Late shift in atmospheric conditions helps save Oahu from Douglas’ wrath
Hurricane Douglas appeared to have its sights set on Hawaii for the better part of a week and deviated from its track only slightly. In the end it was enough to spare the islands a lot of pain.
“The main Hawaiian Islands have dodged yet another bullet from a hurricane landfall,” Central Pacific Hurricane Center forecaster Robert Ballard said Monday.
Hawaii’s most populous isle was perhaps the luckiest of all as Douglas passed only about 30 miles north of Kahuku, making it the closest a hurricane has come to Oahu since before Hurricane Dot in 1959.
Increasing upper-level vertical wind shear on Sunday helped push the storm on a northward “jog” and away from Oahu, forecasters said, while Douglas’ most damaging wind and rain bands lashed out farthest to the north and west, away from the island.
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The result was that tropical storm-force winds came only within 10 miles of Oahu, satellite, radar and aircraft reconnaissance data indicated.
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“We were lucky,” said John Bravender, warning coordination meteorologist with the hurricane center. “If there was only a slight shift southward, it would have brought significant damaging winds and rains.”
Some rain and wind blew across Maui and Molokai, but there was no major damage anywhere across the state and Douglas was last seen threatening the Northwest Hawaiian Islands as a downgraded tropical storm.
While the near-miss was a blessing, Bravender said he’s hoping people don’t get complacent or weary about preparing for any future storms.
“That is something we struggle with,” he said.
In Texas, he said, a near-miss means the devastation happens 30 miles down the coast.
“We’re a small target on a big ocean,” he said. “Douglas passed 30 miles north of Oahu. Because we don’t see the impacts of that, it makes it difficult to communicate preparedness.”
While the islands were fortunate this time, the busiest part of the hurricane season — August and September — lies ahead. Residents should remain vigilant and prepared for the next storm with supplies and an emergency plan, Bravender said.
“We were really lucky in this case, but we won’t always be that lucky,” he said.
In May, forecasters predicted the Central Pacific would see two to six tropical cyclones during the annual hurricane season, which runs from June 1 to Nov. 30.
Douglas formed in the Eastern Pacific early July 20 as Tropical Depression Eight-E but gathered strength quickly, becoming a tropical storm before the day was out.
The next day, Hawaii appeared in the storm’s National Weather Service pathway cone even as it was hundreds of miles from entering the Central Pacific at 140 degrees west.
Fueled by warm waters, Douglas moved quickly and gathered strength to achieve Category 4 status, packing sustained winds of 130 mph as it entered the Central Pacific on Thursday — all the while keeping a bull’s-eye on the islands.
The hurricane lost some of its power as it passed over a section of cooler waters but maintained Category 1 strength as it approached the islands on a west-northwest track. Warmer waters and weakened wind shear near the islands allowed the storm to maintain its 90 mph intensity despite forecasts that predicted it would gradually lose some of its punch.
For a couple of days, Douglas appeared to have a beeline drawn toward Oahu, steered by a solid ridge of high pressure. But forecasters said a weakness in the ridge aloft and increasing vertical wind shear, mainly at higher levels, likely caused the hurricane to jog northward Sunday just as it was gunning for Oahu.
“I think we can feel really fortunate that it took the path that it did and that things were not as bad as it could have been,” said Eric Lau, National Weather Service meteorologist.
Data from U.S. Air Force Reserve Hurricane Hunters and weather radars indicated that Douglas’ center came closest to Kahuku at about 7 p.m. Sunday.
Hurricane Dot came about 60 miles southwest of the Waianae Coast on Oahu before making landfall on Kauai in August 1959. Previous weather records are generally considered unreliable.
Atmospheric scientists say most hurricanes approaching Hawaii in the Central Pacific generally end up weakening because of wind shear. A global-scale tropical atmospheric circulation known as the Hadley Cell keeps wind shear blowing and protecting the islands 90% of the time, research has shown.
But climate change, scientists say, may be playing havoc with such wind patterns and driving storms on more northerly tracks and with greater intensity. A number of studies predict that the Central Pacific will see more hurricanes, stronger storms and ones that intensify faster.