Joe Lundberg

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Evidence Mounting For Historic Storm to Strike the Northeast

October 25, 2012; 9:05 AM ET

Thursday, 11:10 A.M.

The weather from central and East Texas to the Florida Panhandle up to the Great Lakes is nothing short of stunning today. There is a lot of sunshine at this very hour, temperatures more reflective of early September, if not late August, and there's seemingly not a care in the world! Yet, it has turned much colder overnight down into the Texas Panhandle behind a strong cold front. Snow accumulated a few inches around Denver and Boulder overnight, and a wind-driven cold rain is mixing with snow as I write this in the suburbs of Minneapolis.

Meanwhile, on the southeast coast of Florida, winds are gusting to 30 miles an hour with bands of rain rotating through on northwest flank of Sandy, a strong hurricane that only lost some of her punch in crossing Cuba early today. The cold front coming across the Plains and Sandy coming out of the Caribbean appear to be on somewhat of a collision course that many now agree could lead to an historic storm early next week.

If you've been reading over the past couple of days, you've no doubt picked up on my grave concerns about the potential impacts of this storm, and how I've been leaning toward this storm being caught by the approaching upper-level trough and forced inland for the end game. Nothing I've seen since yesterday has caused me to change my mind, with the possible exception of being even more concerned about the storm impacts, and the increasing likelihood of the storm hitting anywhere from Cape Hatteras to Montauk.

The one consistent outlier in all of this has been the GFS operational model. It has insisted pretty much all along that Sandy plods along to the north, then northeast, and stays well east of the mid-Atlantic coast. The last few runs have at least shown Sandy getting pulled in at the last minute, with the 0z run favoring a hit on Nova Scotia Wednesday afternoon, and the 6z run striking the Maine coast early Wednesday morning from the east-southeast.

However, if you look at the ensemble runs of the GFS, you get a rather different story. Let me post one image for you that, while hard to read, I think is a telling image:

I know, I know. It's almost impossible to read those 12 different weather maps! They're for the 6z run of the GFS ensembles, each one representing a slightly different "perturbation," valid 120 hours out, or 6z Tuesday (wee hours of Tuesday morning). Here's the physical link to that image:

http://www.meteo.psu.edu/~fxg1/ENSPRSNE_6z/ensprsloopmref.html#picture

While several of the members do, indeed, have the storm well off the coast at that time, many more have it near the coast, or even inland. Now let me show you a composite surface pressure forecast for the NAEFS ensembles for Monday evening:

The forecast 24 hours later has that low over Lake Ontario!

Meanwhile, the European ensembles are father southwest. The actual operational forecast brings a sub-940 mb low (hard to see exactly how deep it is, but clearly strong than before Sandy made landfall on Cuba early this morning!) into Delaware and southern Maryland late Monday afternoon, right over Assateague, where I biked just three short weeks ago in glorious sunshine and warmth! The ensemble mean has the center just southeast of Atlantic City, N.J., and would seem to mirror some of the individual members of the 6z GFS ensembles.

So, in the final analysis, the evidence is clearly mounting in favor of an historic storm striking the Northeast. The window of landfall points may be as far south as Cape Hatteras (the Navy NoGaps model favors this solution), and as far north as Nova Scotia. My gut feeling is the window is probably tighter, more like from the Delmarva peninsula to Long Island.

There are a couple of other things to note about Sandy itself. For one, it deepened far more than anyone expected yesterday and last night. Following along with penchant for relating it to all things cycling, it's analogous to going down a nice hill, with a only a short (tenth or two tenths of a mile) stretch where it flattens out. You keep pedaling, lose only a little speed, then pick it up again as the slope increases once more. In looking at the last couple of recon reports, the pressure appears to be falling again as Sandy moves away from Cuba.

For another, Sandy is a huge storm. The clouds extend from the latitude of South Carolina all the way to the southern Caribbean! And a third thing, it is moving along at a good pace, 18 mph at the most recent advisory. The forecasts that had it still south of the latitude of Cape Hatteras Monday morning seem very unlikely at this point, unless it slows down dramatically in the next 48 hours. It will likely slow some as it begins to send the blocking ridge over the northwest Atlantic, but not as much as some of the models had been implying, particularly the aforementioned GFS and its tropical counterparts. The implications of all of the above suggest this storm will come faster. To me, that also suggests less room for escape.

If you've been a reader for years, you know I'm not one given to hyping events all that often. I am reluctant to do it here, especially days before anything happens with still so much uncertainty, but given the evidence before me, I feel compelled to reiterate many of the concerns I've voiced the past few days about the potential deadly impacts of this storm.

1) Storm surge. Putting numbers to it, we may be looking at a 5- to 10-foot surge near and to the northeast of the landfall point. Remember, the full moon is Monday, so the tides are already going to be abnormally high, so that only increases the height of high tides.

1a) Coastal destruction. This includes many things in combination with the storm surge, the pounding waves and the high winds. This could literally rearrange the coastline, cutting new channels that previously never existed, and severely damaging homes, businesses and infrastructure.

2) High winds over a wide area. As the storm comes north, it will undergo a transformation to something other than purely tropical. Essentially, that will result in an expansion of the wind field, instead of concentrating the highest winds in a smaller area near the core of the storm. In turn, not just the point of landfall may be bracing for winds of 60 to 80 mph or more. It could be over a 200- or 300-mile-wide swath in the worst case scenario, which would lead to widespread downed trees and power outages, extending well inland.

3) Excessive rains. This storm will bring its environment with it from the tropics. As the colder air associated with the upper-level trough and the attendant cold front get injected into it, rather than destroy the storm, it would be like giving it a shot of steroids. That's why some of the pressure forecasts are so extremely low. In turn, this should squeeze that tropical moisture out and produce 5 to 10 inches of rain in many areas, perhaps even higher amounts. That equates to a lot of flooding inland.

4) Heavy wet snow. This will be restricted to the southwest quadrant of the storm, and probably to the higher ground of central and western Pennsylvania and West Virginia. While many trees in these areas have lost their leaves, not all have, and even a few inches of heavy wet snow could add to the carnage. And the potential is there for much, much more.

One point I feel needs to be brought up. This storm should just be called Sandy right through the point of landfall. There's some debate as to whether or not it will be considered an extratropical storm by Monday, or a subtropical storm, or a tropical storm. Maybe the strongest winds will be below hurricane force at that point, so a tropical storm designation would be warranted. In my mind, unless the latter point is the case, it should still be considered a hurricane, because it will pack the punch of one, and any different classification of it will only lead to confusion. It's kind of like calling Mitt Romney "Governor Romney" at this point. He once WAS the governor of Massachusetts, but hasn't been for quite a while. Still, because he once held that office, he's given that stature to avoid the confusion, and most everyone is fine with that. In the case of Sandy, even though technically it may not be "tropical" in nature before Monday, that distinction will be lost on most people, so why confuse them any more?

I know one thing I'll be doing shortly - enjoying a quick ride outdoors in the remaining warmth and sunshine in my backyard. And I'll do it again tomorrow, and maybe even Saturday. After that, the gig is up. Even if the storm does not directly affect me, it will be much colder, and snow could easily be in the air Monday and Tuesday. But, so long as the roads are good, I'll get out. As my friends at SkirtSports encourage us all to do, don't let cold weather send you into hibernation, but stay active! I just may have to adjust those activities to using a snow shovel and cross-country skis sooner than I'd like!

The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or AccuWeather.com

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Joe Lundberg
Joe Lundberg, a veteran AccuWeather.com forecaster and meteorologist, covers both short and long-term U.S. weather on this blog.