Sandy’s Historic Encounter with the Northeast U.S. Looking Very Likely

Hurricane Sandy formed just four days ago north of Panama. In its short lifetime so far, it has claimed 21 lives in Jamaica, Haiti, and Cuba and unexpectedly intensified to a strong Category 2 storm immediately after exiting mountainous eastern Cuba. It passed over the central Bahamas on Thursday with 105mph sustained winds, and brought tropical storm conditions to Miami, West Palm Beach, and the southeast Florida peninsula. Today, conditions over southern Florida are improving as Sandy crawls north at 6mph. As of 11am this morning, Sandy’s maximum sustained winds are 80mph (a Category 1 hurricane) and the wind field is expanding. Tropical storm force winds (35mph+) now reach 275 miles from the storm’s center, and weaker though still noteworthy winds extend approximately 800 miles from the center. It is located 190 miles due east of West Palm Beach, FL.

The official track from the National Hurricane Center shows Sandy moving slowly to the north through Saturday, then northeast for a couple of days before getting pulled back westward toward the coast. Tropical storm watches and warnings are in effect for the U.S. east coast from the southern tip of Florida to the Outer Banks of North Carolina.

The longer range forecast is becoming more certain as nearly every model now agrees on a similar track and evolution. Unfortunately, the solution being converged upon is a devastating and historic “perfect storm” scenario for the entire northeast U.S. from the coast to hundreds of miles inland.

There’s a fine line between over-hyping a situation, and giving plenty of advanced warning prior to a potentially catastrophic situation. When it comes to a forecast for something like this, think of a spectrum of possibilities: a chance that it won’t be so bad and all the hype is overkill, a chance that it will live up to or even exceed the hype, and then the middle ground of a bad storm, but nothing to panic about. Of course, we don’t know with 100% certainty which of these possibilities will be realized, but since the high-end impact scenario is presently a very real one, it would be prudent to over-prepare and be safe than under-prepare and regret it.

In an effort to aid forecasters as much as possible, weather balloons are being released four times per day rather than the typical two times per day across the entire nation. These enhanced upper-air observations upstream of the storm are fed into models, and starting with more accurate knowledge of the true state of the atmosphere would ideally lead to more accurate forecasts. Secondly, there are two aircraft flying around in the storm this morning: one from NOAA’s Hurricane Research Division and one from the Air Force’s Hurricane Hunter fleet. This will help guide storm-scale data assimilation, while the additional weather balloons will help with large-scale environmental data assimilation. These resources are being utilized due to the looming “perfect storm” scenario unfolding over the next few days.

From Sunday through the middle of next week (and beyond?), this system is forecast to intensify while expanding at the same time. This would bring extraordinary storm surge and rainfall to the entire mid-Atlantic and northeast U.S. regions. If you lived in those areas during Irene last year, consider that a practice run. This setup is truly rare and is not your typical hurricane or Nor’easter riding up along the coast.

Several days of heavy rain combined with the strong wind can easily result in widespread flooding, tree damage, and power outages. The Monday-Tuesday period should be core of the worst weather in the northeast, but it won’t just end abruptly either. Immediately along the coast, very high storm surges combined with beach erosion could lead to significant seawater flooding. The full moon on Monday will make the normal high tides even higher, and raising the base sea level.

We will have another update tomorrow when Sandy is located east of Georgia and South Carolina and about one day prior to impacts being felt in the majority of the mid-Atlantic region.

Brian McNoldy
Senior Research Associate
& Author of Tropical Atlantic Update
Follow Brian on Twitter: @BMcNoldy

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