This satellite image taken Monday shows tropical storm Hermine spinning in the western Gulf of Mexico. (Weather Underground/Associated Press)

Tropical storm Hermine came ashore in northeastern Mexico on Monday night, about 65 kilometres south of Brownsville, Texas.

The U.S. National Hurricane Center in Miami said Hermine's centre made landfall about 9:30 p.m. ET with winds of about 105 km/h. The storm was expected to move into south Texas.

As the storm approached, Mexican authorities urged people to move to shelters while officials in Texas distributed sandbags and warned of flash floods.

It is the second major storm to hit the area this season. Hurricane Alex roared ashore there in June, killing at least 12 people as remnant rains drenched a wide swath of northeastern Mexico for days.

As of 11 p.m. ET, the centre of Hermine was located about 45 kilometres south of Brownsville and was moving north-northwest at 22 km/h. Winds had decreased to about 95 km/h and additional weakening was forecast.

Emergency officials readied pumping equipment and distributed sandbags in Cameron County, said John Cavazos, the county's emergency management co-ordinator. People in recreational vehicles in county parks along the coast were encouraged to move.

No evacuations were ordered in Texas, but schools around Brownsville were closed Tuesday as a precaution.

Hermine is expected to dump 100 to 200 millimetres of rain on northeast Mexico and south Texas.

With files from The Associated Press