An El Nino-related tropical storm has formed southwest of Hawaii, only the third such system to develop in January in over 40 years.

The Central Pacific Hurricane Center says Tropical Storm Pali (pah-lee) was about 1,400 miles southwest of Honolulu as of 11 a.m. Friday. It's not near land.

Pali is slowly moving west-northwest at 5 mph. Hurricane forecaster Kevin Kodama says the storm will slowly weaken over the next three to five days.

Kodama says warm ocean temperatures near the equator caused the storm to form.

El Nino is the natural warming of the central Pacific that changes weather worldwide.

Kodama says the last January tropical storm in the central Pacific was in 1992, when there was a significant El Nino. The other was in 1989.