353
FXUS62 KJAX 161743
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
143 PM EDT Sun Jun 16 2024

...New AVIATION...

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

.AVIATION...
(18Z TAFS)
Issued at 143 PM EDT Sun Jun 16 2024

Showers and thunderstorms currently developing along the inland
moving Atlantic and Gulf coast sea breezes will converge upon the
Interstate 75 corridor during the mid to late afternoon hours.
Vicinity showers and thunderstorms are expected during the next
few hours at VQQ, with higher chances for impacts at GNV after
20Z. We kept a TEMPO group for MVFR conditions and briefly gusty
winds in the 20Z-00Z window at GNV. MVFR visibilities are expected
to develop at VQQ overnight, with periods of IFR visibilities
possible during the predawn hours. Periods of MVFR ceilings will
be possible from the predawn through late morning hours on Monday
at the SSI and SGJ coastal terminals, as showers developing over
the adjacent near shore waters potentially move onshore towards
sunrise. These MVFR ceilings may then periodically impact the
Duval County terminals after 13Z. Confidence remains too low to
indicate anything other than scattered ceilings at the regional
terminals during the predawn and morning hours on Tuesday. Gusty
east-northeasterly surface winds that will be sustained around 15
knots this afternoon, except around 10 knots at VQQ and GNV, will
persist in the 10-15 knot range overnight through the early
morning hours at the coastal terminals, while speeds inland fall
to around 5 knots or less after 04Z. Gusty easterly surface winds
will then redevelop before 15Z Monday.

&&

.UPDATE...
Issued at 1119 AM EDT Sun Jun 16 2024

Late morning surface analysis depicts strengthening high pressure
(1027 millibars) centered over New England, with a decaying
frontal boundary wedging southward through the Carolinas and the
southern Appalachians. Aloft...stout ridging prevails over the
southeastern states, with the feature steering shortwave energy
around its western periphery from the southern Plains states
northeastward to the Great Lakes region. Latest GOES-East derived
Total Precipitable Water imagery indicates that a drier than
average air mass remains over most of our region, except for
locations near the Suwannee River, where values were around 1.8
inches, which is closer to climatology. PWAT values elsewhere
were generally in the 1.3 - 1.5 inch range, with higher PWATS
just north of our region near the decaying frontal boundary. Our
local pressure gradient is beginning to tighten as high pressure
wedges down the southeastern seaboard, with breezy onshore winds
taking shape at area beaches late this morning. Southeasterly low
level flow has shaped a healthy cumulus field across our area, and
temperatures at 15Z were already in the upper 80s and lower 90s
across our area, with dewpoints mostly in the 70s.

Breezy easterly winds will overspread inland locations as the
afternoon progresses, with onshore winds increasing to the 15-20
mph range with occasional gusts up to 30 mph by late this
afternoon and early this evening along the Atlantic coast. The
strengthening surface ridge along the New England coast will
generally advect a dry and subsident air mass onshore, with the
Atlantic sea breeze progressing well inland towards the I-75
corridor by the late afternoon hours. This boundary will encounter
higher PWAT values located along and west of the Suwannee River,
with scattered to numerous showers and thunderstorms expected to
erupt by late afternoon for locations along and west of I-75 in
the Suwannee Valley and north central FL. In advance of the
approaching Atlantic sea breeze boundary, highs will soar to the
mid and possibly upper 90s across the Suwannee Valley and inland
southeast GA, where dewpoints will crash through the 60s this
afternoon, keeping maximum heat index values around 100. Breezy
onshore winds will keep highs in the lower 90s for locations east
of U.S. Highway 301, and coastal temperatures will fall into the
80s by late afternoon as onshore winds strengthen.

Showers and thunderstorms developing along the I-75 corridor
during the mid to late afternoon hours will progress westward
across the Suwannee and Alapaha Rivers by sunset. Breezy and
convergent low level easterly flow may begin to advect isolated
showers developing over the Atlantic waters onshore along the
northeast FL coastal counties towards sunrise on Monday. The
onshore breeze will be slow to weaken along the coast overnight,
keeping lows in the upper 70s to around 80 for locations east of
I-95, while lows elsewhere fall to the low and mid 70s.

&&

.MARINE...
Issued at 1119 AM EDT Sun Jun 16 2024

High pressure centered over New England will strengthen as it
moves slowly offshore this afternoon. This feature will result in
strengthening easterly winds by late this afternoon and evening
throughout our local waters, with winds and seas gradually
increasing early this week as this high pressure center remains
anchored off the New England coastline. Small Craft will need to
Exercise Caution if venturing into our local waters on Monday and
Monday night, as easterly winds strengthen to 15-20 knots and seas
build to 3-5 feet on Monday and 4-6 feet by Monday evening. Small
Craft Advisory conditions are expected to begin both near shore
and offshore on Tuesday, as onshore winds strengthen to around 20
knots and seas build to 5-7 feet.

Low pressure is expected to develop over the southwestern Atlantic
early this week, with this feature gradually organizing towards
midweek as it moves westward across the Bahamas, with a low risk
for tropical development as this system approaches our local
waters late on Wednesday night and Thursday. Please stay tuned to
updates from the National Hurricane Center this week for potential
changes to this forecast. Coverage of showers and thunderstorms
will gradually increase across our local waters, with widespread
activity likely by mid to late week. Seas will continue to build,
with near shore seas climbing to the 8-11 foot range by Thursday,
while seas offshore build to 9-13 feet.

Rip Currents: Strengthening easterly winds this afternoon will
result in building and increasingly rough surf, especially during
the outgoing tide late this afternoon and early this evening. A
High Risk of rip currents is expected by late afternoon at the
northeast FL beaches, with a high end moderate risk for the
southeast GA beaches, where wave heights should remain around 2
feet or less today. A high risk of rip currents is expected for
the upcoming work week at all area beaches due to gradually
strengthening onshore winds and building seas.

&&

.FIRE WEATHER...
Issued at 1119 AM EDT Sun Jun 16 2024

Easterly surface and transport winds will become breezy this
afternoon, creating good to marginally high daytime dispersion
values for locations along and north of the Interstate 10
corridor. Generally fair dispersion values are expected for north
central FL this afternoon. A dry air mass will prevail for inland
locations across southeast GA and also for northern portions of
the Suwannee Valley today and again on Monday, where afternoon
humidity values will fall to the 30-35 percent. Breezy easterly
transport winds will prevail area-wide on Monday and Tuesday, with
windy surface conditions expected along the I-95 corridor during
the afternoon and early evening hours. Good to high daytime
dispersion values are forecast throughout our region for the
early to middle portions of this week.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  72  92  71  91 /   0  10  10  20
SSI  80  87  80  85 /  10  30  20  40
JAX  74  90  73  88 /  10  20  20  50
SGJ  79  87  80  88 /  10  30  20  60
GNV  73  92  72  90 /  10  10  10  50
OCF  73  92  73  92 /  20  10   0  50

&&

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

GA...None.
AM...None.
&&

$$