Posted by: coastlinesproject | September 3, 2016

Hermine is a freak storm that could be as damaging as Hurricane Sandy.

From Brian Norcross of the Weather Channel….
Another Freak Storm for the Mid-Atlantic and Northeast
Hermine is just getting started. All of the drama last night in Florida with Gulf water rising up and pushing into coastal communities, and the rain and wind in the Carolinas today, were just a preview. All indications are that Hermine is going to be another epic storm that breaks all the rules for the Mid-Atlantic and Northeast.
It’s not that the various factors in play have never happened. Storms have combined with cold fronts and the jet stream to get stronger and bigger. Other storms have stalled and looped or gone the wrong way. But when it all happens at once, and is forecast to do it right offshore of the most populated coast in the country, the threat adds up to an extremely dangerous and expensive scenario.
The meteorology is simple enough. Over the Carolinas, Hermine will begin to get some of its energy from the jet stream, which has dipped down to yank it up the east coast. When it heads back over the ocean, it will be energized by both the warm water and the jet-stream winds. That means a strengthening storm will head north.
Then the freak show starts. That jet stream dip abandons the storm as it sits off the Delmarva or New Jersey coast over ocean water that is dramatically warmer then normal. So this huge orphan circulation sits and spins and pushes ocean water into the bays, sounds, and rivers in the Mid-Atlantic. And it does not let it out.
Every time the tide comes up – about every 12 hours – the water gets higher, and only part of the tide can go down because of the pressure from the wind. So the water piles higher and higher until Hermine finally backs off. Indications are that won’t happen until Thursday, and then only slowly.
All this begins tomorrow in southeast Virginia and up into the Chesapeake Bay and the Potomac River. Ocean water will push into the Bay and up the rivers at the same time that torrential rain is dumping water that wants to flow out to sea. The only good news is that Hermine will keep moving by so things should get better on Sunday.
But then the storm grows bigger and stronger… and stalls. And more annoyingly, at some point – right now the computer model says on Sunday – Hermine loops closer to the coast bringing flooding rain and damaging wind, along with an even bigger push of storm surge.
This begins tomorrow (Saturday) on the Delmarva and eventually into South Jersey later in the day. By Sunday morning the winds are howling out of the east on Long Island and eventually into New England, beginning the big push of ocean water into the bays and sounds along the Jersey Shore, surrounding New York City, and north into New England. At the same time, Hermine is forecast to strengthen, possibly back to hurricane strength.
When the worst of the weather comes ashore, exactly where, and for how long is an open question. We can look at one model or the other and get a different answer. But it is unanimous that this exceptional and extraordinary threat will develop.
The best case seems to be that the damaging winds and flooding rains stay offshore and “all” we get is surging, damaging ocean water pushing into the bays, sounds, and along the coast. The worst case is a hurricane slowly moving ashore in the Mid-Atlantic with all its hazards. An unprecedented, but not unrealistic, scenario.
The fact that this is Labor Day weekend makes it even more dangerous. The storm may disrupt travel in untold ways, and people may have to leave locations threatened by rising water.
It is essential that everybody pay extremely close attention to the latest information. Just because you get the forecast in the morning doesn’t mean it won’t change in the afternoon. Freak-show storms that are stalled or moving slowly are usually the most difficult to forecast very far in advance.

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William Sargent’s latest book, Plum Island; 4,000 Years on a Barrier Beach, available in local bookstores and at http://www.ingram.content.com.

 

 

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Bill Sargent will be leading a beach walk starting from the Plum Island Point lighthouse Sundays at 2pm. Cost $10.

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