Tropical Storm Sally Update - 09/13/2020 5:00pm

Click HERE for an update concerning Tropical Storm Sally.

Changes from previous update: 

• The forecast track has shifted slightly back to the right the previous advisory.

• A HIGH RISK of excessive rainfall is possible Tuesday.

• 10 to 20+" of rainfall is possible generally east of I-55 to the MS/AL line. This could lead to significant flash flooding and eventually river flooding.

Overview:

Tropical Storm Sally is forecast to move generally west northwestward the rest of this weekend over the eastern Gulf of Mexico. It will track towards

the northern Gulf Coast later tonight into Monday. The storm will slow as it makes landfall.

REMEMBER slower moving storms produce more rainfall and higher storm surge than you'd typically expect for its wind speed strength/category

Confidence:

• There is normal confidence in the track and intensity forecast. The expected impacts could still change depending on its intensity.

Impacts:

Storm Surge:

• A Storm Surge Warning is in effect from the Mouth of the Mississippi River to the MS/AL border.
• Possible storm surge inundation levels:
  • The Mouth of the MS River to Ocean Springs: 7 to 11 feet
  • Ocean Springs to MS/AL Border: 4 to 7 feet
  • Lake Pontchartrain and Maurepas: 4 to 6 feet
  • Mouth of the MS River to Port Fourchon: 4 to 7 feet
  • Morgan City to Port Fourchon: 1 to 3 feet

• Expect low-lying, coastal roads to become impassable due to flooding

• Some areas may become cut off or inaccessible 

Rainfall/Flooding:

• Flash Flood Watch in effect tonight through Wednesday afternoon.

• Rainfall of 6 to 12 inches with locally higher amounts of over 20 inches possible

• Depending on where the heavy rain falls in relation to river drainage basins, river flooding could develop.

• Possible slow movement of this system could create significant rainfall and associated flooding threats

Wind and tornado:

• Sustained tropical storm force winds with higher gusts are forecast with hurricane force wind gusts possible. Parts of SE LA may see sustained hurricane force winds.

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

• A few tornadoes will be possible in the storm’s rain bands. Tornadoes in these situations are typically short-lived, but they move very quickly.

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/

Next Update and Contact Information:

The next update will be sent around 5AM Monday.