Nasa / Reuters

Tropical Storm Gordon, seen over the Atlantic Ocean in this NASA handout satellite image Thursday, became a hurricane Saturday.

Updated at 6:30 p.m. ET: Tropical Storm Helene made landfall off the Gulf of Mexico on Saturday and weakened into a tropical depression as it plowed up Mexico's east coast, the U.S. National Hurricane Center said.

The depression was about 65 miles west-northwest of Tampico and had maximum sustained winds of 30 miles per hour, the NHC said in its 4 p.m. CDT bulletin.

Tropical storm warnings were discontinued on the Mexican coast, although Helene still was expected to produce two to four inches of rain in the states of Veracruz and Tamaulipas.

Helene was predicted to continue weakening and dissipate within 48 hours, the NHC said.

There were no reports that Helene had affected the Gulf of Mexico's oil installations, which are built to resist much more powerful hurricanes.

Earlier, Portugal posted warnings for the central and eastern Azores islands as Tropical Storm Gordon moved eastward across the Atlantic and later turned into a hurricane.

The National Hurricane Center said Gordon had maximum sustained winds of 75 mph and was headed east at 18 mph.

In the northern part of Veracruz, a lush coastal state with hundreds of towns and villages sitting along streams and rivers that can swell dangerously in heavy rain many were evacuated as Ernesto approached last week, and flood damage made some 10,000 people homeless.

State of emergency
Mexico's government declared a state of emergency in more than 100 population centers in Veracruz and was providing them with emergency aid. The country's national weather service warned of intense rains and winds along the Veracruz and Tamaulipas coasts, with heavy rain, hail and lightning possible.

A storm surge could raise water levels by as much as 1 to 2 feet above normal along the immediate coast and to the north of where landfall is made.

Heavy rain was expected in the city of Tampico, an oil-refining center and important port in the southernmost part of Tamaulipas state. The Tampico metropolitan area has roughly 790,000 inhabitants, sits just above sea level and is surrounded by lakes and lagoons that are already full and could easily flood in the event of heavy rains.

Civil protection authorities in Veracruz issued a yellow alert, one level below the highest warning, for population centers in the north and center of the state, warning residents to familiarize themselves with the locations of emergency shelters, avoid crossing swollen streams and rivers, and keep listening to radio and TV for storm updates.

The Associated Press and Reuters contributed to this report.

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