Last week, I attended (virtually) the National Tropical Weather Conference live hurricane update from Dr. Phil Klotzbach, of Colorado State University. He took over Dr. William Gray’s hurricane forecasting when Dr. Gray passed in 2016. Phil always begins his talks with a tribute to Dr. Gray who began predicting in 1984:
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We reported on this forecast last week with Dr. Klotzbach’s forecast of 17 storms this year, eight of which will become hurricanes and, of those, four will become major (Category 3+) storms.
This is above the new average of 14-7-3 vs. the old average of 12-6-3 (the old average was based on 1980-2010 storms while the new one is based on activity from 1990-2020). Here’s the graphic put out by the National Hurricane Center last week:
Regardless of average, this looks to be a busy year.
Reasons why it’s going to get busy
To dig in just a little deeper than a quick mention on the news, the primary indicators for this forecast are the water temperatures in the Atlantic and Pacific oceans and wind shear. Think of wind shear as winds being strong enough to shear apart a developing storm so that it can’t get organized. Hurricanes like nice quiet atmospheres with plenty of moist air (which they get from warm water) and light winds.
First, the Pacific, which continues to be cooler than normal due to La Niña and model forecasts indicate that La Niña will continue at least a little bit, perhaps becoming more neutral by September/October. With cooler waters comes calmer air, meaning less strong winds for that wind shear coming across to the Caribbean.
La Niña in the Pacific means a busier season in the Atlantic. This time last year we weren’t sure if La Niña would get any stronger, but it did, and 2020 became the most active hurricane season on record.
Below you can see the current water temperature anomalies in the Pacific (in blue) and the warm Atlantic (in red). I’ve circled both:
There are, by the way, many more forecasts to come out over the next seven weeks from private groups, universities and governments, but so far the average forecast for the number of hurricanes this season is 9, and we know, it only takes one.
I’ll continue to update you. For now, get ready.
Frank