1. Isaias will produce heavy rains and potentially life-threatening flash flooding and mudslides across the Dominican Republic, northern Haiti, Turks and Caicos, and the Bahamas. Heavy rains associated with Isaias may begin to affect South and east-Central Florida beginning late Friday night, and the eastern Carolinas by early next week, potentially resulting in isolated flash and urban flooding, especially in low-lying and poorly drained areas. Isolated minor river flooding is possible in the Carolinas early next week.

2. Hurricane conditions and dangerous storm surge are expected in portions of the Bahamas today 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 Watchremains in effect. While storm surge watches are not currently needed for this area, they may be required later today if the forecast track shifts closer to the coast. Heavy rains associated with Isaias may begin to affect South Florida and east-Central Florida beginning late tonight, potentially resulting in isolated flash and urban flooding, 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 Tropical Storm Warning for Haiti has been discontinued.

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
- 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 later today. The Tropical Storm Warning for the Dominican Republic will likely be discontinued later this morning.

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 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 Bahamas.

WIND: Tropical storm conditions will continue across portions of the Dominican Republic and the Turks and Caicos this morning. Hurricane conditions are expected to begin in the southeastern Bahamas this morning and spread into the central and northwestern Bahamas tonight and into 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 Saturday:

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.

Heavy rains associated with Isaias may begin to affect the eastern Carolinas by early next week. This rain could result in isolated flash and urban flooding, especially in lowlying and poorly drained areas, as well as isolated minor river flooding.

SURF: Swells generated by Isaias are affecting portions of 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 later today and along the east coast of Florida on Saturday. These swells are likely to cause lifethreatening surf and rip current conditions. Please consult products from your local weather office.

At 800 AM EDT (1200 UTC), the center of Hurricane Isaias was located by NOAA and Air Force Reserve Hurricane Hunter aircraft near latitude 21.3 North, longitude 73.9 West. Isaias is moving toward the northwest near 17 mph (28 km/h), and a generally northwestward motion with some decrease in forward speed is expected for the next couple of days followed by a turn toward the northnorthwest. On the forecast track, the center of Isaias will move near or over the Southeastern Bahamas today. Isaias is forecast to be near the Central Bahamas tonight, and move near or over the Northwestern Bahamas and be near or east of the Florida peninsula on Saturday and Sunday.

Maximum sustained winds are near 80 mph (130 km/h) with higher gusts. Some strengthening is possible today, and Isaias is expected to remain a hurricane for the next few days.

Hurricaneforce winds extend outward up to 45 miles (75 km) from the center and tropicalstormforce winds extend outward up to 205 miles (335 km). A private weather observing site at Long Bay Beach in Providenciales recently reported a sustained wind of 55 mph (86 km/h) and a gust to 59 mph (95 km/h).

Reports from the reconnaissance aircraft indicate that the minimum central pressure is 990 mb (29.24 inches).

Satellite images indicate that Isaias is maintaining a smallcentral dense overcast, with a new burst of convection recentlyforming near the center. Earlier aircraft data indicated that thepressure had fallen to 990 mb, although there was little from theaircraft that supported more than the previous advisory's intensityof 70 kt.

The hurricane has been moving between west-northwest and northwestduring the last several hours, estimated at 305/15 now. Isaiasshould gradually turn to the north-northwest and north over theweekend as it moves around the western periphery of a weakeningwestern Atlantic subtropical ridge. Guidance is in fairly goodagreement over the first couple of days of the forecast, so little change is made at that time, other than a small westward adjustment near the Bahamas. After that time, there is a considerable spread, growing to over 700 miles, in the reliable models on how quickly Isaias moves northeastward near the east coast of the United States. The large spread appears to be related to both how strong the cyclone is by early next week and how much mid-level ridging remains near the Carolinas. There are no obvious reasons to choose either the fast GFS or slow ECMWF right now, so the official forecast will remain close to the previous one and the model consensus. It should be noted that given this large spread, the extended forecast could be subject to large speed/timing changes if either of those solutions become more likely.Strengthening is expected during the next day or so while the hurricane remains over the very warm waters near the Bahamas with reasonably low vertical shear. The forecast for the first 24 hours has been raised from earlier, at the top of the guidance spread. Increasingly southwesterly flow aloft should cause an increase in shear over the weekend, which is forecast by most of the guidance to lead to a gradual decrease in intensity. The details are not very clear at all, especially considering the track uncertainty, but there is a notable chance of a hurricane moving close to the U.S. East coast, so the forecast continues to show that scenario.