Hurricane forecasting group maintains prediction for above-average storm season
Chance of landfall this year is 25% for the East Coast and 31% for Gulf Coast
Hurricane Delta shortly before landfall on Friday, Oct. 9, 2020 (Image courtesy of NOAA/NESDIS/STAR GOES-East).
With peak hurricane season starting in mid-August, a prominent hurricane forecasting group said Thursday it will maintain its prediction for an above-average Atlantic hurricane season because of unusually hot sea surface temperatures.
Colorado State University researchers anticipate 18 named storms, including the five that have already happened, with winds of at least 39 miles per hour. This includes nine hurricanes, five with winds of at least 74 mph, and four with winds of at least 111 mph.
Last year’s hurricane season was about 75% the activity of the average season, the researchers said. This season will be about 130% normal activity, they predict.
They also forecasted a 48% chance of a landfall somewhere on the U.S. coastline, 25% for the East Coast and 31% for the Gulf Coast. These probabilities are a few percentage points higher than normal.
The researchers originally expected below-average hurricane activity this year, but reversed their forecast in July and said the Atlantic basin was in for more activity than normal. This latest forecast, its last for the season, preserves their July prediction.
This hurricane season is a battle between two competing forces. The Atlantic’s record-hot sea surface temperatures are favorable for storm formation, but they’re running up against the hurricane-curbing force of El Niño, which is expected to grow stronger through the remainder of hurricane season.
Colorado State University researchers think “the extreme anomalous warmth in the tropical and subtropical Atlantic” counteract the impact of El Niño. It is the primary reason for the researchers’ above-average seasonal hurricane forecast.
Given the conflicting forces though, “the team stresses that there is more uncertainty than normal with this outlook.”
The researchers emphasized one landfall is all it takes to cause serious harm.
“As is the case with all hurricane seasons, coastal residents are reminded that it only takes one hurricane making landfall to make it an active season for them,” the forecasters wrote. “They should prepare the same for every season, regardless of how much activity is predicted.”
Louisianans know that all too well.
“In the Gulf of Mexico, we always have the chance of getting a bad storm, no matter the year, no matter the other constraints,” LSU climate scientist Jill Trepanier, who studies extreme weather, told the Illuminator earlier in the season. “Because in the peak of the season, from August, September and October, the Gulf of Mexico is so hot that…a storm can be created just in that warm environment and turn into a really bad storm.”
Colorado State University has been doing hurricane forecasts for 40 years. This latest forecast lists three authors, Philip J. Klotzbach, Michael M. Bell and Alexander J. DesRosiers.
The Atlantic hurricane season runs from June 1 to Nov. 30 each year, with peak activity from mid-August to mid-October. But some scientists, including the state climatologist, think the annual timeline should be expanded.
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