Couple quick housekeeping things: First, can we stop calling and comparing this to “The Perfect Storm?” It’s a completely different and unique meteorological setup.
In the 12-15 years or so I’ve followed models and weather very closely, I have seen a number of modeled storms….which are eye candy storms that models can’t resolve and end up never happening. I mean…many, many modeled storms that failed. That said, I very rarely have ever seen a modeled storm…less than 5 days away, with high agreement that it will occur, ever not happen. In other words: It would be a catastrophic failure of all the weather models we use and the meteorological community in general if this storm did NOT happen. Thus, the odds of this not happening (in some fashion) is very, very low.
Now that we’ve got that out of the way, what’s the latest?
a.) Models continue their dance: Euro goes south of Ocean City, MD, GFS goes into Long Island, their respective ensembles go into NYC.
b.) All models continue to indicate a high impact storm that is capable to equal or exceed Hurricane Irene last year in terms of duration and problems, impacting much of the Northeast and Mid-Atlantic.
I want to draw your attention to a couple things. First, I will show a map of the track of Irene from last year below:
Now let’s take a look at Sandy’s forecast track from a few models. Focus on the circled area:
Notice how different this is. The storm starts out to sea…but it cuts back west after its exit is blocked and it’s captured by an upper level trough digging into the Northeast. This forces the storm to cut West…and how quickly it does this and where it comes ashore is obviously still uncertain. But I think the window is obvious…NJ to Long Island. Why does this matter? Because a storm hitting the coast at a perpendicular angle has the potential to be much worse than one paralleling it, regardless of exactly HOW strong it is. While the storm will be weakening somewhat, it will also be broadening out…spreading its winds out over a large area and behaving much like a nor’easter that deepens as it lifts north of Cape Hatteras. So we have the potential to have 40-60 mph wind gusts (higher gusts possible initially near the coast or just inland) spread out over a 300 mile radius, in addition to massive waves and a storm surge on top of an already astronomically high tide because of the full moon in addition to heavy rain, especially along and just west of the I-95 corridor. Got all that?
Bottom line: There is no longer any “good” solution regarding Sandy. Each one is menacing and poses a share of pretty wicked problems. So to quickly summarize.
If Sandy tracks into Long Island or New England: Worst surge/flooding impacts are Boston to Rhode Island/eastern CT and Long Island. Heavy rain west of Philly north into New England. Strong winds of 40-60 mph from the Jersey Shore to New England with 60-80 mph gusts on Long Island and coastal New England. Snow will be possible in the mountains of PA and Western NY.
If Sandy tracks into New York City: Substantial coastal flooding is possible from North Jersey/Raritan Bay through New England, including in Lower Manhattan. Back Bay flooding may be severe in NJ and blowout tides are possible in Delaware Bay as well. 40-60 mph wind gusts widespread over the Northeast and Mid-Atlantic. 60-80 mph gusts will be possible on Long Island and possibly close to NYC, especially in high rises. Heavy rain in Southern New England, Upstate NY, and Pennsylvania. Snow possible in the mountains of PA, MD, and WV.
If Sandy hits the Jersey Shore: North of the track will be severe to historic coastal flooding through Long Island Sound. South of the track will be back bay flooding and blowout tides. 40-70 mph gusts on the coast…40-60 mph gusts inland. Heavy rain inland from DC/Maryland through Upstate NY and parts of Southern New England. Snow possible in the mtns of Western PA, Maryland, and much of West Virginia.
If Sandy hits Delmarva or tracks up the Delaware Bay: Severe to historic coastal flooding for the entire Jersey Shore. Possible tidal flooding in Philadelphia. Mod to severe coastal flooding NYC into New England. Winds still 40-70 mph or so over a wide area. Heavy rain inland from Virginia north through PA, with mod to heavy rain in NY and New England. Snow possible in West Virginia.
All Scenarios: Heavy rain, localized to widespread flooding, moderate to severe coastal flooding, and power outages…possibly extended for a long period of time in the hardest hit areas.
Time to prepare and not panic…still a long way to go, and Sandy still has a fair amount of wind shear to go through. I don’t think it matters much, but the weather is full of surprises. There are not many benchmarks in the historical record to compare this storm to: It is truly a unique and devilish beast, and one that will be fodder for numerous journal articles down the line….whether it happens or not.