1. There is the danger of life-threatening storm surge inundation of

2.to

4.feet above ground level from Edisto Beach South Carolina to Cape Fear North Carolina along the immediate coastline and adjacent waterways. Life-threatening storm surge is possible along the North Carolina coast from Cape Fear to Duck. Residents in these areas should follow advice given by local emergency officials. 2. Tropical storm conditions will spread northward within the Tropical Storm Warning area from Florida to North Carolina through Monday night. Isaias is expected to be near hurricane strength when it reaches the coast of northern South Carolina and southern North Carolina Monday night, and strong tropical storm force winds are likely with hurricane conditions possible in the Hurricane Watch area.

3. Heavy rainfall from Isaias will continue to result in potentially life-threatening flash flooding in the Northwest Bahamas through tonight. Flash and urban flooding, some of which may be significant in the eastern Carolinas and the mid-Atlantic, are expected through midweek along and near the path of Isaias across the U.S. East Coast. Widespread minor to isolated moderate river flooding is possible across portions of the Carolinas and the mid-Atlantic.4. A tropical storm watch is in effect for the U.S. mid-Atlantic coast, including the Chesapeake Bay, Delaware Bay, and Long Island Sound, as tropical storm force winds are possible in these areas on Tuesday and Tuesday night. Additional watches and warnings will likely be issued tonight and Monday as Isaias is expected to move northward near or over the mid-Atlantic and New England states Tuesday and Wednesday.

CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Storm Surge Warning is in effect for...
- Edisto Beach South Carolina to Cape Fear North Carolina

A Storm Surge Watch is in effect for...
- Cape Fear to Duck North Carolina
- Pamlico and Albemarle Sounds

A Hurricane Watch is in effect for...
- South Santee River South Carolina to Surf City North Carolina

A Tropical Storm Warning is in effect for...
- Sebastian Inlet Florida to Ocracoke Inlet North Carolina

A Tropical Storm Watch is in effect for...
- Ocracoke Inlet North Carolina to Watch Hill Rhode Island
- Pamlico and Albemarle Sounds
- Chesapeake Bay
- Tidal Potomac River
- Delaware Bay
- Long Island and Long Island Sound

Interests elsewhere along the northeast coast of the United States should monitor the progress of Isaias. Additional watches or warnings may be required tonight or early Monday.

A Storm Surge Warning means there is a danger of lifethreatening inundation, from rising water moving inland from the coastline, during the next 36 hours in the indicated locations. For a depiction of areas at risk, please see the National Weather Service Storm Surge Watch/Warning Graphic at hurricanes.gov. This is a lifethreatening situation. Persons located within these areas should take all necessary actions to protect life and property from rising water and the potential for other dangerous conditions. Promptly follow evacuation and other instructions from local officials.

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.

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 somewhere within the warning area, generally 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...

Edisto Beach SC to Cape Fear NC...24 ft Sebastian Inlet FL to Edisto Beach SC...13 ft North of Cape Fear NC to Kiptopeke VA including Pamlico Sound, Albemarle Sound, Neuse River, Pamlico River, Chesapeake Bay, and the Tidal Potomac River...13 ft

The deepest water will occur along the immediate coast in areas of onshore winds, 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.

WIND: Hurricane conditions are possible in the watch area in South and North Carolina Monday night and early Tuesday.

Tropical storm conditions will spread northward within the Tropical Storm Warning area from Florida to North Carolina through Monday night.

Tropical storm conditions are possible in the Tropical Storm Watch area beginning on Tuesday.

RAINFALL: The following rainfall accumulations are expected along and near the track of Isaias:

Northwest Bahamas: Additional 1 to 3 inches, isolated storm totals 12 inches.

Eastern Florida: Additional 1 to 3 inches, isolated storm totals 4 inches.

Coastal Georgia: 1 to 2 inches.

Carolinas and the MidAtlantic: 3 to 6 inches, isolated maximum totals 8 inches.

Southeast New York and much of New England: 2 to 4 inches, isolated maximum totals 6 inches.

Heavy rainfall from Isaias will continue to result in potentially lifethreatening flash flooding in the Northwestern Bahamas through tonight. Flash and urban flooding, some of which may be significant in the eastern Carolinas and the MidAtlantic, is expected through midweek along and near the path of Isaias across the East Coast of the United States. Widespread minor to isolated moderate river flooding is possible across portions of the Carolinas and the MidAtlantic.

SURF: Swells generated by Isaias are affecting portions of the Bahamas and the southeast coast of the United States and will spread northward along the U.S. east coast during the next couple of days. These swells are likely to cause lifethreatening surf and rip current conditions. Please consult products from your local weather office.

TORNADOES: A few tornadoes will be possible over coastal South Carolina during the afternoon and evening on Monday, and across eastern North Carolina Monday evening and overnight.

At 800 PM EDT (0000 UTC), the center of Tropical Storm Isaias was located by a NOAA Hurricane Hunter aircraft near latitude 28.2 North, longitude 79.7 West. Isaias is moving toward the northnorthwest near 9 mph (15 km/h), and this general motion is expected to continue through tonight. A turn toward the north and northnortheast along with an increase in forward speed is anticipated on Monday and Tuesday. On the forecast track, the center of Isaias will pass just to the east of the Florida east coast through tonight. The center of Isaias will then move offshore of the coast of Georgia and southern South Carolina on Monday, move inland over eastern South Carolina or southern North Carolina Monday night and move along the coast of the midAtlantic states on Tuesday.

Maximum sustained winds are near 70 mph (110 km/h) with higher gusts. Some fluctuations in strength will be possible during the next 36 hours, but Isaias is expected to be a strong tropical storm when it reaches the coast of eastern South Carolina or southern North Carolina Monday night. Slow weakening is forecast after Isaias makes landfall in the Carolinas and moves across the U.S. midAtlantic region late Monday and Tuesday.

Tropicalstormforce winds extend outward up to 115 miles (185 km) from the center. NOAA buoy 41009, located just off the coast of Cape Canaveral, recently reported a sustained wind of 45 mph (72 km/h) and a gust of 54 mph (87 km/h). A Florida Institute of Technology observing station at Sebastien Inlet measured a sustained wind of 39 mph (63 km/h) and a gust of 48 mph (78 km/h) during the past couple of hours.

The minimum central pressure estimated from NOAA Hurricane Hunter aircraft observations is 993 mb (29.32 inches).

The earlier intense recent burst has waned since this morning, but the large convective cell has persisted. At the peak of the activity around 1500Z, several small patches of Doppler velocities of 90-96 kt were co-located with the pronounced mid-level circulation that was evident in the Melbourne radar reflectivity data. However, these intense wind speed values were short-lived for only about 20 minutes and, thus, were not considered to representative of Isaias' tangential wind field. Since that time, the cyclone has become more steady state with Doppler radar and Air Force Reserve aircraft data indicating surface winds in the 56-63 kt range. Therefore, the initial intensity of 60 kt is an average of these values.

Radar and aircraft fixes indicate that Isaias is still moving toward the north-northwest or 345/08 kt. The latest model guidance remains in excellent agreement on Isaias moving north-northwestward through a break in the subtropical ridge tonight and turning northward by Monday morning, all the while remaining offshore of the coast from east-central Florida to Georgia. By Monday night, Isaias is forecast to turn northeastward and accelerate toward the Carolinas, reaching the mid-Atlantic states on Tuesday and New England by early Wednesday. The new NHC forecast track during the first 24 hours lies a little east of the previous one, but is essentially just an extension of the previous advisory track thereafter, and lies close to the various consensus models, which are lightly packed around the previous NHC foreast.

Isaias will continue to move slowly over the warm Gulfstream waters for the next 36 h or so. Despite unfavorable vertical shear conditions of around 25 kt, Isaias is expected to maintain its current intensity until landfall, and could restrengthen to hurricane status in 24-36 h when the vertical shear vector is forecast to switch from westerly to southwesterly which would align the shear along the direction of storm motion. Some baroclinic interaction is expected on days 2-3 when Isaias will move into the right-rear quadrant of an anticyclonically curved jet streak, which is expected to hold the intensity a little above what would normally be expected for a post-landfall tropical cyclone. The NHC intensity forecast is similar to the HFIP corrected consensus model and the IVCN intensity consensus model, which agree well with the GFS and ECMWF model intensity forecasts.