Weather Science

The two forces that make #Sandy quite unlike Irene

Batten down the hatches; Mother Nature is about to unleash her wrath on the eastern seaboard Monday afternoon. Just in case you’ve been living under a rock, meteorologists have predicted for many days that Hurricane Sandy was going to be be “the storm”. You know, that storm people will reference back to and compare every other storm to twenty years down the road. She will be strong, she will be relentless and she will be sure to leave her mark on the Rochester region.

Without a doubt Upstate New Yorkers have faced their fair share of powerful tropical cyclones, Hurricanes Bob, Isabel and most recently Irene to name a few. These hurricanes packed a powerful punch in terms of precipitation, closing down the Thruway and paralyzing small communities due to localized flooding. However, these three storms were not able to provide the wind Sandy is projected to produce.

This is because Sandy will eventually transition from a tropical cyclone into an extra-tropical cyclone. As Sandy moves onshore, she will become integrated into a deep trough and upper-level jet stream associated with the cold air present over the northeast. When she merges with the deep trough, her central pressure will drop, winds will strengthen and she will spread out over a huge area. Tropical-storm force winds will extend over 500 miles northward of the center of Sandy – an unprecedented size! As a result, Sandy will produce sustained winds over 40 mph and gusts exceeding 55mph in the Rochester area.

Hurricane Sandy is projected to make landfall somewhere between southern Jersey and Delaware around midnight Tuesday and dump anywhere from ten to twelve inches of rain in the area. Although Rochester won’t see that much precipitation, parts of Western and Central New York could see over three inches of rain from Sandy, more than enough to cause localized flooding.

That amount of precipitation has the ability to dampen the ground so that with the strong winds, trees could be uprooted. Given the counter-clockwise flow around Sandy, winds will be coming from the northeast, opposite the typical prevailing wind direction, which could put added stress on trees. A positive thing to note though is that most of the leaves have fallen off the trees, lightening their weight. Nevertheless, be alert if your house is situated near tall trees, especially if they have a weak root structure.

As if there is not enough to worry about, Rochesterians will have to pay special attention to Lake Ontario throughout the storm. Sandy’s winds will blow across the flat lake, causing over 20 feet waves, almost unprecedented heights for Ontario.

It’s fair to say that the hype Sandy has brought is nothing short of extraordinary. However we will have to wait to see if she puts her money where her mouth is. My guess is, Sandy is not fooling around and the 50 million people she is projected to impact should take the necessary precautions to stay out of harms way.