Is hurricane season dead? Or could La Niña help provide one last punch
By Jennifer Gray and Haley Brink, CNN meteorologists
As we get into the latter part of the busiest three-month period of hurricane season (August, September, October), can we start to take a deep breath and exhale?
Is this it? Have we seen the worst of hurricane season? Is it over?
In August, Colorado State University called for the season to end with 18 named storms, eight hurricanes and four major hurricanes (Category 3 or higher), which would make this season above average. An “average” season produces 14 named storms, seven hurricanes and three major hurricanes.
So far this season we have already seen 20 named systems, seven hurricanes and four major hurricanes, putting 2021 already well above average, despite the fact we have not had any named systems in the Atlantic for roughly two weeks.
So it begs the question: Is it over?
Colorado State just put out its two-week hurricane outlook and believes this week will be quiet, but things could pick up next week.
“The Climate Forecast System (CFS) model is generally predicting below-normal shear across the Caribbean during week two, which could favor Atlantic Tropical Cyclone development in the Caribbean during that time,” says the outlook.
One factor which could keep the season alive is the arrival of La Niña. It was announced last week La Niña has officially arrived, which typically signals more activity in the Atlantic basin for tropical systems.
During La Niña, weaker winds between the ocean surface and upper levels of the atmosphere impact global jet streams and can influence the track and severity of winter storms and hurricanes during warmer months.
“La Niña is associated with reductions in vertical wind shear in the Caribbean and tropical Atlantic,” said Phil Klotzbach, a research scientist at Colorado State University. “Too much shear is typically what ends the Atlantic hurricane season, so La Niña can extend the active part of the season.”
“Last year is a great example of this, as we had six hurricanes and five major hurricanes in October-November,” he said. “While we certainly don’t expect to see that much activity the remainder of this season, the development of La Niña does leave the window open for more late-season storm activity this year.”
So, we wouldn’t write off the 2021 season just yet. Areas around Florida and the Caribbean are where tropical systems usually spin up at this point in the season.
It means we could have shorter lead time if one does form, because it will be forming closer to home.
“We are all happy when the first fall cold front passes through and cools off the air in the South, but the water temperature in the Gulf of Mexico south of Pensacola is still 81 degrees and near the Cayman Islands it is still over 85. That is plenty warm enough to generate additional tropical storms,” said CNN meteorologist Chad Myers.
No doubt this season will be remembered the most for Hurricane Ida, which devastated not only portions of south Louisiana, but the Northeast as well.
Ida will go down as one of the top 5 costliest hurricanes on record, with a price tag of $60 billion and still climbing.
The human cost was much greater, with nearly 100 people killed.
People not only died from the storm, but the heat that followed in the days and weeks after the storm passed, for people who had lost electricity in the storm and could not keep cool.
How climate change made Ida worse
What La Nina’s arrival means for the rest of the country
With the arrival of La Niña, there are more impacts than the increase in hurricane activity.
La Niña — translated from Spanish as “little girl”– is a natural ocean-atmospheric phenomenon marked by cooler-than-average sea surface temperatures across the central and eastern Pacific Ocean near the equator that consequently impact weather across the world.
La Niña typically brings wetter than normal conditions to the Pacific Northwest, but drier conditions for the desert Southwest.
This means, portion of the drought-stricken West could stay abnormally dry for the foreseeable future.
La Niña was also present last winter, which exacerbated drought conditions across the west.
NOAA will release its winter outlook October 21, and the presence of La Niña is expected to weigh heavily in the forecast for the season. The prediction center put the odds near 90% La Niña would be in place through the winter of 2021-2022.
Parade of storms for the west
A series of storm systems will crisscross the country this week, bringing snow to the mountains and rain to the east.
“Monday’s storm is just the first in a series of storms that will move into the West Coast this week and help bring some drought relief,” said CNN meteorologist Dave Hennen.
Portions of the Sierras will pick up one to three inches of snow above 5,000 feet with the first system, while the Rockies will see snow totals range from six inches to a foot of fresh snow for higher elevations.
By midweek, the first system will push east and a second will come onshore in the west.
The second system will have more rain than snow for the west, but could produce nice rainfall totals for portions of California that need it most.
Central and northern California will get the brunt of the rainfall, while much of Oregon and Washington will be in the rain as well.
As the storms push east, it will be all rain.
See if rain is in your forecast this week >>>
While we are not anticipating severe weather, we could see heavy rainfall stretch across the Midwest and Ohio Valley midweek.
Most areas will see about an inch or two of rain, but some isolated locations could pick up more.
Good news for the wildfire fight in the short term
“Wildland firefighters continue to work toward containment goals on 18 large fires and complexes that have burned 2,253,764 acres,” the National Interagency Fire Center said Monday. “No new large fires were reported over the weekend, and the Tiltill Fire in Yosemite National Park and Antelope Fire in the Klamath National Forest were contained.”
Nationally, fire containment continues to show vast improvement with more than 20 large active wildfires contained since Thursday.
There are still eight large fires burning in California. The Alisal Fire has been one of the worst during the past week, burning more than 17,000 acres in Santa Barbara County.
The fire is now 80% contained, up from only 11% containment this past Thursday. “Onshore flow will strengthen across the area, bringing cooler temperatures and higher relative humidity,” says the US Forest Service daily fire update.
It should help firefighters in the region somewhat, however, the winds will remain. They could see localized wind gusts of up to 25 to 40 mph through the beginning of the week.
At least 27 people killed after torrential rain in India
Deadly landslides were triggered after devastating rains in India.
Satellite estimates show more than 229 mm (9 inches) of rain fell in a 24-hour period October 17 in Kerala, which is substantial.
The flooding in India was caused by a combination of the dwindling Monsoon, as well as a low-pressure system in the southwest Arabian Sea, which pushed an influx of moisture into southwest India.
The forecast calls for the low pressure in the Arabian Sea to dissipate, which will ease rainfall in the area. Rainfall amounts of 50-100 mm could be expected with the monsoon still in place over the region.
The ground is saturated and unstable, especially in the higher elevations of eastern Kerala, so any additional rainfall could pose additional threats such as landslides until the area dries out.
Two day cumulative rainfall for two locations in Kerala:
• Idukki – 547 mm
• Kottyam – 389 mm
The state of Kerala is already at 14% above average for rainfall for the whole for the month of October.
Ominous waterspout caught on camera
Check out a waterspout in Cuba caught on camera October 16.
The waterspout occurred on the south side of Cuba in the town of Cienfuegos, and lasted for about 8 minutes, not causing any damage.
Cuba sees a steady stream of tropical moisture, which can enhance convective thunderstorms in the region and result in waterspouts.
Waterspouts are quite common in the Gulf of Mexico and the Caribbean.
The-CNN-Wire
™ & © 2021 Cable News Network, Inc., a WarnerMedia Company. All rights reserved.
CNN meteorologists Judson Jones, Brandon Miller, Haley Brink and Michael Guy contributed to this weather column
