Surface high pressure centered over New England will shifted south which continued strong northeasterly flow over the region. A more stable and drier airmass was in place which produced less widespread shower activity moving onshore compared to previous couple of days.
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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.
Surface high pressure centered over New England will shifted south which continued strong northeasterly flow over the region. A more stable and drier airmass was in place which produced less widespread shower activity moving onshore compared to previous couple of days. Gusty northeasterly winds continued with the highest gusts 40-45 mph along the immediate northeast Florida coast. A wind advisory was in effect through the day for coastal northeast Florida.
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 Sep 21, 12:28 PM EST, 8 minutes earlier.
Area Forecast Discussion
National Weather Service Jacksonville FL
128 PM EDT Mon Sep 21 2020
.AVIATION...
[Through 18Z Tuesday]
Stratus moving inland off the Atlantic will lead to periods of
restrictions. Isolated to scattered showers will also be possible.
Winds will remain elevated and gusty this afternoon. Winds will
diminish inland Tonight, but remain elevated through the night along
the coast and into Tuesday. Inland winds will become gusty again
Tuesday morning.
&&
.PREV DISCUSSION [745 AM EDT]...
.NEAR TERM [Through Tonight]...
Surface high pressure centered over New England will shift
southward continuing to funnel cooler and drier air and keep
strong northeasterly flow over the region. With a more stable and
drier airmass, isolated to widely scattered showers will move
onshore and be mainly focused along the northeast Florida coast.
Gusty northeasterly winds continue today with the highest gusts
along the immediate northeast Florida coast where gusts up to 45
mph are possible. A wind advisory will persist into this evening
for coastal northeast Florida. These prolonged onshore winds and
higher than normal tides will also continue moderate coastal
flooding along the Atlantic coast and the St. Johns River basin.
Winds begin to slowly weaken tonight but will remain breezy along
the Atlantic coast. Less cloud cover today will allow temperatures
to warm up slightly with highs in the mid 70s to low 80s. Lows
tonight will dip into the upper 50s across inland southeast
Georgia while breezy onshore winds will keep the Atlantic coast in
the low 70s.
.SHORT TERM [Tuesday Through Wednesday]...
Tuesday...High pressure north of the region will slowly weaken, but
onshore flow will still be strong enough for at least breezy
Northeast winds of 15-25 mph with gusts up to 35 mph at the coast
with scattered showers still possible across coastal NE FL and the
St Johns River Basin through the day, while temps return closer
to seasonable normals with highs in the lower to middle 80s across
NE FL and upper 70s/near 80 degrees across SE GA. Onshore flow
weakens further Tue Night with shower activity coming to an end
and under partly cloudy skies will see cool temps in the upper 50s
across inland SE GA and lower/middle 60s across inland NE FL and
near 70 degree readings along the coast.
Wednesday...Weakening High Pressure over the Carolinas will start
to lift out towards the Northeast and steering flow will become
more East to Southeast and seasonable late Sept conds are expected
with Highs generally in the lower to middle 80s area-wide with
rainfall chances generally 10% or less. Fair skies and seasonable
overnight lows in the 60s inland Wed Night with lower 70s along
the coast and continued mainly dry conditions.
.LONG TERM [Thursday Through Sunday]...
Thursday...High pressure ridge continues to push further offshore and
steering flow becomes southerly and with an increase in moisture
and daytime heating with Max Temps into the mid/upper 80s, a few
isolated showers will be possible.
Fri/Sat/Sun...While most of the moisture from TS Beta will ridge north
of the mid level ridge across the SE US, the SW mid level flow
and SE to S steering flow in the lower levels will return enough
deep moisture across NE FL/SE GA with Precipitable Water Amounts
(PWATs) of 2 inches or more to increase rainfall chances back into
the 40-70% each day with scattered to numerous showers and
possible storms, depending on the intensity of mid level
disturbances that track across the region this period. Long-range
models not having great consensus on timing or intensity of these
features, but overall a wetter pattern is expected to develop for
the weekend across the region.
.MARINE...
Gale Warning for all adjacent marine waters continues today with
sustained Northeast Winds at 25 to 30 knots with frequent gusts to
gale force and seas in the 10-15 feet range. Winds and waves begin
to subside on Tuesday into Wednesday as high pressure weakens and
the pressure gradient loosens over the coastal waters.
Surf/Rip Currents: High Surf/High Risk of Rip Currents still on
track through Tuesday. Surf/breakers in the 8-12 feet range and
significant beach erosion are expected to continue during high
tide cycles today.
Coastal Flood: Current Coastal Flood Warnings for the Atlantic Coast
and St. Johns River basin are on track, with peak total water
rises expected through today's high tides leading to widespread
moderate flooding. Peak tide levels along the Atlantic coast are
expected to peak in the 2.5-3 ft MHHW range with isolated levels
up to 3.5 ft MHHW possible. The St. Johns River basin is expected
to peak in the Moderate flood stage around 1.5-2.5 ft MHHW.
Coastal Flooding will continue into Tuesday, with a gradual
decrease in peak tidal levels as strength of onshore flow
weakens.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 57 77 58 78 63 / 0 10 0 0 10
SSI 68 77 65 79 70 / 10 10 0 0 10
JAX 69 80 65 82 68 / 20 10 0 10 10
SGJ 71 81 69 83 71 / 40 20 10 10 10
GNV 68 81 64 84 67 / 20 10 0 10 10
OCF 69 83 66 85 68 / 20 20 0 10 10
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Coastal Flood Warning until 6 PM EDT this evening for Clay-
Coastal Duval-Coastal Flagler-Coastal Nassau-Coastal St.
Johns-Inland Duval-Inland Flagler-Inland St. Johns-Putnam.
High Rip Current Risk through Tuesday morning for Coastal Duval-
Coastal Flagler-Coastal Nassau-Coastal St. Johns.
High Surf Advisory until 8 AM EDT Tuesday for Coastal Duval-
Coastal Flagler-Coastal Nassau-Coastal St. Johns.
Wind Advisory until 8 PM EDT this evening for Coastal Duval-
Coastal Flagler-Coastal Nassau-Coastal St. Johns.
GA...Coastal Flood Warning until 6 PM EDT this evening for Coastal
Camden-Coastal Glynn.
High Rip Current Risk through Tuesday morning for Coastal Camden-
Coastal Glynn.
High Surf Advisory until 8 AM EDT Tuesday for Coastal Camden-
Coastal Glynn.
AM...Gale Warning until 6 PM EDT this evening for Coastal waters from
Altamaha Sound to Fernandina Beach FL out 20 NM-Coastal
waters from Fernandina Beach to St. Augustine FL out 20 NM-
Coastal waters from St. Augustine to Flagler Beach FL out
20 NM-Waters from Altamaha Sound GA to Fernandina Beach FL
from 20 to 60 NM-Waters from Fernandina Beach to St.
Augustine FL from 20 to 60 NM-Waters from St. Augustine to
Flagler Beach FL from 20 to 60 NM.
&&The national radar mosaic for the moment the first event began.
2 coastal flood, 1 astronomical low tide. Local standard time, as filed.
The NOS tide gauge at Fernandina Beach measured a peak high tide of 2.75 ft MHHW datum. This value was within the moderate flood category for the site.
At 1300, a NWS employee reported River Road along Riverfront Park and near Landon Park including portions of San Marco Ave. were flooded in the Riverside area of Jacksonville. Wakes from vehicles driving through the tidal flooding impacted some structures. At 1345, a NWS employee reported that Palm Ave and Cedar Street hade tidal flooding across the streets. At 1430, a NWS employee reported street flooding along South Shores Road and Guilford Road in the South Hampton neighborhood of Jacksonville along the east bank of the St. Johns river, just east of downtown Jacksonville. Several drainage canals between properties were over bank-full. Water levels at the time of the observation were about 2 ft lower than when Hurricane Irma surge impacted the neighborhood in 2017 and caused major flooding. At 1436, the tide gauge at the Mainstreet Bridge in downtown Jacksonville measured a total water rise of 2.02 ft MHHW datum. This was within the moderate flood category for this site. Also around 1436, a NWS employee reported that near the Marsh Hammock area just north of J. Turner Blvd and east of San Pablo Blvd there was total water rise of 2.5 ft MHHW datum. Yards and docks were flooded. At 1445, a NWS survey reported that Pottsburg Creek was well out of bank-full and flooded the parking lot at the boat ramp. Flood water was up to the side of a sporting goods store in the parking lot. At 1515, the public reported tidal flooding along Lakeside Drive in the Ortega River area around high tide. Water covered the property and surrounding area along the 4300 block of Lakeside Drive.
At 1800, Emergency Management reported tidal flooding between 19th and 25th streets in South Flagler Beach. Flood water threatened structures. Water was also reported over the road in North Flagler Beach between North 5th and 6th Streets. Tidal flooding impacted western Beverly Beach and also spilled over canals in Palm Coast and the Hammocks. Water flooded into garages, but there were no reports of intrusion into living spaces. Minor flooding was reported on Dead Lake at the Fish Camp in the afternoon. High water covered the boat ramp and docks, but structures were not flooded. Also on this date, major beach erosion was reported along the coast.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Florida in 2020Every state in 2020This day in weather historyWarnings in Florida, September 2020
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: 921719, 921718, 921721.