New seasonal hurricane forecasts released, quiet week across the tropical Atlantic

Latest update on the tropics provided by Local 10 Hurricane Specialist and Storm Surge Expert Michael Lowry


When it comes to seasonal hurricane forecasts – the prognosticators that analyze climate patterns and long-range weather models to predict the number of hurricanes and tropical activity through November – we receive periodic updates throughout the year.

The seasonal hurricane forecast business has blossomed over the years, with a number of shops now providing forecasts.

The group at Colorado State University (CSU), led now by Dr. Phil Klotzbach, were first on the scene with seasonal hurricane forecasts beginning back in 1984, with Dr. William Gray, a pioneer in tropical meteorology, paving the way.

The CSU team issues seasonal hurricane forecasts beginning in December of the year prior, with updates in April, June, July, and finally August – just ahead of the traditional ramp up in hurricane activity.

In addition to the pioneering group at CSU, the National Oceanic and Atmospheric Administration, the parent agency of the National Weather Service, began issuing hurricane season outlooks for the U.S. government starting in 1998.

They issue only two seasonal forecasts each year: the first in late May and an update released in early August.

Between the NOAA and CSU forecasts, we have monthly seasonal forecasts from the European Center for Medium Range Weather Forecasts (ECMWF), the group responsible for developing and maintaining the European or “Euro” model you probably hear discussed so often for hurricane forecasts.

In fact, it’s the very same European computer modeling system that they use to update their seasonal hurricane forecast at the beginning of each month across all tropical ocean basins.

Their June Atlantic Hurricane Season Forecast raised eyebrows across the tropical community, calling for 19 named storms and 11 hurricanes this hurricane season.

This was a significant increase from their May predictions (16 named storms and 8 hurricanes), and the highest overall activity forecast by the center since it began producing monthly forecasts some 30 years ago.

In general, the ECMWF forecasts have had been less skillful in their forecasts than the teams at CSU or NOAA, which use a more blended approach to less frequent forecasts.

That said, the ECMWF forecasts provide a good monthly temperature check on the tropics and in recent years have tended to lowball forecasts, so the June outlook was noteworthy.

(European Centre for Medium-Range Weather Forecasts (ECMWF))

On Tuesday, the European Center issued their July Atlantic Hurricane Season forecast, which revised downward its June forecast from 19 named storms and 11 hurricanes to a still-active 15 named storms and 8 hurricanes.

This is above the 1991-2020 average of 14 named storms and 7 hurricanes. Also, it’s worth noting that this is the most seasonal hurricane activity forecast by the European Center in July going back 12 years for the Atlantic.

Needless to say, with only three named storms so far in the Atlantic and no hurricanes, we have a lot of season left ahead of us.

(European Centre for Medium-Range Weather Forecasts (ECMWF))

Thankfully Tuesday, the tropical Atlantic is looking sleepy.

Bonnie in the eastern Pacific is plateauing as a strong Category 2 hurricane and, other than outer rain bands and swells to southern Mexico, poses no significant threat to land.

On the Atlantic side, we’re not expecting any organized tropical activity at least through the workweek.

About the Author:

Michael Lowry is Local 10's Hurricane Specialist and Storm Surge Expert.