Tropical Storm — Lower Jefferson, Louisiana

2019-07-12 to 2019-07-13 · Lower Jefferson, Louisiana

Event narrative

Occasional to frequent tropical storm force wind gusts were noted in the parish with a peak wind gust of 45 knots measured at the Grand Isle C-MAN station during late evening hours of the 12th.

Wider weather episode

Hurricane Barry initially developed from a disturbance that moved from Georgia southwest to the northeast Gulf of Mexico on July 8-9, 2019. The weak low pressure system continued to move west-southwest and strengthen, and was eventually classified as Tropical Storm Barry on the morning of July 11th, 95 miles south southeast of the Mouth of the Mississippi River.

Barry continued to move slowly west then northwest and briefly reached hurricane strength on the morning of July 13th before landfall in south-central Louisiana near Intracoastal City, LA, in Vermillion Parish. Tropical storm force winds, reached the southeast Louisiana coast by midday on Friday, July 12th and spread slowly northwest reaching the Baton Rouge area during the evening of July 12th. Tropical storm wind impacts had ended across all of southeast Louisiana by midday on July 14th. Tropical storm force winds were primarily measured in gusts across southeast Louisiana. The

exception was in Terrebonne and Assumption Parishes, close to the landfall location, where sustained tropical storm force winds and frequent gusts caused more significant power line and tree damage. A few tropical storm wind gusts were recorded in the metro New Orleans area but were not very impactful. No hurricane force wind gusts were recorded in southeast Louisiana. A WeatherFlow site at Dulac, Terrebonne Parish, recorded both the maximum sustained wind and highest wind gust on 07/13/2019 at 0739CST: 42kt/48 mph and 59kt/ 68 mph, respectively. The lowest minimum pressure measured in southeast Louisiana was at the Bootheville, LA ASOS with a pressure of 999.3mb on July 12th, at 1706CST.

Mostly minor to moderate storm surge flooding occurred across coastal southeast Louisiana, including Lake Pontchartrain, and a small part of the Mississippi Coast. Terrebonne Parish had significant storm surge flooding in the lower portion of the parish with storm tides of 5 to 8 feet, locally up to 9 feet. Several local levees were overtopped on the morning of July 13th, flooding roads and a few houses. The highest storm tide reading was 9.11 feet NAVD88 at a USGS tide gage at Caillou Lake near Dulac, Terrebonne Parish. The remainder of the area had storm tide readings in the 3 to 5 foot range.

Storm total rainfall was generally between 4 and 8 inches with a maximum rainfall of 8.83 inches recorded northeast of Denham Springs, Livingston Parish. Isolated flash flooding of streets and secondary roadways occurred on Sunday, July 13th in the greater Baton Rouge area, but flash flooding was not widespread or significant.

The lower Mississippi River was at unusually high stages from late August with the stage at the New Orleans Carrolton gauge near 16.5 ft. The combination of storm surge entering the lower Mississippi River with very high river stages prompted concern of potential overtopping of MS River levees in lower Plaquemines Parish, prompting some evacuations in that area.

Source: NOAA Storm Events Database, event_id 845815. Narrative written by the NWS forecast office that issued the report.