1. A prolonged period of catastrophic winds and storm surge will affect the Abaco Islands today. Everyone there should take immediate shelter and not venture into the eye. These catastrophic conditions are likely on Grand Bahama Island later today or tonight, and efforts to protect life and property there should be rushed to completion.

2. Storm surge and hurricane watches and tropical storm warnings are in effect for portions of the Florida east coast. Life-threatening storm surge and dangerous hurricane-force winds are possible along portions of the Florida east coast through mid-week, as only a slight deviation to the left of the official forecast would bring the core of Dorian near or over the coast. Residents should listen to advice given by local emergency officials.

3. There is an increasing likelihood of strong winds and dangerous storm surge along the coasts of Georgia, South Carolina, and North Carolina later this week. Residents in these areas should continue to monitor the progress of Dorian.

4. Heavy rains, capable of producing life-threatening flash floods, are possible over northern portions of the Bahamas and coastal sections of the southeast and lower mid-Atlantic regions of the United States through late this week.

WHAT'S NEW:

A Hurricane Watch has been issued for the east coast of Florida from north of Deerfield Beach to the Volusia/Brevard County Line.

A Storm Surge Watch has also been issued from north of Deerfield Beach to the Volusia/Brevard County Line.

A Tropical Storm Watch has been issued for Lake Okeechobee.

SUMMARY OF ALERTS:

A Storm Surge Watch is in effect for...
- North of Deerfield Beach to the Volusia/Brevard County Line

A Hurricane Warning is in effect for...
- Northwestern Bahamas excluding Andros Island

A Hurricane Watch is in effect for...
- Andros Island
- North of Deerfield Beach to the Volusia/Brevard County Line

A Tropical Storm Warning is in effect for...
- North of Deerfield Beach to Sebastian Inlet

A Tropical Storm Watch is in effect for...
- North of Golden Beach to Deerfield Beach
- Lake Okeechobee

A Storm Surge Watch means there is a possibility of life threatening inundation, from rising water moving inland from the coastline, in the indicated locations during the next 48 hours. For a depiction of areas at risk, please see the National Weather Service Storm Surge Watch/Warning Graphic, available at hurricanes.gov.

A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area. 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 tropicalstormforce winds, conditions that make outside preparations difficult or dangerous.

A Tropical Storm Warning means that tropical storm conditions are expected 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 elsewhere along the east coast of Florida should continue to monitor the progress of Dorian, as additional watches or warnings may be required later today. 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.

WIND: [TOP] Catastrophic hurricane conditions are occurring in the Abacos Islands and will spread across Grand Bahama Island later today and tonight.

Hurricane conditions are possible within the hurricane watch area in Florida by late Monday or early Tuesday.

Tropical storm conditions are expected within the tropical storm warning area on Monday and Tuesday.

Tropical storm conditions are possible within the tropical storm watch area by Monday night.

STORM SURGE: [TOP] A life-threatening storm surge will raise water levels by as much as 18 to 23 feet above normal tide levels in areas of onshore winds on the Abaco Islands and Grand Bahama Island. Near the coast, the surge will be accompanied by large and destructive waves.

The combination of a dangerous storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide...

Volusia/Brevard County Line to Jupiter Inlet FL...4 to 7 ft North of Deerfield Beach to Jupiter Inlet FL...2 to 4 ft

The surge will be accompanied by large and destructive waves. Surge-related flooding depends on the how close the center of Dorian comes to the Florida east coast, and can vary greatly over short distances. For information specific to your area, please see products issued by your local National Weather Service forecast office.

RAINFALL: Dorian is expected to produce the following rainfall totals through late this week:

Northwestern Bahamas...12 to 24 inches, isolated 30 inches. Coastal Carolinas...5 to 10 inches, isolated 15 inches. Central Bahamas and the Atlantic Coast from the Florida peninsula through Georgia...2 to 4 inches, isolated 6 inches.

This rainfall may cause life-threatening flash floods.

SURF: [TOP] Large swells are already affecting east-facing shores of the Bahamas, the Florida east coast, and will spread northward along 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 1100 AM EDT (1500 UTC), the extremely distinct eye of Hurricane Dorian was located near latitude 26.5 North, longitude 76.8 West. Dorian is moving toward the west near 7 mph (11 km/h). A slower westward motion should continue for the next day or two, followed by a gradual turn toward the northwest. On this track, the core of extremely dangerous Hurricane Dorian will continue to move over Great Abaco and move near or over Grand Bahama Island later tonight and Monday. The hurricane should move closer to the Florida east coast late Monday through Tuesday night.

Maximum sustained winds have increased to near 180 mph (285 km/h) with higher gusts. Dorian is a extremely dangerous category 5 hurricane on the Saffir-Simpson Hurricane Wind Scale. Some fluctuations in intensity are likely, but Dorian is expected to remain a powerful hurricane during the next few days.

Dorian has grown larger in size. Hurricane-force winds extend outward up to 45 miles (75 km) from the center and tropical-storm- force winds extend outward up to 140 miles (220 km). Ham radio reports indicate that Hope Town in the Abacos just reported wind gust to 100 mph.

The minimum central pressure measured by both NOAA and Air Force reconnaissance plane was 913 mb (26.96 inches).

Air Force and NOAA reconnaissance planes penetrated the distinct eye of Dorian, and found that the hurricane has become extremely intense with a stadium effect in the eye. The NOAA plane reported a peak flight-level wind of 159 kt, while the SFMR from both planes have measured winds between 155 and 170 kt. A dropsonde from the NOAA plane measured a wind gust of 176 kt at the surface. A blend of these measurements yield to an initial intensity of 155 kt, making Dorian the strongest hurricane on record in the northwestern Bahamas.

For the next few days, Dorian should experience some fluctuations in intensity, and in addition to eyewall replacement cyclone, the interaction with the northwestern Bahamas should weaken the hurricane slightly. After 3 days, as Dorian moves northward along or offshore of southeast United States coast, the shear is forecast to increase, resulting in a more distinct gradual weakening.

Reconnaissance plane and satellite fixes indicate that Dorian, as anticipated, has slowed down and is moving toward the west or 270 degrees at 6 kt. The steering currents are collapsing and Dorian is expected to slow down even more, prolonging its catastrophic effects in the northwestern Bahamas. The NHC forecast calls for a slow west to west-northwest motion during the next 48 hours, with a turn to the north and an increase in forward speed as the mid-level trough along the eastern United States deepens and becomes the dominant steering feature. The current forecast is only a few miles west of the previous one and is basically on top of the multi-model consensus. Both the deterministic and consensus tracks have shown the usual variability to the right or to the left from run to run, but the overall trend is for the hurricane to turn northward offshore but very close to the Florida peninsula.

Given the uncertainty in the track forecast and the anticipated increase in size of the hurricane, a Hurricane Watch and Storm Surge Watch have been issued for a portion of the east Florida coast. It is emphasized that although the official track forecast does not show landfall, users should not focus on the exact track. A small deviation to the left of the track could bring the intense core of the hurricane its dangerous winds closer to or onto the coast.