Flood in Florida, September 9 to 13, 2024

Area Forecast Discussion
National Weather Service Jacksonville FL
149 AM EDT Mon Sep 9 2024

...New AVIATION...

.UPDATE...
Issued at 739 PM EDT Sun Sep 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

A frontal boundary will remain stalled across the area Tonight.
Showers and a few embedded thunderstorms will continue to move east
northeast across the area. Skies will remain cloudy with lows
ranging from the mid 60s across interior SE GA, to the middle 70s
along the coast.

&&

.NEAR TERM...
(through Tonight) Issued at 206 PM EDT Sun Sep 8 2024

Shortwave energy embedded within the deep west-southwesterly flow
aloft will trigger an increasing coverage of convection this
afternoon for locations south of the frontal boundary in northeast
and north central FL. Downpours in this warm and exceptionally
humid environment will have the potential to train repeatedly over
the same locations, especially across north central FL and for
locations along the I-95 corridor. Rainfall amounts of 1-2 inches
are expected at these locations through early this evening, with
locally higher totals of 3-4 inches being possible where downpours
repeatedly train over the same locations. Localized flooding will
be the main threat through around sunset, especially at urban and
coastal locations along the I-95 corridor and south of the I-10
corridor. An isolated strong storm or two will be possible across
north central and coastal northeast FL, where cell mergers could
yield a wet microburst that would potentially contain 40-50 mph
winds, along with frequent lightning strikes. Rainfall will
continue to remain largely stratiform and lighter in nature for
locations along and north of the Interstate 1o corridor, although
a few embedded downpours / isolated elevated convection cannot be
ruled out through this evening.

Afternoon and evening convection are expected to wane across
northeast and north central FL before midnight tonight, with
isentropic lift / overrunning keeping chances for light rainfall
and sprinkles in place across southeast GA. Meanwhile, high
pressure building east-southeastward towards the Ohio and
Tennessee Valleys will begin to wedge down the southeastern
seaboard during the overnight and predawn hours, with
strengthening low level convergence potentially developing
convection before sunrise along the southeast GA coast. Locally
heavy downpours could impact the morning commute along the I-95
corridor in southeast GA as northeasterly winds become breezy
towards sunrise. Otherwise, a drier air mass may cross the
Altamaha / Ocmulgee Rivers later tonight, potentially dropping
lows to the upper 60s at inland locations, especially for areas
north of Waycross. Lows elsewhere will generally fall to the low
and mid 70s, with a few upper 70s possible at coastal locations.

&&

.SHORT TERM...
(Monday through Tuesday night)
Issued at 206 PM EDT Sun Sep 8 2024

The stationary front still lingers over North Florida, continuing
the wet weather pattern for Monday. The high pressure slowly
building behind the front will help keep inland southeast Georgia
a little drier, with PWAT values over the area around 1.75 inches.
Northeast Florida, with PWAT values 2 to 2.4 inches, continues to
have high rain chances through the day and into the evening
hours. The main concern for Monday will be excessive rainfall and
embedded thunderstorms that could lead to localized flooding,
frequent lightning and gusty winds. Cloudy skies and continued
rain fall will keep temperatures in the upper 70s to mid 80s with
overnight temperatures in the mid 60s to mid 70s.

Tuesday, high pressure builds behind the front and pushes it south
of the area, bringing some drier air to Southeast Georgia and
concentrating most of the rain just north of US-301 in northeast
Florida. Scattered embedded thunderstorms will be possible along
the front where higher PWAT values and instability exists. High
daytime temperatures will be in the 80s, cooling overnight into
the upper 60s to mid 70s.

&&

.LONG TERM...
(Wednesday through next Sunday)
Issued at 206 PM EDT Sun Sep 8 2024

The stalled boundary stays just south of the area before weakening
and rebounding north at the tail end of the week. however,
unsettled conditions and ample moisture remains in the area for
much of the time period, with high pressure creating onshore winds
and daily sea-breeze convergence. Scattered to numerous showers
are forecast along the coast in the mornings and showers and
thunderstorms each afternoon where sea-breezes meet. Daily high
temperatures will be in the 80s, slowly building back into the
upper 80s to low 90s by the weekend. Overnight temperatures will
be in the low to mid 70s.

&&

.AVIATION...
(06Z TAFS)
Issued at 146 AM EDT Mon Sep 9 2024

Low end MVFR and IFR restrictions expected through mid morning
as light north to northeast flow north of a stalled frontal
boundary allows low stratus to linger through sunrise with tempo
groups for LIFR ceilings 07-11Z at GNV and VQQ. Will keep VCSH
at the duval and coastal TAF sites through sunrise as well. The
front will continue to remain near or south of GNV and SGJ Monday
with showers increasing after 16Z and spreading south and west
from the coast. Have tempo restrictions for thunderstorms and
IFR ceilings/gusty winds through the early afternoon with the
initial wave of convergent showers moving southwest, with another
round of showers and storms prompting tempo groups for low end
MVFR ceilings through the reminder of the afternoon.

Light northeast to northerly winds at the coast around 5 knots
and variabel inland through sunrise. Monday, winds will become
breezy at SSI around 15 knots with gusts to 20-25 knots with less
breezy winds around 10 knots at JAX/CRG/SGJ/VQQ as high pressure
wedges down the east coast and pinches the gradient over the local
waters north of the front which will sink southward into central
FL by the end of the period. Thunderstorms cease after 00Z with
only VCSH coverage to end the period.

&&

.MARINE...
Issued at 1214 PM EDT Sun Sep 8 2024

Showers and thunderstorms will continue across our local waters
through this evening due to a stalled frontal boundary that is
situated across the northeast Florida waters. Seas of 3-5 feet
will prevail both near shore and offshore through tonight.
Meanwhile, high pressure building towards the Ohio and Tennessee
Valleys in the wake of this frontal boundary today will begin to
wedge down the southeastern seaboard on Monday, resulting in
strengthening northeasterly winds across the Georgia waters by the
afternoon hours, where wind speeds may increase to Small Craft
Advisory levels of around 20 knots. Seas will build to Caution
levels of 4-6 feet across the Georgia waters by Monday afternoon,
with seas remaining in the 3-5 foot range for the northeast FL
waters.

High pressure center will then pivot towards the Mid-Atlantic
coast by Tuesday and Wednesday as it strengthens slightly, likely
resulting in strengthening onshore winds for the northeast Florida
waters by Tuesday, where Small Craft Advisory conditions may
develop. Waves of showers and thunderstorms will continue through
the week as the stalled frontal boundary begins to lift northward
late this week. Otherwise, winds will likely shift to
southeasterly late this week as a developing tropical cyclone over
the southwestern Gulf of Mexico lifts northward towards the upper
Texas or Louisiana coasts.

Rip Currents: Onshore winds will combine with a northeasterly
ocean swell to create a moderate rip current risk at all area
beaches today. Strengthening northeasterly winds and building seas
on Monday may create a high risk at the southeast GA beaches,
with a higher end moderate risk currently anticipated at the
northeast FL beaches. Persistent onshore winds and rough surf will
likely result in a high risk at all area beaches from Tuesday
through at least Wednesday, possibly extending through week's end.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  80  67  83  69 /  40  10  10  10
SSI  82  74  83  75 /  60  40  40  40
JAX  83  73  84  74 /  80  50  70  50
SGJ  84  75  85  75 /  80  60  70  50
GNV  83  72  85  72 /  80  20  70  20
OCF  86  74  87  74 /  80  20  80  20

&&

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