New Jersey Becomes Focal Point For Sandy Landfall, Pressure To Go Below 960, Perhaps 950 mb!

Written by on October 27, 2012 in North and South America, United States of America with 0 Comments

Computer Model Tracks

Prepare for Sandy with a Family Disaster Plan

With all the information constantly coming in via countless computer models, it’s got to the point of where and not if with Sandy and impact on the Northeast. This storm IS going onshore and it’s likely to break multiple records for rain, snow, perhaps wind, and most likely.. pressure!

When would this storm hit? Likely Monday night into Tuesday…

Potential for major storm surge in Philadelphia, New York or Providence with Sandy!

The Mid-Atlantic and Northeast better be prepared for this storm as it’s coming whether you like it or not. The convergence of all the different tracks now show the Jersey shore as the likely landfall point but exactly where that centre strikes, will depend on how badly Philadelphia or New York City may be affected by a storm surge. Pressure as well as location of the centre as it comes ashore is very important too as lower pressure can add more weight to the ocean surface and this can generate a greater surhe height. A storm coming from the SE in not only rare but also a potentially ‘worst case scenario’ for the cities of Philadelphia, New York or even Providence, why? A storm hitting just to the south of one of these three cities would drive a storm surge up the appropriate bays. For Philadelphia, a storm striking the mouth of Delaware Bay would drive water up the river and would could flood the city. For NYC, a storm striking the central or north Jersey shore would drive water in between Sandy Hook and Brooklyn and into NY Harbour, presenting a flood situation for parts of Manhattan. It’s a funnel effect with little room for the extra water to go to as it piles in. Severity of the flooding would depend on height of surge. If a storm struck, the central or north Jersey shore, factoring in the counterclockwise circulation of the storm, winds blowing NE down Long Island sound would also drive water into Manhatten also, so that would be two surges which meet around Manhattan. Now that is a worst case double whammy for NYC and a scenario well looked at in emergency planning meetings.

The perfect environment for the perfect storm

The models are also becoming consistent in sending Sandy in as a powerful sub-960 mb low. This looks highly likely given the rare environment evolving with tropical and baroclinic extremes converging with a powerful storm system. This is a truely fascinating situation from a meteorological standpoint. An historic, perhaps once-in-a-lifetime event may be about to unfold.

Here are factors which is likely to help bombogenesis (rapid deepening).

As Sandy approaches.. it will interact with

1) a DEEP, cold core trough.

2) The Strong polar jet, dropping out of the NW into the storm. The front right entrance region of the jet should support enhanced lift or upward motion within the storm.

3) The Sub tropical jet which will also be unusually fast flowing, will inject added fuel and energy to the storm from the SW.

3) Convergence between a warm, humid air mass and a very cold, dry air mass will support bombogenesis which is why pressures will be so low as it comes ashore.

4) Abnormally warm waters off the Mid-Atlantic and Northeast coast which will help Sandy maintain a warm core, tropical characteristics. With a strong multi layered flow drawing deep tropical moisture in from the SE, across these warm waters and into a colder environment. This will increase rainfall rates and totals. A widespread 6 inches is likely with pockets of 8, 10, 12+ inch totals.

All these factors will play a major role in bringing a very unusual, record-breaking storm into this highly populated part of the country. It will impact ALL of the Mid-Atlantic and Northeast as it’s windfield is spreading out as I write and will cover a vast area. The impacts will be vast.

It’s likely to bring mayhem as it crashes ashore. Extremely low pressure with a vast windfidl covering hundreds of miles, means very strong, damaging winds will occur as far north as perhaps Maine, as far west as Ohio and as far south as the Carolinas. A howlling gale will affect areas on the western side of the storm. This in a sense will be different to a true hurricane as it’s effects won’t decrease as the centre comes ashore. With a hurricane, they decrease as the fuel is soley from ocean heat content. The fact that this will have properties of both tropical and baroclinic is worrying as Sandy will likely come ashore at least partially WARM CORE, thanks to the system maintaining itself over the abnormally warm waters which can be found all the way to just off the coast.

So factoring all this in with tightening as the circulation interacts with the coast and we may have the ‘perfect storm’.

Lets look at impacts..

Combine a 75-100 mph onshore wind which would drive a 5-10 foot storm surge and this in itself would bring tremendous damage and coastal flooding anywhere from Ocean City, MD all the way to the northern tip of Long Island extending all the way to Maine. Major beach erosion would be a given. Then factor in a major rainstorm which could bring devastating flooding in it’s own right (remember what happens when you’ve got a deep tropical moisture plume slamming up against a cold environment… it squeezes all that moisture out).

40-55 inches of snow in the mountains?

Lets not forget the snowstorm that will occur inland. Hurricane-force and heavy snow could combine to create a major snowstorm or blizzard from the Catskills of New York down to West Virginia, maybe even North Carolina. How much snow? Models are still printing out anywhere from 30 to nearly 60 INCHES. It’s important to think about this.. snow rates of 2-4 inches in the heaviest bands which are supported by thunder and lightning thanks to powerful upward motion, but throw in a 40+ mph sustained wind and gusts to hurricane-force (75 mph) and that’s the perfect recipe for a crippling blizzard which could shut down areas from Western New York, Pennsylvania West Virginia and maybe the high country of Garrett Co, Maryland.

Here are some graphics produced by The Weather Channel which include important information…

U.S. Threat Index

Power Outage Potential

Heavy Rain Threat

Heavy Snow Threat

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