Tropical Storm Isaias on Tuesday brought rain, flooding and the most dangerous wind gusts since Superstorm Sandy to New Jersey, destroying property and leaving millions in the Atlantic region without power as the pandemic raged on.
But despite the damage, Isaias wasn’t a major hurricane. The conditions that allowed it to occur could strengthen the coming months. And the peak of the Atlantic hurricane season is still weeks away, experts said.
“We expect continued activity and a greater chance of stronger hurricanes,” said David Robinson, the state climatologist. “It’s far, far, far too early to relax. The peak of the season is the second week of September.”
Isaias is the ninth named storm this season. New Jersey has already seen two — Isaias and last month’s Tropical Storm Fay.
That’s unusual: At this point in the season, typically only one or two named storms have occurred, much less affected the Garden State.
“The atmospheric conditions are favorable,” Robinson said. “Waters are warmer than average, which helps to fuel these storms. They’ve been steered in all sorts of directions.”
Isaias organized and made landfall in the Dominican Republic on July 30. It reached the Bahamas two days later and weakened, dropping below hurricane strength.
But as it neared Florida, Isaias again intensified. It made landfall Tuesday in North Carolina as a hurricane and worked its way up the East Coast.
The storm’s path of destruction ended Tuesday night, when it lost tropical characteristics while over Canada.
A storm’s trajectory determines the conditions it brings. The west side of the storm is typically wetter, while the east side is drier but windier.
In Isaias’ case, much of New Jersey remained on the windier side, with the heaviest rain only in the western part of the state.
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Had the storm’s path shifted 50 miles or so east, “we would have gotten a soaking,” Robinson said.
The storm’s characteristics help explain limited river flooding activity in North Jersey. Bergen, Passaic and Essex counties, for example, saw elevated river levels, but few of those waterways reached flood action levels, according to real-time U.S. Geological Survey stream data.
Ahead of the storm, Steve Decker, director of the undergraduate meteorology program at Rutgers, said the storm surge threat from Isaias was low, a factor that would prevent Isaias from becoming another Sandy.
Storm surge, according to the National Oceanic and Atmospheric Administration, “is an abnormal rise of water generated by a storm, over and above the predicted astronomical tides.”
Often the greatest threat from hurricanes, storm surge results when forceful, cyclonic winds push water toward the shore.
Extreme flooding arises when storm surges coincide with normal high tides, a phenomenon known as storm tide.
The storm struck New Jersey on the heels of the state’s warmest month on record.
The average temperature, 78.9 degrees Fahrenheit, was 4.3 degrees above normal. It surpassed the previous record, held jointly by 1955, 1999 and 2011, by half a degree.
In late May, National Weather Service experts predicted a 60% chance of an above-normal Atlantic hurricane season. The season runs from June 1 through Nov. 30.
The predictions included 13 to 19 named storms, which have wind speeds of 39 mph or more.
The first named storm, Arthur, occurred May 16, before the outlook was even announced. Isaias marked the earliest ninth named storm on record.
“It’s been an early active season in the Atlantic basin,” Robinson said. “This was the earliest storm that got to the letter I. Fay was the earliest to the letter F.”
Among the named storms, experts expect six to 10 hurricanes with winds 74 mph or higher. The first hurricane, Hanna, made landfall in Texas in mid-July.
But neither Isaias nor Hanna, both Category 1 storms, met the threshold for a major hurricane. Major hurricanes — Category 3, 4 or 5 storms, such as Sandy — have wind speeds stronger than 111 mph.
Experts expect three to six major hurricanes this season, although they can’t predict what trajectory they’ll follow or whether they’ll make landfall.
The next storm will be named Josephine, followed by Kyle, Laura, Marco and Nana.
Alexis Shanes is a local reporter for NorthJersey.com. For unlimited access to the most important news from your local community, please subscribe or activate your digital account today.