Tropical Storm Laura Prompts Hurricane Watch for Northwest Gulf Coast

The potential threat from Tropical Storm Laura prompted the issuance of a Hurricane Watch for a portion of the northwest Gulf Coast on Monday afternoon.  At 5:00 p.m. EDT on Monday the center of Tropical Storm Laura was located at latitude 21.7°N and longitude 82.2°W which put it about 40 miles (65 km) east of the Isle of Youth, Cuba.  Laura was moving toward the west-northwest at 20 m.p.h. (32 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 1001 mb.

A Hurricane Watch was issued for the portion of the coast from Port Bolivar, Texas to Morgan CIty, Louisiana.  A Tropical Storm Watch was issued for the portion of the coast from Morgan City to the Mouth of the Mississippi River.  A Tropical Storm Warning remained in effect for the Florida Keys from Craig Key to Key West and the Dry Tortugas.  Tropical Storm Warnings were also in effect for the Cuban provinces of Ciego de Avila, Sancti Spiritus, Villa Carla, Cienfuegos, Matanzas, Mayabeque, La Habana, Artemisa, Pinar del Rio and Isle of Youth.

The appearance of Tropical Storm Laura did not change much on Monday afternoon.  Many of the stronger thunderstorms were occurring in bands in the southern half of the circulation.  bands in the northern half of the circulation consisted primarily of showers and lower clouds.  Winds to tropical storm force extended out 175 miles (280 km) from the center on the eastern side of Laura.  Winds were blowing at less than tropical storm force in the western half of the circulation.

Tropical Storm Laura will move near Cuba for another 12 to 18 hours.  So, the flow of air across Cuba is likely to continue to disrupt the northern half of the circulation during the time period.  When Laura moves over the Gulf of Mexico on Tuesday , it will move into an environment favorable for intensification.  Tropical Storm Laura will move over water where the Sea Surface Temperature is near 30°C.  It will move into an area where the upper level winds will be weak and there will be little vertical wind shear.  Tropical Storm Laura will intensify into a hurricane over the Gulf of Mexico and it could strengthen into a major hurricane.

Tropical Storm Laura will move around the western end of a subtropical high pressure system over the Atlantic Ocean.  The high will steer Laura toward the west-northwest during the next 12 to 24hours.  Laura will move more toward the north when it reaches the western end of the high.  On its anticipated track Tropical Storm Laura could make landfall on the northwest coast of the Gulf of Mexico on Wednesday night.  Laura could be a major hurricane when it makes landfall.

Elsewhere,  the center of Tropical Storm Marco was very close to the Mouth of the Mississippi River.  At 5:00 p.m. EDT on Monday the center of Tropical Storm Marco was located at latitude 29.0°N and longitude 88.9°W which put it about 15 miles (25 km) east-southeast of the Mouth of the Mississippi River.  Marco was moving toward the northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 1008 mb.  All coastal watches and warnings for Tropical Storm Marco have been discontinued.