Tropics are Unusually Quiet Right Now (10/15)

Bill's Blog

The Atlantic-Gulf of Mexico-Caribbean is quiet at the moment (Oct. 17) and is likely to stay quiet this week.


Active Storms  |  Marine Forecasts 2-Day Graphical Tropical Weather Outlook  |  5-Day Graphical Tropical Weather Outlook

Same story in the Eastern Pacific


Active Storms  |  Marine Forecasts 2-Day Graphical Tropical Weather Outlook  |  5-Day Graphical Tropical Weather Outlook

And…no tropical depressions or tropical storms in the Central Pacific.


Active Storms  2-Day Graphical Tropical Weather Outlook  |  5-Day Graphical Tropical Weather Outlook

It’s been warm in Hawaii. Honolulu checked in with a high/low temp. of 85/73 on Saturday 10/16.

Tropical Storm Lionrock

In the Western Pacific,”Namtheun”) is now just a weakening tropical depression far from land. Its remnants will drift toward the Aleutian Islands.

There is no tropical activity in the Indian Ocean or in the Southern Hemisphere.

We are now more than a month past the peak of the hurricane season in N. America. I do expect more tropical depressions and storms in both the Atlantic and Pacific, but most of this year’s storms are in the rear-view mirror. We’ve made it down through the letter “V” for tropical storm names. The next Atlantic storm will be named “Wanda”. After that, there is a 2nd list of names that will be used (instead of Greek letters) that starts with “Adria” and “Braylen”.

Ace Index and Hurricane Summary for the Atlantic Ocean for 2021 thru 10/7

Here’s the latest Hurricane Summary from Colorado St. Univ. “Sam” was an extraordinary storm and you probably didn’t hear anything about it. Meteorologists use the ACE Index – a measure of both the strength and longevity of tropical storms. “Sam” piled up a very impressive ACE Index of 53.8, surviving as a hurricane for 11 days. It managed to pretty much miss all land areas as it meandered north through the central Atlantic. Hurricane “Larry” accumulated 32.8 ACE points. “Larry” also pretty much missed land areas. “Sam” and “Larry” have accounted for 62% of the ACE points this season.

Ace Index and Hurricane Summary for the entire globe

Here’s the global hurricane summary from Colorado St. Univ. through Oct. 7. Note the ACE Index on the right side of the table. The N. Atlantic has accumulated 139.5 ACE points this season, compared to an average ACE-to-date of 90.9. That’s 153% of average. Compare that to the E. Pacific at 71% of average-to-date and the W. Pacific (the most active region for tropical storms) at only 74% of average-to-date.

Globally for 2021, we have an ACE Index of 408.3, compared to an average ACE Index-to-date of 440.2 (inc. the 0.9 in the S. Indian Ocean). So, for the entire planet, we’re at 93% of average-to-date ACE.

The top five years for the ACE Index in the Atlantic sector are 1933, 2005 (Katrina), 1893, 1926 and 1995. The highest ever ACE estimated for a single storm in the Atlantic is 73.6, for the San Ciriaco hurricane in 1899, likely because it was a Category 4 hurricane which lasted for 4 weeks. That single storm had an ACE higher than many whole Atlantic storm seasons.

Hurricane Tracks of 2021

Here’s the tropical storm/hurricane tracks for the Atlantic/Caribbean/Gulf of Mexico for 2021.

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