316
FXUS62 KJAX 191745
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
145 PM EDT Fri Jul 19 2024

...New AVIATION...

.UPDATE...
Issued at 900 AM EDT Fri Jul 19 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

Another day of SW steering flow with plenty of deep layer moisture
to fuel numerous afternoon showers and storms as the airmass
becomes more unstable into the afternoon. Morning Gulf Coast
showers and storms will expand inland and increase in coverage and
intensity into the afternoon, with additional convection
developing near the slowly inland progressing east coast sea
breeze which will near the I-95 corridor and St. Johns River basin
in the late afternoon. Additional storms are expected across our
inland SE GA zones into the afternoon as another weak short wave
trough passes over the area from the west.

Morning cloudiness across inland SE GA and parts of NE FL near
I-10 will delay heating a little bit and create differential
heating boundaries to the north and south of the mid cloud deck.
These boundaries ultimately will serve as additional convective
foci into the afternoon as sea breezes move inland. The best
coverage of storms is once again expected toward the I-95 corridor
and St. Johns River basin into north-central FL where boundary
collisions will focus this afternoon and into the evening.

The main isolated strong to severe storm hazards today continue
to be gusty wet downbursts of 40-60 mph and a localized flooding
rainfall threat due to deluges under collapsing storm cores. The
12z JAX RAOB continued to show cooler than normal mid level temps
with 500 mb values around -8degC with stronger WSW upper level
flow around 15-20 kts and PWAT still above 2 inches. Given the
nudge upward in anvil levels winds, some small hail is possible
today.

Max temps will near the low-mid 90s mainly near the I-95 and St.
Johns River corridor toward the Atlantic coast before convection
tempers heat. Heat index values will top out near 105 deg for most
locations.

SW flow will push convection offshore into the evening, with dry
conditions expected by midnight through sunrise Saturday morning.
A rouge shower may drift inland toward sunrise across portions of
the Suwannee River Valley as convection begins to nudge inland
from the Gulf Coast region Saturday morning. Mild low temperatures
will range in the low/mid 70s inland to upper 70s toward the
coast.

&&

.NEAR TERM...
(Today and Tonight)
Issued at 233 AM EDT Fri Jul 19 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

Southwest steering flow at the surface and in the mid levels
combined with atmospheric PWATs around 2 inches will continue a
near repeat of conditions from yesterday as late morning/early
afternoon convection over inland areas that will track East to
Northeast at 10-20 mph and reach the East Coast sea breeze that
should reach into the US 17 to US 301 corridors in the mid/late
afternoon hours and expect this convergence to trigger numerous
showers and storms with strong/gusty winds to 50 mph along with
heavy rainfall/localized flooding and frequent lightning. This
activity should then continue at strong levels as it pushes E-NE
through the Atlantic Coastal Counties/I-95 corridor through the
early evening hours and into the Atlantic Coastal waters around
sunset, with convection fading towards the late evening hours and
ending by midnight. Timing of the onset of convection will
determine eventual daytime Max temps, but overall expect
widespread lower to middle 90s inland and around 90F at the
Atlantic beaches and these combined with dewpoints into the middle
70s should push heat indices into the 104-108F range, likely just
below Heat Advisory levels at this time. Overnight lows in the 70s
over inland areas and near 80F at the Atlantic beaches.

&&

.SHORT TERM...
(Saturday through Sunday night)
Issued at 233 AM EDT Fri Jul 19 2024

A mostly southerly flow through the weekend as high pressure sits
to the east of the region, allowing for the sea breezes to
venture inland. PWATs hovering around the 2" range, will see
enough moisture for convection to develop along the sea breezes.
Saturday, the higher chances for any convective development, will
likely begin along the I-75 corridor and US-301 during the early
afternoon and spread eastward towards the I-95 corridor by the
late afternoon to early evening. The same pattern will look to
continue on Sunday as well.

Early afternoon showers will keep temperatures in check in the
lower to mid 90s. Heat index values currently expected to stay
just below criteria for heat advisory at this time for the
weekend, but higher values will be expected along the coast.

&&

.LONG TERM...
(Monday through Thursday)
Issued at 233 AM EDT Fri Jul 19 2024

The high pressure will still be present at the start of the period
to the east of the region, with a northeast shift beginning
sometime late Tuesday into Wednesday. We can expect to see the
same pattern of afternoon showers and storms for the first two
days of the upcoming week as moisture moves in from the SE keeping
PWAT values hovering near the 2" mark. As the high pressure shifts
towards the NE, precipitation chances will dip a bit as some dry
air moves into the area, but still likely will see the daily
shower and storm activity along the sea breezes. Temperatures will
trend near to above normal with highs in the low-mid 90s and lows
in the 70s.

&&

.AVIATION...
(18Z TAFS)
Issued at 142 PM EDT Fri Jul 19 2024

Mid cloud deck delayed onset of developing by 1-2 hours this
afternoon and adjusted TEMPO groups slightly. Storms firing west
of the terminals will continue to approach through late afternoon
under SW steering flow, with high rainfall chances (over 60%) for
all terminals into the evening as sea breezes and boundaries
coverage. TEMPO groups for all terminals continue to advertise
MVFR restrictions and gusty winds VRB 30kts. Stronger winds and
IFR conditions possible in heavier TS activity, with AMDs likely
later this afternoon based on convective trends.

Convection will press offshore of the Atlantic coast the 00-02Z
time frame with lingering VFR convective debris clouds overnight
and light SSW winds at coastal terminals after 06z (< 6 kts) to
calm winds inland. Shallow ground fog/mist possible after 07z
Saturday where heavy rainfall recently occurred, but confidence
not high enough to include in TAFs and only have 6SM for GNV and
VQQ at this time. After daybreak Saturday, light SSW winds will
develop with prevailing VFR conditions until the onset of
convection into the afternoon once again nearing GNV first from
the west.


&&

.MARINE...
Issued at 233 AM EDT Fri Jul 19 2024

No headlines expected over the next 5 days as high pressure ridge
from the Western Atlantic will be across or just south of the
local waters through early next week. This will continue a general
south to southwest flow through the period at 10-15 knots with
seas 2-4 ft, along with daily sea breeze along the local beaches
from the Southeast. A few evening/nocturnal southerly wind surges
could briefly reach into the 15-20 knot range, but not likely to
last long enough to warrant any headlines. Main impacts will be
offshore moving storms during the afternoon and evening hours with
strong/gusty winds to 30-40 knots, heavy rainfall and dangerous
lightning.

Rip Currents: Low to moderate risk of rip currents will continue
through the weekend as mainly south to southwest flow becomes
briefly onshore Southeasterly during the afternoon hours at the
local beaches with surf/breakers around 2 ft.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  72  93  74  93 /  50  60  30  70
SSI  78  90  78  90 /  70  60  40  70
JAX  75  93  76  93 /  50  80  30  70
SGJ  77  93  76  92 /  60  70  20  60
GNV  73  93  74  93 /  50  80  20  80
OCF  74  93  75  93 /  60  80  20  80

&&

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

$$