National Hurricane Center, Miami, Florida (8:00PM Update August 22, 2012): The center of Tropical Storm Isaac was located near latitude 15.7 north, longitude 62.2 west. Isaac is moving toward the west near 21 mph (33 km/h) and this general motion is expected to continue for the next couple of days. On the forecast track, the center of Isaac should move away from the Leeward Islands during the next few hours, pass near or south of the Virgin Islands and Puerto Rico on Thursday and approach the Dominican Republic Thursday night and Friday. Maximum sustained winds are near 45 mph (75 km/h) with higher gusts.
Some strengthening is forecast during the next 48 hours and Isaac could become a hurricane Thursday night or Friday. Tropical storm force winds extend outward up to 140 miles (220 km) mainly to the north and east of the center. The estimated minimum central pressure based on hurricane hunter aircraft and surface observations is 1004mb (29.65 inches).
Hazards affecting land:
Wind: tropical storm conditions continue to spread across portions of the Leeward Islands. Tropical storm conditions are expected over Puerto Rico and the US and British Virgin Islands on Thursday. Hurricane conditions are possible over Puerto Rico and the US Virgin Islands on Thursday. Hurricane conditions are expected over portions of the Dominican Republic by Thursday night.
Rainfall: total rain accumulations of 4 to 8 inches are possible over the Northern Windward Islands and the Leeward Islands. Total rain accumulations of 1 to 3 inches with maximum amounts of 6 inches are possible over Puerto Rico and the Virgin Islands. Total rainfall accumulations of 8 to 12 inches with maximum amounts of 20 inches are possible over Hispaniola. These rains could cause life-threatening flash floods and mud slides.
Storm Surge: a storm surge will raise water levels by as much as 3 to 5 feet above normal tide levels along the Southern coast of the Dominican Republic. A storm surge will raise water levels by as much as 1 to 3 feet above normal tide levels in the Northern Leeward Islands, Puerto Rico, and the US and British Virgin Islands. Near the coast the surge will be accompanied by dangerous waves.
Surf: dangerous surf and rip current conditions will affect the Windward and Leeward Islands, the Virgin Islands and Puerto Rico during the next couple of days. Please consult products from your local weather office for more information.
Technical data (8:00PM AST 0000UTC Update | August 22, 2012):
Location: 15.7N, 62.2W
About 65 miles (110 Km) SW of Guadeloupe
About 320 miles (510 Km) SE of San Juan Puerto Rico
Maximum Sustained Winds: 45 mph (75 km/h)
Present Movement: West or 265 degrees at 21 mph (33 km/h)
Minimum Central Pressure: 1004mb (29.65 Inches)
Watches and Warnings:
Changes with this advisory: The Government of the Dominican Republic has issued a hurricane warning for the south coast from Isla Saona westward to the Haiti-Dominican Republic southern border. A hurricane watch has been issued for all of Haiti.
Summary of watches and warnings in effect:
A Hurricane Warning is in effect for:
•South coast of Dominican Republic from Isla Saona Westward to the Haiti-Dominican Republic Southern border
A Tropical Storm Warning is in effect for:
•St. Martin/St. Maarten
•St. Kitts and Nevis
•Antigua and Barbuda
•British Virgin Islands
•Puerto Rico, Vieques, Culebra
•US Virgin Islands
A Hurricane Watch is in effect for:
•Puerto Rico, Vieques, Culebra
•The US and British Virgin Islands
A Tropical Storm Watch is in effect for:
•North coast of Dominican Republic from the Haiti-Dominican Republic Northern border Eastward to North of Isla Saona
A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area. A Warning is typically issued 36 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous. Preparations to protect life and property should be rushed to completion.
A Hurricane Watch means that hurricane conditions are possible within the Watch area. A Watch is typically issued 48 hours before the anticipated first occurrence of Tropical-Storm-force winds; conditions that make outside preparations difficult or dangerous.
A Tropical Storm Warning means that Tropical Storm conditions are expected somewhere within the Warning area within 36 hours.
A Tropical Storm Watch means that Tropical Storm conditions are possible within the Watch area generally within 48 hours.
Interests in Cuba and Jamaica should monitor the progress of Isaac.
For storm information specific to your area in the United States, please monitor products issued by your local national weather service forecast office. For storm information specific to your area outside the United States, please monitor products issued by your national meteorological service.
Next Complete Advisory: 11:00pm AST.