There is bad news for residents of the Gulf coast. The upcoming hurricane season has similarities to the 2005 storm season when hurricanes Katrina and six other major storms exploded in strength and fury as they passed over the high temperatures in the eddy of the Gulf current.
The same storm season also brought us, Rita and Wilma, which rapidly intensified, bringing death and destruction from Cozumel to Texas and Florida. It also was responsible for Hurricane Harvey and Ida in 2017 and 2021.
The Gulf already has high surface water temperatures, and heat energy in the Gulf is expected to only increase over the summer months.
The Gulf of Mexico Loop Current brings warm water from the Yucatan into the Gulf. The current this year is much further north, warmer, and saltier than average, which inhibits ocean mixing and may bring a grim summer for the United States.
NOAA predicts an above-average hurricane season with 14-21 named storms. Of those 6-9 hurricanes, three to six could be major hurricanes, category three or higher.
Jeff Masters writes in Yale Climate Connections:
Potential trouble is brewing in the Gulf of Mexico for the coming Atlantic hurricane season: waters with a high amount of heat energy. Sea surface temperatures (SSTs) in mid-May were 27-28 degrees Celsius (81-82° F) across most of the Gulf, 0.5 to 1.5 degrees Celsius (0.9-2.7°F) above the 1981-2010 average. That’s a lot of heat energy for potential hurricanes to feast on.
What’s more, the Gulf waters have the potential to be at near record-warm levels during the peak part of hurricane season, if the southeastern U.S. gets a sustained heat wave that brings light winds and hot conditions to the Gulf for an extended period. (The first half of May was record-warm for Galveston, Texas, which contributed to the unusually warm ocean temperatures off the Texas coast.)
But sea surface temperatures don’t tell the whole story. When a hurricane traverses a shallow area of warm ocean waters, its powerful winds will churn up cold waters from the depths, cooling the surface and putting the brakes on any rapid intensification the hurricane may have had. But when unusually warm ocean waters extend to great depth, 100 meters or more below the surface, the hurricane’s churning winds simply stir up more warm water, allowing dangerous rapid intensification to occur if wind shear is low. Thus, total Ocean Heat Content (OHC) is a key metric used to determine the potential for hurricane rapid intensification. And unfortunately, given the present ocean current configuration, there will be high ocean heat content in the Gulf of Mexico this hurricane season.
Nick Shay from the University of Miami writes in The Conversation.
Warm ocean water doesn’t necessarily mean more tropical storms. But once tropical storms reach waters that are around 78 F (26 C) or warmer, they can strengthen into hurricanes.
Hurricanes draw most of their strength from the top 100 feet (30 meters) of the ocean. Normally, these upper ocean waters mix, allowing warm spots to cool quickly. But the Loop Current’s subtropical water is deeper and warmer, and also saltier, than Gulf common water. These effects inhibit ocean mixing and sea surface cooling, allowing the warm current and its eddies to retain heat to great depths.
In mid-May 2022, satellite data showed the Loop Current had water temperatures 78 F or warmer down to about 330 feet (100 meters). By summer, that heat could extend down to around 500 feet (about 150 meters).
The eddy that fueled Hurricane Ida in 2021 was over 86 F (30 C) at the surface and had heat down to about 590 feet (180 meters). With favorable atmospheric conditions, this deep reservoir of heat helped the storm explode almost overnight into a very powerful and dangerous Category 4 hurricane.
The Washington Post’s Capital Weather Gang writes on the key elements that NOAA is monitoring:
Sea surface temperatures. Hurricanes thrive when water temperatures reach the lower to mid-80s. Hurricanes are heat engines, extracting thermal energy from “oceanic heat content.” A greater, deeper reservoir of exceptionally mild ocean water translates to more fuel to generate or sustain a hurricane.
- Water temperatures throughout the entire Gulf of Mexico and western Atlantic are running 1 to 3 degrees above average. The unusually warm water boosts the “potential intensity,” or maximum theoretical strength, a hurricane can achieve.
The loop current. Some researchers say unusually high temperatures in the Gulf of Mexico loop current are an ominous sign for the season ahead. The loop current is a warm-core eddy that meanders north of the Florida Straits and Yucatán Peninsula. The current could give storms an extra boost if they cross over it — but it’s one piece in a much larger atmospheric puzzle.
La Niña. La Niña is a dropping of sea surface temperatures in the eastern tropical Pacific. It sets in motion a chain-reaction process that favors increased Atlantic hurricane activity. Specifically, it cools the air over that relative temperature minimum in the eastern Pacific, spurring sinking motion there. That makes it easier for air over the Atlantic to rise and feed big storms.
Wind shear. Wind shear is a change of wind speed or direction with height. Too much shear can disrupt a fledgling storm’s circulation and tear it apart before it has the opportunity to organize. Shear can also spell the demise of a strong hurricane.
One of the many weapons of a hurricane is heavy rainfall far inland from the coast. Yeah, we got a lot of rain where I live.
The Verge writes about how climate change influences wind storms, storm surges, and heavy rainfall.
NOAA also pointed to an “enhanced” west African monsoon affecting this year’s Atlantic season. The west African monsoon, a major wind system, can drive stronger easterly waves that “seed many of the strongest and longest lived hurricanes during most seasons,” NOAA says in its season outlook.
Stronger hurricanes are expected to become more common as climate change heats up the world’s oceans. Warmer than average sea surface temperatures in the Atlantic Ocean and Caribbean Sea are also likely to boost hurricane activity this season, NOAA said today.
There’s also evidence that hurricanes have begun to intensify more quickly and keep their strength for longer after making landfall as global average temperatures rise. The Loop Current’s warm eddies also seem to hold more heat than they have in the past, Shay says, although scientists can’t yet pinpoint why.
Should NOAA’s predictions for 2022 come true, it would be the seventh consecutive above-normal season for the Atlantic.
What happens in the Arctic doesn’t stay in the Arctic.