Coastal Flood in Florida, September 20, 2020

Name: Coastal Flood in Florida, September 20, 2020
Start: 2020-09-20T10:58
End: 2020-09-20T17:30
Location: Florida

September 20, 2020 · NWS JAX · 4 events in 4 counties and zones

Where it happened

Every event with a place to put it; 2 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 4

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.

What happened

The episode as NWS JAX wrote it up.

A strong NE Flow event peaked across the local area with sustained winds along the coast in the 25-35 mph range and observed gusts of 40-50 mph with the highest values along the NE FL coast. A wind advisory was issued. The combination of the strong onshore flow and seasonally high King Tides produced widespread moderate coastal flooding around high tides.

What forecasters said that day

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 20, 9:56 AM EST, 1 hour 2 minutes earlier.

Area forecast discussion, Sep 20, 9:56 AM EST, 1 hour 2 minutes before

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The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

4 coastal flood. Local standard time, as filed.

Coastal Flood, Coastal St. Johns

When: September 20, 10:58 AM EST to 5:30 PM EST
Where: Coastal St. Johns forecast zone
Reported by: Official NWS Observations

At 1158, a NWS employee reported a foot of water at the intersection of State Road 16 and Lewis Speedway across the street from the San Sebastian River. At 1226, the Emergency Manager reported significant coastal flooding around the Maria Sanchez Lake in downtown St. Augustine but homes were not impacted at the time. At 1226, a NWS employee reported significant inundation of flood water across several roads in Davis Shores. Water was across the entire roadway at the intersection of Anastasia Blvd and Moultrie (up to 1 ft deep in some areas). At 1830, the tide gauge at Racy Point on the St. Johns River measured a peak high tide of 2.24 ft MHHW datum. This was within the moderate flood category for the site.

Coastal Flood, Coastal Duval

When: September 20, 11:12 AM EST to 12:24 PM EST
Where: Coastal Duval forecast zone
Reported by: Official NWS Observations
Coordinates: 30.335, -81.648 (the zone’s center; the record gives no point)

At 1212, the tide gauge at Mayport measured a peak high tide of 2.44 ft MHHW datum. This was within the moderate flood level for this location. At 1324, the tide gauge at the Main Street bridge along the St. Johns River in downtown Jacksonville measured a peak high tide of 1.84 ft MHHW datum. This values was within the minor flood stage for this location.

Coastal Flood, Coastal Flagler

When: September 20, 12:40 PM EST to 2:24 PM EST
Where: Coastal Flagler forecast zone
Reported by: Emergency Manager
Coordinates: 29.471, -81.293 (the zone’s center; the record gives no point)

At 1340, Emergency Management reported canals in Palm Coast were above the bulkheads. At 1515, Emergency Management reported tidal flood water covered Flagler Avenue at 23rd Street in Flagler Beach. At 1524, the tide gauge at Bings Landing on the Matanzas River measured a high tide of 2.87 ft MHHW datum. This value fell within the Moderate flood category for this station. At 1730, Emergency Management reported severe beach erosion along Jungle Hut Road were 4-5 ft of sand was missing. At 1928, a mesonet site measured a non-convective wind gust of 51 mph at Marineland from the ENE.

Coastal Flood, Clay

When: September 20, 2:15 PM EST
Where: Clay forecast zone
Reported by: Park/Forest Service

The tide gauge on the Buckman Bridge measured high tide of 1.90 ft MHHW datum within the St. Johns River. This value was within the minor flood stage for this location, and it was only 0.10 ft under the moderate flood threshold.

What these are

Coastal Flood: Flooding of coastal land by the sea, from storm surge, onshore wind or high tides.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Florida in 2020 Every state in 2020 This day in weather history Warnings in Florida, September 2020

Sources

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: 921702, 921703, 921704, 921705.