Strong Wind in Florida, December 16, 2023

Area Forecast Discussion
National Weather Service Jacksonville FL
719 PM EST Sat Dec 16 2023

...New UPDATE...

.UPDATE...
Issued at 719 PM EST Sat Dec 16 2023

For the latest NE FL and SE GA Daily Key Messages please visit:
https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf

No major updates needed on the forecast this evening. Widespread
rain has moved into northeast Florida and southeast Georgia,
conditions will begin to deteriorate over the next couple hours as
heavier rain pushes inland. Convective models are indicating the
strongest thunderstorm activity to be across north central Florida
around midnight, gradually spreading northward overnight. The
highest potential for isolated severe thunderstorms will be over
northeast Florida and along the Atlantic coast, with damaging
winds, locally heavy rainfall, and an isolated tornado remaining
the main threats overnight through morning.

&&

.NEAR TERM...
(Through Tonight)
Issued at 300 PM EST Sat Dec 16 2023

For the latest NE FL and SE GA Daily Key Messages please visit:
https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf

The forecast for tonight shows the deepening surface low coming
at us from the southwest and moving northeast across the forecast
area Sunday morning. A triple point low expected to develop near
our coast around the 06z-12z time frame and may take over as
the primary low pres lifting to the northeast on Sunday/Sunday
afternoon. The rain forecast continues to show widespread rain,
some of it heavy with a flood watch in effect and rainfall totals
of 3-5 inches possible. Minor flooding is certainly possible in
poor drainage areas along with the threat of severe storms. Sfc
based instability does not really look good for storms until after
05z/06z, and peaks about 10z-14z over portions of northeast FL
and coastal southeast GA. Main threat from severe storms would be
a wind damage threat and a tornado threat. Significant tornado
parameter per HRRR maxes out near 1, so not too impressive from
that standpoint. SPC highlights the slight risk of severe storms
from Ocala to Jacksonville and points eastward, and marginal risk
from Trenton FL to Brunswick GA and points eastward. Winds will
ramp up to 15-25 mph with occasional gusts to 40 mph, potentially
higher in strong showers or any t-storm activity. Wind advisory
was expanded through the entire area into Sunday. Lows tonight
upper 50s northwest zones and lower/mid 60s elsewhere.

&&

.SHORT TERM...
(Sunday through Monday night)
Issued at 300 PM EST Sat Dec 16 2023

Sun & Sun Night...Widespread rainfall Sunday morning will
progressively shift ENE through midday with drying conditions into
the afternoon as the surface low crosses north-central FL, then
lifts quickly to the NNE into Sunday afternoon. Isolated morning
storms will be possible near the local Atlantic coast and over the
adjacent coastal waters, otherwise expect mainly stratiform
moderate to heavy rainfall for most locations at daybreak with
localized flooding potential. With any thunderstorm activity,
stronger wind gusts of 50-60 mph will be possible, as well some
rotating cells (tornado/waterspout) potential right at the start
of the period near the coast where higher helicity meets
instability. Strong dynamics in the morning and trailing pressure
rises from the west behind the departing surface low into Sunday
afternoon continue to support strong wind gusts of 40-50 mph along
the coast to 30-40 mph inland into the afternoon, with gradually
decreasing wind strength into Sunday evening. Precipitation
tappers off from SW to NE through the afternoon, with mainly just
trailing light showers/sprinkles into the early evening possible
across SE GA. Low clouds will linger into the evening until the
850 mb trough axis presses downstream of the area into Sunday
night. Daily high temperatures will hover in the upper 50s SE GA
to the mid 60s across NE FL during the morning with further
cooling into the afternoon as cooler NW flow develops. Sunday
night, low-mid level cold air advection drops lows in the 40s by
daybreak Monday morning, but combined with breezy winds overnight
in the 10-15 mph range, wind chills will drop into the 30s for
parts of SE GA.

Mon through Tuesday...Dry, breezy, clear and cold as deep cold
air advection occurs across the region and surface high pressure
builds to the WNW. High temps will top out in the upper 50s to low
60s Monday with lows Monday night falling into the 30s for most
locations. Lows will near freezing Tue morning across inland SE
GA, but there may be too much wind trailing the passage of a
reinforcing (dry) cold front Monday evening for a freeze event and
certainly now frost, but wind chills will fall into the mid to
upper 20s for many by daybreak Tuesday (just above Wind Chill
Advisory criteria for now). Very cold Tuesday with highs only near
50 for much of SE GA to low/mid 50s for NE FL despite full sun.
The surface high builds north of the region Tuesday night with
increasing high cirrus clouds from the west. The cold air in place
will bring a night of freezing temperatures inland, but frost
will be limited given the high clouds, and with the surface high
building NNE of the region, local onshore flow will begin to
develop which will bring warmer temps to coastal areas in the 40s.

&&

.LONG TERM...
(Tuesday through next Saturday)
Issued at 300 PM EST Sat Dec 16 2023

Wednesday through Saturday...Moderating temperatures and continued dry
weather as onshore flow develops with a surface high north of the
region and an upper ridge builds across the Gulf of Mexico and
over the local area through the end of the week. Another inland
freeze for SE GA possible Wed night, then lows rebound into the
40s into the weekend with highs in the 60s.

&&

.AVIATION...
(00Z TAFS)
Issued at 610 PM EST Sat Dec 16 2023

Light rain from the Gulf low is slowly filling across northeast
Florida and southeast Georgia. Conditions will begin to
deteriorate over the next few hours, with all TAF sites dropping
to IFR conditions around 10pm-1am due to low ceilings and heavy
rain lowering visibilities. Brief periods of LIFR visibilities
within heavy rain showers cannot be ruled out. Outside of
thunderstorms, winds will be gusty, and within thunderstorms winds
will also be gusty but variable in direction. Heavy rain and
thunderstorms will move clear of the TAF sites Sunday late morning
to early afternoon, with IFR ceilings lingering through late
afternoon to evening. Placed in AMD NOT SKED at SGJ due to
inconsistent reporting.

&&

.MARINE...
Issued at 300 PM EST Sat Dec 16 2023

As low pressure approaches, guidance has shown fairly persistent
forecast of strong to gale force winds, and gusts of storm force
offshore. Given the strength of the low and potential secondary
low development, opted to go with storm warning for the offshore
waters and maintain a gale warning for the nearshore. Storm
warning conditions develop overnight from about 05z to 14z when
the strongest winds appear to occur. Winds will shift to the west
and northwest after about 16z-20z Sunday as trough of low pressure
swings through. Gale conditions expected to linger after 18z and
into Sunday evening. The pressure gradient weakens gradually into
Monday into Tuesday but advisory level winds and seas likely to
continue, especially for offshore waters. NWPS wave guidance looks
on target for now, though with slight bump up tonight by 1-2 feet.

Rip Currents: High surf and high rip current risk extended through
at least Sunday night, and may still have elevated rip current
risk Mon and Tue despite offshore flow. Beach erosion will occur,
and could be significant in some areas.

&&

.HYDROLOGY...
Issued at 300 PM EST Sat Dec 16 2023

Flood Watch has been expanded for much of the area from this
evening into Sunday morning. Periods of heavy rainfall still
expected to spread from south to north across our area early this
evening through early Sunday with widespread 3-5 inches of storm
total rainfall. Locally higher amounts possible. HREF showing
totals exceeding 6 inches from Suwannee Valley into parts of
southeast GA. So potential for flooding in low lying and urban
locations, especially locations where ongoing coastal flooding
prevents drainage of water and also in other rural areas, as well
as secondary roads could be washed out.

Coastal Flooding:

Coastal flood advisory continues into Sunday for the Atlantic
coast, ICWW and St Johns river. Gages have been cresting into
Action stage just below minor flood these past high tide cycles.
The surge levels will increase but will peaking during the lower
of the high tides and a low tide at about 5-6AM. Nonetheless,
potential for a site to reach moderate coastal flooding levels.
At this time, will maintain the coastal flood advisory and extend
into the high tide into the afternoon, with potential extensions
in time. At this time it would be prudent for those in tidal flood
prone areas to prepare for at least minor flooding impacts this
weekend and consider early mitigation for moderate tidal flood
impacts.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  56  60  45  58 / 100 100   0   0
SSI  59  66  47  62 / 100  90  10   0
JAX  60  68  46  62 / 100  80   0   0
SGJ  62  70  49  63 / 100  60   0   0
GNV  60  66  46  62 / 100  60   0   0
OCF  61  68  48  63 / 100  50   0   0

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Flood Watch through Sunday morning for FLZ020-021-023-024-030-
     031-033-035-038-122-124-125-132-133-136>138-140-222-225-232-
     236-237-240-325-340-425.

     Wind Advisory until 3 PM EST Sunday for FLZ020-021-023-024-030-
     031-033-035-038-122-124-125-132-133-136>138-140-222-225-232-
     236-237-240-325-340-425.

     Coastal Flood Advisory until 1 PM EST Sunday for FLZ033-038-124-
     125-132-133-137-138-225-325.

     High Rip Current Risk through late Sunday night for FLZ124-125-
     133-138.

     High Surf Advisory until 8 PM EST Sunday for FLZ124-125-133-138.

GA...Flood Watch through Sunday morning for GAZ132>136-149-151>154-
     162-163-165-166-250-264-350-364.

     Wind Advisory until 3 PM EST Sunday for GAZ154-162-163-165-166-
     264-350-364.

     Coastal Flood Advisory until 1 PM EST Sunday for GAZ154-166.

     High Rip Current Risk through late Sunday night for GAZ154-166.

     High Surf Advisory until 8 PM EST Sunday for GAZ154-166.

     Wind Advisory from 4 AM to 3 PM EST Sunday for GAZ132>136-149-
     151>153-250.

AM...Gale Warning until 10 PM EST Sunday for AMZ450-452-454.

     Storm Warning until 10 AM EST Sunday for AMZ470-472-474.

     Gale Warning from 10 AM to 10 PM EST Sunday for AMZ470-472-474.

&&