608
FXUS62 KJAX 081233
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
833 AM EDT Mon Jul 8 2024

...New UPDATE...

.UPDATE...
Issued at 833 AM EDT Mon Jul 8 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

No significant changes planned in forecast update. Will maintain
heat advisory for this afternoon, although heat index values might
not get to criteria if dew points mix down slightly into the mid
70s...some locations might briefly get near criteria before then.
Expecting greatest storm coverage this afternoon to be over Hwy
301 corridor down toward the GNV area...maintaining highest POP
values there. Activity could continue into the evening while
gradually diminishing.

&&

.NEAR TERM...
Issued at 337 AM EDT Mon Jul 8 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

Today, above average moisture levels are in place (PWATs above the
90th percentile ranging 2.25 to 2.40 inches) as a weak frontal
boundary remains just north of the area from northern AL/GA into
eastern NC. A weak pressure pattern expected as Bermuda surface
high pressure ridging which had been over the area yesterday will
begin to reform into south FL as an upper level trough approaches
slowly from the east. This will allow for more south to SW low
level steering flow over the area today and pin the Atlantic
seabreeze closer to I-95 by mid afternoon while the Gulf seabreeze
moves inland towards highway 301 with numerous showers and T`storms
developing due to the combination of strong diurnal instability,
above average moisture levels, and lift along the seabreezes.
The best focus for strong T`storms will be between highway 301
and I-95 with gusty wet downburst winds 40-50 mph, with low
chances for any severe potential today as mid level temperatures
of -6 C are still a little warmer than the average of -7 C.
Locally heavy rainfall totals also expected east of highway 301
towards the coast with very efficient rainfall rates and slow
T`storm motions producing 1-3 inch totals with isolated 4 inch
amounts possible with a Marginal Risk (about 5%) of Excessive
rainfall, or risk of exceeding flash flood guidance, in place
by the Weather Prediction Center for a majority of the area today.

Highs will be in the mid 90s for much of the area away from the
coastline with lower 90s at the beaches. Peak heat index values
will reach heat advisory levels over 108 degrees up to about 111
degrees for all of NE FL and for portions of SE GA generally along
and south of US 82 including Brunswick, St Simons Island, and also
Waycross. Therefore, a heat advisory will go into effect from 11AM
this morning until 7PM, with cooling outflow boundaries potentially
providing relief a bit earlier as T`storms develop. Northern
portions of SE GA will see heat index values 104-107 degrees.

Tonight, convection will fade by around midnight due to the loss
of heating and outflow boundaries exhausting remaining instability
with mostly cloudy skies as debris clouds linger. Lows will be in
the middle to upper 70s for most areas. Some patchy, shallow ground
fog is possible over locations that receive locally heavy
rainfall.

&&

.SHORT TERM...
(Tuesday through Wednesday night)
Issued at 337 AM EDT Mon Jul 8 2024

High pressure continues to dominate the region with a synoptic
west-southwesterly flow pattern pinning the Atlantic/east coast sea
breeze pretty close to the coast. Convection will develop early
over the Gulf/Apalachee Bay and will race east. Meanwhile,
convection that develops along the east coast sea breeze will try
to gradually move west but will converge with the Gulf convection.
Convection will train echo/propagate across discrete areas and
with PWATS 2.00+ inches locally heavy convection will develop.
will see a marginal (5%) chance of exceeding flash flood guidance
and flooding is possible especially in urbanized areas. With
broken to overcast cloud coverage highs will be in the upper 80s
to lower 90s. With high RH values will top out with heat index
values in the 105-107F range.

Convection will diminish between 11 p.m. and 2 a.m. Some patchy Fog
is possible over the interior areas.

On Wednesday a low level trough sets up over the upper Gulf coast
with more of a westerly flow advecting moisture across the
region. Convection will move across the region almost all day with
the east coast sea breeze once again pinned along the coast. Once
again will be looking at a Marginal risk of flooding. High
temperatures will once again be in the upper 80s to lower 90s with
Heat Index values of 105-108F.

Wednesday night`s convection will be slow to diminish with some
activity continuing until well after midnight. overnight lows will
be in the mid 70s with high relative humidity values overnight
leading to sticky conditions.

&&

.LONG TERM...
(Thursday through Sunday)
Issued at 337 AM EDT Mon Jul 8 2024

A frontal system drops down to be along the FL-GA state Line for
much of the period and will be the focusing mechanism for
widespread convection each day and scattered convection overnight.
Total precipitation along the east coast counties could be in the
3 to 5 inch range by Sunday night with PWATS remaining 2.00+
inches. Other than areas where the rainfall rates overwhelm the
drainage systems a lot of the east coast areas can use the
rainfall as the strong sea breeze has blocked convection from
getting back to a lot of those coastal areas. Temperatures remain
the same into late week with highs in the mid 90s over the
weekend.

&&

.AVIATION...
(12Z TAFS)
Issued at 708 AM EDT Mon Jul 8 2024

VFR conditions expected Today and Tonight with mid level clouds
this morning and cumulus late morning through afternoon. Scattered
SHRA/TSRA midday will become more numerous as the afternoon
progresses, continuing into the evening while gradually
decreasing. Locally lower CIGs and gusty winds expected with
stronger storms. Surface winds will be light S to SW, becoming SE
5-10kts with passage of east coast sea breeze this afternoon
except at KGNV.

&&

.MARINE...
Issued at 337 AM EDT Mon Jul 8 2024

A weak front will lay to the north through the middle of the week
as high pressure ridging aloft remains across the area. The remnant
low pressure of Hurricane Beryl will move along the boundary and
the accelerate it southward toward the waters toward the end of
the work week. Daily afternoon storms are possible with the sea
breeze development with increasing thunderstorm potential over the
local waters from midweek onward as the front approaches the waters.

Rip Currents: Moderate risk of rip currents are expected for all
area beaches today with a low risk expected on Tuesday due to more
prevailing offshore flow.  |

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  94  77  90  76 /  60  50  80  20
SSI  91  78  89  79 /  50  50  90  50
JAX  94  77  90  77 /  70  60  90  50
SGJ  94  76  89  78 /  50  50  90  60
GNV  94  75  85  76 /  70  50  90  40
OCF  94  76  86  76 /  70  50  90  40

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Heat Advisory until 7 PM EDT this evening for FLZ021-023-024-030-
     031-033-035-038-120-124-125-132-133-136>138-140-220-225-232-
     236-237-240-322-325-340-422-425-522.

GA...Heat Advisory until 7 PM EDT this evening for GAZ152>154-162-163-
     165-166-250-264-350-364.

AM...None.
&&

$$