We see troughs phase with systems moving up the coast several times throughout the year, however, we have never really seen such a deep trough associated with the Polar Jet phase with a warm-core system...once this phasing takes place Sandy will actually begin moving either due west towards the US coast or moving towards the US Coast in a more northwesterly direction...this is uncharted. This phasing will rapidly intensify Sandy to become a MONSTER storm and lead to the build up of incredibly high waves, possibly as high as 25-35' crashing into the coast line from southern NJ up through eastern southern New England.
With this said, with what computer models are showing and with what we understand about meteorology and how the atmosphere we would expected to see some extremely damaging impacts from Sandy for much of the region. Because we really have nothing to compare this too this does make it difficult to really have a true understanding of how this will unfold. Now that this was said let's get down and dirty.
As mentioned above, Sandy which is a very large in size will eventually be tugged in west towards the coast by a deepening trough associated with the Polar Jet and phase. Once this phasing occurs Sandy will undergo what is called rapid bombogenesis...this is just a fancy word for saying she will rapidly intensify. As Sandy continues to grow in size and phase with the trough/Polar Jet the wind fields just above the surface will expand, this will mean winds just above the surface will be very strong and for a quite a distance away from the storm's center. In fact, computer models are generating wind speeds of anywhere from 60 knots to as much as 100 knots as close as 2000-3000ft above the surface! This is absolutely remarkable to see winds of that caliber so close to the surface. With Sandy increasing in size and very strong winds over the ocean wave heights will rapidly build. As Sandy continues to close in on land very high waves will begin crashing into much of the eastern sea board from the Carolina's to the outer Cape. This system will also be loaded with moisture so there will be some extremely heavy rainfall as well.
The one question we are still faced with is where Sandy will make landfall. We are still uncertain as to exactly where Sandy will make landfall. Some computer guidance suggests she will make landfall around southern NJ/DE area while other computer models suggest she will make landfall further northward...around northern NJ or perhaps even near NYC. While the first mentioned scenario would still probably bring major impacts to the entire region the second scenario would bring extreme issues to the region. While the computer models are giving us uncertainties within the track based on the pattern setup along with other factors I would think we see a landfall closer to the northern NJ/NYC solution meaning we would see the worst case scenario across our region. With this said we will now break down all the hazards and what we should expect from each:
Coastal Flooding:
It's appearing extremely likely we will see at least major coastal flooding from NJ up to Long Island Sound, coastal MA and coastal MA. In fact, we may be looking at the potential for catastrophic coastal flooding/beach erosion across the areas as wave heights could potentially exceed 25-35'. When taking into account a full moon and high tides, if the highest wave heights occur during high tide we would be looking at catastrophic coastal flooding across many coastline areas causing substantial damage and destruction to any buildings that are located right along the coast.
Damaging Winds:
Damaging winds can be expected even a far distance from the Sandy's center. In fact, the threat for damaging winds should extend as far north as portions of VT/NH. Depending on exact landfall, areas across NJ/SE NY/coastal CT/RI/SE MA could see sustained winds as strong as 40-50 mph with wind gusts exceeding 60-70 mph with gusts as high as 80 mph possible. A bit further inland we could see sustained winds of 30-40 mph with gusts as high as 50-60 mph and perhaps even as high as 70 mph...this would include all of CT up through central MA. Further north from here sustained winds of 25-35 mph is possible with gusts as high as 45-50 mph possible. For the higher elevations of northern New England above 1000' and especially 2000' winds could gusts as high as 65-75 mph. Not only will we be looking at the potential for such strong sustained winds and extremely strong wind gusts but the duration of these winds could last for up to 24-hours, although the higher end range of the gusts should be closer to 8-12 hours. Winds of this magnitude for such a long duration would lead to widespread tree damage/power line damage resulting in widespread power outages and leaving some people in the dark for days.
Torrential Rains/Inland Flooding:
The heaviest rainfall totals are expected to be to our southwest and west where as much as 5-8'' of rainfall can be expected, however, across New England some areas will receive as much as 4-6'' of rainfall. What we have to watch for are areas just to the east of the Berkshire Mountains, Worcester Hill, Green Mountains, and White Mountains as SE/E winds would lead to upsloping, making for areas of very intense rainfall rates leading to higher totals. While the inland flooding threat doesn't appear to be too extreme we certainly will see areas of flooding, especially along rivers/streams/brooks.
Impacts from Sandy may begin as early as tomorrow evening (however, waves/surf will begin increasing as early as tonight) as winds begin to slightly pick up and bands of heavy showers move into the region. The worst of Sandy is expected to occur between late overnight Sunday, lasting through all of Monday and into the first part of Tuesday. This is expected to be a very dangerous storm causing numerous issues across a very large area. Below is a graphic showing where the main hazards exist:
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