Tropical Depression 4E formed Tuesday afternoon more than 1,000 miles east-southeast of Kailua-Kona. Big Islanders could begin feeling its effects as early as Friday.
Tropical Depression 4E formed Tuesday afternoon more than 1,000 miles east-southeast of Kailua-Kona. Big Islanders could begin feeling its effects as early as Friday.
Warm ocean temperatures of 82 to 83 degrees combined with low wind shear will fuel strengthening during the coming 48 hours, said Matt Foster, a forecaster with the Central Pacific Hurricane Center in Honolulu. Forecasters were expected to upgrade the depression, located about 1,080 miles east-southeast of Kailua-Kona and about 1,025 miles east-southeast of Hilo, to a tropical storm late Tuesday or early today.
If upgraded, it would be named Ela, and would be the first named storm of the 2015 Central North Pacific hurricane season. Hawaiian names are assigned only to storms that form in the Central North Pacific basin.
As of 5 p.m. Tuesday, the depression was packing maximum sustained winds of 35 mph and moving toward the west-northwest at about 17 mph.
Pushing the storm on its current path are southeast winds aloft that are expected to keep the storm heading north of the state, Foster said. It is forecast to peak as a tropical storm, packing 50 mph winds Thursday evening before moving north of the Big Island on Friday morning.
Though the island will be spared for the most part from damaging winds, heavy rain and thunderstorms can be expected, Foster said. The majority of the rain is forecast for windward and northern areas.
Leeward areas can expect humid and warm conditions through the weekend, Foster said. The heat index, which is what the temperature feels like to the human body when relative humidity is combined with the air temperature, could peak at nearly 100 degrees in some low-lying coastal areas.
“I wouldn’t rule out that we could see some stuff firing in the afternoon on the leeward Kona side,” Foster said, explaining any such showers would be a result of high humidity prompted by the storm combined with normal afternoon sea breezes.
Meanwhile, within the Central North Pacific basin, showers and thunderstorms persist near a surface low about 750 miles southeast of Hilo. However, the system remains disorganized and forecasters said it is unlikely the system will develop into a tropical cyclone in the coming 48 hours.
West of the Big Island, showers and thunderstorms associated with a broad area of low pressure appear to have become better organized. The disturbance, located about 1,100 miles south-southwest of Honolulu, could see some development during the next couple of days as it moves toward the northwest, forecasters said. It has a 60 percent chance of becoming a tropical depression within two days.
Elsewhere, no tropical cyclones are expected through Thursday afternoon.
Forecasters called for an above-average hurricane season with five to eight tropical cyclones — a category that includes tropical depressions, tropical storms and hurricanes — to pass through the Central North Pacific basin this year. Last year, forecasters also called for an above-normal season with four to seven tropical cyclones forecast to pass through the Central Pacific. During the season, Wali, Genevieve, Iselle, Julio and Ana traversed its boundaries.
On average, the Central Pacific annually sees four to five tropical cyclones in its waters. Storms, for the past 25 years, have occurred most frequently in August, followed by July, September and October.
Many factors affect the level of tropical cyclone activity from year to year. Among them are El Niño, which correlates with warmer ocean temperatures and reduced vertical shear that cause increased storm activity, and La Niña, which features cooler waters and historically has produced below normal activity seasons. Warmer waters fuel convection and storms.
Currently, the Central North Pacific basin is experiencing El Niño conditions that are forecast to continue through at least the fall, and possibly longer. El Niño, which also favors westward-tracking storms, can strengthen storms during the hurricane season.
The Central North Pacific and Eastern Pacific hurricane seasons continue through Nov. 30.
Email Chelsea Jensen at cjensen@westhawaiitoday.com.