Tropical Storm Marco could become a hurricane Saturday: Latest NHC updates for Saturday

Tropical Storm Marco is strengthening quickly and is expected to become a hurricane later Saturday. 

Laura is expected to bring heavy rainfall to portions of Puerto Rico on Saturday, according to the 10 a.m. National Hurricane Center update. Tropical storm watches could go into effect for the Florida Keys later Saturday. 

Tropical Storm Laura is located about 20 miles southwest of Ponce, Puerto Rico, 

Tropical Storm Laura is moving west at a rate of 18 mph and is expected to move west-northwestward over the next few days. Maximum sustained winds have reached 40 mph, and slow strengthening is expected over the next few days. 

The track and intensity of the tropical storm are uncertain as it moves toward the Florida Straits early next week, according to the National Weather Service.

More: Tropical Storm Laura pounds Puerto Rico; Tropical Storm Marco to become hurricane: What we know

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Forecasters with the National Weather Service in Mobile, Alabama, said in their 6 a.m. update that the storm's uncertain track means it's still too soon to determine impacts to the Panhandle, outside of high rip currents.

Tropical Storm Marco

Tropical Storm Marco is expected to move into the southeastern Gulf of Mexico by Saturday evening. The storm is located 105 miles east-northeast of Cozumel, Mexico. It is traveling north-northwest at 12 mph.

More: Hurricane forecast: Gulf convergence of Laura, Marco an anomaly for the ages | WeatherTiger

Tropical Storm Marco could strengthen to a hurricane later Saturday and is expected to weaken on Monday and Tuesday.

Both storms could impact the United States within days of each other, according to forecasters.