Active hurricane season likely in store for isles

With a tropical storm forming Tuesday in the eastern Pacific earlier than ever recorded, can the first hurricane threat of the season be far behind?

As a matter of fact, forecasters say Hawaii is likely to see an active hurricane season if signs of a developing El Nino continue to hold true.

“There’s an increasing chance of El Nino developing in the late summer or fall,” Hawaii state climatologist Pao-Shin Chu said Tuesday. “If that’s the case, it’s not good for us.”

National Weather Service meteorologist Matt Foster said that while the Central Pacific Hurricane Center has yet to make its official forecast for the season, climate forecasters so far indicate that the trend is toward El Nino conditions. If that’s true, there is likely to be a greater number of tropical storms in our future.

The El Nino weather phenomenon occurs every two to seven years when warm Pacific Ocean water pools at the equator and ends up changing weather patterns around the world.

In Hawaii, El Nino translates into summer heat, warmer ocean water, summer rainfall and a greater threat of tropical cyclones, followed by winter drought and large ocean swells.

Two years ago Hawaii endured one of the strongest El Nino episodes on record, and the islands saw weather anomalies in the extreme, including the wettest summer in 30 years, winter waves large enough to run the Eddie Aikau big-wave surfing contest and a record number of hurricanes plying the Central Pacific.

The Central Pacific hosts four to five named tropical storms in a typical year. But 2015 witnessed 14 named storms, including eight hurricanes, five of which became major hurricanes. It was the most active season since reliable record keeping began in 1971.

Last year brought a weak La Nina episode — El Nino’s polar opposite. But the Central Pacific still saw an above-average hurricane season with six tropical cyclones, probably due to a phenomenon involving residual warm water left over from the El Nino season.

Conditions are now considered neutral, and most experts weren’t expecting such a quick turnaround for another El Nino year. In fact, the El Nino-La Nina-El Nino sequence in three successive years has occurred only once since 1950 — in the mid-1960s, according to the National Weather Service.

Chu, a meteorology professor at the University of Hawaii at Manoa, said among the indicators pointing to El Nino is the fact that current sea surface temperatures in the equatorial Pacific are a half-degree warmer on average than usual.

“It looks like there is a good chance it will develop into El Nino,” he said.

Chu said the upcoming El Nino episode is highly unlikely to be as strong as the one in 2015, but it appears likely to arrive just in time to give Hawaii’s peak hurricane season month of August an extra boost.

“June and July will be crucial months to see how this El Nino develops,” he said. “We will have to keep watch.”

As for Tropical Storm Adrian, the storm that formed off the Central American coast Tuesday — a record six days before the start of the eastern Pacific hurricane season — experts say there is little, if any, relation to the Central Pacific hurricane season, which officially starts June 1.

National Weather Service officials said that during the last two months, strong warming occurred in the eastern Pacific Ocean near the west coast of Central and South America. That makes ideal conditions for tropical storm formation, they said.

Phil Klotzbach, a hurricane researcher with Colorado State University, said there have been eight seasons since 1980 with named storms forming prior to May 20 in the northeast Pacific. Of those eight seasons, only three ended up well above average, he said, while the other five saw near- to below-average storms in the Central Pacific.

As of Tuesday night the National Weather Service predicted Adrian would move up the coast of Central America, growing into a hurricane by Friday and threatening Mexico by Sunday night.