1. Hurricane conditions and dangerous storm surge are expected in portions of the Bahamas through Saturday, and Hurricane Warnings are in effect.

2. Hurricane conditions are expected along portions of the Florida east coast late Saturday and Saturday night, and a Hurricane Warning has been issued. 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 in these areas should follow advice given by local emergency officials. 4. Isaias will produce heavy rains and potentially life-threatening flash and urban flooding, especially in low-lying and poorly drained areas across south to east-central Florida, and across the Carolinas to the mid Atlantic. Isolated minor river flooding is possible across the eastern Carolinas and into Virginia early next week.5. There is a risk of impacts from winds, heavy rainfall, and storm surge spreading along much of the the U.S. east coast through early next week, and interests there should monitor the progress of Isaias and updates to the forecast.

CHANGES WITH THIS ADVISORY:

The government of the Bahamas has discontinued the Hurricane Warning for the Southeastern Bahamas, and discontinued the Tropical Storm Warning for the Turks and Caicos Islands.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

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

A Hurricane Watch is in effect for...
- Hallendale Beach to south of Boca Raton Florida
- VolusiaBrevard County Line to the Flagler/Volusia County Line

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

A Tropical Storm Watch is in effect for...
- Flagler/Volusia County Line to Ponte Vedra Beach Florida

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

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 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: 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 Bahamas.

WIND: Hurricane conditions will continue to spread northwestward into the central and northwestern Bahamas tonight and Saturday.

Hurricane conditions are expected to reach the coast within the hurricane warning area in Florida late Saturday and Saturday night. Winds are expected to first reach tropical storm strength on Saturday, making outside preparations difficult or dangerous. Preparations to protect life and property should be rushed to completion.

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

Bahamas, Turks and Caicos: 4 to 8 inches.

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

These rainfall amounts could lead to lifethreatening flash and urban flooding, especially in lowlying and poorly drained areas.

From Friday night through Tuesday:

South Florida into eastCentral 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.

Heavy rainfall from Isaias could result in isolated flash and urban flooding, especially in lowlying and poorly drained areas. Isolated minor river flooding is possible across the eastern Carolinas and into Virginia.

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

At 800 PM EDT (0000 UTC), the center of Hurricane Isaias was located by Air Force and NOAA Hurricane Hunter aircraft near latitude 22.9 North, longitude 75.9 West. Isaias is moving toward the northwest near 15 mph (24 km/h), and a general northwestward motion with some decrease in forward speed is expected for the next day or so, followed by a turn toward the northnorthwest by late Sunday. On the forecast track, the center of Isaias will move near or over the Central Bahamas tonight, near or over the Northwestern Bahamas Saturday and near the east coast of the Florida peninsula Saturday afternoon through Sunday.

Maximum sustained winds are near 80 mph (130 km/h) with higher gusts. Additional strengthening is expected later tonight and early Saturday, and Isaias is forecast to remain a hurricane for the next couple of days.

Hurricaneforce winds extend outward up to 35 miles (55 km) from the center and tropicalstormforce winds extend outward up to 175 miles (280 km). Staniel Cay in the Exumas recently reported sustained winds of 40 mph (65 km/h) with a gust to 52 mph (83 km/h).

The minimum central pressure estimated from Air Force Hurricane Hunter aircraft observations is 987 mb (29.15 inches).

Deep convection, with occasional overshooting cloud tops of -85C to-90C just north of the center, has continued to develop during thenormal diurnal convective minimum period, which is quite impressive.The most recent Air Force Reserve recon flight-level wind data,along with ASCAT surface wind data, indicate that the inner-core andouter wind field have both contracted in size. Furthermore, radardata from the Bahamas and an 1810Z AMSR-2 microwave pass alsoindicate that a small 10-nmi-wide mid-level eye is forming. The lastrecon central pressure was 991 mb and the 700 mb height haddecreased by 30 meters since the earlier maximum height around1230Z. These data indicate that Isaias is getting better organized. The initial intensity remains 65 kt based on an earlier 700-mb flight-level wind speed of 72 kt, which reduces to a 65-kt surface wind speed using a 90-percent adjustment factor.

The initial motion remains northwestward or 305/12 kt. The 12Z global models have once again made a westward shift due to the ridge to the north of Isaias not weakening as quickly as expected. This is partly due to the ridge being stronger than expected and a shortwave trough over the central United States moving a little slower into the southeastern U.S. than previously indicated. The UKMET and ECMWF explicitly show Isaias making landfall in 36-48 hours along the southeast Florida coast, but appear to weaken the system below hurricane strength. The GFS similarly brings the cyclone close to the southeast and east-central Florida coasts, but also as a somewhat weaker system. In the 48 to 60-hour period, the cyclone is forecast to move slowly north-northwestward and northward through a break in the subtropical ridge extending westward from the Atlantic across Florida and into the northern Gulf of Mexico. By that time, however, Isaias is expected to weaken below hurricane strength due to the combination of strong southwesterly vertical wind shear and interaction the Florida peninsula. Around 72 hours, the cyclone should accelerate northeastward and possibly strengthen some before passing over eastern North Carolina on day 4, and across eastern New England on day 5. The NHC track forecast lies close to a blend of the consensus models TVCA and NOAA-HCCA and is east of the UKMET and ECMWF with the system forecast to be stronger than those models indicate. Due to the westward shift in the NHC forecast track, a Hurricane Warning and Storm Surge Watch have been issued for portions of the Florida east coast.

The center of Isaias is now located in the center of an expandingCDO feature. The improved inner-core wind field and aforementionedconvective structure, along with very warm SSTs near 30C, shouldsupport some strengthening overnight and early Saturday morning.However, increasing southwesterly vertical wind shear is expected tocause a gradual decrease in intensity by Sunday and continue intoearly next week. The new official intensity forecast is a littlelower than the previous advisory and is near the higher end of theintensity guidance.