Now up to 25 named storms, hurricanes predicted for season by federal scientists

The Eastern Seaboard, including Long Island, now can expect even more named storms and hurricanes — a total of 19 to 25, up from the 13 to 19 named storms predicted in May, federal scientists said on Thursday.

The latest prediction, which includes the nine named storms that already have developed, is based on atmospheric and oceanic conditions that are “primed to fuel storm development in the Atlantic, leading to what could be an ‘extremely active season,’ " the Climate Prediction Center said.

With thousands and thousands of Long Islanders still waiting for their power to be restored after Tropical Storm Isaias hit Tuesday, the scientists stressed planning for powerful storms well ahead of their arrival.

The four main factors the forecasters cited on a conference call with reporters are: “warmer than average sea surface temperatures in the tropical Atlantic Ocean and Caribbean Sea, reduced vertical wind shear, weaker tropical Atlantic trade winds and an enhanced West African monsoon.”

It is quite unusual for so many names storms to have erupted this early in the season, which “has the potential to be one of the busiest on record,” the experts said.

The agency, part of the National Oceanic and Atmospheric Administration, updates its predictions for the June 1 to Nov. 30 storm season in early August, just as the likelihood of storms increases.

The number of possible named storms now forecast is double the average of 12. Half those storms become hurricanes and just three of them major hurricanes, the center said.

The probability of an above average season is 85%, a normal season has a 5% probability and a below average one 10%.  A named storm has minimum winds of 39 mph, for a hurricane, the definition is 74 mph and for a major hurricane, 111 mph.

While the experts will not be able to determine what impact global warming may be exerting until after the storm season ends, they explained the East Coast was in the 26th year of a period with lots of storms, thanks in part to the Atlantic MultiDecadal Oscillation. 

These phases of either warm or cool sea surface temperatures last 20 to 40 years and affect the Atlantic from Greenland south to the equator, NOAA says.

“We don’t know how long it is going to last” this time, said Gerry Bell, the center’s lead seasonal hurricane forecaster who invented a number of its models and who retires this year after three decades of service.

During warm periods — like the current one — both the number of storms and their force rises.

There is another risk factor this season: the possibility of a La Niña, defined by NOAA as the cooling of the Pacific in its eastern equatorial and central waters. This pattern lowers wind shear and winds at lower levels above the Caribbean that otherwise could curb storms.

The new forecast falls short of one of the worst seasons the East Coast experienced this century. There were 28 named storms in 2005, the experts said, adding they had anticipated 21 that year.

However, “we’ve never forecast up to 25 named storms,” Bell said.  Later, he added: “We’re seeing very conducive conditions; we’re not seeing them at the level we saw in 2005.”

The increase in the tally of named storms in 2020 is not due to improved computerized models, the scientists said, as their criteria have not changed though they now can spot and track them earlier.

The interplay of all these weather patterns remains somewhat mysterious. Said Bell: “The writing is not on the wall with any of this."