National Hurricane Center Update – Hurricane Irene Drenching the Mid-Atlantic States With Heavy Rains, August 27, 2011 11 PM EDT Update)

Miami, Florida—(ENEWSPF)—August 27, 2011 – UPDATE 11 PM EDT.  Hurricane Irene is drenching the Mid-Atlantic states with heavy rains as it skirts the Delmarva Peninsula.

Summary of 1100 PM EDT (0300 UTC) Information

Hurricane Irene is located 37.3N 75.4W about 70 mi (115 Km SSW of Ocean City, Maryland, about 255 mi (415 km) SSW of New York City.  Maximum sustained winds of 80 mph (130 km/h). Present movement is NNE or 20 degrees at 1t6 mph (26 km/h). Minimum central pressure is 954 mb (28.17 inches).

Watches and Warnings

Changes in Watches and Warnings With This Advisory

None.

Summary of Watches and Warnings in Effect

A Hurricane Warning is in effect for:

  • Cape Lookout, North Carolina northward to Sagamore Beach, Massachusetts, including the Pamlico, Albemarle, and Currituck Sounds, Delaware Bay, Chesapeake Bay south of Drum Point, New York City, Long Island, Long Island Sound, coastal Connecticut, Rhode Island, Block Island, Martha’s Vineyard and Nantucket.

A Tropical Storm Warning is in effect for:

  • Chesapeake Bay from Drum Point northward and the Tidal Potomac  
  • North of Sagamore Beach to Eastport, Maine  
  • United States/Canada border northeastward to Fort Lawrence including Grand Manan  
  • South coast of Nova Scotia from Fort Lawrence to Porters Lake

Interests elsewhere in Eastern Canada should monitor the progress of Irene.

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 the United States, please monitor products issued by your National Meteorological Service.

Discussion and 48-Hour Outlook

At 11 PM EDT (0300 UTC), the center of Hurricane Irene was located near latitude 37.3 north, longitude 75.4 west. Irene is moving toward the north-northeast near 16 mph (26 km/h) and this motion accompanied by a gradual increase in forward speed is expected during the next day or so.  On the forecast track, the center of Irene will move near or over the Mid-Atlantic coast tonight and Sunday morning, and move over southern New England by Sunday afternoon. Irene is forecast to move into eastern Canada Sunday night.

Reports from an Air Force Reserve Unit Hurricane Hunter Aircraft indicate maximum sustained winds remain near 80 mph (130 km/h) with higher gusts.  Irene is a category one hurricane on the Saffir-Simpson Hurricane Wind Scale.  Irene is forecast to remain a hurricane as it moves near or over the Mid-Atlantic coast and approaches New England on Sunday.  The hurricane is forecast to weaken after landfall in New England and become a post-tropical cyclone Sunday night or early Monday.

Irene is a large tropical cyclone. Hurricane-force winds are located over a relatively small area roughly 125 miles (205 km) to the east of the center.  Tropical-storm-force winds extend outward up to 240 miles (390 km) from the center. Tropical Storm conditions will spread northward into southern New Jersey and Long Island overnight into Sunday morning.

A wind gust to 67 mph was recently reported as far south as Cape Hatters, North Carolina, and a wind gust to 52 mph was reported as far north as the Philadelphia International Airport.

A storm surge height of about 5 feet has been observed at Oregon Inlet, North Carolina, and a storm surge height of about 4 feet has occurred thus far at the mouth of the Chesapeake Bay. The preliminary water level at the Chesapeake Bay Bridge Tunnel has recently peaked near the record level that was established during Hurricane Isabel in 2003.

Rainfall amounts of 10 to 14 inches have already occurred over a large portion of eastern North Carolina and extreme southeastern Virginia, with the highest amount thus far of 14.00 inches reported at Bunyan, North Carolina.

The latest minimum central pressure reported by reconnaissance aircraft was 954 mb (28.17 inches).

Hazards Affecting Land

Tropical-storm-force winds will continue to spread northward along the Mid-Atlantic coast tonight and early Sunday morning, with gusts to hurricane force possible by sunrise Sunday morning.

Tropical Storm conditions are expected to reach Long Island and southern New England early Sunday morning, with hurricane-force winds, especially in gusts, expected by noon Sunday. Winds affecting the upper floors of high-rise buildings will be significantly stronger than those near ground-level.

An extremely dangerous storm surge will raise water levels by as much as 4 to 8 feet above ground level within the hurricane warning area from the North Carolina/Virginia border northward to Cape Cod, including southern portions of the Chesapeake Bay and its tributaries. Near the coast, the surge will be accompanied by large, destructive and life-threatening waves.

Higher than normal astronomical tides are occurring this weekend. Coastal and river flooding will be highest in areas where the peak surge occurs around the time of high tide. Storm tide and surge values are very location-specific and users are urged to consult products issued by their Local National Weather Service Offices.

Along the North Carolina coast, including the Albemarle and Pamlico Sounds, water level values will gradually subside overnight.

Irene is expected to produce rainfall accumulations of 6 to 12 inches, with isolated maximum amounts of 20 inches, from eastern North Carolina northward through the Mid-Atlantic states into eastern New York and interior New England.  These rains, combined with heavy rains over the past few weeks, could cause widespread flooding, life-threatening flash floods, and significant uprooting of trees due to rain-softened grounds.

Large swells generated by Irene are affecting much of the east coast of the United States.  These swells will cause life-threatening surf and rip current conditions.

Isolated tornadoes are possible over southern Delaware, eastern New Jersey, southeastern New York, and extreme southern New England tonight through Sunday morning.

Surface Wind Field

Click image to zoom in [Image of initial wind radii]
About this product:

This graphic shows the areas potentially being affected by the sustained winds of tropical storm force (in orange) and hurricane force (in red). The display is based on the wind radii contained in the latest Forecast/Advisory (indicated at the top of the figure). Users are reminded that the Forecast/Advisory wind radii represent the maximum possible extent of a given wind speed within particular quadrants around the tropical cyclone. As a result, not all locations falling within the orange or red shaded areas will be experiencing sustained tropical storm or hurricane force winds, respectively.

In addition to the wind field, this graphic shows an approximate representation of coastal areas under a hurricane warning (red), hurricane watch (pink), tropical storm warning (blue) and tropical storm watch (yellow). The white dot indicates the current position of the center of the tropical cyclone, and the dashed line shows the history of the center of the tropical cyclone. 

source: nhc.noaa.gov