The forecast track for Sally has shifted slightly left from the previous advisory and the forecast intensity has increased from the previous advisory. The Flash Flood Watch has been expanded. Hurricane Watch has been upgraded to a Hurricane Warning for parts of SE Louisiana and coastal Mississippi. And the Tropical Storm Watch have been upgraded to Tropical Storm Warning for parts of interior parishes of SE LA and parts of SW Mississippi.
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.
There is normal confidence in the track and below average confidence in the intensity forecast. The expected impacts could still change depending on its intensity.
A Storm Surge Warning is in effect from the Mouth of the Mississippi River to the MS/AL border. Possible storm surge inundation levels: Lake Borgne and 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: 3 to 5 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.
A 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. Expect ponding of water in low lying areas and some potential for localized flash flooding. Possible slow movement of this system could create significant rainfall and associated flooding threats.
Sustained tropical storm force winds with higher gusts are forecast with hurricane force wind gusts possible. The area along the coastlines 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.