Tropical Storm — Coastal St. Johns, Florida

2022-09-28 to 2022-09-30 · Coastal St. Johns, Florida

Event narrative

St. Johns county experienced strong tropical storm force winds with gusts near hurricane force, storm surge inundation and freshwater rainfall flooding as a result of Hurricane Ian. The county sheriff reported less than 40 rescues were made during the storm. Emergency resources responded to over 300 rescue calls related to flooding in downtown St. Augustine, Summer Haven, Hastings, Flagler Estates and Matanzas Inlet.

Tropical storm force winds started Wednesday night 9/28. At 7 pm, the St. Augustine C-man station SAUF1 reported NE winds 39 mph with gusts to 47 mph. At 10 pm, the C-man reported NNE winds sustained at 45 mph with a gust to 55 mph. At 10:20 pm, a mesonet station about 2 miles SSE of South Ponte Vedra Beach recorded a wind gust from the NE of 56 mph. At 10:55 pm, a mesonet site about 2 miles NW of St. Augustine called XLWS Lewis measured a wind gust from the NNE of 59 mph.

On Thursday 9/29 at 6 am, the SAUF1 C-man station measured a sustained wind of 46 mph with a gust to 56 mph. At 7 am, the C-man measured a sustained wind of 54 mph with a gust to 57 mph. At 9 am, the C-man measured a sustained wind of 49 mph with a gust to 57 mph. At 9:06 am, the AWOS at the St. Augustine Airport (KSGJ) measured a wind gust of 52 mph. At 9:50 am, a mesonet station in the city of St. Augustine measured sustained winds of 44 mph with a gust to 49 mph. At 9:55 am, a mesonet site XLWS Lewis about 2 miles NW of St. Augustine measured a wind gust to 61 mph. At 10 am, the C-man station measured sustained winds of 53 mph with a gust to 61 mph. At 2:15 pm, the Lewis mesonet site measured a wind gust to 63 mph. At 3 pm, the C-man station measured a sustained winds of 58 mph (strong tropical storm force) with a gust to 67 mph.

Storm surge and heavy rainfall flooding begin in downtown St. Augustine the morning of Thursday 9/29. At 9:48 am, the public reported flooding of Avenida Menendez and the Bridge of Lions was closed. At 11:02 am, emergency management reported flash flooding in St. Augustine with water entering homes. At 11:10 am, flooding of King Street was reported in St. Augustine. At 11:53 am, Fire Rescue in St. Augustine reported storm surge flooding was near or slightly exceeded Hurricane Matthew levels in 2016. At 12:02 pm, emergency management reported storm surge inundation about 1 mile south of Vilano Beach where the Intracoastal Waterway bridge approaches were cut-off by storm surge flooding. Major flooding was reported on A1A near north Vilano Beach. At 12:05 pm, county emergency management reported numerous road closures along the coastline were impassable due to storm surge inundation. At 12:44 pm, broadcast media reported from the Davis Shores area of St. Augustine on Anastasia Island and showed major storm surge flooding inundation with levels near that of Hurricane Matthew in 2016. This flooding infiltrated homes in the neighborhood. At 1:58 pm, a WeatherStem camera on the grounds of Marineland showed storm surge flood water into the Whitney Lab. At 2:45 pm, the Pellicer Creek tide gauge peaked at 4.29 ft MHHW datum. The level was just below the record values of 4.34 ft MHHW set during Hurricane Matthew. Major flooding begins at this location above 3.3 ft MHHW. At 7:30 pm, the St. Johns River tide gauge at Racy Point peaked at 3.66 ft MHHW datum. Major flooding begins at 3 feet MHHW for this location. An NWS employee reported 3-4 ft of storm surge inundation along the Matanzas River just south of St. Augustine.

At 5 am Friday 9/30, the tide gauge along Deep Creek reached a stage of 5.18 ft MHHW datum due to the combination of storm surge and rainfall. Major flooding begins above 4.2 ft MHHW. At 5:15 am, the St. Johns River tide gauge at the Shands Bridge peaked at 3.27 ft MHHW datum. Major flooding begins above 3 ft MHHW. At 7:42 am, the emergency manager relayed that aerial photography damage assessments indicated that the El Penon inlet near Summer Haven re-opened. This was likely due to overwash and undetermined at this time if it was a true breach.

Flooding rainfall impacted much of St. Johns county. At 11:13 pm on 9/29, the public reported 9.51 inches of storm total rainfall in Elkton.

Wider weather episode

Hurricane Ian made landfall as a powerful Category 4 Hurricane on the SW Florida peninsula coast near Punta Gorda on Wednesday, September 28th. The center tracked NE across south-central FL, north of Lake Okeechobee through Wednesday Night and then moved offshore of the central FL Atlantic coast Thursday Morning, September 29th, just near Cape Canaveral as a Tropical Storm. Ian regained Category 1 Hurricane Strength offshore of the northeast Florida Atlantic coast as it tracked NNE into Thursday Night and Friday morning as it made landfall along the South Carolina Atlantic coast. Locally, a strong nor'easter developed through the day Wednesday, September 28th, as a front lifted northward up the FL peninsula ahead of Ian. Tropical Storm force winds and bands of rainfall started to impact northeast Florida through the day Wednesday, the peak in local winds through the day Thursday as Ian's center tracked northward and offshore of the local Atlantic coast. Water levels increased within the St. Johns River basin Wednesday due to the strong nor'easter and annually high spring tides already created water level departures of 0.5 to 1 ft MHHW datum prior to the nor'easter further 'charging' the St. Johns River basin. The peak storm surge along the local Atlantic coast occurred Thursday, then the peak surge pressed into the St. Johns River basin Thursday night into Friday morning. Major to moderate tidal flooding continued into the weekend especially for Putnam, St. Johns and Flagler counties where trapped tides and northerly flow caused extended tidal flooding. Record setting rainfall occurred across the headwaters of the St. Johns River across east-central Florida, and water levels increased the week after Ian passed as the St. Johns River drains south to north, which was also leading up to the peak Spring tides between Oct 8th through Oct 11th.

Source: NOAA Storm Events Database, event_id 1051095. Narrative written by the NWS forecast office that issued the report.