976
FXUS62 KJAX 150837
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
437 AM EDT Sun Sep 15 2024

...BECOMING WINDY AT COASTAL LOCATIONS TODAY...
...MINOR COASTAL FLOODING DURING THE EVENING HIGH TIDE...
...DANGEROUS BEACH CONDITIONS EARLY THIS WEEK...

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

.SYNOPSIS...
Issued at 437 AM EDT Sun Sep 15 2024

Early morning surface analysis depicts developing low pressure
(1009 millibars) located over the Gulf Stream waters adjacent to
the Georgia and South Carolina coasts. Meanwhile, strong high
pressure (1030 millibars) was centered over Maine and was wedging
down the southeastern seaboard. Otherwise, a wavy and stationary
frontal boundary situated along the Interstate 4 corridor in
central FL extends westward across the FL panhandle and along the
northern Gulf coast. Aloft...a persistent "Rex Block" remains in
place over the eastern half of the nation, with stout ridging
centered over the eastern Great Lakes region and New England,
keeping Francine`s remnant trough trapped over the lower
MississippiValley and the Deep South. A drier air mass has
advected across our region, with latest GOES-East derived Total
Precipitable Water imagery indicating that PWAT values have fallen
back to near climatological values for mid-September, with values
of 1.6 to 1.8 inches prevailing area-wide. Multi-layered cloud
cover was increasing across our our area overnight, but only a few
light showers or sprinkles were located near the southeast GA
coast. Temperatures and dewpoints were in the 70s across
northeast and north central FL as of 08Z, while dewpoints have
fallen to the upper 60s across inland portions of southeast GA.

&&

.NEAR TERM...
(Today and Tonight)
Issued at 437 AM EDT Sun Sep 15 2024

Low pressure will continue to gradually organize and will remain
nearly stationary through tonight over the Gulf Stream waters
adjacent to GA and SC. Meanwhile, strong high pressure will remain
situated over New England, with this feature continuing to wedge
down the southeastern seaboard today, tightening our local
pressure gradient. Breezy north-northeasterly winds will continue
at coastal locations this morning, with windy conditions
developing this afternoon as speeds increase to 15-25 mph with
occasional gusts up to 35 mph. Breezy conditions will develop at
inland locations this afternoon. Deeper tropical moisture will
remain offshore today, but low level onshore flow will become more
convergent, with showers and a few embedded thunderstorms expected
to increase in coverage along the GA coast by the mid to late
morning hours, with this low-topped activity then pushing
southwestward across the rest of our area as the afternoon
progresses. While briefly heavy downpours are possible, the lack
of deeper moisture should make activity transient in nature as it
shifts southwestward, and chances for widespread thunderstorms
appear to be unlikely this afternoon. Higher coverage of showers
and a few embedded thunderstorms are expected to remain along and
north of the Interstate 10 corridor, with another corridor of
higher coverage located west of I-75 in the Suwannee Valley later
this afternoon, possibly extending into the evening hours. Breezy
conditions and multi-layered cloudiness will keep highs generally
in the low to mid 80s, with upper 80s forecast across north
central FL.

Breezy onshore winds will shift to a more north-northwesterly
direction at coastal locations overnight. Widely scattered showers
developing to the south of the organizing low pressure center off
the Carolina coast may occasionally brush locations along and east
of I-95 overnight. Otherwise, low stratus clouds may develop
during the predawn hours across inland portions of southeast GA,
where winds will decouple, allowing lows to fall to the upper 60s.
Lows elsewhere will fall to around 70 inland, ranging to the mid
and upper 70s at coastal locations.

&&

.SHORT TERM...
(Monday through Tuesday)
Issued at 437 AM EDT Sun Sep 15 2024

Frontal boundary remains draped across FL as its associated low
pressure system shifts north-northwestward and potentially moves
onshore to the Carolinas and into the Mid-Atlantic region Monday
into Tuesday. NHC has a 50% chance that this low may become a
subtropical or tropical storm early this week if the associated
front dissipates and showers and thunderstorms become sufficiently
organized. Regardless of tropical or subtropical development,
local impacts for Monday will be breezy north-northeasterly winds
along the coast, coastal flooding, high risk of rip currents and
dangerous marine conditions. A lingering moist airmass over NE
FL, convergence along the frontal boundary, and upper energy from
the remnants of Francine will support daily scattered to numerous
showers with embedded thunderstorms. Highs will be in the low 80s
in SE GA to around 90 in north-central FL. Overnight lows will be
in the upper 60s and low 70s.

&&

.LONG TERM...
(Wednesday through Saturday)
Issued at 437 AM EDT Sun Sep 15 2024

Frontal boundary over northern FL on Wednesday will dissipate and
shift southward as its associated low weakens over the mid-
Atlantic region. Upper trough over the eastern US will place the
region under north-northwesterly flow aloft advecting in some
drier air for the latter half of the week. Rain chances decrease
through the week bringing an end to the wet pattern. High pressure
wedges down the eastern seaboard for the end of the week bringing
as return of northeasterly flow. Temperatures will be around
seasonal with highs in the 80s and lows in the upper 60s and low
70s.

&&

.AVIATION...
(06Z TAFS)
Issued at 209 AM EDT Sun Sep 15 2024

MVFR ceilings will prevail through the TAF period at the SSI and
SGJ coastal terminals. Ceilings at the inland terminals will lower
to MVFR during the overnight and predawn hours, with periods of
IFR conditions expected at GNV around sunrise through the early
morning hours. IFR conditions will also be possible at VQQ during
the early morning hours, but confidence was too low to include in
the overnight TAF package. Ceilings at GNV should lift to MVFR by
14Z. Showers will increase in coverage over the Atlantic waters
adjacent to southeast GA during the early to mid-morning hours,
with activity likely impacting the SSI terminal during the late
morning and early afternoon hours. A PROB30 group was placed in
the SSI TAF for wind gusts up to 30 knots and IFR conditions
during heavier downpours. Showers and a few embedded thunderstorms
will then shift over the northeast FL terminals during the
afternoon hours. PROB30 groups for wind gusts up to 30 knots and
MVFR conditions during heavier downpours were placed in these TAFs
during the afternoon hours on Sunday. Ceilings may lift to VFR
towards sunset on Sunday evening at the inland terminals.
Northeasterly surface winds will remain sustained at 5-10 knots
overnight at the SSI and SGJ coastal terminals, and around 5 knots
at the inland terminals. Surface winds will shift to north-
northeasterly towards sunrise, with sustained  speeds increasing
to 15-20 knots by early afternoon at the coastal terminals and
10-15 knots and gusty at the inland terminals.

&&

.MARINE...
Issued at 437 AM EDT Sun Sep 15 2024

Low pressure will continue to organize over the Gulf Stream waters
adjacent to the Carolina coastline, with this feature potentially
acquiring tropical characteristics as it pushes northward towards
the Carolina coast on Monday night or early Tuesday morning. Small
Craft Advisory conditions over the Georgia waters and the
offshore waters north of St. Augustine this morning will
overspread the rest of the northeast Florida waters by this
afternoon as north-northeasterly winds strengthen to 20-25 knots
and seas build. Winds may occasionally gust to around Gale Force
over the Georgia waters this afternoon and evening. Seas will peak
in the 5-8 foot range for the near shore waters tonight and 7-10
feet offshore. Small Craft Advisory level seas will continue on
Monday night for the offshore waters, with Caution level seas of
4-6 feet forecast near shore.

Waves of showers and a few embedded thunderstorms will develop
across our local waters through Monday night. Winds will shift to
northwesterly on Monday night while diminishing, with seas then
gradually diminishing through midweek. Otherwise, a frontal
boundary positioned across the Florida peninsula will lift
northward over the northeast Florida waters on Wednesday, keeping
chances for mainly afternoon and evening thunderstorms in place.
This front will then shift south of our local waters late this
week.

Rip Currents/Elevated Surf: Strengthening north-northeasterly
winds and increasingly rough surf conditions will keep a high rip
current risk in place at all area beaches through Monday. Breaker
heights will build to 3-5 feet this afternoon and will peak in the
4-6 foot range on Monday, which is just below High Surf Advisory
criteria. Winds will become northwesterly on Monday night and
Tuesday, with decreasing breaker heights potentially allowing for
a high end moderate risk at area beaches by Tuesday.

&&

.COASTAL FLOODING...
Issued at 437 AM EDT Sun Sep 15 2024

Trapped tides within the St. Johns River basin from downtown
Jacksonville southward will result in mostly minor flooding during
times of high tide during the next several days, with water
levels potentially touching moderate flood levels at times. The
upcoming "Harvest" Full Moon will result in increasingly high
astronomical tides along the Atlantic coast, with these higher
tides being enhanced by strengthening onshore winds today and
Monday. We have extended the Coastal Flood Advisory to include the
Atlantic coast for this evening`s high tide cycle, as water levels
generally peak around 2 feet above Mean Higher High Water (MHHW).
Water levels may remain elevated along the Atlantic coast through
the Monday evening high tide cycle before subsiding on Tuesday.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  83  68  81  66 /  60  30  20  10
SSI  82  74  81  71 /  50  40  20  10
JAX  84  71  83  70 /  50  40  40  10
SGJ  85  76  84  73 /  40  40  40  10
GNV  86  71  85  69 /  50  20  40  20
OCF  88  72  88  71 /  40  20  60  20

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Coastal Flood Advisory until 5 AM EDT Tuesday for FLZ033-038-132-
     137-325.

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

     Coastal Flood Advisory from 6 PM this evening to 5 AM EDT
     Tuesday for FLZ124-125-133-138.

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

     Coastal Flood Advisory from 6 PM this evening to 5 AM EDT
     Tuesday for GAZ154-166.

AM...Small Craft Advisory until 5 AM EDT Tuesday for AMZ450-470-472.

     Small Craft Advisory from 2 PM this afternoon to 5 AM EDT
     Tuesday for AMZ452-454-474.

&&

$$