Latest track of Hurricane Irene and what it means for Pa., N.J. and Del.

Hurricane Irene is likely to become the first hurricane since Isabel in 2003 to make landfall on the East Coast in the Carolinas or north.

While there is uncertainty on specific track with the storm, Irene will be a large and relatively powerful storm system, with its impacts felt across the region this weekend as it churns north. It’s important to not focus totally on where the eye of Irene goes as this is a large storm; however, the position of the eye is critical in determining where the worst impacts ultimately fall.   As of now, here are thoughts on what ultimately pans out with Irene.  Timing:  Overrunning rain event starts on Saturday south of Philadelphia and spreads north slowly through Saturday p.m. towards Saturday night, with rain gradually increasing in intensity and coverage as time progresses.  Worst of storm generally impacts region Sunday into afternoon and early evening hours regardless of track before ending from south to north.Rainfall:  The potential for several inches of rain exists.  There is uncertainty to placement of heaviest rains but if Irene’s eye tracks across New Jersey or just along the coastline in a fashion similar to Gloria, the heaviest rains will align across Eastern Pennsylvania.   At minimum, most of the region could see at least four inches of rain.  If the “close to coast” track takes hold, some spots could see double that. Wind:  This area is where the eye track makes most of the difference.  In hurricanes, winds are strongest just ahead and east of the eye track.  If Irene makes landfall across North Carolina and takes a more inland track, the strongest winds will generally be confined to the Shore and could reach hurricane strength in gusts, with gusty winds into Philadelphia that could reach 30-50 mph.  An eye track along or just offshore could mean sustained winds to hurricane force at the Shore.Also, flooding from storm surge may occur along the New Jersey and Delaware coastlines and several feet of water is possible along shore towns if the track of the eye is close to the coast.  If the eye track is a bit farther west, Delaware Bay may also experience flooding along its beaches and marshes.

5 p.m. The University of Delaware, Rowan University and Rutgers University have adjusted their student move-in schedules this weekend. UDel’s move-in is postponed until further notice. Rowan students will move in between Monday and next Saturday, and Rutgers has postponed its move-in until Monday.

3:50 p.m. Christie’s evacuation order for Cape May County is now mandatory, as of Friday at 8 a.m.

1 p.m. N.J. Gov. Chris Christie has declared a state of emergency and advised people to stay away from the Shore this weekend.

Update: Thursday morning, Avalon issued a voluntary evacuation for the borough. That order could become mandatory as the storm moves in during the weekend.

Tom Thunstrom is the founder, editor, and primary forecaster at Phillyweather.net, a site devoted to discussing weather and climate in the Delaware Valley.

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