Tropical Depression Three-C Forms in the Central Pacific; May Threaten Hawaii as Hurricane Kilo

August 20,2015

• Tropical Depression Three-C formed in the central Pacific Ocean Thursday afternoon (EDT).
• The system was located about 645 miles south-southeast of Hilo, Hawaii as of 11 p.m. EDT Thursday (5 p.m. HST Thursday).
• The depression is forecast to strengthen into Tropical Storm Kilo by Friday and Hurricane Kilo this weekend as it moves slowly to the west-northwest.
• This new system is likely to be pulled northward toward the Hawaiian Islands early next week. Interests in Hawaii should monitor the progress of this system very closely.

(MORE: Expert Analysis | Hurricane Central)

Storm Information and Satellite

Tropical Depression Three-C has formed in the central Pacific and is forecast to strengthen into Hurricane Kilo during the next 48 hours.
If this system does intensify to gain the name "Kilo", it would be the fourth named storm to have formed in the central Pacific basin this season and the sixth to track through the basin this year, including eastern Pacific storms Guillermo and Hilda.
Four to five tropical cyclones typically form in the central Pacific each year, according to the Central Pacific Hurricane Center. CPHC says a record 11 named storms formed in 1992 and 1994.
(MORE: Twin Typhoons in the Pacific)
Yet again, Hawaii needs to watch this one. What is now Tropical Depression Three-C may get pulled northward later this weekend into early next week as a hurricane, or a tropical storm at the very least. However, uncertainty remains with exactly where this northward turn may occur, which will dictate what impacts Hawaii may see.
The official forecast, reflecting the American GFS computer forecast model, curves the storm northward soon enough to bring the core of future Kilo into the Hawaiian Islands, particularly near Kauai or Oahu. Many hurricane track models also curve the cyclone northward into some part of the populated section of the Hawaiian Islands.
However, the European forecast model has this northward turn occurring later, which would pass the core of future Kilo to the west of the eight main Hawaiian Islands. That said, some peripheral rain and wind impacts would still occur even with the latter forecast track possibility.

Projected Path

Another question that remains is what the strength of this system will be if it gets pulled near the Aloha State.
A well-established upper-level low pressure system and vigorous southern branch jet stream remains in place near the islands. That subtropical jet will have to at least weaken or pull north to avoid ripping this system apart.
However, virtually all hurricanes near the Hawaiian Islands since 1950 have approached from the southeast, south, or southwest.
In El Nino years, the trade winds that sometimes trap tropical cyclones well south of the islands relax, making these lingering storms south of the islands more susceptible to be drawn northward. Of course, an El Nino does not guarantee a hurricane will impact Hawaii.
(MORE: Hawaii's Hurricane History)
So, this system bears watching closely. The official forecast calls for the tropical cyclone to curve north and approach portions of the Hawaiian Islands by Tuesday of next week.
(FORECASTS: Honolulu | Hilo | Kona Coast | Maui)
NOAA's 2015 Central Pacific hurricane season outlook cited El Nino's tendency for reduced wind shear and more storm tracks coming from the eastern Pacific as reasons to expect an active season in the central Pacific Basin.
Lowry says dating to 1950, there is a 13 percent increase in the chance of a named storm to track within 100 miles of the Hawaiian Islands during an El Nino year compared to a neutral year.
Stay tuned to The Weather Channel and check back with weather.com for updates on this system.

MORE: Hurricanes by the Numbers