Editor’s note: Tropical Storm Lala has formed. Up to 20 inches of rain is possible in some locations, with the highest amounts over windward areas of Maui and the Big Island. Follow USA TODAY’s latest coverage for Thursday, August 13.

Two weather systems have formed in the central Pacific Ocean, with one forecast to threaten Hawaii as a tropical storm with rough winds, high seas and heavy rain later this week and into the weekend.

“Potential Tropical Cyclone One-C” is forecast to become a strong tropical storm on Aug. 13 and could bring direct impacts to the Hawaiian Islands. It’s likely name would be Lala.

At 11p.m. ET on Aug. 12, the system had maximum sustained winds of 40 mph and was centered about 1045 miles east-southeast of Honolulu, according to the Central Pacific Hurricane Center. It was moving westward at 9 mph.

The system is expected to move westward as it gradually strengthens and approaches the Hawaiian Islands, said Michael Brennan, director of the National Hurricane Center.

It will be “in the vicinity of the Big Island of Hawaii as we go from Friday night into early Saturday morning and then continuing west-northwestward near or over the rest of the main Hawaiian Islands during the day Saturday (and) Saturday night,” Brennan said. The center is expecting “some potentially significant wind impacts in the main islands.”

The center has advised residents to closely monitor the latest forecast updates and have preparedness plans in place. Even if the center of the storm travels south of the islands, winds on the north side could still impact the islands, the hurricane center said.

Meanwhile, Tropical Depression Eight has formed in the eastern Pacific, about 1,445 miles west of the southern tip of Baja California. The hurricane center said that system could briefly become a tropical storm on Thursday, then weaken on Friday.

Likely impacts on Hawaii

Heavy rainfall associated with the system nearest Hawaii is expected to begin to impact the Big Island Friday, Aug. 14, spreading westward into Maui on Saturday, Aug. 15, and across Lanai, Molokai, Oahu and Kauai on Sunday, Aug. 16, forecasters said. This rainfall may produce life-threatening flooding and mudslides, especially in areas of steep terrain.

“We are expecting very heavy rainfall across much of the Hawaiian Islands, widespread rainfall totals of 5 to 10 (inches,) in maximum amounts as high as 20 (inches) in some locations,” Brennan said.

The center warned of an increasing risk of wind and wave impacts in the Hawaiian Islands regardless of the exact track and intensity of the system. Hurricane or tropical storm watches may be required for portions of the Hawaiian Islands by early Thursday, Aug. 13.

Wildfires are also a concern, according to the National Weather Service in Honolulu: “Fire weather concerns increase on Friday [Aug. 14]. Winds will begin to strengthen and a dry and stable air mass with low relative humidity in advance of the storm will likely lead to high wildfire potential.”

El Niño’s influence on Hawaii

While El Niño gets much more attention for its pacifying effect on tropical storms and hurricanes in the Atlantic Ocean, it intends to increase tropical activity in the Pacific Ocean.

When an El Niño strengthens, trade winds weaken and ocean temperatures warm near and to the east of Hawaii, Malte Stuecker, director of the University of Hawai’i at Manoa’s International Pacific Research Center, previously told USA TODAY. The warmer ocean temperatures together with the wind pattern will increase the risk of a hurricane hitting the islands during the June to November hurricane season, Stuecker said.

If the approaching tropical storm brushes Hawaii with high surf, wind or rains this week, it would be the third system to send impacts to the island chain in 2026. Both Hurricanes Fausto and Genevieve affected surf conditions along the islands. Fausto brought high surf and dangerous currents, while Genevieve later contributed long period swells.

How many times has Hawaii been hit by a storm?

While dozens of storms like Fausto have brushed Hawaii with winds, rains or rough seas, only 13 tropical storms or hurricanes have made landfall on, or passed within 10 miles of the main islands since 1950, according to the Historical Hurricane Tracks feature from the National Oceanic and Atmospheric Administration. Two hurricanes have made landfall on Kauai: Iniki in September 1992 and Dot in 1959.

Doyle Rice and Dinah Voyles Pulver are national correspondents with USA TODAY, specializing in weather and climate. Reach Rice at drice@usatoday.com and Pulver at dpulver@usatoday.com.