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BOSTON (CBS) – We are honing in on a track and timeline for Sandy as weather models are finally able to resolve some of the complex atmospheric issues at play.
Sandy weakened to a very strong tropical storm overnight, but had returned to hurricane strength by Saturday morning with sustained winds of 75 mph. Her status may continue to flip flop over the weekend between a minimal hurricane and strong tropical storm. Either way, it’s not going to matter.
She is located about 350 miles southeast of Charleston, South Carolina. Don’t be fooled into thinking that Sandy is becoming less dangerous with the slight weakening overnight. It is going to be a very powerful storm as it approaches the northeast.
Gallery: Latest Sandy Forecast Maps
Sandy is currently encountering a bit of wind shear, hence the ragged appearance on satellite imagery and the slight loss of strength. By late Sunday night and early Monday morning computer models are forecasting it to begin to transition from a pure tropical system to a northern latitude nor’easter type storm.
This is a very complex transformation and the main reason why computer models have had such a hard time forecasting Sandy’s next move. As Sandy begins to lose the tropical warm-core at its center, the wind field will expand quickly. Typically tropical storm force winds from a storm like Sandy may extend out a few hundred miles from its center.
Sandy already has winds of 40 mph of greater out some 450 miles and that is going to continue to expand over time. This almost makes Sandy’s eventual landfall irrelevant. While areas closest to its center will see slightly stronger winds, Sandy is going to produce strong, tropical storm force winds over nearly the entire Northeastern U.S.
So here are the details as I see them this Saturday morning…
Landfall: Sandy is likely to make landfall somewhere on the shore of New Jersey late Monday night.
Timeline: We will begin to see outer rain bands as early as early Monday morning. Easterly winds will increase steadily during the day on Monday and seas will build rapidly as well. The peak of this storm will last about 24 hours from Monday evening through Tuesday afternoon. By Tuesday night and Wednesday Sandy will rapidly lose strength spinning around inland in Pennsylvania.
Effects: Again, despite the fact that Sandy will make landfall in New Jersey, Southern New England is expected to feel some of the most dramatic effects due to the large and expanding nature of Sandy on Monday.
Coastal Issues: The Coastline will get hit hardest without question. A storm surge of 3-6 feet or higher is likely all along the South Shore, Cape and Islands. There will widespread moderate to major coastal flooding, peaking around midnight Monday with the high tide. Seas just offshore will swell to 25-30 feet or higher. Farther north, closer to Boston and the North Shore, minor to moderate coastal flooding is expected Monday night and early Tuesday with storm surge 2-3 feet.
Wind: This is the biggest concern from Sandy over the largest area. Wind damage will be widespread in all of Southern New England, causing many trees and limbs to be taken down. Power outages are expected to be widespread and potentially last for several days in some locations. Winds will be greatest over areas with the least resistance and protection including coastal locations, The South Coast, and higher elevated locations inland.
In these areas winds may gust to near hurricane force Monday night, 60-80 mph at the peak of the storm. For the majority of inland locations in Southern New England winds will gust 30-60 mph, tropical storm force. These peak wind gusts will likely come between Monday evening and midday Tuesday.
Rain: I believe this will be the least of our concerns. Most models forecast the heaviest rain amounts in the Mid Atlantic states. While we will certainly see bands of very heavy, torrential rainfall amounts should not reach higher than 3″ or 4″ in any given spot in Southern New England. This is still a tremendous amount of rain and is sure to cause local street and basement flooding, but no widespread large river flooding is expected.
There is still time for slight changes in Sandy’s track and intensity but at this point confidence is certainly growing that a powerful and historic event is about to unfold for the entire Northeastern United States.
You should take the calm before the storm this weekend to make any preparation for your home and family. Do not take this storm lightly, prepare for the worst and stay tuned to updates to this forecast over the weekend.
You can follow Terry on Twitter at @TerryWBZ.