1. A Hurricane Watch is now in effect for the northwestern Bahamas, where the risk of life-threatening storm surge and hurricane-force winds this weekend has continued to increase. Residents should begin to execute their hurricane plans and listen to advice given by local emergency officials.

2. There is an increasing likelihood of a prolonged period of hazardous weather conditions that could last for a couple of days in parts of Florida early next week.

3. The risk of life-threatening storm surge along portions of the Florida east coast has increased, although it is too soon to determine where the highest storm surge will occur. The risk of devastating hurricane-force winds along the Florida east coast and peninsula early next week has also increased, although it is too soon to determine where the strongest winds will occur. Residents should have their hurricane plan in place, know if they are in a hurricane evacuation zone, and listen to advice given by local emergency officials.

4. Regardless of the exact track of Dorian, heavy rains are expected to occur over portions of the Bahamas, Florida, and elsewhere in the southeastern United States this weekend and into the middle of next week.

WHAT'S NEW:

The government of the Bahamas has issued a Hurricane Watch for the northwestern Bahamas.

SUMMARY OF ALERTS:

A Hurricane Watch is in effect for...
- Northwestern Bahamas

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 tropicalstormforce winds, conditions that make outside preparations difficult or dangerous. Interests in southern and central Florida should monitor the progress of Dorian. For storm information specific to your area, please monitor products issued by your national meteorological service.

WIND: [TOP] Hurricane conditions are possible within the watch area by Sunday, with tropical storm conditions possible by Saturday night or Sunday morning.

STORM SURGE: [TOP] A dangerous storm surge is expected to produce significant coastal flooding in areas of onshore winds in the northwestern Bahamas. Near the coast, the surge will be accompanied by large and destructive waves.

RAINFALL: Dorian is expected to produce the following rainfall accumulations this weekend into the middle of next week:

The northwestern Bahamas and coastal sections of the Southeast United States...6 to 12 inches, isolated 15 inches. The central Bahamas...1 to 2 inches, isolated 4 inches.

This rainfall may cause life-threatening flash floods.

SURF: [TOP] Swells are likely to begin affecting the east-facing shores of the Bahamas and the southeastern United States coast during the next few days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office.

At 500 AM AST (0900 UTC), the center of Hurricane Dorian was located near latitude 23.8 North, longitude 69.1 West. Dorian is moving toward the northwest near 12 mph (19 km/h), and this motion is expected to continue through the day. A slower west-northwestward to westward motion is forecast to begin tonight and continue through the weekend. On this track, Dorian should move over the Atlantic well east of the southeastern and central Bahamas today, approach the northwestern Bahamas Saturday, and move near or over portions of the northwestern Bahamas on Sunday.

Maximum sustained winds are near 105 mph (165 km/h) with higher gusts. Strengthening is forecast during the next few days, and Dorian is expected to become a major hurricane later today. Dorian is likely to remain an extremely dangerous hurricane while it moves near the northwestern Bahamas and approaches the Florida peninsula through the weekend.

Hurricane-force winds extend outward up to 25 miles (35 km) from the center, and tropical-storm-force winds extend outward up to 105 miles (165 km).

The minimum central pressure based on data from an earlier Hurricane Hunter mission is 979 mb (28.91 inches).

There hasn't been a lot of new data since the Hurricane Hunter planes departed Dorian several hours ago. The convective pattern on infrared satellite imagery has been nearly steady state, although the latest Dvorak estimates from TAFB and SAB rose to T5.0/90 kt. These estimates, combined with the earlier aircraft data, support maintaining an initial intensity of 90 kt.

Dorian's heading is very gradually turning toward the left, with the latest estimate northwestward, or 320 degrees at 10 kt. Dorian is now being steered between a mid-tropospheric high centered near Bermuda and a mid-/upper-level low located over the Bahamas. The high is expected to expand westward, with a blocking ridge becoming established over the western Atlantic during the next several days. With the exception of COAMPS-TC and HMON, the other reliable models are in excellent agreement through day 3, with Dorian turning westward south of the ridge and moving near or over the northernmost islands in the Bahamas Sunday and Monday. After day 3, steering currents collapse as a break develops in the ridge, and Dorian will likely slow down considerably as it approaches the Florida peninsula. There is more spread among the deterministic models and their ensemble members during that time, with disagreement on exactly when and where Dorian will turn northwestward and northward on days 4 and 5. That being said, the tracks of the simple and corrected consensus models on this cycle did not warrant much change to the official NHC forecast, with perhaps just a slight southward adjustment on days 3 and 4. The biggest concern will be Dorian's slow motion when it is near Florida, placing some areas of the state at an increasing risk of a prolonged, drawn-out event of strong winds, dangerous storm surge, and heavy rainfall.

The upper-level low to the west of Dorian continues to impart some southwesterly shear over the hurricane, which has prevented it from strengthening rapidly. However, Dorian is expected to enter a more favorable upper-level environment during the next 24 hours, which should allow its structure to become more well developed. Although overall the environment ahead of the storm appears conducive for strengthening, some models (in particular the ECMWF) suggest that some northerly shear could come into play while Dorian moves through the northwestern Bahamas, and for that reason the NHC official intensity forecast is not quite as bullish as the HCCA, Florida State Superensemble, and HWRF models. Still, Dorian is forecast to become a dangerous major hurricane later and maintain that status as it heads for the northwestern Bahamas and the Florida peninsula.