Nate continued to rapidly weaken Sunday morning as its center of circulation moved north through Mississippi and Alabama, with heavy rain affecting parts of the Florida Panhandle, much of Alabama, western Georgia, and eastern Kentucky. Numerous flash flood warnings remained in effect across Alabama and the far northwest suburbs of Atlanta Sunday morning.
At 11 a.m., the National Hurricane Center said the storm was downgraded to a tropical depression with maximum sustained winds of 35 mph, and all coastal warnings had been cancelled. Tropical-storm-force wind gusts were expected to continue over the the Florida Panhandle and parts of Alabama and Georgia through Sunday afternoon. Water levels remained elevated along portions of the northern Gulf coast, according to the Hurricane Center, but should gradually subside this afternoon.
Nate first made landfall as a Category 1 storm at the mouth of the Mississippi River at 8 p.m. Saturday evening with maximum sustained winds of 85 mph. Then at 1:30 a.m. Sunday, Nate made a second landfall near Biloxi, Miss. at the same intensity. The storm was the first hurricane since Hurricane Katrina in 2005 to come ashore in Mississippi.
Earlier, a significant storm surge or rise in ocean waters above normally dry land had affected the area from the Mississippi-Alabama border to the Okaloosa/Walton County line in Florida. The storm surge resulted in a new record water level in Pascagoula, along the Mississippi coast near the Alabama border.
— Brad Panovich (@wxbrad) October 8, 2017
At one point, more than 100,000 residents in Mississippi and Alabama had lost electricity, according to the Associated Press. Tens of thousands of power outages were still being reported Sunday morning across Alabama and Mississippi, with the worst of the remaining rain and wind passing near Birmingham, Ala., Sunday morning into the afternoon. There were numerous reports of trees down across Alabama and at 8 a.m., Alabama Power reported 71,000 outages across the state, with many in the Mobile and Birmingham areas. A jacknifed tractor trailer had closed a portion of a major highway in Birmingham.
— Stephen Quinn (@StephenQ3340) October 8, 2017
A swath of heavy rain is expected to be the main impact going forward as the remnants of Nate stream northward and interact with a cold front. A widespread two to six inches of rain is forecast through Sunday and Sunday night, with higher amounts likely in spots. All of this rain will fall in under 24 hours, so flash flooding is a concern.
See our previous post for additional storm highlights from before, during, and after landfall overnight and yesterday.
Impacts in D.C. area
This system will be fast moving, which will limit the rain accumulation potential. That said, the D.C. area should still receive some much needed rain, even as the center of circulation will likely past west of the area late Sunday night or early Monday morning.
Scattered showers are likely across the D.C. area Sunday into Sunday night, with heavier rain likely early Monday morning through around midday. Most of the model forecasts keep total rainfall below about an inch for the D.C. region, with heavier amounts of 2-3″ staying well west over the mountains.
As for severe thunderstorm potential, the track of the storm carries the strongest energy to our west. In addition, abundant clouds and periods of showery rain will tend to reduce the instability and wind shear (increase in wind speed with altitude) necessary for widespread severe storms. There is an outside chance, say 10-20%, that enough spin energy associated with the remnant circulation will consolidate and intensify into a rotating thunderstorm. Such a storm may or may not produce a tornado.