1. Tropical storm conditions are expected in the U.S. and British Virgin Islands and Puerto Rico on Wednesday, and are possible in portions of the Dominican Republic Wednesday night and Thursday. Hurricane conditions are possible in Puerto Rico on Wednesday.

2. Heavy rainfall over portions of Puerto Rico and the Dominican Republic could produce flash flooding during the next few days. Heavy rains are expected to occur over portions of the Bahamas and Florida later this week and into early next week.

3. The threat of tropical storm or hurricane conditions, along with storm surge, in the Bahamas and along portions of the Florida east coast have increased. Residents in these areas should monitor the progress of Dorian and ensure that they have their hurricane plan in place.

4. Uncertainty in the intensity forecast later this week remains higher than usual due a large spread in model guidance. storm.

WHAT'S NEW:

The government of Antigua has issued a Tropical Storm Warning for the British Virgin Islands. The government of the Dominican Republic has changed the Tropical Storm Warning to a Tropical Storm Watch from Isla Saona to Samana.

SUMMARY OF ALERTS:

A Hurricane Watch is in effect for...
- Puerto Rico

A Tropical Storm Warning is in effect for...
- Puerto Rico
- Vieques
- Culebra
- U.S. Virgin Islands
- British Virgin Islands
- Dominican Republic from Isla Saona to Samana

A Tropical Storm Watch is in effect for...
- Dominican Republic from Isla Saona to Puerto Plata

A Hurricane Watch means that hurricane conditions are possible within the watch area, in this case within 24 hours.

A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area, in this case within 24 hours.

A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, in this case within 24 hours. For storm information specific to your area in the United States, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office. For storm information specific to your area outside of the United States, please monitor products issued by your national meteorological service.

RAINFALL: Dorian is expected to produce the following rainfall accumulations:

Guadeloupe to Dominica...1 to 4 inches. Puerto Rico...4 to 6 inches, isolated 8 inches. Virgin Islands, Haiti, and Dominican Republic...1 to 3 inches, isolated 4 inches. Bahamas...2 to 4 inches. Florida...3 to 5 inches, isolated 7 inches.

This rainfall may cause life-threatening flash floods.

WIND: [TOP] Tropical storm conditions are expected and hurricane conditions are possible in Puerto Rico on Wednesday. Tropical storm conditions are expected in the U.S. and British Virgin Islands on Wednesday. Tropical storm conditions are possible in portions of the Dominican Republic late Wednesday and Thursday.

SURF: [TOP] Swells generated by Dorian should gradually subside in the Lesser Antilles tonight. Swells are expected to increase along the southern coasts of Puerto Rico and Hispaniola on Wednesday and they could cause life-threatening surf and rip current conditions. Please consult products from your local weather office.

At 1100 PM AST (0300 UTC), the center of Tropical Storm Dorian was located near latitude 16.0 North, longitude 63.0 West. Dorian is moving toward the northwest near 13 mph (20 km/h), and this general motion is expected to continue through Thursday. On the forecast track, the center of Dorian will move across the northeastern Caribbean Sea overnight, pass over or near Puerto Rico on Wednesday, and move near or just east of eastern Hispaniola Wednesday night. Dorian is forecast to move near or to the east of the Turks and Caicos and the southeastern Bahamas on Thursday night, and near or to the east of the central Bahamas on Friday.

Maximum sustained winds are near 50 mph (85 km/h) with higher gusts. Slow strengthening is forecast during the next 24 hours, and Dorian is forecast to be near hurricane strength when it approaches Puerto Rico on Wednesday. Some weakening is expected after Dorian moves across the higher terrain of Puerto Rico. Dorian is expected to gradually re-strengthen on Thursday and Friday while passing near or to the east of the Turks and Caicos and southeastern and central Bahamas.

Tropical-storm-force winds extend outward up to 45 miles (75 km) from the center.

The minimum central pressure reported by the Hurricane Hunter aircraft is 1006 mb (29.71 inches).

Reports from an Air Force Hurricane Hunter aircraft indicate that Dorian is yet to strengthen, and the initial intensity remains near 45 kt. The storm's cloud pattern remains rather ragged-looking with no clear convective banding features. Since the storm has strong upper-level outflow over the western semicircle of the circulation and vertical shear should remain low for the next day or two, strengthening is still forecast before Dorian reaches Puerto Rico on Wednesday. Some weakening is likely by 24 hours due to the interaction of the circulation with Puerto Rico. The intensity forecast in 3-5 days remains problematic because of a significant spread in the model guidance and some run-to-run inconsistencies. The official intensity forecast has been increased in comparison to the previous ones. However, it is now near the low end of the numerical guidance suite.

Dorian has turned toward the northwest, and the initial motion estimate is 310/11 kt. Over the next couple of days, the cyclone will be headed toward a weakness in the subtropical ridge. In 3-4 days, the global models show the ridge rebuilding somewhat over the western Atlantic. This scenario should cause Dorian to turn toward the left later in the forecast period. The official forecast has been shifted to the north of the previous one. This is in close agreement with the ECMWF model track, but south and southwest of the latest simple and corrected consensus predictions.