December 11, 2023

The Colorado State University Tropical Weather Team, led by Phil Klotzbach, expects a more active 2023 Atlantic hurricane season, with its latest update adding two more hurricanes to the forecast, one of which is expected to be a major hurricane.

2023 Hurricane Season 1This is the second time Colorado State University (CSU) has raised its forecast for the 2023 hurricane season.

Back in April, the CSU Tropical Forecasting Team predicted 13 tropical storms, six hurricanes and two major hurricanes for the season with an accumulated cyclonic energy (ACE) of 100.

That’s below the recent average of 14 named storms, seven hurricanes and three major hurricanes between 1991 and 2020.

On June 1, the team included an unnamed subtropical storm that formed in the Atlantic in January, but in the next forecast update, one of each type was added.

Thus, as of the first official day of the Atlantic hurricane season, CSU is forecasting 15 named tropical storms (that’s 14, minus one preseason subtropical event), seven of which are expected to become hurricanes (thus now adding 1), there will be 3 large hurricanes with intensity of Category 3 or above (add 1 again).

Now, fast forward another month or so, and exceptionally warm Atlantic sea surface temperatures (SST) prompted the forecasting team to revise their forecasts even higher.

Late yesterday, the CSU Forecast Team released an updated forecast that included 18 named tropical storms (that’s 17, minus one preseason subtropical event), nine of which are expected to become hurricanes (thus adding another 2), and 4 major hurricanes of Category 3 or greater intensity are now forecast (increasing the major hurricane forecast by 1).

On June 1, the cumulative cyclone power forecast had jumped to 125, but yesterday’s update raised it to 160.

An above-average Atlantic tropical storm and hurricane season is now forecast, with the months since April varying considerably, with a reasonable increase in the last month alone.

The Colorado State University Forecasting Team commented: “While we continue to expect a strong El Niño at the peak of the Atlantic hurricane season, sea surface temperatures will now be record warm across much of the tropical and subtropical Atlantic. and tropical Atlantic vertical wind shear, but extreme anomalous warmth in the tropical and subtropical Atlantic may offset some of the typical El Niño-driven increases in vertical wind shear.”

Specifically for the insurance, reinsurance, and insurance-linked securities (ILS) sectors, they also said that “the estimated probability of major U.S. hurricane landfall is higher than the long-term average.”

The CSU team has increased the probability of all landfall for a major hurricane hitting the coast during the 2023 hurricane season to:

  1. The entire U.S. coastline is at 50%, right in line with the 1880-2020 average (up from 43% on June 1).
  2. The US East Coast (including Florida) was at 25%, again in line with the average (up from 21% on June 1).
  3. The Gulf Coast region, from the Florida Panhandle to Brownsville, again averaged 32% (up from 27% on June 1).

With the new CSU forecast update, the Artemis average among the forecasters we track now expects 15 named storms (up 1), 7 hurricanes (flat), and 3 major hurricanes ( Flat), currently slightly above recent average storms.

But keep in mind that there are now 3 tropical storms, 2 of which are beyond the above numbers (since Arlene was not counted in our data long before the season).

But even accounting for these early storms, the forecast for the current nine hurricanes to develop (four of which will become Category 3 or stronger) as the season progresses, along with an elevated probability of landfall, should give us Reason to be cautious and make sure all eyes are on the tropics as the peak of the season approaches later this summer.

track 2023 Atlantic Tropical Storm and Hurricane Season On our dedicated page we will update you as new information becomes available.

Colorado State University has again raised its 2023 hurricane forecast, with a higher probability of landfall, Publisher:
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