Tropical storm warning for South Texas coast: Update

Updates with closure of Galveston, Texas City ports.

A tropical storm warning has been issued for parts of south Texas and northeastern Mexico, bringing with it the risk of heavy rainfall and flooding.

The warning is in effect for the Texas coast from Port O'Connor south to the mouth of the Rio Grande, as well as the northeastern coast of Mexico, according to the National Hurricane Center.

"The disturbance is very large with rainfall, coastal flooding, and wind impacts likely to occur far from the center along the coasts of Texas and northeastern Mexico," the center said overnight.

Maximum sustained winds this morning remained near 40 mph and the disturbance is forecast to become a tropical storm by Wednesday. The system has been classified as a potential tropical cyclone by the center since it has not yet become better organized, but is expected to become the first named storm system of the year by early Wednesday.

The port of Corpus Christi in South Texas and the Houston Ship Channel remained open as of Tuesday morning, but the nearby ports of Galveston and Texas City closed to inbound and outbound shipping traffic at 10pm ET Monday due to heavy weather, the US Coast Guard said.

The system was expected to disrupt ship-to-ship transfer operations off the Texas coast as of Monday evening because of heavy seas. In the Gulf of Mexico, the transfer typically is from an Aframax or Suezmax onto a very large crude carrier (VLCC) at designated lightering zones near Corpus Christi, Galveston and Beaumont-Port Arthur.

Prolonged lightering delays can prevent crude tanker tonnage from becoming available and exert upward pressure on freight rates, while also adding to demurrage fees.

The storm is expected to turn towards the west-northwest and west tonight and Wednesday, with the system forecast to approach the western Gulf coast late Wednesday, the NHC said.

Rainfall totals of 5 to 10 inches are seen across northeast Mexico into South Texas, with maximum totals of 15 inches possible. Flash and urban flooding are likely to follow with river flooding.

By Stephen Cunningham and Tray Swanson