City of Central

Southeast Louisiana and Southern Mississippi partners - 

Here is an update concerning freshly named Tropical Storm Isaias. See the full briefing attached for graphics and full details.

Changes from previous update: 

• The forecast track has shifted east from the previous advisory.
• The forecast intensity has increased from the previous advisory.
• Confidence in the extent and timing of impacts continues to increase.

Overview:

• Isaias is forecast to become a high-end Category 2 hurricane in the next two days as it moves east over the Gulf.
• The storm is forecast to turn north on Friday and accelerate, bringing impacts to the northern Gulf coast by Friday afternoon and into Saturday.
• This storm will likely bring multi-hazard impacts including coastal flooding, excessive rainfall, and gusty winds to the local area.
• Further adjustments to timing and extent of impacts could occur. Continue to monitor this situation closely even if you’re no longer in the cone.

Confidence:

• Confidence in the forecast track of this storm is gradually increasing.
• If the current forecast holds, we are confident that minor/moderate impacts will be experienced across portions of Southeast Louisiana and Southern Mississippi.

Impacts:

• Specific impacts will depend on the exact track and intensity of this system as it passes the area. However, it will likely bring multi-hazard impacts to the local area Friday through Saturday.

Storm Surge:

• At least minor coastal flooding is possible today and Thursday and likely on Friday into Saturday.
• At least 1 to 3 ft of inundation is forecast along immediate coastal areas. 
• If these values are realized, low-lying, coastal roads will flood and a few could become impassable.
• Higher coastal flooding inundation exceeding 3 feet will be possible for areas east of the Mississippi River such as Waveland and Shell beach, but this will be highly dependent on the track.

Rainfall/Flooding:

• There will be a sharp gradient for rainfall on the west side of the hurricane.
• Coastal Mississippi has the highest chance for locally heavy rainfall of 2 to 5 inches.
• Some areas west of I-55 may see less than 0.5” from this storm.
• Forecast rain totals may continue to decrease if the forecast track shifts farther east.

Wind and Tornado:

• Sustained winds of up to 20 to 30 mph with higher gusts up to 40 to 45 mph are forecast with the strongest winds expected east of the I-59 corridor.
• Winds of this magnitude will blow around lightweight, loose household items and cause hazardous driving conditions, especially on bridges and elevated roadways
• There is a low chance of tornadoes in the storm’s outer rain bands along the Mississippi Coast. Tornadoes in these situations are typically short-lived, but they move very quickly.