Reminder: The 2021 Atlantic Hurricane Season Is Just 30 Days Away

 

#15,936

Although the end of the record setting 2020 hurricane season seems far less than 5 months ago, we are once again on the cusp of another Atlantic tropical hurricane season, and once again early forecasts - while not as aggressive as last year (see map below) -  suggest a busier than usual season. 

Credit NOAA

With 30 named storms, 14 of which became hurricanes (six of them major (CAT 3+) ) - the United States saw an all-time record of 11 landfalls.. Fortunately major population centers were spared the worst of the storms and many stayed out to sea - and while damage was extensive - in many ways we got lucky.

The early (April 8th) 2021 Hurricane forecast from CSU (Colorado State University) suggests a robust, but not record-setting, hurricane season ahead.  

The number of hurricanes doesn't tell the whole story, of course.  One Category 5 storm hitting a populated region (think: New Orleans, Tampa, Miami, New York City, etc.) at the right angle could far exceed the damage and loss of life from last year's entire season. 

NOAA will offer up its 2021 Hurricane forecast later this month, while NOAA/NHC will kick off Hurricane Preparedness week a bit earlier than usual this month (May 9th-15th) because each of the last 5 years has seen the development of a pre-season named storm. 

This year NOAA has also adjusted the `average' number of hurricanes upwards from 12 to 14, based on data collected since 1991.  While this increase may be due to a warming planet, hurricane activity also follows a 20-40 year cycle called the AMO (Atlantic Multi-decadal Oscillation) where we see decades of high activity followed by decades of less activity (see chart and article below).

Between 1949 and 1970 hurricane activity was high, followed by 23 years (1971-1994) of relatively low activity.  We've been in an upswing for the past 25 years, although remarkably we went from 2006 to 2017 (11 years) without a major landfalling hurricane in the United States. 

Another factor being better satellite coverage, which allows more precise measurements of storm intensities when they are far out to sea.

NOAA explains their decision to increase the `average' number of storms in the following press release. 

‘Average’ Atlantic hurricane season to reflect more storms

Higher averages based on most recent 30-year climate record

April 9, 2021

Beginning with this year’s hurricane season outlooks, NOAA’s Climate Prediction Center (CPC) will use 1991-2020 as the new 30-year period of record. The updated averages for the Atlantic hurricane season have increased with 14 named storms and 7 hurricanes. The average for major hurricanes (Category 3, 4 or 5) remains unchanged at 3. The previous Atlantic storm averages, based on the period from 1981 to 2010, were 12 named storms, 6 hurricanes, and 3 major hurricanes.

NOAA is updating the set of statistics used to determine when hurricane seasons are above-, near-, or below-average relative to the climate record. This update process occurs once every decade.

“This update allows our meteorologists to make forecasts for the hurricane season with the most relevant climate statistics taken into consideration,” said Michael Farrar, director of NOAA’s National Centers for Environmental Prediction. “Our work illustrates the value of NOAA’s investments in next-generation technologies to capture the data that underpins our outlooks and other forecast products. These products are essential to providing the public and local emergency managers with advance information to prepare for storms, and achieving NOAA’s mission of protecting life and property.”

The increase in the averages may be attributed to the overall improvement in observing platforms, including NOAA’s fleet of next-generation environmental satellites and continued hurricane reconnaissance. It may also be due to the warming ocean and atmosphere which are influenced by climate change. The update also reflects a very busy period over the last 30 years, which includes many years of a positive Atlantic Multi-decadal Oscillation, which can increase Atlantic hurricane activity.

“These updated averages better reflect our collective experience of the past 10 years, which included some very active hurricane seasons,” said Matt Rosencrans, seasonal hurricane forecaster at NOAA’s Climate Prediction Center. “NOAA scientists have evaluated the impacts of climate change on tropical cyclones and determined that it can influence storm intensity. Further research is needed to better understand and attribute the impacts of anthropogenic forcings and natural variability on tropical storm activity.”

For the Eastern Pacific and Central Pacific basins the averages over the 1991 - 2020 period do not change. The Eastern Pacific basin will remain at 15 named storms, 8 hurricanes, and 4 major hurricanes. The Central Pacific basin will maintain an average of 4 named storms, 3 hurricanes and 2 major hurricanes.

NOAA will issue its initial seasonal outlook for the 2021 hurricane season in late May. The Atlantic hurricane season officially runs from June 1 through November 30.

Regardless of the cause, we appear to remain in a high activity cycle, and prudent residents who live in vulnerable areas will use the month of May to prepare.  

As always, I'll be devoting blog space to preparedness issues during this hurricane season, and to  the public health impacts of big storms.  I'll be updating my preps, and doing another upgrade to my home solar power project. 

And of course, in September, we'll be observing National Preparedness Month, where we look at far more than just hurricane preparedness. 

Disasters can strike anywhere and at anytime. While being prepared doesn't guarantee you and your loved ones will come away unscathed, it does increase your chances of a good outcome.