Tropical Storm Marco weakened near Louisiana on Monday morning.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Marco was located at latitude 28.5°N and longitude 88.5°W which put it about 55 miles (90 km) southeast of the Mouth of the Mississippi River.  Marco was moving toward the north-northwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 1006 mb.

A Tropical Storm Warning was in effect for the portion of the coast from Morgan City, Louisiana to the Mississippi/Alabama border including New Orleans, Lake Pontchartrain and Lake Maurepas.

An upper level trough over Texas produced strong southwesterly winds which sheared the top off of Tropical Storm Marco on Monday morning.  Stronger thunderstorms were confined to a few bands northeast of the center of circulation.  Bands around the center and in other parts of Marco consisted of showers and lower clouds.  Winds to tropical storm force were only occurring in the thunderstorms northeast of the center.

Since the wind shear is expected to continue, the circulation around Tropical Storm Marco is expected to spin down.  As Marco weakens it will be steer more by the winds in the lower atmosphere.  A subtropical high pressure system over the Atlantic Ocean is expected to expand to the west during the next several days.  The high will turn the low level circulation of Tropical Storm Marco more toward the west.  On its anticipated track Tropical Storm Marco will make landfall over southeastern Louisiana on Monday night.  Marco will bring gusty winds and some rain, but its impact is likely to be minor.

Elsewhere, Tropical Storm Laura was moving near the south coast of Cuba.  At 11:00 a.m. EDT on Monday the center of Tropical Storm Laura was located at latitude 21.2°N and longitude 80.6°W which put it about 65 miles east-southeast of Cayo Largo, 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 1002 mb.

Tropical Storm Warnings were in effect for the Florida Keys from Craig Key to Key West and for the Dry Tortugas.  Tropical Storm Warnings were in effect for Little Cayman and Cayman Brac.  Tropical Storm Warnings were also in effect for the Cuban provinces of Camaguey, Las Tunas, Ciego De Avila, Sancti Spiritus, Villa Clara, Cienfuegos, Matanzas, Mayabeque, La Habana, Artemisa, Pinar Del Rio and Isle of Youth.

The circulation around Tropical Storm Laura was not as well organized on Monday morning.  Passage of Hispaniola and eastern Cuba disrupted the northern half of the circulation.  The strongest 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) on the eastern side of Laura.  The winds on the western side of the circulation were blowing at less than tropical storm force.

Tropical Storm Laura will move near the south coast of Cuba for another 18 hours.  Since nearly half the circulation will be blowing across Cuba, it will continue to disrupt the northern half of the tropical storm.  Laura will move over the Gulf of Mexico on Tuesday.  When Tropical Storm Laura reaches the Gulf, it will move into a very favorable environment.  Laura will move over water where the Sea Surface Temperature is near 30°C.  It will move into a region where the upper level winds are 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 rapidly strengthen into a major hurricane.  Laura is expected to move over the northwestern Gulf of Mexico on Wednesday.