Hurricane Nate Makes Second Landfall Near Biloxi, Mississippi, as a Category 1

Hurricane Nate has made its second and final landfall as a Category 1 hurricane near Biloxi, Mississippi, and will now spread its swath of heavy rain from the northern Gulf Coast to the Appalachians and possibly parts of the Northeast Sunday into Monday.

Nate made its first landfall as a Category 1 hurricane near the mouth of the Mississippi River earlier Saturday evening.

(COMPLETE NATE COVERAGE: Hurricane Central)

Happening Now

The latest data from NOAA and the Air Force Reserve Hurricane Hunter aircraft suggest that maximum sustained winds are at 85 mph, which makes Nate a Category 1 hurricane. According to The Weather Channel senior meteorologist Stu Ostro, Nate met the criteria for rapid intensification by Saturday morning.

Nate's center is currently about 35 miles south-southwest of Biloxi, Mississippi, moving rapidly north at 20 mph. 

Hurricane-force winds extend up to 35 miles from the center of Nate, while tropical-storm-force winds currently reach up to 125 miles from the center. These winds are mainly occurring east of Nate's center, something commonly seen with hurricanes moving this fast.

Destructive, hurricane-force winds are now moving ashore along the Mississippi coast within Nate's northern eyewall.

Water levels have exceeded 4 feet above normal tides at Mobile, Alabama (Coast Guard station). Storm-surge inundation of 4.75 feet above normal tide levels has been observed at Shell Beach, Louisiana. Bay Waveland Yacht Club, Mississippi, has recorded an inundation over 4.1 feet above normal tides.

Watches and Warnings

A hurricane warning is in effect from the mouth of the Pearl River to the Alabama/Florida border.

A storm surge warning has been posted from the mouth of the Mississippi River to the Okaloosa/Walton county line in Florida. This means a life-threatening inundation is likely in these areas with the landfall of Nate, in this case, tonight into early Sunday.

(MAPS: NHC Storm Surge Watch/Warning Areas)

Tropical storm warnings are in effect for the New Orleans metro area and Lake Pontchartrain, Lake Maurepas, from Grand Isle to Morgan City, Louisiana, and east of the Alabama/Florida border to Indian Pass, Florida.

Tropical storm watches extend well inland into north Georgia.

U.S. Forecast Timeline

Nate's center will make a second landfall along the northern Gulf Coast, between southeast Louisiana and the far western Florida Panhandle, tonight into early Sunday, likely as a Category 1 hurricane.

Here's a timeline of events with this system, regarding the U.S. Gulf Coast:

• Overnight: Damaging, hurricane-force winds in hurricane warning and possibly in watch areas; second landfall expected with storm-surge flooding in surge flood warning and possibly watch areas; bands of heavy rain; worst of the impacts will be to the north and east of the center track.
• Sunday morning: Again, second landfall will occur before dawn with storm-surge flooding, hurricane- or tropical-storm-force winds near and east of the center; areas of heavy rain spread into other parts of the Southeast, southern Appalachians.
• Sunday afternoon/night: Nate weakens over the Tennessee Valley with some lingering strong wind gusts, but heavy, potentially flooding rain continues in the Appalachians, Tennessee Valley.
• Monday: Lingering heavy rain, flash flooding possible in the Appalachians, eastern Ohio Valley and parts of the Northeast.

(INTERACTIVE MAP: Nate Forecast Path)

U.S. Impacts

Storm Surge

The peak storm surge will occur with the closest approach of the center of Nate tonight into early Sunday morning.

Here are the potential peak water levels above ground you may see within the few hours before and after Nate's landfall, according to the National Hurricane Center. This should be thought of as the worst-case flooding expected with Nate, if the storm surge arrives at high tide.

(MORE: NHC Potential Storm Surge Inundation Map)

Unfortunately, there is high tide during the overnight hours tonight as Nate's center draws near. Here are the times of high tide, in local time, for several locations that are expected to see storm-surge flooding from Nate:

• Grand Isle, Louisiana: Saturday 11:31 p.m.
• Waveland, Mississippi: Sunday 1:20 a.m.
• Dauphin Island, Alabama: Saturday 11:50 p.m.
• Pensacola, Florida: Sunday 12:19 a.m.

Battering waves will also ride atop the storm surge, capable of additional damage to docks and buildings.

Winds

Nate's wind field is not particularly large, compared to mammoth-sized recent storms like Sandy or Ike.

However, Nate's Category 1 intensity and, also importantly, its rapid forward speed, will likely push tropical-storm-force and hurricane-force winds somewhat farther inland than a typical landfall.

Therefore, hurricane-force winds capable of structural damage, significant tree damage and multi-day power outages may penetrate about 100 miles or so inland over parts of eastern Mississippi and southwest Alabama into Sunday, mainly contained in Nate's eyewall.

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Due to the lopsided nature of Nate, the impacts of wind are expected to be considerably lower on the west side of wherever Nate makes landfall. 

Tropical-storm-force winds, capable of at least some power outages, some downed trees and perhaps some light structural damage, may penetrate as far north as the Smoky Mountains, and may occur in cities such as Birmingham, Huntsville, Atlanta, Chattanooga and Knoxville Sunday and Sunday night. 

Rainfall Flooding

A swath of 3 to 6 inches of rain, with locally up to 10 inches possible, is expected not just near the landfall area along the Gulf Coast this weekend, but also well inland through Monday into the Tennessee Valley.

Two to 5 inches of rain, with isolated amounts up to 7 inches, are expected as far inland as the mid-Atlantic states and parts of the Ohio Valley.

This may trigger serious inland flash flooding Sunday into Monday in the Appalachians, as happens often with inland tropical cyclones. 

Tornadoes

Isolated tornadoes will be possible generally to the east and north of where Nate makes landfall, with the most likely tornado locations being from southeast Louisiana eastward to the central Florida Panhandle and inland to southern Alabama and southern Georgia.

NOAA's Storm Prediction Center has issued a tornado watch valid until 2 a.m. CDT for southern Alabama, the western Florida Panhandle and southeast Mississippi.

Recap

This latest tropical system originated on the eastern end of a larger feature, called a Central American gyre.

Enough spin and thunderstorm activity was collected east of Nicaragua on Oct. 4 that the National Hurricane Center upgraded Invest 90L to a tropical depression. Heavy rain partially from the gyre and from newly upgraded Tropical Depression 16 spread across Central America. 

According to the National Hurricane Center, Nate was upgraded from a tropical depression on the morning of Oct. 5 based on radar from San Andrés, an island east of Nicaragua, indicating a partial eyewall and a surface pressure measurement over Nicaragua found to be lower than previous advisories. Nate moved ashore over northeastern Nicaragua and eastern Honduras later that day. 

On Oct. 6, Nate accelerated through the northwestern Caribbean and through the Yucatan Channel while organizing and intensifying. A wind gust of 52 mph was reported in Isabel Rubio in western Cuba as Nate shot the goal posts between the Yucatan and Cuba. Hurricane hunters reported a building eyewall in Nate's eastern semicircle. 

Hurricane Nate made its first official U.S. landfall on the evening of Oct. 7 as a Category 1 hurricane near the mouth of the Mississippi River.

Nate then made its second and final U.S. landfall around 12:30 a.m. CDT Oct. 8 as a Category 1 hurricane near Biloxi, Mississippi.

What Spawned This? More on Central American Gyres

This "gyre" is a large, broad area of low pressure over the Central American isthmus and western Caribbean Sea. This feature can lead to the development of a tropical cyclone in the Caribbean Sea and/or in the eastern Pacific Ocean.

These gyres most often form in the late spring and early fall, when cold fronts become uncommon in this region of the world. They're most common in September, but can be a source of tropical storms and hurricanes into November, and as early as May.

We typically see up to two gyres like this one set up each year, and they can spawn tropical storms in both the Atlantic and eastern Pacific basins, sometimes in each basin at the same time. Not all gyres produce tropical cyclones, but they all produce heavy rainfall.

Roughly 50 percent of Central American gyres have a tropical cyclone associated with them, according to Philippe Papin, Ph.D. candidate at the University of Albany. "When a tropical cyclone does occur, it tends to form on the eastern side of the [gyre] and rotates counterclockwise around the larger circulation." 

Gyre-like tropical systems are much more common in the western Pacific closer to southeast Asia, where the monsoon plays a larger role in the weather.

A notable example of gyre-induced tropical cyclone formation occurred in 2010 when Tropical Storm Nicole formed just south of Cuba from the gyre in late September.

Nicole was a short-lived and ill-formed tropical storm that tried to cross Cuba. It brought heavy rain to the Cayman Islands, Jamaica, Cuba and portions of South Florida.

Hurricane Stan in 2005 is another good example of a hurricane's interaction with a Central American Gyre, according to Papin.

Following Stan's dissipation over the mountains of central Mexico, its remnant spin became part of a larger gyre that caused heavy rainfall over Central America. While Stan's direct circulation resulted in around 80 deaths, according to the National Hurricane Center, heavy rainfall resulting from the gyre took more than 1,000 lives across Central America. 

Other examples include Tropical Storm Andrea (2013), Hurricane Ida (2009 – assist from the gyre) and Hurricane Patricia (2015 – assist from the gyre, not a direct result).