A meandering front, very high moisture and diurnal heating combined with sea breezes triggered locally heavy rainfall across inland areas. Very weak storm motion produced slow moving, heavy rainfall producing storms.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS JAX wrote it up.
A meandering front, very high moisture and diurnal heating combined with sea breezes triggered locally heavy rainfall across inland areas. Very weak storm motion produced slow moving, heavy rainfall producing storms.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Jacksonville, FL wrote its last area forecast discussion before the first event at Aug 26, 1:27 PM EST, 2 hours 13 minutes earlier.
Area Forecast Discussion
National Weather Service Jacksonville FL
227 PM EDT Mon Aug 26 2024
...LATE AFTERNOON AND EARLY EVENING STORMS FOCUS ALONG THE I-75
CORRIDOR THROUGH TUESDAY...
...DRY AND HOT WEATHER EXPECTED ALONG AND NORTH OF I-10 ON
WEDNESDAY AND THURSDAY...
For the latest NE FL and SE GA Daily Key Messages please visit:
https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf
.SYNOPSIS...
Issued at 226 PM EDT Mon Aug 26 2024
Afternoon surface analysis depicts troughing progressing west-
northwestward across our region. Meanwhile, high pressure (1025
millibars) was centered over the southern Appalachians.
Aloft...ridging blanketing the Midwest was gradually building
towards the southeastern states, while stubborn troughing remains
in place over New England and the Mid-Atlantic states. Latest
GOES-East derived Total Precipitable Water imagery indicates that
deep tropical moisture, featuring PWATS of around 2 inches,
remains in place for locations south and east of Waycross, while a
slightly drier air mass persists for the rest of inland southeast
GA, where PWATs were generally in the 1.7 - 1.9 inch range.
Slow moving showers and thunderstorms have been more prevalent
for locations along and west of I-95 in southeast GA, as well as
across north central FL, while coverage along the inland moving
Atlantic sea breeze boundary has decreased in coverage since the
late morning hours. Temperatures at 18Z have risen to the mid and
upper 80s at most locations that have not received rainfall thus
far, with dewpoints in the 70s area-wide.
&&
.NEAR TERM...
(through Tonight)
Issued at 226 PM EDT Mon Aug 26 2024
The Atlantic sea breeze boundary and the retrograding surface
trough will ignite and increase coverage of convection by the mid
to late afternoon along and west of the U.S. Highway 301 corridor.
Convection will continue to migrate westward across the I-75
corridor by sunset. The main hazards with this activity today will
be flooding from slow moving downpours moving across saturated
soil conditions that prevail for most of our region. Slow moving
downpours will be capable of producing 1-2 inch rainfall amounts
within an hour, with localized amounts of 3-4 inches possible
where downpours train repeatedly over the same locations. A drying
trend will take shape for locations along and east of U.S.-301 by
late afternoon, followed by convection exiting to the west of the
Suwannee River shortly after sunset. This weather pattern should
allow the Flood Watch across coastal southeast GA and northeast FL
to expire early this evening.
Persistent onshore winds could develop a few coastal showers
overnight. Otherwise, fog and low stratus ceilings are expected to
develop beneath the slightly drier and increasingly subsident air
mass across inland southeast GA overnight, with fog developing
further south for the Suwannee Valley towards sunrise. Lows
tonight will remain in the 70s area-wide.
&&
.SHORT TERM...
(Tuesday through Wednesday night)
Issued at 226 PM EDT Mon Aug 26 2024
Lower precipitation chances as the stalled frontal boundary from
the past few days begins to clear to the south of the area with
high pressure aloft building over the eastern CONUS. With the high
pressure, drier air (PWATs ~1.5") will begin to spread into the
area on Tuesday, lowering PoPs for SE GA and most of NE FL into
the 20% to 40% range for most locations. Late afternoon and
evening storms will be possible to develop along the I-75 corridor
Tuesday as the easterly flow will again bring the Atlantic
seabreeze well inland and meet with the Gulf sea breeze.
By Wednesday, with the frontal boundary to the south of the area,
dry air brought in with the high pressure will begin to limit
shower and thunderstorm development past midweek heading into the
end of the week.
Daytime highs in the lower 90s for inland locations with cooler
highs along coastal locations thanks to continuing onshore flow on
Tuesday and Wednesday. Overnight lows will hover near the mid 70s
for inland locations with upper 70s along coastal locations.
&&
.LONG TERM...
(Thursday through next Monday)
Issued at 226 PM EDT Mon Aug 26 2024
Dry air will remain over the area on Thursday and Friday as the
high pressure sits over the eastern CONUS, limiting the chances
for showers and storms for most of the area, save for north
central Florida counties. The high pressure will begin to broaden/
weaken, as a trough begins to move through the Florida peninsula
during the weekend, leading to an increase in Precipitation
chances as PWAT values will begin to rebound to about 2". High
temperatures will be near normal through the period along the
coast to around 90 and rise to above normal levels into the low to
mid 90s inland through the end of the week. Lows will remain a
few degrees above normal in the mid to upper 70s along the coast
and near normal in the low 70s inland due to drier air.
&&
.AVIATION...
(18Z TAFS)
Issued at 140 PM EDT Mon Aug 26 2024
Showers have moved west of the SSI and SGJ coastal terminals as
well as CRG, where VFR conditions should prevail through at least
09Z Tuesday. Showers and thunderstorms are expected to increase in
coverage for locations along and west of the U.S. Highway 301
corridor after 19Z, with impacts most likely at GNV, where a TEMPO
group was used from 20Z-00Z for briefly gusty winds and MVFR
conditions during heavier downpours. Confidence was only high
enough for vicinity shower activity at JAX and vicinity
thunderstorm coverage at VQQ, where amendments may become
necessary after 18Z depending on convective coverage. Convection
should then move west of the GNV terminal towards sunset, with
VFR conditions expected to prevail at the regional terminals by
01Z. MVFR to IFR conditions are likely to develop after 06Z at
VQQ and GNV, with MVFR visibilities possible at JAX and CRG after
09Z. MVFR ceilings will likely develop during the mid to late
morning hours on Tuesday at the regional terminals, and a few
showers may move onshore and across the coastal terminals before
16Z. Northeast to easterly surface winds sustained around 10
knots will continue through around sunset, followed by speeds
subsiding to 5 knots at the coastal terminals overnight and less
than 5 knots elsewhere.
&&
.MARINE...
Issued at 226 PM EDT Mon Aug 26 2024
A surface trough will shift to the west of our local waters
tonight as high pressure gradually weakens over the southeastern
states. Scattered showers and a few embedded thunderstorms will
remain possible across our local waters through Wednesday as
generally light onshore winds prevail. High pressure will then
shift off the southeastern seaboard, becoming anchored near
Bermuda later this week. Coverage of showers and thunderstorms
will decrease later this week as winds shift to a southeasterly
direction. Winds should become more southerly during the upcoming
holiday weekend, resulting in a gradual increase in showers and
thunderstorms across our local waters. Seas of 2-3 feet will
prevail both near shore and offshore throughout this week and
into the upcoming weekend.
Rip Currents: Onshore winds will combine with a persistent
easterly ocean swell to create a lower-end moderate risk at all
area beaches through midweek.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 72 91 72 93 / 10 20 0 10
SSI 79 88 77 89 / 20 20 10 10
JAX 75 90 76 91 / 20 30 0 30
SGJ 78 89 77 90 / 20 40 10 30
GNV 74 91 73 93 / 40 50 10 40
OCF 74 93 74 93 / 60 60 10 50
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Flood Watch until 8 PM EDT this evening for FLZ024-124-125-225-
325-425.
GA...Flood Watch until 8 PM EDT this evening for GAZ153-154-165-166.
AM...None.
&&The national radar mosaic for the moment the first event began.
7 heavy rain. Local standard time, as filed.
A personal weather station in the West Park | section of Gainesville measured 2.55 inches | of rainfall which began around 4:40 pm. | Other nearby observations measured 1.6 to | 1.9 inches in the West Hills and Rutledge | sections of town, just east of I-75.
A private weather station along Pathfinder | Lane measured 2.08 inches of rainfall since | around 6:10 pm.
A weather station along SW Gertrudis Drive | measured 3.34 inches of rainfall between | 6:20 pm and 8:30 pm.
The Columbia County Sheriff,s office weather | station measured 3.72 inches of rain between | 6:30 pm and 8:20 pm.
A public weather station along US 90 and at | the intersection of NE McCloskey Avenue | measured 3.18 inches of rain between 6:30 pm | and 8:30 pm.
A private weather station along SE Romeo | Lane measured 3.62 inches of daily rainfall | as of 9:05 pm. Most of the rain fell after | 6:30 through 9 pm.
A cooperative observer measured 2.13 inches | of rainfall in 1 hour.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Florida in 2024Every state in 2024This day in weather historyWarnings in Florida, August 2024
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1203893, 1203894, 1203898, 1203896, 1203897, 1203899, 1203895.