As of the latest advisory, Irene is heading N at 12kts with 90kt sustained winds. It's about 330 miles S of Cape Hatteras NC. The latest forecast track, watches, and warnings can be found at http://www.nhc.noaa.gov/storm_graphics/AT09/refresh/AL0911W+gif/092739W_sm.gif The track is very ominous, and one of the worst-case scenarios for the entire northeast coast. It's been 6 years since the US has experienced a major hurricane landfall, and that was Wilma when it hit just south of Naples FL with 105kt winds. The last non-major (Cat 1-2) US hurricane landfalls occurred in 2008: Dolly, Gustav, and Ike (TX, LA, TX).
The first and strongest US landfall is expected in the early morning hours on Saturday, near Morehead City, NC, as a Category 2 (90kt) storm. In addition to the powerful winds gusting up to 125mph, the storm surge will be quite high... up to 9' in surge-prone areas like Pamlico Sound. Keep in mind that large violent waves are on top of that storm surge, and both are on top of the normal tides.
A long-range radar loop from Morehead City can be found here:
and a short-range radar loop can be found here:
Also, the exact time and location of landfall is almost irrelevant for a storm this large... the effects of the hurricane will be felt far from the center and for at least 12 hours before the eye crosses the coastline.
Further north and a day later, Irene will be just off of the NJ coast, and creating a large storm surge in the Chesapeake and Delaware Bays as well as along the ocean. Norfolk VA is in a very sensitive area, and can expect a 6-7' surge. It could still be a powerful Category 1 storm at that time, so wind gusts up to 120mph could affect coastal VA, MD, DE, and NJ. There is still a lot of concern for New York City, where low-lying parts of the city exposed to water are home to large numbers of people. Again, the evacuation map for NYC can be found here: http://www.nyc.gov/html/oem/downloads/pdf/hurricane_map_english.pdf
The image below shows what the latest forecast storm surge will be in the DE/MD/NJ/NY area:
Then on top of all of this is the rainfall. The image here shows the 5-day forecast accumulated rainfall totals (in inches). Many areas in the northeast have just gotten a lot of rain unrelated to the hurricane, so the ground is saturated prior to getting up to a foot of additional rain.
Please visit my tropical Atlantic headquarters.