NWS National Hurricane Center Miami FL
500 PM AST Sat Aug 22 2020
Tropical Storm Laura
A couple of hours ago an observing site on the southeast coast of Puerto Rico reported sustained winds of 52 kt.
These winds were apparently associated with a mesocyclone embedded within the larger circulation and not representative of the intensity of the tropical storm. WSR-88D Doppler velocities from San Juan support an intensity of 45 kt. Since the centre should be moving over land for the next 48 hours or so, no
additional intensification is anticipated until Monday night when the centre moves over the Southeastern Gulf of Mexico.
Over warm waters, with anticipated weak vertical shear, and anticyclonic flow aloft, Laura will likely strengthen into a hurricane before it reaches the northern Gulf of Mexico coast.
The NHC intensity forecast is close to the multi-model consensus, but given the possibility of a favourable upper-air environment over the Gulf, this forecast could be conservative.
Center locations from earlier today give Laura a motion of 280 Degrees @16 kt. Laura should move west-north-westward along the southern side of a tropospheric anticyclone centered near the Southeastern U.S. coast through 72 hours. She is then expected to turn north-westward to northward on the western side of the high. The official track forecast is on the right side of the
track guidance suite.
- Tropical storm conditions are expected to continue across portions of the U.S. Virgin Islands and Puerto Rico through this evening. Tropical storm conditions are also expected across portions of the Dominican Republic and Haiti, the Turks and Caicos, the Southern Bahamas, and central and eastern Cuba through Sunday.
Heavy rainfall is likely across these areas and could cause mudslides and flash and urban flooding through Sunday, with widespread river flooding possible in Puerto Rico.
Tropical storm conditions are possible over portions of the Central Bahamas and Andros Island Sunday night and Monday, and in the Florida Keys on Monday.
The details of the long-range track and intensity forecasts remain uncertain since Laura is forecast to move near or over portions of the Greater Antilles through Monday. However, Laura is forecast to strengthen over the Gulf of Mexico and could bring storm surge, rainfall, and wind impacts to portions of the U.S. Gulf Coast by the middle of next week. This could result in a prolonged
period of hazardous weather for areas that are likely to be affected by Tropical Storm Marco earlier in the week.