low to our
east moves away. Overall, this pattern will make for a dry Sunday
and Monday, followed by scattered showers and isolated
thunderstorms Monday night and Tuesday, then another dry break
Tuesday night through the remainder of the period. Temperatures
will be cooler than normal this weekend and into early next week,
with afternoon highs mostly in the upper 50s to mid 60s and lows
mostly in the upper 30s to upper 40s, with low 50s possible in
northern central Florida and along the immediate coastline.
Strong northeast winds will continue to gradually lower tonight,
with seas lowering accordingly behind them. Small Craft Advisory
conditions should dissipate over our offshore waters by Thursday
evening. After that, winds and seas will remain low for the rest
of the work week. Friday night into Saturday morning, the wind
gradient will begin to tighten again as a low pressure system to
our east deepens. Though the system will move away from US on
Saturday, it's growing strength will lead to enhanced winds, with
gusts to gale force possible Saturday night. By early next week,
winds will fall below 15 knots, with seas lowering more slowly
Rip currents: a high risk of rip currents today and tomorrow along northeast
Florida beaches. A high risk of rip currents today and moderate
risk of rip currents Thursday along southeast Georgia beaches.
Coastal flooding: the higher than normal tides will continue to
slowly return towards normal as we move away in time from the full
moon (which was yesterday) and as strong north-northeast winds
also gradually lower through Thursday. A coastal flood advisory
continues through Thursday while these tides continue to peak
around 1 to 1.5 feet above mhhw along the Intracoastal Waterway
and St. Johns River.
Preliminary point temps/pops...
Amg 38 57 46 58 46 / 0 40 90 70 70
ssi 43 66 52 63 51 / 20 30 90 70 70
jax 45 70 54 65 51 / 20 40 90 50 50
sgj 57 73 60 69 54 / 30 40 90 50 50
gnv 48 73 56 66 50 / 10 40 80 40 20
ocf 54 76 61 70 52 / 10 40 80 40 20
Florida...coastal flood advisory until 5 PM EST Thursday for Clay-coastal
Duval-coastal Flagler-coastal Nassau-coastal St. Johns-
inland Duval-inland Flagler-inland Nassau-inland St. Johns-
High rip current risk through Thursday evening for coastal Duval-
coastal Flagler-coastal Nassau-coastal St. Johns.
Georgia...coastal flood advisory until 5 PM EST Thursday for coastal
Camden-coastal Glynn-inland Camden-inland Glynn.
Am...Small Craft Advisory until 10 PM EST Thursday for 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
Small Craft Advisory until 2 PM EST Thursday for waters from
Altamaha Sound Georgia to Fernandina Beach Florida from 20 to 60 nm.
Small Craft Advisory until 4 am EST Thursday for coastal waters
from Altamaha Sound to Fernandina Beach Florida out 20 nm-
coastal waters from Fernandina Beach to St. Augustine Florida