413
FXUS62 KJAX 061030
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
630 AM EDT Sat Jul 6 2024

...New AVIATION...

.NEAR TERM...
Issued at 304 AM EDT Sat Jul 6 2024

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

Higher shower and thunderstorm chances today for inland areas as
a surface front across GA edges farther south, with a plume of
very high precipitable water content (PWAT) of 2.2-2.5 inches
settling across SE GA and the Suwannee River Valley this afternoon
and evening. This deep layer moisture combined with diurnal
instability will fuel scattered to numerous showers and
thunderstorms this the afternoon and evening. Given weak 1000-500
mb steering flow < 5 kts, both west and east coast sea breezes
will develop and press inland...very slowly...with the deepest
convective growth focused near boundary mergers during the late
afternoon and early evening. Weak shear and warm mid level
temperatures do not favor severe storms, however, the very high
moisture content combined with weak storm motion will bring
localized flooding rainfall potential and gust wet downbursts
winds near 40 mph. Drier air (PWATs < 2 inches) will hug coastal
areas today with most moisture below 700 mb. This will limit deep
convective growth (thunderstorm) potential and mainly favor
showers along the inland progressing east coast and river breezes.

Despite increased convection today, the persistent 500 mb dome of
high pressure remains in place across the local area. This will
continue to bring above normal temperatures with highs again
reaching the mid to upper 90s inland to lower 90s coast. This heat
combined with juicy dew pts in the mid to upper 70s will once
again create heat index values of 105-112 degrees F. A heat
advisory is in effect for inland SE GA and much of inland NE FL,
west of a Baker to Alachua county line. As a reminder, local heat
advisories are issued when forecast heat index values of 108-112
degrees are expected.

Tonight, convection will slowly fade in coverage and intensity,
likely lingering across SE GA a bit longer compared to NE FL.
Given such a saturated airmass and lingering convergent
boundaries, a few rouge showers could develop overnight as muggy
temps fall into the mid 70s inland to upper 70s/near 80 toward the
Atlantic coast.

&&

.SHORT TERM...
(Sunday through Monday night)
Issued at 304 AM EDT Sat Jul 6 2024

Sunday, cold frontal boundary will stretch from near the FL
panhandle to central GA and NE into the coastal Carolinas and
will likely not budge much due to the mid to upper level ridging
parked over the eastern Gulf/FL peninsula. With the weak surface
pressure gradient, both seabreezes should merge inland. Some wet
downbursts will present gusty winds, through not expected to reach
severe speeds, in the 40-50 mph range. High moisture levels over
the area will exceed the 90th percentile (PWATs 2.10-2.30 inches)
which along with weak storm motions will create very efficient
rainfall rates in heavy downpours with locally heavy rainfall
totals of 1-3 inches/isolated 4 inch amounts creating localized
flooding in urban and low lying areas. Highs will be in the mid
90s over NE FL into SE GA south of Waycross with low 90s further
north towards the Altamaha river basin and around 90 degrees along
the beaches. Peak heat index values will range 105-110 degrees and
a heat advisory may be issued over much of the area away from the
coast.

Sunday night, showers and T`storms will dwindle by midnight with
mostly cloudy skies remaining from mid and high level cloudiness
persisting from earlier T`storms. Lows will be above normal in the
mid 70s inland and the upper 70s to near 80 at the coast.

Monday will be similar with a very moist airmass and weak pressure
pattern allowing both seabreezes to push inland with showers and
T`storms becoming numerous by afternoon most prominently near the
highway 301 corridor over NE FL and away from the coast in SE GA.
Warm mid level temperatures will help preclude a severe T`storm
threat, but locally heavy rainfall will be the main hazard along
with strong, sub-severe wind gusts 40-50 mph where cell mergers do
occur. Highs will be in the low 90s at the coast and I-95 areas
with mostly cloudy skies and mid 90s inland where skies will be
partly cloudy before T`storms develop. Peak heat index values will
range 102-106.

&&

.LONG TERM...
(Tuesday through Friday)
Issued at 304 AM EDT Sat Jul 6 2024

The forecast pattern will not change overall into next week as mid
to upper level ridging remains entrenched from the central Gulf
coast into the coastal SE. Bermuda high pressure ridging will build
into South FL and bring more southwesterly weak low level steering
over the area through Wednesday, focusing the highest coverage of
T`storms to the I-95 corridor as the Gulf seabreeze progresses
towards the east coast before merging with the pinned Atlantic
seabreeze with locally heavy rainfall, frequent lightning, and
strong wind gusts from wet downbursts. By Thursday, Bermuda high
pressure surface ridge axis will nudge into central FL and then
into the area Friday which will allow the best focus to T`storms
away from the coast as the Atlantic seabreeze pushes farther inland
before merging with the Gulf seabreeze.

Temperatures will begin the period near normal Tuesday with highs
in the lower 90s and and then warm to above normal the rest of the
week as highs inland reach the mid 90s with isolated upper 90s
possible and heat advisories may return midweek. Lows will be a
little above normal in the low to mid 70s inland and the upper 70s
to near 80 at the immediate coast and St Johns river basin.

&&

.AVIATION...
(12Z TAFS)
Issued at 629 AM EDT Sat Jul 6 2024

VFR conditions Today and Tonight. East coast sea breeze will move
inland during the afternoon. It will produce a few SHRA/TSRA
during the mid and late afternoon hours, with more numerous
SHRA/TSRA expected interior section of NE FL around KGNV by late
afternoon as east coast and west coast sea breezes merge there.
Convection will gradually decrease after 00z. Light S to SW wind
will shift to SE 5-10 kts this afternoon where sea breeze passes
through.

&&

.MARINE...
Issued at 304 AM EDT Sat Jul 6 2024

A surface front will linger across Georgia through mid-week next
week with surface high pressure across the Florida peninsula.
Daily sea breezes and an increase in mainly afternoon and evening
thunderstorms are expected.

Rip Currents: Rip current assessments from near shore buoys
continued to indicate a solid Moderate risk for today for NE FL
and SE GA beaches with a continued ESE swell down to 0.5-1.5 ft
with periods 9-10 seconds. A moderate rip current risk is expected
Sunday.

&&

.CLIMATE...
Issued at 304 AM EDT Sat Jul 6 2024

Above average temperatures continue today, then high temperatures
begin to cool as storminess increases over the area starting
Sunday. Today, record high minimum temperatures could be
challenged.

July 6:
KJAX: 79/1902
KGNV: 78/1900

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  95  75  93  74 /  70  70  70  50
SSI  92  80  91  79 /  20  10  40  30
JAX  96  76  94  76 /  20  20  60  40
SGJ  93  77  93  77 /  10  10  50  30
GNV  93  75  94  74 /  60  60  60  40
OCF  95  76  95  76 /  60  50  60  30

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Heat Advisory from 11 AM this morning to 7 PM EDT this evening
     for FLZ021-023-030-031-035-120-136-220-236-322-422-522.

GA...Heat Advisory from 11 AM this morning to 7 PM EDT this evening
     for GAZ132>136-149-151-152-162-163-250-264-350-364.

AM...None.
&&

$$