Tropical Storm — Inland Duval, Florida

2017-09-10 to 2017-09-11 · Inland Duval, Florida

Event narrative

This narrative is from the NWS Jacksonville Post Storm Report for Hurricane Irma which is a compiled list of reports from the storm survey, Emergency Management, private and public weather observation networks and broadcast media sources. Tropical storm force wind gusts started to impact Duval County during the morning 9/10, with a gust of 50 mph around 6:21 am at Huguenot Park. At 7 am, a Weatherflow Mesonet station at Buck Island on the St. Johns River measured a sustained winds of 37 mph and a gust to 50 mph. At 9:20 pm, a Mesonet station about 2 miles WNW of Fort Caroline measured sustained winds of 35 mph with a gust to 50 mph. At 10:26 pm, the ASOS at the Jacksonville International Airport near the NWS office measured a 58 mph wind gust. On 9/11 at 1:45 am, The NOS tide gauge at Mayport measured water levels of 2.9 ft to 3 ft above MHHW datum. At 3:23 am, the Mayport ASOS measured a sustained wind of 51 mph (44 kt) and a gust of 74 mph (64 kt). At 3:38 am, the Mayport ASOS measured a sustained wind of 68 mph (59 kt) and a gust of 87 mph (76 kt). This was the highest official recorded wind speed of Irma across the NWS Jacksonville county warning area. At 3:41 am, the ASOS at the Jacksonville International Airport measured sustained winds of 59 mph (51 kt) and a gust of 86 mph (75 kt) within the same potent rain-band that stretched eastward across Mayport. This was the most intense rainfall and wind rain band that impact the area with Irma. At 3:41 am, the Weatherflow sensor at Huguenot Park measured sustained winds of 66 mph and gusts to 85 mph, again under the same rain band. At 3:42 am, multiple trees were blown down outside of the NWS Jacksonville office at the Jacksonville International Airport following the 86 mph wind gust. One tree fell on the NWS office sign and damaged it. At 4:30 am, the roof was blown off of a home in the Sans Souci neighborhood. At 5:45 am, the St. Johns River at Main Street in downtown Jacksonville reported a water level of 4.39 ft NAVD88, which broke the record from Hurricane Dora of 4.12 ft NAVD88 set in 1964. At 8:26 am, the ASOS at Craig Airfield measured a wind gust of 70 mph. At 10:09 am, the ASOS at Naval Air Station (NAS) Jacksonville in Orange Park along the St. Johns River measured a wind gust of 67 mph. At 10:14 am, a peak wind gust of 69 mph was measured at NAS Jacksonville. At 3:59 pm, an evacuee in San Marco along the St. Johns River near downtown Jacksonville reported water rose into his home up to his neck (about 5 ft inundation in his home). Historic record setting flooding of the St. Johns River and tributaries due to combination of elevated water levels from the Nor'easter event, high astronomical tides, river surge and storm rainfall from Irma. The river gauge at the Main Street bridge in downtown Jacksonville surpassed hurricane Dora 1964 record flooding the morning of 9/11 at low tide with a value of over 5 ft datum NAVD88 (Dora record was 4.12 ft NAVDd88 datum). The river at this location crested around 12:30 pm at 5.57 ft NAVD88, which is an all-time record stage. Major flooding impacted the St. Johns River Basin, and about 350 water rescues were conducted in Duval County, especially in the Riverside, San Marco and downtown Jacksonville areas. The St. Johns River at the Buckman Bridge set a record flood stage At 5.63 feet on Sept 11th at 0718 EDT. Major flooding occurred at this level. The Broward River below Biscayne Blvd crested at 4.08 feet on Sept 11th at 0045 EDT. Moderate flooding occurred at this level. Clapboard Creek near Sheffield Road set a record flood stage at 5.31 feet on Sept 11th at 0430 EDT. Major flooding occurred at this level. Dunn Creek at Dunn Creek Road set a record flood stage at 6.38 feet on Sept 11th at 0930 EDT. Major flooding occurred at this level. The St Johns River at the Dames Point Bridge set a record flood stage at 5.05 feet on Sept 11th at 1324 EDT. Major flooding occurred at this level. The Cedar River at San Juan Avenue set a record flood stage at 6.35 feet on Sept 11th at 1230 EDT. Major flooding occurred at this level. Julington creek at Old St Augustine road set a record flood stage at 6.20 feet on Sept 11th at 1030 EDT. Major flooding occurred at this level. The St Johns River at the Main Street Bridge set a record flood stage at 5.57 feet on Sept 11th at 1224 EDT. Major flooding occurred at this level. The St Johns River at Mayport crested at 5.58 feet on Sept 11th at 0254 EDT. Major flooding occurred at this level. The Nassau River near Tisonia sets a record flood stage at 8.18 feet on Sept 11th at 0330 EDT. Major flooding occurred at this level. The Ortega River at Argyle Forest Blvd sets a record flood stage at 12.99 feet on Sept 11th at 1215 EDT. Major flooding occurred at this level. The St Johns River at Buffalo Bluff crested at 3.31 feet on Sept 12th at 2315 EDT. Moderate flooding occurred at this level. Pottsburg creek at Beach Blvd set a record flood stage at 5.84 feet on Sept 11th at 1300 EDT. Major flooding occurred at this level. Pottsburg Creek at Bowden Road set a record flood stage at 10.04 feet on Sept 11th at 0800 EDT. Major flooding occurred at this level. The Trout River at Lem Turner Road crested at 4.16 feet on Sept 11th at 0200 EDT. Moderate flooding occurred at this level. Storm total rainfall included 11.04 inches 10 mile SW of Jacksonville, 11 inches 12 miles SSE of Jacksonville, 9.2 inches at the Jacksonville International Airport, 7.96 inches at Mayport Naval Air Station and 7.08 inches at Jacksonville Naval Air Station.

Wider weather episode

Hurricane Irma's eye passed west of the local forecast area, with the region on the storm's turbulent east side. Widespread tropical storm force winds with gusts to hurricane force were felt across much of the area, with the strongest winds surging up the Florida east coast during the pre-dawn hours of Sept. 11th. Extensive tree and power line damage occurred across the local area from the winds. One of the greatest local impacts exacerbated by Irma's rainfall and storm surge was river flooding. Prior to Irma's arrival, a local nor'eastern developed 3 days prior, with strong onshore flow pumping water into the St. Johns River basin. Elevated water levels of 1-2 ft above normal tidal departure were already ongoing for several tidal cycles before Irma's surge and rainfall. The nor'easter also brought localized heavy rainfall bands, with some areas near the coast realizing 4-6 inches in 24 hrs the days prior to Irma. In addition, precursor conditions to the nor'easter included an above average rainfall across the region during the summer months. Major, historic river flooding was forecast along Black Creek and the Sante Fe a week prior to Irma. Realized river values along the St. Johns surpassed prior record levels set by Hurricane Dora in 1964, during low tide the morning of Sept. 11th. The St. Johns River basin continued to rise with the combination of trapped tides due to the nor'easter, astronomically high tides heading into the spring tide season, storm surge of up to 5 ft in some areas, fresh water rainfall of 7-11 inches, and strong southerly winds pushing the water across the basin on the east side of Irma. Historic river flooding occurred across much of NE Florida Sept 11th through the following week as water levels were slow to funnel out of the St. Johns basin. Coastal infrastructure that was already weakened about 1 year ago due to Hurricane Matthew suffered the most damage from Irma's storm surge.

Source: NOAA Storm Events Database, event_id 720547. Narrative written by the NWS forecast office that issued the report.