Tropical Depression Nicholas and Heavy Rain Update - September 15th, 2021 4 PM

Click Here for an update concerning Nicholas and the heavy rain threat for today and through Friday. 

Changes from previous update:

• Expect scattered to numerous showers and storms every day for the next few days

• SW MS counties and NW LA parishes removed from Flash Flood Watch

Overview: 

WHAT: 

• MARGINAL RISK to MODERATE RISK of Heavy Rain tonight
• SLIGHT to MARGINAL RISK of Heavy Rain Thursday and Friday 

WHEN:

• Tonight for the Moderate Risk, but a Marginal and Slight Risk for tomorrow and Friday 

WHERE: Entire area today and then most of SE LA and Coastal MS Thursday and Friday CONFIDENCE: 

We are confident that additional bands of showers and thunderstorms will bring minor to moderate impacts in the form of locally heavy rainfall and an isolated tornado or two across portions of SE LA and coastal MS.

Minor coastal flooding will continue through Thursday night.

Impacts:

Rainfall/Flash Flooding:

• Additional rainfall of 2 to 5 inches is currently forecast with locally higher amounts will be possible through Friday. The highest rain rates of 1 to 3 inches per hour through Friday.

• Expect ponding of water in low-lying areas and some localized flash flooding due to the very saturated grounds and high rainfall rates.

• Rises on a few rivers will lead to some going into moderate or major flood stage.

Coastal Flooding:

• Elevated tides will continue through Friday morning during the high tide cycle for most of coastal Southeast Louisiana and coastal Mississippi.

• 1 to 2 feet of inundation will be possible along immediate coastal areas. Hancock county could approach 3 feet.

• Expect low-lying, coastal roads to be flooded and a few may become impassable.

Tornado:

• A few tornadoes will be possible tonight. Tornadoes in these situations are typically short-lived, but they move very quickly.

The attached briefing highlights the threats associated with this system.

Additional Information and Resources:

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

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

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 Weather Reporting: https://www.weather.gov/lix/submit_storm_report Request for information

Please relay any reports of flash flooding to our office ASAP.  You can send reports via NWSChat or by phone.  If emailing pictures, please send them to <sr-lix.forecasters@noaa.gov>. Next Update and Contact Information:

The next update will be sent by 7AM tomorrow morning.  If you have any questions in the interim or need additional information, please do not hesitate to contact us.  We can be reached by phone at 504-522-7330 or 985-649-0429.  Use extension 4 to speak with a forecaster.  Alternatively, you can reach us by email by replying to this message or sending an email to sr-lix.forecasters@noaa.gov.