Quantcast
Climate
This NOAA GOES East satellite infrared image taken at 6:15 a.m. EDT (1015 UTC) of Hurricane Nate shows the storm moving through the Gulf of Mexico on Oct. 7 at 6:15 a.m. EDT (1015 UTC). NASA / NOAA GOES Project

Hurricane Nate Heads Into Gulf and Toward Saturday Night Landfall

By Bob Henson and Dr. Jeff Masters

A hurricane warning was in effect from Grand Isle, Louisiana, to the Alabama/Florida border on Friday evening as Tropical Storm Nate, with sustained winds of 70 mph as of 11 p.m. EDT, sped through the narrow Yucatan Channel between Mexico and Cuba and into the Gulf of Mexico.

Update: Nate was upgraded to hurricane strength by the NOAA/NWS National Hurricane Center at 11:30 p.m. EDT Friday, with top sustained winds of 75 mph based on Hurricane Hunter reported.

Very intense thunderstorms were erupting on Friday night near Nate's center, located about 90 miles northeast of Cozumel as of 8 p.m. EDT Friday. Nate was in the process of closing off an eyewall, and it is likely to be a Category 1 hurricane on Saturday night when it makes landfall on the U.S. Gulf Coast between Southeast Louisiana and the Florida Panhandle.


Nate's strongest winds and heaviest rains missed the northeast tip of the Yucatan Peninsula, which was located on the left (weak) side of the storm. As of 9 p.m. EDT Friday, the top winds in Cozumel, Mexico and Cancun, Mexico had not exceeded 20 mph, and only intermittent light rain had been reported. The Hurricane Hunters found Nate's strongest winds were the southeast of the center, over the Yucatan Channel, where Buoy 42056, 120 nm ESE of Cozumel, reported sustained winds of 56 mph, gusting to 69 mph, just after 4 p.m. EDT Friday.

Above: Microwave satellite view of Nate taken at 7:45 p.m. EDT Oct. 6, showing a calm area at Nate's center surrounded by precipitation. The wavelength at which this image was collected, 37 GHz, senses precipitating clouds but does not highlight deep convection (intense showers and thunderstorms). Imagery at the 85 GHz wavelength, which does distinguish deep convection, showed that Nate lacked a complete eyewall at this point. Naval Research Laboratory

Dangerous heavy rains from Nate have affected large parts of Central America. As of Friday evening, Nate had led to a total of 25 deaths in Central America; hardest hit were Nicaragua with 12 deaths, and Costa Rica with nine. Satellite rainfall estimates show that Nate has dumped 8+" of rain on the Pacific side of Costa Rica, Nicaragua and Panama, and also along the northern coast of Honduras and the eastern coast of the Yucatan Peninsula, in both Mexico and Belize.

Figure 1. Infrared GOES-16 satellite image of Tropical Storm Nate at 9:02 p.m. EDT Oct. 6. The white areas indicate very strong thunderstorms surrounding Nate's center. Image credit: NASA/MSFC Earth Science Branch. GOES-16 data are considered preliminary and non-operational.

Forecast for Nate Through Landfall

Satellite images early Friday evening showed that Nate continued to struggle to consolidate; the storm lacked symmetry and had an odd, clumpy appearance to its heavy thunderstorms. However, by late evening, Nate had finally developed a well-formed central dense overcast (CDO) over its center—the large, thick area of high cirrus clouds that normally appears when a storm becomes well-organized and nears hurricane strength. Microwave imagery showed that Nate appeared to be wrapping an eyewall around its east side.

Conditions will be quite supportive of intensification through Saturday. Wind shear will be light to moderate, around 10 knots, and the surrounding atmosphere will remain quite moist, with mid-level relative humidity in the 70 – 80 percent range. Sea-surface temperatures along Nate's path will remain near or above 29°C (84°F)—about 1°C above average for early October—until a few hours before landfall. The eastern part of Nate's circulation will be passing over a warm eddy associated with the Loop Current, which will help keep Nate from churning up cooler water. Nate's rapid forward speed will have a similar effect.

Figure 2. Ocean Heat Content (OHC) for Oct. 6. Forecast positions for Nate from the 8 a.m. EDT Friday NHC forecast are also shown. OHC values in excess of 80 kilojoules per square centimeter (yellow-green colors) are often associated with rapid intensification of hurricanes. On Saturday, the eastern part of Nate's circulation will be passing over the northern portion of the Loop Current, where a warm eddy appears to be attempting to break off. University of Miami Rosenstiel School of Marine and Atmospheric Science

NHC defines rapid intensification as an increase in sustained winds of at least 30 knots (35 mph) in 24 hours. Given the factors above, this seems possible, though it's far from guaranteed. Nate remains an asymmetric storm, embedded in a complex larger circulation, so it is unlikely to crank up as dramatically as some other rapid intensifiers we've seen this year. The 0Z Saturday run of the SHIPS statistical model gave Nate a 31 percent chance of gaining at least 30 knots of intensity in 24 hours, and a 47 percent chance of gaining at least 25 knots. However, Nate's less-than-ideal structure is not reflected in the SHIPS output. Our top dynamical models, including those tuned for intensity prediction such as the HWRF and HMON, were surprisingly low-key on the odds of Nate strengthening. The 18Z Friday runs of the GFS, HWRF, and HMON dynamical models all bring Nate to the U.S. Gulf Coast as a tropical storm. Nate's upgrade to hurricane strength late Friday night makes these model projections quite suspect, though.

Taking all these mixed signals into account, the prudent approach is to get ready for Nate to arrive on the Gulf Coast as a higher-end Category 1 storm—with a chance of pushing into the Cat 2 range—and keep our fingers crossed that Nate will fail to maximize its potential, as the dynamical models insist.

Impacts From Nate

The track forecast for Nate is quite straightforward. As Nate enters a region of strong upper-level steering, it will continue briskly toward the north-northwest on Saturday and will be approaching the U.S. Gulf Coast on Saturday night, most likely somewhere between New Orleans and Pensacola. Nate is projected to angle toward the north-northeast around this time, and the exact location of this turn will be crucial to the landfall location. If the turn is delayed, landfall could be in far southeast Louisiana, whereas a faster turn will bring the center closer to the coast of Alabama or the far western Florida Panhandle.

Winds: Peak winds in Nate will hinge on how quickly the storm intensifies on Saturday. The hurricane-force wind field at landfall is not expected to be broad—perhaps just 20 or 30 miles wide. Tropical-storm-strength winds could affect a much broader region, up to 200 miles wide, as Nate pushes inland. As we saw with Hurricane Irma in Florida, sustained winds below hurricane strength can still be enough to bring down trees and power lines in wet soil and produce widespread power outages.

Since Nate will make landfall as a fairly fast-moving system (around 15 – 20 mph), there will be a stronger-than-usual asymmetry to its wind field, with the bulk of the strong winds to the right (east) of Nate's center. NOAA's Atlantic Oceanographic & Meteorological Laboratory explained: "In general, the strongest winds in a hurricane are found on the right side of the storm because the motion of the hurricane also contributes to its swirling winds. A hurricane with a 90 mph [145 km/hr] winds while stationary would have winds up to 100 mph [160 km/hr] on the right side and only 80 mph [130 km/hr] on the left side if it began moving (any direction) at 10 mph [16 km/hr]. Note that forecasting center advisories already take this asymmetry into account and, in this case, would state that the highest winds were 100 mph [160 km/hr]."

Figure 3. Diagram showing the additive and subtractive effect of storm motion on peak winds at either side of a tropical cyclone's center. Chris Landsea (NOAA / NHC), courtesy NOAA / AOML

Surge: A storm surge warning is up for the Gulf Coast from Morgan City, Louisiana, to the Okaloosa/Walton county line in Florida, as well as along the northern and western shores of Lake Pontchartrain. The highest surge from Nate will arrive quickly on Saturday night, and will likely peak before dawn Sunday, so residents need to take the surge threat seriously and make final preparations as soon as possible on Saturday. As of 8 p.m. EDT Friday, the following inundations above ground level are possible with Nate, assuming the storm were to arrive during high tide:

  • Morgan City, Louisiana to the mouth of the Mississippi River ... 4 to 6 ft
  • Mouth of the Mississippi River to the Alabama/Florida border ... 5 to 8 ft
  • Alabama/Florida border to the Okaloosa/Walton County Line ... 4 to 6 ft
  • Okaloosa/Walton County Line to Indian Pass, Florida ... 2 to 4 ft
  • Indian Pass to Crystal River, Florida ... 1 to 3 ft

Because the daily high tide across this region occurs during the pre-dawn hours, it is quite possible that Nate will reach the coast near high tide. Tidal range between low and high tide is 1 - 1.3' along the central Gulf Coast, so the timing of Nate's storm surge with respect to the high tide can cause an additional foot or so of flooding. High tide in Mobile, Alabama is at 1:46 a.m. local time Sunday, and it will be one of the highest high tides of the year, due to the full moon. Low tide is at 10:12 a.m. Saturday. At Shell Beach, Louisiana, on the east side of New Orleans, high tide is at 4:29 a.m. local time Sunday, and low tide is at 12:14 p.m. Saturday.

Rains: Nate's rapid motion will limit the total amount of rainfall at any one spot, and the overall accumulations should be less than those observed during slower-moving tropical cyclones. However, Nate is embedded in a very moist atmosphere, and torrential rain could still fall in short periods. Nate's quick-hitting rains could exacerbate the strain on the troubled levee system in and around New Orleans, especially if Nate tracks toward the western end of its forecast range. Localized rainfall totals of 6 - 10" are expected close to Nate's landfall location, and intense rainbands will stream onshore well east of Nate's center across the Florida Panhandle. A large area of 4 - 12" rains, perhaps including Atlanta and Nashville, may develop as Nate accelerates into the southern Appalachians on Sunday. Rains of 2 - 6" will stream across the northern Appalachians and into southern New England on Monday, as Nate races northeast as a fast-weakening tropical cyclone.

This animation of NOAA's GOES East satellite imagery of Tropical Storm Nate from Oct. 5 at 5:45 a.m. EDT (0945 UTC) to Oct. 7 ending at 6:00 a.m. EDT (1000 UTC) ends after Nate strengthened into a hurricane while moving through the Gulf of Mexico. TRT: 00:27. NASA / NOAA GOES Project

Reposted with permission from our media associate Weather Underground.

Show Comments ()

EcoWatch Daily Newsletter

Sponsored
Business
velkr0 / Flickr / CC BY 2.0

Texas Supreme Court Rules Cities Cannot Ban Plastic Bags

The Texas Supreme Court struck down the city of Laredo's plastic bag ban—a decision that will likely overturn similar bans in about a dozen other cities, including Austin, Fort Stockton and Port Aransas.

Keep reading... Show less
Politics
Ryan Zinke visits Wall Drug in Wall, South Dakota on May 25. Sherman Hogue / U.S. Dept. of the Interior

Report: Trump Admin. Suppressing Media Access of Government Scientists

A new Trump administration protocol requires U.S. Geological Survey (USGS) scientists to run interview requests with the Department of the Interior, its parent agency, before speaking to journalists, the Los Angeles Times reported.

The move is a departure from past media practices that allowed government scientists to quickly respond to journalists' inquiries, according to unnamed USGS employees interviewed by the Times.

Keep reading... Show less
Climate
Icebergs calving from an ice shelf in West Antarctica. NASA / GSFC / Jefferson Beck / CC BY-SA 2.0

Good News From Antarctica: Rising Bedrock Could Save Vulnerable Ice Sheet

After last week's disturbing news that ice melt in Antarctica has tripled in the last five years, another study published Thursday offers some surprising good news for the South Pole and its vulnerable West Antarctic Ice Sheet (WAIS).

The study, published in Science by an international research team, found that the bedrock below the WAIS is rising, a process known as "uplift," at record rates as melting ice removes weight, potentially stabilizing the ice sheet that scientists feared would be lost to climate change.

Keep reading... Show less
GMO
Soybeans with cupped leaves, a symptom of dicamba injury. University of Arkansas System Division of Agriculture / Flickr / CC BY-NC 2.0

Dicamba Damage Roars Back for Third Season in a Row

University weed scientists have reported roughly 383,000 acres of soybean injured by a weedkiller called dicamba so far in 2018, according to University of Missouri plant sciences professor, Kevin Bradley.

Dicamba destroys mostly everything in its path except the crops that are genetically engineered (GE) to resist it. The drift-prone chemical can be picked up by the wind and land on neighboring non-target fields. Plants exposed to the chemical are left wrinkled, cupped or stunted in growth.

Keep reading... Show less
Sponsored
Food
Memphis Meats

FDA Takes First Steps to Regulating Lab-Grown Meat

By Dan Nosowitz

Lab-grown meat—also known as cultured meat or in vitro meat—has long been enticing for its potential environmental, social and economic benefits.

Keep reading... Show less
Politics
Scott Pruitt speaking at meeting at the USDA headquarters in Washington, DC, on Jan. 17. Lance Cheung / USDA

Breaking: Sierra Club Demands Pruitt’s Emails After Only 1 Disclosed by EPA

As part of ongoing litigation, the Sierra Club has demanded that the U.S. Environmental Protection Agency (EPA) search Scott Pruitt's personal email accounts for work-related emails, or certify clearly and definitively that the administrator has never used personal email for work purposes. The demand comes on the heels of a successfully litigated Freedom of Information Act (FOIA) request for all of EPA Administrator Scott Pruitt's email and other communications with all persons and parties outside the executive branch. These facts were first reported in Politico early this morning.

Keep reading... Show less
Sponsored
Animals

Iceland Flouts Global Ban to Slaughter First Protected Fin Whale of New Hunting Season

Iceland's multi-millionaire rogue whaler Kristján Loftsson and his company Hvalur hf have resumed their slaughter of endangered fin whales in blunt defiance of the international ban on commercial whaling.

The hunt is Iceland's first in three years and marks the start of a whaling season that could see as many as 239 of these majestic creatures killed.

Keep reading... Show less
Food
Life- Trac / CC BY-SA 3.0

Farm Bill With Huge Giveaways to Pesticide Industry Passes House

A farm bill that opponents say would harm endangered species, land conservation efforts, small-scale farmers and food-stamp recipients passed the U.S. House of Representatives 213 to 211, with every House Democrat and 20 Republicans voting against it, The Center for Biological Diversity reported.

Keep reading... Show less
Sponsored

mail-copy

The best of EcoWatch, right in your inbox. Sign up for our email newsletter!