Is there a correlation between lack of Atlantic hurricanes, significant weather elsewhere?

By Kristina Pydynowski, AccuWeather senior meteorologist

By Alex Sosnowski, AccuWeather senior meteorologist

August 27, 2018, 6:24:00 PM EDT

There may be a correlation between a lack of hurricanes in the Atlantic and above-average storminess elsewhere in North America and the Pacific Ocean off of the West Coast.

While the Atlantic Basin has been relatively quiet so far this summer, the eastern part of the United States was struck with historic rain and Hurricane Lane was part of a flurry of tropical activity in the eastern Pacific Ocean, including Hawaii.

Dr. Joel N. Myers, president and founder of AccuWeather and former professor at the Pennsylvania State University, has studied global weather patterns for decades and speculates that these events may be interconnected.

A bridge along S. Town Line Road in Lodi, N.Y., was washed away by a flooded Breakneck Creek, Tuesday, Aug. 14, 2018. Flash floods caused by heavy pre-dawn downpours drenched New York state's Finger Lakes region Tuesday. (AP Photo/Heather Ainsworth)

Myers states there must be a balance in the upward and downward motion in the atmosphere corresponding with storms and high pressure areas.

Storms, such as hurricanes, are associated with upward motion which causes clouds and precipitation, while high pressure areas are associated with downward motion and dry air.

"Hurricanes are violent storms with violent updrafts and heavy rainfall," Myers stated.

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"Thus far, powerful hurricanes have been non-existent in the Atlantic basin," Myers said. The opposite is true in the Pacific Ocean.

Tropical Storm Miriam formed on Sunday, marking the thirteenth named storm in the eastern Pacific Ocean off the coast of Mexico. On average, there are not this many storms in the basin until the end of September.

On contrast, there have only been five named storms thus far during the 2018 Atlantic hurricane season. Of the five systems, Hurricane Chris was the strongest with peak winds of 105 mph, or Category 2 strength.

There were three Atlantic hurricanes in 2017 up to this point in the season, including Hurricane Harvey, which became a Category 4 hurricane before barreling into Texas with catastrophic flooding. There were five additional named tropical storms to date in 2017.

While the tropical Atlantic will stay quiet most of this week, AccuWeather Hurricane Expert Dan Kottlowski is monitoring the potential for development at the start of September.

Accumulated cyclone energy (ACE) is another tool meteorologists can compare tropical activity from basin to basin and season to season. The ACE measures the strength of hurricanes and tropical storms over their duration.

The ACE for the Atlantic through Aug. 27 is 17.5, which data from Colorado State University indicates is below the normal to date value of 23.8 to date.

Meanwhile, the ACE value is double the normal 70.8 value through the same date in the eastern Pacific Ocean.

"Since we are heading into El Niño, it is not surprising that the Pacific has been more active than the Atlantic," according to Kottlowski. "The Pacific should have more upward motion and storms, while the Atlantic has and will continue to have more frequent episodes of sinking motion."

Weather is essentially the result of the atmosphere trying to balance itself, as shown in the tropics this year. Rising air and stormy weather in one area will always be accompanied by sinking air and dry weather in another region.

"Hurricanes are a mechanism that the atmosphere has for taking heat out of the tropics and pushing it into the middle and northern latitudes," Myers said.

In an effort for the atmosphere to achieve that process, a similar number of tropical cyclones may need to be produced overall from year to year.

"So if there is a lack of hurricanes in the Atlantic, they may have to occur in other parts of the Northern Hemisphere," according to Myers.

Kottlowski concurs and stated that between 85-90 tropical cyclones (with strengthen equivalent to tropical storms and hurricanes in the Atlantic or eastern Pacific oceans) typically develop around the globe each year.

In 2017, the ACE index was flipped between the Atlantic and eastern Pacific Oceans.

The active Atlantic season yielded an ACE value of 226, when normal for the whole season is around 100. The ACE in the eastern Pacific was somewhat below normal with a value of 98.2 (112 is normal).

The International Space Station passing over Hurricane Lane on Wednesday. (Photo/NASA Astronaut Ricky Arnold)

Myers stressed that ACE is a tool but should not be taken as gospel when comparing seasons to seasons.

"The problem with ACE is that it depends on having measurements where data is sparse," Myers said. "Before the era of satellites, many tropical storms and hurricanes were missed. Now, we have better satellites that cover more areas and there is a heightened awareness."

"Further, there is no standard for naming storms," he said. "In the past, some years a storm was named when it had 40-mph winds. In other years, a storm may not have been named until it had 60-mph winds."

The impact of the Atlantic Basin being quiet so far this hurricane season may extend beyond the tropics, according to Myers.

"In absence of violent hurricanes over the Atlantic, these strong areas of upward motion may have been compensated for by the upward motion during the rounds of non-tropical, but torrential rainstorms in the northeastern U.S. this summer."

While there was a lull in activity between Hurricane Chris and Tropical Storm Debby from later July to early August, rounds of torrential rain triggered major flooding from the mid-Atlantic to New York state and southern New England.

More heavy rain targeted the Northeast right before Tropical Storm Ernesto developed in mid-August.

"The weather pattern this summer is one of the most dramatic outbreaks of rain ever to hit Pennsylvania and other states in the region in a non-tropical storm setting," according to AccuWeather Chief Meteorologist Elliot Abrams.

The deluge that occurred from from July to mid-August was on par with the type of rainfall that can be unleashed by a tropical storm or hurricane.

Myers said that more research must be done to prove the speculation of a correlation between a lack of hurricanes in the Atlantic and significant weather elsewhere across the Northern Hemisphere.

Several AccuWeather meteorologists note that other factors were also in play that contributed to the extreme rain events in the Northeast, such as a persistent stream of tropical moisture.

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