Hurricane Norma set to hit Cabo San Lucas area, while Tammy bears down on Leeward Islands

Norma weakened to tropical storm strength Saturday after bringing hurricane-force winds, flash flooding and storm surge to Mexico's Pacific coast. Meanwhile, another late-season storm continued to threaten island nations in the Atlantic.

Norma made landfall as a Category 1 hurricane with winds of 80 mph over the far southern portion of Mexico's Baja California Sur - which includes Cabo San Lucas - Saturday afternoon, the National Hurricane Center said.

Meanwhile in the Atlantic, Hurricane Tammy made landfall in Barbuda as a Category 1 storm Saturday night, churning maximum sustained winds of 85 mph. Tammy has triggered hurricane warnings, with strong winds and heavy rainfall across portions of the Leeward Islands, a chain of several island nations and territories between the Caribbean Sea and the open Atlantic.

Neither storm is a threat to the US mainland.

Norma's maximum sustained winds decreased to 70 mph, and the tropical storm was centered about 30 miles north-northeast of Cabo San Lucas as of Saturday night, the hurricane center said.

The tropical storm is expected to cross the southernmost portion of Baja California Sur in the evening before emerging over the southern Gulf of California on Sunday.

Mexico's government downgraded the hurricane warning spanning from Todos Santos to Los Barriles to a tropical storm warning Saturday night, the hurricane center said.

However, threats from Norma still remain, as it could bring life-threatening conditions to a tourist-friendly region of Mexico, home to a few hundred thousand people. A dangerous storm surge "is likely to produce coastal flooding in areas of onshore winds within the hurricane warning area" Saturday, the hurricane center said.

Heavy rains and flash flooding from Norma are forecast to persist through the weekend, the hurricane center said.

"Near the coast, the surge will be accompanied by large and destructive waves," the hurricane center said.

Norma will bring heavy rainfall and flooding to the area. Rainfall totals of 6 to 12 inches with isolated totals approaching 18 inches are possible.

The weakening cyclone should turn toward the northeast and east-northeast and slowly approach the coast of Sinaloa in western Mexico on Sunday night into early Monday as a tropical storm, according to the hurricane center.

Norma is forecast to move inland by early Monday and dissipate over the rugged terrain of western Mexico by Tuesday.

In the Atlantic, Tammy maintained maximum sustained winds of 85 mph by Saturday night, with slow strengthening possible over the next few days, the National Hurricane Center said in its update at 8 p.m. ET Saturday.

Tammy is expected to move near or over portions of the Leeward Islands - including Antigua and Barbuda - through Saturday night, and then move north of the northern Leeward Islands on Sunday.

Hurricane-force winds extended outward up to 25 miles from the storm's center and tropical storm-force winds extended outward up to 125 miles.

Hurricanes in this part of the Atlantic are rare for late October. Tammy is only the third hurricane to form this far southeast in the Atlantic since 1900, according to hurricane expert Michael Lowry.

It's also the latest-forming hurricane in this part of the Atlantic since 1966, according to Phil Klotzbach, a research scientist in the Department of Atmospheric Science at Colorado State University.

Experts previously warned hurricanes could form in unusual areas later in the season this year because of the exceptionally warm Atlantic Ocean.

A storm surge of 1 to 3 feet is possible for parts of the Leeward Islands.

Heavy rainfall will be one of the storm's most serious threats and could result in flash flooding and mudslides. Rainfall totals for the Leeward Islands are expected to be 4 to 8 inches, but could reach a foot in places where the heaviest rain sets up. Rain should be lighter in Puerto Rico and the British and US Virgin Islands, where 1 to 2 inches of rain is most likely.

Conditions will begin to improve from south to north across the island chain by late Sunday as the storm moves north out of the region.

With Tammy in the Atlantic, only two names are left - Vince and Whitney - on the standard Atlantic storm name list before the hurricane center turns to an alternate list of names.

CNN's Sara Tonks, Phil Gast, Keith Allen and Ashley R. Williams contributed to this report.