Hurricane Marco and Tropical Storm Laura Update - Sunday August 23, 4:30pm

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Here is an update concerning Hurricane Marco and Tropical Storm Laura. 

Changes from previous update: 

• Marco's track has shifted southward with a more pronounced turn to the west as it approaches the coast

• TS Laura's forecast track has shifted slightly west and the intensity has nudged slightly upward

Overview:

• Hurricane Marco is forecast approach the coast on Monday, bringing coastal flooding, heavy rainfall and gusty winds to SE LA and S MS

• Tropical Storm Laura is forecast to be at least a category two as it approaches the Northwest Gulf coast on Wednesday

Confidence:

• We are confident Marco will bring impacts to the local area

• We are confident Laura will bring some impacts (mainly potential for coastal flooding and heavy rain) to the local area, but less confident in the magnitude of impacts

Impacts from Marco:

• Storm Surge Inundation Potential:

  • Open coast from Morgan City to MS River: 4 to 6 ft

  • Open coast MS River to Ocean Springs: 3 to 5 ft

  • Lakes Pontchartrain and Maurepas: 2 to 4 ft

  • Open coast Ocean Springs to AL Border: 1 to 3 ft

• Rainfall

  • Rainfall of 3 to 6 inches with locally higher amounts of double or more will be possible

  • Expect ponding of water in low lying areas and some potential for localized flash flooding

  • A Flash Flood Watch is in effect for the lower parishes of southeast Louisiana. This watch may be expanded, depending on future track adjustments.

• Wind

  • Sustained hurricane force winds are unlikely across land areas, but could occur in gusts along the coast of SE LA

  • Sustained tropical storm force winds will be more widespread across extreme SE LA, with tropical storm force gusts possible farther inland

  • These winds could result in minor damage mainly to trees, powerlines, and weaker structures. 

• Tornadoes

  • Short-lived and fast-moving tornadoes can occur in Marco's outer bands as it moves ashore and inland.

• Other Considerations:

  • TS Laura could bring additional coastal flooding and heavy rainfall, as well as gusty winds to portions of the area mainly west of the MS River

  • Keep in mind that preparation for TS Laura may be made more difficult by lingering impacts from TS Marco.

Additional Information and Resources:

NWS New Orleans Website: www.weather.gov/neworleans

NWS New Orleans DSS Website: http://www.weather.gov/lix/embrief

NWS New Orleans Tropical Page: https://www.weather.gov/srh/tropical?office=lix

River Gauges and Forecasts: http://water.weather.gov/ahps2/index.php?wfo=lix

NWS New Orleans Facebook: www.facebook.com/NWSNewOrleans

NWS New Orleans Twitter: https://twitter.com/NWSNewOrleans

Online Severe Weather Reporting: https://www.weather.gov/lix/submit_storm_report

National Hurricane Center Website: https://www.nhc.noaa.gov/