1. Isaias will produce heavy rains and potentially life-threateningflash flooding and mudslides across the Dominican Republic, northernHaiti, Turks and Caicos, and the Bahamas.

2. Hurricane conditions and dangerous storm surge are expected in portions of the southeastern Bahamas overnight, central and northwestern Bahamas late Friday and Saturday, and Hurricane Warnings are in effect for these areas. Preparations to protect life and property should be rushed to completion.

3. Tropical storm conditions are possible along portions of theFlorida east coast beginning Saturday, and a Tropical Storm Watchis in effect. While storm surge watches are not currently neededfor this area, they may be required on Friday if the forecast trackshifts closer to the coast. Heavy rains associated with Isaias maybegin to affect South Florida and east-Central Florida beginninglate Friday night, potentially resulting in isolated flash and urbanflooding, especially in low-lying and poorly drained areas.

4. There is a risk of impacts from winds, heavy rainfall, and stormsurge late this weekend from the northeastern Florida coast andspreading northward along the remainder of the U.S. east coastthrough early next week. The details of the track and intensityforecast remain uncertain, and it is too soon to determine themagnitude and location of these potential impacts, but interestsalong the entire U.S. east coast should monitor the progress ofIsaias and updates to the forecast.

CHANGES WITH THIS ADVISORY:

The government of the Bahamas has issued a Hurricane Warning for the central and southeastern Bahamas, which include the Acklins, Crooked Island, Long Cay, the Inaguas, Mayaguana, the Ragged Islands, Cat Island, the Exumas, Long Island, Rum Cay, and San Salvador.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Hurricane Warning is in effect for...
- Northwestern Bahamas including Andros Island, New Providence, Eleuthera, Abacos Islands, Berry Islands, Grand Bahamas Island, and Bimini
- Southeastern Bahamas including the Acklins, Crooked Island, Long Cay, the Inaguas, Mayaguana, and the Ragged Islands
- Central Bahamas, including Cat Island, the Exumas, Long Island, Rum Cay, and San Salvador

A Tropical Storm Warning is in effect for...
- Dominican Republic entire southern and northern coastlines
- North coast of Haiti from Le Mole St Nicholas eastward to the northern border with the Dominican Republic
- Turks and Caicos Islands

A Tropical Storm Watch is in effect for...
- East coast of Florida from Ocean Reef to Sebastian Inlet
- Lake Okeechobee

Interests elsewhere along the southeast coast of the United States should monitor the progress of this system. Additional watches or warnings may be required for a portion of the Florida peninsula on Friday.

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 tropicalstormforce winds, conditions that make outside preparations difficult or dangerous. Preparations to protect life and property should be rushed to completion.

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.

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.

Key messages for Isaias can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT4, WMO header WTNT44 KNHC, and on the web at www.hurricanes.gov/text/MIATCDAT4.shtml.

STORM SURGE: A dangerous storm surge will raise water levels by as much as 3 to 5 feet above normal tide levels in areas of onshore winds in the central and northwestern Bahamas. Storm surge will raise water level by as much as 1 to 3 ft above normal tide levels in the southeastern Bahamas.

WIND: Tropical storm conditions will continue to spread across portions of the Dominican Republic, Haiti, the southeastern Bahamas and Turks and Caicos tonight and early Friday. Hurricane conditions are expected to begin in the central Bahamas Friday morning and spread into the northwestern Bahamas beginning late Friday. Hurricane conditions are expected within portions of the the northwestern Bahamas Friday night and Saturday.

Tropical storm conditions are possible in the watch area in Florida beginning Saturday.

RAINFALL: Isaias is expected to produce the following rain accumulations through Friday night:

Dominican Republic and northern Haiti: 4 to 8 inches, with isolated maximum totals of 12 inches.

Bahamas, Turks and Caicos: 4 to 8 inches.

Cuba: 1 to 2 inches, with isolated maximum totals of 4 inches.

These rainfall amounts will lead to lifethreatening flash flooding and mudslides, as well as river flooding. Urban and small stream flooding is expected for the U.S. Virgin Islands and Hispaniola.

From Friday night through Monday:

South Florida into eastCentral Florida: 2 to 4 inches, with isolated maximum totals of 6 inches.

These rainfall amounts could result in isolated flash and urban flooding, especially in lowlying and poorly drained areas.

SURF: Swells generated by Isaias are affecting portions of the Leeward Islands, the Virgin Islands, Puerto Rico, the Dominican Republic, the Turks and Caicos Islands and the southeastern Bahamas. These swells will spread along the coast of Cuba and into the central and northwestern Bahamas over the next day or two. These swells are likely to cause lifethreatening surf and rip current conditions. Please consult products from your local weather office.

At 1200 AM EDT (0400 UTC), the center of Hurricane Isaias was located near latitude 20.4 North, longitude 72.2 West. Isaias is moving toward the northwest near 18 mph (30 km/h), and a generally northwestward motion with some decrease in forward speed is expected for the next couple of days followed by turn toward the northnorthwest. On the forecast track, the center of Isaias will move near or over the Southeastern Bahamas overnight. Isaias is forecast to be near the Central Bahamas Friday night and move near or over the Northwestern Bahamas and near South Florida on Saturday.

Maximum sustained winds have increased to near 80 mph (130 km/h) with higher gusts. Little change in strength is forecast during the next 48 hours.

Hurricaneforce winds extend outward up to 30 miles (45 km) from the center and tropicalstormforce winds extend outward up to 240 miles (390 km).

The estimated minimum central pressure based on Air Force Reserve Hurricane Hunter data is 995 mb (29.39 inches).

An Air Force Reserve Hurricane Hunter found that Isaias has become a hurricane. Maximum flight-level winds so far were 87 kt at 850 mb, with believable SFMR values of at least 65 kt. A blend of these values gives an initial wind speed of 70 kt. Some further strengthening is likely over the next 24 hours before increasing southwesterly shear could weaken the system. The intensity forecast is modified upward from 5-10 kt through 48 hours and unchanged afterthat time.There are no changes to the previous track forecast.