Miami, Florida -- Tropical Storm Dolly formed in the western Caribbean and approached Mexico on Sunday, as Tropical Storm Cristobal edged closer to the North Carolina coast.

Satellite image taken at 10:45 a.m. ET Sunday shows locations of the two storms.

The National Hurricane Center issued a tropical storm warning for Mexico's Yucatan Peninsula from Campeche to the border with Belize.

At 11:45 a.m. ET, the hurricane center said the center of Dolly -- the fourth tropical storm of the Atlantic season -- was about 270 miles east of Chetumal, Mexico, and 230 miles southeast of Cozumel.

Dolly was moving northwest at about 17 mph, with top sustained winds near 45 mph - See Dolly's projected path.

Meanwhile, Cristobal moved "parallel and very close" to the North Carolina coast Sunday morning, but the storm was expected to drift away from the eastern coast by Monday. See Cristobal's projected path.

"The center of the tropical storm is expected to move parallel and very close to the coast of North Carolina today and begin to move away from the coast by Monday," the hurricane center said in its 11 a.m. advisory. It is expected to dump 1 or 2 inches of rain along the North Carolina coast Sunday, it said. Video Watch Cristobal near the Outer Banks of North Carolina »

A discussion posted online by hurricane center forecasters said the satellite view of Cristobal "remained unimpressive-looking" and predicted that the storm would "lose tropical characteristics" over the next two or three days.

A tropical storm warning -- meaning tropical storm conditions with maximum winds of 39 mph are expected within the next 24 hours -- was canceled for an area from north of Little River Inlet, North Carolina, to the North Carolina-Virginia border. Another warning remained in effect from north of Surf City to the North Carolina-Virginia border.

As of 11 a.m. ET Sunday, Cristobal's center was about 15 miles southwest of Cape Lookout, North Carolina, and about 70 miles southwest of Cape Hatteras, North Carolina. It was moving northeast at near 7 mph.

The storm's maximum sustained winds were near 50 mph, with higher gusts.

Cristobal evolved Saturday from a tropical depression that formed Friday.

Meanwhile, Bertha was downgraded from a hurricane to a tropical storm Saturday evening. The storm, centered about 670 miles east-northeast of Cape Race, Newfoundland, is moving quickly into the northern Atlantic, the hurricane center said Sunday morning.

Bertha, the first hurricane of the 2008 Atlantic season, formed July 3 in the eastern Atlantic and dealt a glancing blow to Bermuda before heading north.

The storm set several records: It is the longest-lived tropical cyclone on record during the month of July and the third-strongest July storm on record, behind Dennis and Emily in the 2005 hurricane season.