By Brian Lada
Hurricane Iselle will weaken before reaching Hawaii later this week, but heavy rain, strong winds and rough seas will affect the islands. A second hurricane, Julio, also bears watching.
AccuWeather meteorologists expect Iselle to continue to weaken over the next couple of days and become a tropical storm before reaching the islands. Iselle will be moving into a wedge of cool water and dry air just east of the Hawaiian Islands.
However, even as a tropical storm, Iselle will still pack a punch. Heavy rain, gusty winds and building seas and surf will affect the islands during the second half of the week.
There is the potential for significant flash flooding, mudslides and damaging wind gusts. Ground access to some communities could be cut off.
“Tropical storm-force winds will cause at least scattered power failures on the islands, including in the City of Honolulu,” said Mike Smith, senior vice president of AccuWeather Enterprise Solutions.
Smith stated that based on the current forecast path and strength of Iselle, lengthy power outages are possible on the Big Island (Hawaii).
“Multiple roads could be washed out on the Big Island, Oahu, Lanai and Kauai,” Smith said.
Landfall is forecast on the Big Island Friday morning, local time. However, building seas, squalls and rain will precede the storm by 24 hours or more.
Inexperienced bathers, boarders and boaters should exercise extreme caution, even as the system weakens while approaching the islands.
Visitors and residents alike should check the conditions throughout the week as the approaching storm may cause rough surf and rip currents.
The Big Island of Hawaii will be the first to feel the impacts from Iselle as it is forecast to reach the island by Thursday night, local time.
At present track, the Big Island of Hawaii will take a direct hit from the storm before passing just south of the smaller islands, such as Maui or Oahu.
Due to the projected track of the storm, areas on the eastern portions of the islands will likely feel greater effects than the western sides.
However, if the projected path of the storm shifts, so would the areas expected to feel the highest impacts.
If the storm track was to shift slightly farther to the north, a west wind would direct moisture toward parts of the islands that normally do not receive much rainfall.
In such a scenario, these normally very dry locations could be hit with flash flooding.
A direct hit on the islands does not have to occur for significant impact as the storm is much larger than a single point of latitude and longitude.
The above NOAA image shows Hurricane Iselle in the eastern Pacific Ocean on Tuesday night.
The tropical threat for Hawaii may not end with Iselle. There is potential for a second tropical system to hit about three days later with another round of pounding waves, flooding rain and strong winds.
Hurricane Julio is also churning over the eastern Pacific and is forecast to track towards the Hawaiian Islands right on the heels of Iselle, but perhaps on a slightly different trajectory.
AccuWeather meteorologists believe that this storm will approach the chain of islands late in the weekend or early next week. However, the exact track that it will take remains uncertain.
According to Meteorologist Mark Mancuso, “Julio will be passing over waters churned up and cooled by Iselle, which argues for weakening after initial strengthening.”
Here are some precautions that Smith recommends Hawaiians should take in preparation for Iselle and Julio:
4. If you have a generator, test it before it is needed.
5. Get prescription medications refilled and make provisions for any medicines that must be chilled or that require special handling. Power could be out for more than a week if Julio also strikes.
Keep up to date with the latest on Hurricane Iselle at the AccuWeather.com Hurricane Center.
Senior Meteorologist Alex Sosnowski contributed content to this story.