315
FXUS62 KJAX 180010
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
810 PM EDT Wed Jul 17 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...
(00Z TAFS)
Issued at 811 PM EDT Wed Jul 17 2024

Periods of MVFR visibilities will be possible overnight at VQQ.
Otherwise, VFR conditions will prevail at the regional terminals
through at least 15Z on Thursday. Showers and thunderstorms
developing during the morning hours along the Gulf coast sea
breeze may approach the GNV terminal towards 16Z, with activity
then developing along a slower moving Atlantic sea breeze boundary
towards 18Z. Convection should then increase in coverage along the
Interstate 95 corridor after 19Z as outflow boundaries merge, with
a few strong thunderstorms possible at the regional terminals
through around 23Z. We included PROB30 groups at each terminal for
brief wind gusts around 30 knots and MVFR visibilities during
heavier downpours. Activity should shift east of GNV by 21Z and
will likely move offshore before 00Z Friday. Southerly surface
winds around 5 knots this evening will diminish overnight at the
inland terminals, with southwesterly winds then increasing to 5-10
knots at the terminals before 15Z. The Atlantic sea breeze
boundary is expected to move slowly inland on Thursday,
crossing the SGJ and SSI coastal terminals before 18Z and then
CRG towards 19Z, with southeasterly winds increasing to 10-15
knots outside of developing thunderstorm activity following the
passage of the sea breeze.

&&

.SHORT TERM...
(Thursday through Friday night)
Issued at 247 PM EDT Wed Jul 17 2024

Elevated daily rain chances continue through Friday as SW
steering flow continues across the local area between the 1000-500
mb ridge axis across south-central FL and weak troughs north of
the region. Morning showers and storms will edge inland from the
Gulf Coast region, expanding in coverage and progressing toward
the Atlantic coast through early afternoon as diurnal instability
increases. Additional convection will break across SE GA into the
afternoon and linger into the early evening closer to low level
trough trough axes and lingering outflow boundaries. Mid level
temperatures continue near climo values with -6 to -7 deg C at
500 mb with weak upper level shear (< 25 kts) so convective
ingredients continue to favor mainly pulse strong to isolated
severe storm potential in the afternoon and early evening with
boundary mergers. Storm motion of 10-15 kts will somewhat limit
the localized flash flood threat, but, storms are dropping 2-4
inches within 2 hours where mergers occur...so a couple days of
heavy rainfall could certainly cause localized flood issues.
Storms will fade across inland coverage toward midnight with loss
of instability, then resurrect toward the Gulf Coast toward
sunrise with some inland drift across our Suwannee River Valley
zones.

Temperatures will trend within a few degrees of climo values with
highs in the low-mid 90s and lows in the lower to mid 70s. Peak
heat index values near 105 deg each day prior to convective
cooling.

&&

.LONG TERM...
(Saturday through next Wednesday)
Issued at 247 PM EDT Wed Jul 17 2024

The ridge across south-central FL begins to build northward across
NE FL Saturday then shifts north of the local area Monday. This
will transition prevailing flow from SW over the next couple of
days to SSE this weekend then SE early next week, with a more
dominant east coast sea breeze pattern. Elevated rain chances with
locally heavy rainfall potential will continue through the weekend
with high PWAT trapped under the ridge axis and weak storm motion
(PWATs 1.9-2.25"). Monday through Wednesday night week, deep layer
moisture begins to decrease some into the 1.6-2 inch range
favoring more scattered shower and thunderstorm activity for most
inland areas (40-50% rain chances), then numerous (50-60%) where
sea breezes and boundaries merge during the afternoon and evening
near and west of I-75. Temperatures will trend near to above
normal with highs in the low-mid 90s and lows in the 70s.

&&

.MARINE...
Issued at 247 PM EDT Wed Jul 17 2024

The western periphery of the Bermuda Ridge will be right over our
coastal waters and then the ridge axis will ridge west into the
Gulf south of us. This will keep a general south to southwest flow
pattern over our waters next few days. Will be some breaks in
that pattern with a wind shift to the southeast near shore each
afternoon and evening as the sea breeze develops. As with most of
the peripheral ridge situations will see nocturnal southerly
surges briefly bringing winds close to or above Small Craft
Exercise Caution during the overnight hours. Some afternoon and
evening thunderstorms are possible each day with winds and seas
higher in and near thunderstorms.

Rip Currents: Moderate rip current risk continues through Friday.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  74  92  74  91 /  20  60  40  80
SSI  77  91  79  91 /  30  50  40  60
JAX  76  93  76  93 /  20  60  20  70
SGJ  76  92  77  92 /  20  50  20  60
GNV  75  89  74  91 /  20  60  10  70
OCF  74  91  75  91 /  20  50  10  70

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...None.
&&

$$