338
FXUS62 KJAX 210522
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
122 AM EDT Fri Jun 21 2024

...New AVIATION...

.UPDATE...
Issued at 955 PM EDT Thu Jun 20 2024

Late evening surface analysis depicts a gradually organizing, but
weak low pressure enter (1014 millibars), labeled as Invest 92-L
by the National Hurricane Center. This feature was centered about
300 miles to the east-southeast of Mayport as of 01Z. Thunderstorm
activity has been bursting near a poorly defined center of
circulation this evening, and the National Hurricane Center has
increased the probability for development into a Tropical
Depression to 50% on their evening Tropical Weather Outlook.
Otherwise, high pressure (1028 millibars) was gradually weakening
over the western Atlantic waters as it sinks southward towards
Bermuda. Aloft...stout ridging was centered across the Tennessee
Valley and the southern Appalachians, with a Tropical Upper
Tropospheric Trough (TUTT) being steered quickly westward across
the southern portions of the Gulf of Mexico beneath this ridge. A
few weak rain bands on the western periphery of Invest 92-L were
progressing west-southwestward across the offshore Atlantic
waters to the south of St. Augustine. Scattered multi-layered
cloudiness continues to progress across northeast and north
central FL, with fair skies prevailing across southeast GA. Breezy
northeasterly winds prevail at coastal locations, with winds
decoupling further inland. Temperatures generally ranged from
75-80 degrees at 02Z, with dewpoints mostly in the 60s inland,
ranging to around 70 at coastal locations.

All eyes are on Invest 92-L tonight as this feature moves west-
northwestward towards our coastline. This system could organize
into a Tropical Depression overnight or Friday morning as it
traverses the warm Gulf Stream waters, and outer rain bands should
begin to move onshore along the northeast FL coast during the
predawn hours on Friday. Beneficial rainfall is on its way to the
Interstate 95 corridor, with a dry and subsident air mass closer
to the ridge axis aloft over inland southeast GA and the Suwannee
Valley likely reducing rainfall intensity and coverage as activity
works westward after sunrise on Friday. Heavy downpours and a few
embedded thunderstorms should overspread coastal southeast GA and
locations east of U.S. Highway 17 by sunrise. Multi-layered cloud
cover will otherwise gradually increase from east to west during
the overnight and predawn hours, with lows falling to the upper
60s across inland southeast GA and remaining in the 70s elsewhere.

&&

.SHORT TERM...
(Friday through Saturday night)
Issued at 237 PM EDT Thu Jun 20 2024

Area of low pressure with disorganized convection will move west-
northwest toward SE GA and NE FL during the overnight hours and
then move inland around or just after sunrise Friday morning.
There is not much time for the system to get organized, but there
is a small chance it can be a depression before it comes ashore.
Either way, impacts are the same with rough surf, potential minor
beach erosion during high tide, high risk of rip currents. Expecting
numerous showers with embedded thunderstorms with this feature,
along with elevated winds and gusts particularly I-95 eastward
where some wind gusts exceeding 30 mph are possible. Highs Friday
will be a little cooler than normal due the clouds and rainfall
passing through with highs in the 85 to 90 degree range.

High pressure will build to the northeast behind the low pressure
area Friday night through Saturday. This pattern will continue
the onshore flow pattern, but the gradient will be more relaxed,
so so not expecting winds to be as elevated during this time frame.
Above average shower chances will continue in the onshore flow.
Diurnal heating could lead to a few afternoon storms on Saturday.
Lows Friday night will generally be in the lower to mid 70s,
except a little warmer near the coast. Temperatures Saturday will
trend above normal, with highs ranging from the lower 90s at the
coast, to the mid 90s inland.

The high will move further away to the east northeast Saturday
night, with the flow becoming more from the south/southeast. Lows
away from the coast in the mid 70s, upper 70s coast.

&&

.LONG TERM...
(Sunday through next Thursday)
Issued at 237 PM EDT Thu Jun 20 2024

The high will continue to drift away to the east this period, as a
trough moves into the southeastern US and stalls. An increasingly
moist southwest flow will become the trend this period. This pattern
will produce above normal chances for showers and thunderstorms.
Temperatures will be above normal throughout this period.

&&

.AVIATION...
(06Z TAFS)
Issued at 122 AM EDT Fri Jun 21 2024

MVFR ceilings around 2500ft and heavy showers will move onshore
and impact all TAF sites beginning this morning. Isolated
thunderstorms and gusty easterly winds will also be present
throughout the day. PROB30s are in place for the best chances for
time frame of heaviest showers and/or thunderstorm activity.

&&

.MARINE...
Issued at 955 PM EDT Thu Jun 20 2024

Weak low pressure situated about 300 miles to the east-southeast
of Mayport, Florida late on Thursday evening may organize into a
Tropical Depression overnight or early on Friday as it progresses
west-northwestward across the Gulf Stream waters, with this
feature approaching the northeast Florida coast late on Friday
morning or during the early afternoon hours. Bands of gusty
showers and embedded thunderstorms will increase in frequency and
intensity during the overnight and predawn hours on Friday, with
this activity continuing through late Friday afternoon before
diminishing in coverage as this weak low pressure center
progresses inland.

Meanwhile, strong high pressure centered north of Bermuda will
gradually weaken as it settles southward this weekend. Small Craft
Advisory conditions will continue throughout our local waters
tonight and Friday, followed by winds and seas diminishing to
Caution levels on Friday night and then below Caution criteria on
Saturday. Seas of 5-7 feet near shore and 6-8 feet offshore
tonight and Friday will subside to 4-6 feet on Friday night and
then 3-5 feet during the weekend. Rounds of showers and
thunderstorms will continue to develop over our local waters this
weekend and into next week as prevailing winds become southerly
ahead of a weakening surface trough that will settle over the
southeastern states through midweek.

Rip Currents: Breakers of 5-7 feet will continue at the northeast
FL beaches on Friday, with 4-6 foot breakers expected at the
southeast GA beaches. This rough surf will create a high risk of
dangerous rip currents at all area beaches through Friday. A
moderate risk is expected during the weekend due to onshore winds
and an easterly ocean swell.

&&

.HYDROLOGY...
Issued at 955 PM EDT Thu Jun 20 2024

The Weather Prediction Center has a Marginal risk of excessive
rainfall from Friday through Saturday, as locally heavy rainfall
totals of 2 to 3 inches will be possible along the Interstate 95
corridor as Invest 92-L impacts our region with bands of heavy
downpours. Rainfall amounts further inland will likely remain
below one inch. Rainfall will be mostly beneficial, but there will
be concerns for flooding at urban locations where rain bands
train repeatedly tomorrow and again on Saturday.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  91  74  91  73 /  40  40  80  30
SSI  87  78  87  77 /  80  50  70  50
JAX  88  75  91  74 /  80  60  80  50
SGJ  87  77  89  75 /  80  70  80  60
GNV  91  73  94  72 /  70  60  90  40
OCF  91  74  95  75 /  80  50  90  50

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through late tonight for FLZ124-125-133-
     138.

     High Surf Advisory until 5 PM EDT this afternoon for FLZ124-125-
     133-138.

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

AM...Small Craft Advisory until 5 PM EDT this afternoon for AMZ450-
     452-454-470-472-474.

&&

$$