IRENE AND GHOSTS OF HURRICANES PAST

Hurricane Irene is stalking toward the U.S. on a track that will affect tens of millions of people.

Once departing the Outer Banks of North Carolina late Saturday, it looks as though she’ll churn NNE along or just off the Delmarva Peninsula and Jersey Shore, putting Long Island in her crosshairs.

Irene’s course is expected to be very similar to several other hurricanes of recent and distant past–analog storms, as meteorologists like to call them.

The most recent analog storm was Hurricane Gloria in 1985. Gloria tracked NNE just off the Jersey Shore and thundered over Long Island near Long Beach as a category 2. Winds gusted to 115 mph over eastern Long Island and 85 mph at Islip.

Another analog storm occurred in 1944. It’s known as the Great Atlantic Hurricane and is perhaps somewhat lost in the dust of history because of a more critical event occurring then, World War II.

The Great Atlantic Hurricane, a large one like Irene, steamed NNE just east of the New Jersey beaches and hooked a bit more to the east than Gloria, spinning across extreme eastern Long Island near Montauk as a cat 1. Still, winds in New York City gusted to almost 100 mph! Image the damage such winds would do today.

You really have to go back a long way to dig out the third analog, a storm that blew through NYC in 1821.

Not much information is available on this storm, but we know it swept NNE right over the Jersey Shore, which likely weakened it, and crashed into Long Island near Jamaica Bay.

There were no anemometers in those days, but winds, based on damage reports, probably gusted to at least 75 mph. The one barometer reading available, if reliable, was not impressively low, so chances are this was a minimal hurricane or even a strong tropical storm.

Now, a few thoughts on Irene.

Although she won’t be a major hurricane (even if the eye remains just offshore from the Garden State) when she smacks Long Island, she’ll still cause massive power outages. Anyone in the direct path of Irene should be prepared to be sans electricity for several days.

While total rainfall may not be excessive–Irene will be moving along, not stalling–that’s not what counts. What matters are the heavy bursts, inches per hour, that unload in hurricanes. It’s the blinding but relatively short-lived downpours that overwhelm storm drains and unleash flash flooding.

Storm surge is a real threat. Gloria and the Great Atlantic Hurricane both charged ashore around low tide which kept tidal flooding to a minimum. If Irene barrels in during high tide, surges will be much higher than occurred in either of those analog storms.

Pay close attention to what local NWS offices and the media say about storm surges. They’ll have the times of high and low tides pinned down relative to the arrival of Irene’s eyewall which is where the peak surges will occur.

Be safe everyone.

-August 26, 2011-

IMAGE: What the well-read student hurricane hunter reads while chasing hurricanes. This photo was sent to me by Matt Sitkowski, a grad student at the University of Wisconsin, as he rode with the NOAA Hurricane Hunters into the eye of Irene on August 24.