Sunday, December 30, 2012

Top Weather Stories: Sandy

We're highlighting the weather stories of 2012 in chronological order (sorta) but Sandy is arguably, clear and away, the biggest storm to impact the region over the past year.  Sandy, the hybrid hurricane and coastal storm that made landfall near Ocean City, NJ on October 29th, set plenty of records for pressure, wind, and coastal storm surge across the Mid Atlantic as it came ashore.   There's very little that hasn't been said about Sandy -- from the destruction along the Shore towns to the damage it caused inland from its potent winds to the heavy rainfall it produced inland.  Jen Miller covers the post-Sandy impacts and the scars left by the storm incredibly well and her articles are a must-read over on NewsWorks.

Sandy is notorious for its hybrid characteristics, its large size, and its unusual track.  Sandy was the first tropical (at some point) system to make landfall from the east along the Jersey coast on record.  Most tropical systems that impact the Jersey coastline (think Irene, Gloria, Floyd) come up the coast from the southwest or south-southwest.  Sandy paralleled the East Coast for a couple of days before being fully captured by a developing cold core trough in the mid atmosphere.  The result of these joining of weather features was a storm that barreled into the Mid Atlantic, with record storm surges north of landfall and heavy, heavy rains south.

Seaside Heights (roller coaster pictured below), Long Beach Island (second picture below), and Atlantic City were very hard hit from this storm thanks to the record coastal flood.  Inland, winds reached hurricane force in gusts in Allentown and other locations in Southeast Pennnsylvania in addition to along the Shore.

Heaviest rains with Sandy were to the left of its track -- because of the west-northwest trajectory at landfall this means that the Delmarva and South Jersey ended up with the most rains.  Nearly a foot of rain fell in Wildwood with the storm, resulting in freshwater flooding being as big an issue there as coastal surge flooding farther northeast up the coast.  Rainfall was not that significant across North Jersey and Eastern Pennsylvania as a result of the heaviest rainfall being left-of-track with the storm.  However, in general, the strongest winds were to the north of the storm's center of circulation.

Nearly 40 died in Pennsylvania and New Jersey from Sandy, with damage estimates running over $30 billion in New Jersey alone.  In Pennsylvania, estimates were much lower ($16 million) but impact was still quite high.

This is a once-in-a-generational storm -- the last phasing storm of similar magnitude and strength but different setup anywhere near us in North America was Hazel in 1954.  Hazel moved much faster, was stronger, and phased farther north and northwest than Sandy did.  In between Hazel and Sandy was The Perfect Storm of 1991 which hit New England; however, that storm was a creation of a dying hurricane and a cold core system that created a different, unique storm system from its "parent" storms.  Sandy is very different in its own regard and will be a storm that the entire Delaware Valley will remember for decades to come.