1. Hurricane conditions and dangerous storm surge will continue in portions of the northwest Bahamas today and tonight.

2. Hurricane conditions are expected along portions of the Florida east coast by late tonight and Sunday. Preparations to protect life and property should be rushed to completion.

3. Dangerous storm surge is possible along the Florida east coast from Jupiter Inlet to Ponte Vedra Beach where water rises of 2 to 4 feet above ground level are possible along the immediate coastline and adjacent waterways. Residents there should follow advice given by local emergency officials.

4. Isaias will produce heavy rains and potentially life-threatening flash flooding in the Bahamas, and flash urban flooding, especially in low-lying and poorly drained areas, in eastern Florida, and from the Carolinas to the mid-Atlantic and Northeast U.S. Minor river flooding is possible across portions of the Carolinas and Virginia early next week.

5. Tropical storm watches and warnings are in effect for portions of the northeast Florida and southern Georgia coasts. Additional watches and warnings will likely be issued later today and Sunday along the U.S. east coast as the risk of wind, heavy rainfall, and storm surge impacts continues to increase.

CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Hurricane Warning is in effect for...
- Boca Raton to the Volusia/Flagler County Line Florida
- Northwestern Bahamas

A Hurricane Watch is in effect for...
- Hallandale Beach to south of Boca Raton Florida

A Storm Surge Watch is in effect for...
- Jupiter Inlet to Ponte Vedra Beach Florida

A Tropical Storm Warning is in effect for...
- North of Ocean Reef to south of Boca Raton Florida
- Lake Okeechobee
- Volusia/Flagler County Line to Ponte Vedra Beach Florida

A Tropical Storm Watch is in effect for...
- North of Ponte Vedra Beach Florida to Altamaha Sound Georgia

Interests elsewhere along the southeast coast of the United States should monitor the progress of Isaias. Additional watches or warnings may be required later today.

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 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 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 Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area, in this case within the next 12 to 24 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: 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...

Jupiter Inlet to Ponte Vedra Beach FL...24 ft North Miami Beach to Jupiter Inlet FL...13 ft

The deepest water will occur along the immediate coast near and to the right of the center, where the surge will be accompanied by large waves. Surgerelated flooding depends on the relative timing of the surge and the tidal cycle, 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.

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 Northwestern Bahamas.

WIND: Hurricane conditions will continue to spread over the Northwestern Bahamas through today.

Hurricane conditions are expected to reach the coast within the hurricane warning area in Florida tonight and will spread northward through Sunday. Winds are expected to first reach tropical storm strength later today, making outside preparations difficult or dangerous. Preparations to protect life and property should be rushed to completion. Tropical storm conditions are expected within the tropical storm warning area, and are possible within the watch area, over southern Florida by this afternoon or evening.

Tropical storm conditions are expected in the warning area in northeast Florida by late Sunday, and are possible in the watch area in northeast Florida and southeast Georgia by Monday morning.

RAINFALL: Isaias is expected to produce the following rain accumulations:

Bahamas: 4 to 8 inches, with isolated maximum totals of 12 inches.

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

Eastern Florida: 2 to 4 inches, with isolated maximum totals of 6 inches.

Northeast Florida into coastal Georgia: 1 to 2 inches.

Carolinas into the mid Atlantic, including the southern and central Appalachians: 2 to 4 inches, with isolated maximum totals of 6 inches.

Across the Northeast, from eastern Pennsylvania into New Jersey, southeast New York, and much of New England: 2 to 4 inches, with isolated maximum totals of 6 inches.

Heavy rainfall from Isaias could result in potentially life threatening flash flooding in the Bahamas and flash and urban flooding, especially in lowlying and poorly drained areas in eastern Florida and across the Carolinas to the MidAtlantic and Northeast. Minor river flooding is possible across portions of the Carolinas and into Virginia.

SURF: Swells generated by Isaias are affecting portions of Hispaniola, eastern Cuba, the Turks and Caicos, and the Bahamas. These swells will spread along the east coast of Florida and the southeastern United States coast today. These swells are likely to cause lifethreatening surf and rip current conditions. Please consult products from your local weather office.

At 200 PM EDT (1800 UTC), the center of Hurricane Isaias was located by an Air Force Reserve Hurricane Hunter aircraft and the Miami NOAA Doppler weather radar near latitude 24.9 North, longitude 78.4 West. Isaias is moving toward the northwest near 12 mph (19 km/h). A general northwestward motion with some decrease in forward speed is expected for the next day or so, followed by a northnorthwestward motion by late Sunday. On the forecast track, the center of Isaias will move over the Straits of Florida tonight, and approach the southeast coast of Florida early Sunday morning. Isaias is then forecast to move near or along the the east coast of the Florida peninsula Sunday and Sunday night.

Data from the reconnaissance aircraft and Doppler radar indicate that maximum sustained winds have decreased to near 75 mph (120 km/h) with higher gusts. Although Isaias has weakened after passing over Andros Island, some restrengthening is expected tonight and Sunday morning when the cyclone will be moving over the warm waters of the Straits of Florida and the Gulf Stream. Isaias is forecast to remain a hurricane through Monday, followed by slow weakening beginning Monday night or Tuesday.

Hurricaneforce winds extend outward up to 25 miles (35 km) from the center and tropicalstormforce winds extend outward up to 115 miles (185 km). A wind gust to 49 mph (80 km/h) was recently observed at Nassau, Bahamas. Doppler radar indicates that tropicalstormforce winds are located just offshore Broward and MiamiDade Counties.

The estimated minimum central pressure is 990 mb (29.23 inches).

Data from an Air Force Reserve reconnaissance aircraft around 1410 UTC indicated that the center of the eye of Isaias was located along the southern coast of northern Andros Island about 15 nmi south-southwest of Andros Town. The eye appearance in Bahamas and aircraft radar data, along with the visual reports from the flight crew, has gone from nearly closed a few hours ago to open in the southwestern quadrant more recently. However, the diameter of the eye has been has been holding steady between 20-22 nmi, an indication that Isaias has been able to fight off some modest southwesterly wind shear. The initial intensity has been lowered to 70 kt based on maximum 700-mb flight-level winds of 77 kt, which equals about 70-kt surface wind speed, and the central pressure fluctuating between 987-990 mb.

The initial motion estimate remains 315/10 kt. The latest NHC model guidance is now tightly packed about the previous 18-h worth of official track forecasts, and as a result, no significant changes were made to the previous advisory track. The global and regional models have come into much better agreement compared to 24 hours ago in taking Isaias northwestward slowly for the next 36 h or so, and moving the center near or keeping it just offshore the east-central Florida coast. By 48 hours, the hurricane is expected to turn northward around the western portion of the Bermuda-Azores ridge that will slowly be eroded by an approaching mid-level shortwave trough currently situated over the central United States. By 60 h and beyond, the aforementioned trough is expected to gradually accelerate Isaias northeastward near or along the coast from South Carolina to New England. The new NHC track forecast is basically an extension of the previous one, and lies very close to an average of the simple consensus model TVCA, and the corrected- consensus models NOAA-HCCA and FSSE.

In the near term, Isaias could weaken a little bit this afternoon while passing over northern Andros Island. However, the still impressive vertical structure of the cyclone should allow for some re-strengthening after the center moves back over the warm Gulf Stream by this evening. The current SHIPS analyzed westerly vertical wind shear of 25 kt could be too high due to the model incorporating some of the storm's outflow. The models forecast the shear to weaken somewhat over the next 36 h while Isaias is moving over the Gulf Stream, and the 06Z UKMET shows Isaias moving underneath a 200-mb anticyclone, which would normally favor some strengthening. Given all of these factors, the official forecast maintains a steady intensity through Monday night. Slow weakening is forecast when Isais encounters more significant southwesterly vertical wind shear ahead of a strong upper-level trough that will be approaching the U.S. east coast on days 3-5.