795
FXUS62 KJAX 081632
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
1232 PM EDT Wed May 8 2024

...NEAR RECORD HIGHS CONTINUE THROUGH THURSDAY...
...SQUALL LINE OF STRONG TO SEVERE THUNDERSTORMS POSSIBLE ON
THURSDAY AFTERNOON AND EVENING FOR LOCATIONS NORTH OF I-10...
...STRONG TO ISOLATED SEVERE STORMS POSSIBLE ON FRIDAY...

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

.UPDATE...
Issued at 1232 PM EDT Wed May 8 2024

Early afternoon surface analysis depicts Atlantic high pressure
(1018 millibars) centered to the south of Bermuda, with this
feature extending its axis westward across the FL peninsula.
Meanwhile, a wavy surface front extends from New England and the
Mid-Atlantic states westward across the Great Lakes states and
then southwestward across the Ohio and Tennessee Valleys, the
Ozarks, Southern Plains, and Desert Southwest. Aloft...ridging
centered over the Bay of Campeche (southwestern Gulf of Mexico)
continues to build northeastward across the Gulf of Mexico and
along the southeastern seaboard. Otherwise, a blocking pattern was
in place over the Rockies and Plains states, while a potent
shortwave trough was progressing east-southeastward across eastern
portions of the Great Lakes. Low stratus cloud cover over inland
portions of southeast GA early this morning has since lifted to a
healthy cumulus field, while mid-level cloud cover earlier this
morning that was pushing across north central and portions of
northeast FL have dissipated, leaving behind fair skies with
pockets of mainly flat cumulus cloud cover. Temperatures at the
noon hour were climbing through the mid and upper 80s at most
locations, with dewpoints generally in the mid 60s to lower 70s.

The blocking pattern aloft currently in place across the Rockies
and Plains states will retrograde westward on Thursday and
Friday, allowing for a potent shortwave trough currently near
Hudson Bay, Canada to dive southward across the Great Lakes region
by Thursday afternoon and night. This digging shortwave trough
will flatten ridging in place across the Gulf of Mexico and the
southeastern seaboard, allowing for a more zonal flow pattern to
develop across the southeastern states by Thursday afternoon and
night. A dry, hot, and subsident air mass will remain in place
locally until this ridging begins to flatten, with breezy west-
southwesterly winds boosting highs to near daily record highs (see
Climate section below) this afternoon for inland locations west of
I-95, where temperatures will climb to the low and mid 90s, with a
few upper 90s possible across north central FL. The Atlantic sea
breeze will develop along the coast during the early to mid
afternoon hours, keeping coastal highs closer to 90. Dewpoints
falling through the 60s this afternoon will keep Heat Index values
generally in the 95-100 range at inland locations, except for
north central FL, where values may top out just above 100 this
afternoon.

Breezy southwesterly winds in the boundary later overnight will
likely advect another stratus layer inland from the northeast Gulf
of Mexico across the Suwannee Valley and inland southeast GA after
midnight, with this stratus layer then potentially shifting
eastward across U.S. Highway 301 during the predawn hours. Lows
tonight will only fall to the upper 60s and lower 70s area-wide.

As ridging aloft flattens on Thursday in response to the potent
shortwave trough digging across the Great Lakes region,
strengthening westerly flow aloft will begin to advect shortwave
energy across the Deep South. Meanwhile, a 110-knot jet streak at
250 millibars (around 35,000 feet) at the base of this digging
shortwave trough will traverse the Ohio and Tennessee Valleys
during the late afternoon and evening hours. In addition, a 40-50
knot low level southwesterly jet at 850 millibars (around 5,000
feet) will develop across south central and southeast GA during
the afternoon and evening hours on Thursday. Strengthening winds
aloft and steep low and mid level lapse rates could propel a
squall line of strong to severe thunderstorms ahead of a cold
front that will be entering the southeastern states, with short-
term, high resolution guidance suggesting that this line may
traverse southeast GA during the afternoon hours, potentially
approaching I-95 towards or just after sunset. The Storm
Prediction Center has placed these areas within a Slight Risk
(level 2 out of 5) for severe thunderstorm development, with
damaging wind gusts, hail, and isolated tornadoes possible within
severe thunderstorms that develop along this potential squall
line that could impact our area (especially for locations along
and north of I-10) on Thursday afternoon and evening. Breezy
west-southwesterly winds will likely delay the development of the
Atlantic sea breeze on Thursday, allowing near record heat to
extend all the way to coastal locations, with low to mid 90s
forecast for much of our area on Thursday afternoon before
thunderstorm activity potentially increases.

&&

.AVIATION...
(12Z TAFS)
Issued at 629 AM EDT Wed May 8 2024

Southwest flow off the Gulf bringing in low cloud decks and
MVFR/IFR fog at GNV/VQQ is expected to disperse before 13z. Winds
will build from out of the SW this afternoon with the SE diurnal
sea breeze remaining pinned close to the coast. Winds will become
more mild for sites during the overnight hours and into early
Thursday morning.

&&

.MARINE...
Issued at 1232 PM EDT Wed May 8 2024

Atlantic high pressure will continue to extend its axis westward
across the Florida peninsula through Thursday night. Southerly
evening wind surges are expected this evening and again on
Thursday evening, bringing wind speeds up to Caution levels of 15
to 20 knots for the offshore waters. Seas of 2-4 feet will prevail
through Thursday night for the near shore waters, with 3-5 foot
seas prevailing offshore.

Meanwhile, a strong cold front will enter the southeastern states
on Thursday night, with chances for showers and thunderstorms
increasing ahead of this boundary from Thursday afternoon through
Friday evening. A few rounds of strong to severe thunderstorms
will be possible during this time frame, with damaging wind gusts,
hail, and frequent lightning strikes possible within any severe
thunderstorms that develop. The cold front will cross our local
waters on Friday afternoon and evening, with high pressure then
gradually building to the north of our area later this weekend and
early next week in the wake of this frontal passage, resulting in
prevailing onshore winds during this time period. Seas of 2-4 feet
will prevail both near shore and offshore from Friday through the
weekend.

Rip Currents: Breezy onshore winds developing this afternoon and
again on Thursday afternoon will combine with a northeasterly
ocean swell to create a moderate rip current risk at all area
beaches on both afternoons. Breezy offshore winds on Friday should
reduce the risk to low at all area beaches.

&&

.FIRE WEATHER...
Issued at 1232 PM EDT Wed May 8 2024

Southwesterly transport winds will become breezy at most inland
locations this afternoon, with breezy onshore surface winds
expected to develop by the mid-afternoon hours at coastal
locations as the Atlantic sea breeze boundary moves slowly inland.
Breezy transport winds will combine with elevated mixing heights
to create high daytime dispersion values for locations along the
U.S. Highway 301 corridor, with good dispersion values expected
elsewhere. Southwesterly transport winds will strengthen further
on Thursday, creating high daytime dispersion values for most
locations east of the Interstate 75 corridor during the
afternoon hours. Otherwise, a hot and dry air mass over our region
will result in minimum relative humidity values falling to around
35 percent at most inland locations this afternoon, with minimum
values again around 35 percent forecast for most locations east of
I-75 on Thursday afternoon. Strong west-southwesterly transport
winds on Friday will again create good to marginally high daytime
dispersion values, except for high values across portions of north
central FL. A few rounds of strong to severe thunderstorms will
be possible from Thursday afternoon through Friday evening, with
damaging wind gusts, hail, and frequent lightning strikes possible
within any severe thunderstorms that develop.

&&

.CLIMATE...
Issued at 1232 PM EDT Wed May 8 2024

Daily record Maximum Temperatures at the local climate sites for...

Today, May 8th...JAX 96/1959...CRG 93/1977...GNV 97/1955...AMG 95/1962

Thursday, May 9th...JAX 96/1962...CRG 93/2008...GNV 95/2011...AMG 95/1962

Friday, May 10th...JAX 94/2017...CRG 95/2003...GNV 95/2011...AMG 95/2011

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  91  69  91  71 /   0  10  50  50
SSI  90  74  90  73 /   0   0  50  60
JAX  95  70  95  73 /   0   0  20  30
SGJ  90  73  94  73 /   0   0  10  20
GNV  95  70  93  72 /   0   0  10  20
OCF  96  71  93  72 /   0   0  10  10

&&

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

$$