Friday Evening Update on Sandy for Friends/Fam

So the word “unprecedented” gets tossed around a lot in the modern era. Everything’s unprecedented, the worst in X years, incredible, never before seen, historic, truly amazing, etc. I think social media and the 24 hour news cycle has desensitized a lot of people to things that truly are worthy of those descriptions. All signs, data, signals, and opinions seem to indicate that this storm will be worthy of all those descriptions. Again, as I said, if this were to not materialize or even if it were to be considered a major bust, it would be a catastrophic failure of the entire process of weather modeling.

But I digress….

Hype in weather often comes from what we call “the usual suspects,” various groups and people who tend to scream the loudest whenever a threat presents itself. What I have seen regarding this storm are numerous meteorologists and professionals that I truly respect and admire, with years of experience beyond my own using those very buzzwords mentioned above to describe the storm threat developing. It’s very real, it’s very serious, and you really need to heed all advice and warnings from local emergency management officials.

Feed the Beast: Four independent jet streak structures feeding the development of the Storm. Credit: UCAR

So you’ve seen official forecasts, etc. You’re here to see what I think.So let’s have at it. You don’t see the map to the left (or below or above depending on your browser settings) very often. This shows the truly incredible upper level dynamics at play to feed this monster. The quote I heard or read (sadly, I cannot recall it right now to properly attribute it) was that even without Sandy in the picture at all, this would lead to a major nor’easter in the Northeast. And that is accurate. Sandy just sort of adds insult to injury. You’re looking at the jet stream. Each number represents what we call a “jet streak” or a pocket of stronger winds embedded within the jet stream itself. One thing I should point out, is that #1 is forecast to be as strong as 170 mph and has a wind anomaly you usually only see in the monster storms that regularly occur in the North Pacific. Cliff Mass, who’s one of, if not the foremost expert on the Pacific Northwest, where storms of this magnitude can occur multiple times in a given winter, sums it up best by saying this is a more perfect storm, and will make THE Perfect Storm “look like a zephyr,” a comparison I can live with.

My point here is to show you that, regardless of whatever Sandy does in the next 36 hours, what develops Sunday night and Monday will be utterly incredible.

A new batch of tropical models will come out around 10 PM Eastern, followed by the GFS at 11:30 PM, and the updated Euro while we’re all sleeping (or winding our night down). But this afternoon’s model cluster, which falls in line with what I’m seeing from the main models looked like this.

(Sidebar: Those abbreviations above are for weather models meteorologists use on a daily basis. The two biggies are the GFS (Global Forecast System), run here in the US of A. Sadly, it pales (in most cases) in comparison to the “Euro” or “ECMWF” or model run by the European Centre for Medium Range Weather Forecasts. So when you hear or see terms like that, that’s what we’re referencing.)

The Euro camp has been Delmarva for landfall. This morning that shifted to Atlantic City. The GFS camp has been…everywhere: Out to sea, Maine, loop de loops over New England, but in general north-er. This morning, that shifted toward New York City. Coupled with those tropical models I linked to above that are clustered in Delaware Bay (and have shifted north from an earlier cluster near Ocean City, MD), we get the sense that the trend is to somewhere between about Cape May, NJ and Fire Island, NY on Long Island.

So those are the goal posts. The impacts will be as follows, regardless of where the storm ends up at landfall (except coastal flooding):

Timeline: Sunday afternoon south through Wednesday morning.

Wind: Potential for 60-80 mph gusts on the immediate coast north and east of where the center makes “landfall.” Elsewhere, 40-60 mph wind gusts over the entire region from Virginia through Maine. Widespread and potentially long-term power outages.

Rain: Heavy rain along and southwest of the track. Potential for 5-10″ of rainfall from South Jersey through Pennsylvania, Maryland, DC, and northern Virginia. Flooding likely on streams, creeks, and rivers in those areas. Elsewhere, 3-6″ of rain likely, with localized flooding, but not the destructive massive flooding we saw during Irene. I refer you to this website for the latest rainfall forecast projections.

Snow: Mtns of West Virginia most likely to see snow.

Tidal flooding: Here’s the trickiest forecast and the only one directly impacted by exactly where the storm makes landfall. Along and north of the center, tremendous coastal flooding during the high tides, primarily on Monday night and Tuesday morning. The coastal flooding angle could very well be historic to record type of oceanside (or LI Soundside) flooding. If you are south of the center, tidal flooding will occur, but not quite as severely as the flip side. Flooding of the back bays on to the west side of barrier islands is likely. The most likely areas (AS OF RIGHT NOW) to sustain severe coastal flooding (to me) are from Monmouth County NJ into NYC as well as perhaps along Long Island Sound and Cape Cod.

I never like to speak in hyperbole, so trust me when I tell you this is a serious storm. Even if the worst case scenario of massive coastal flooding does not occur, you can expect Irene-type impacts, if not worse and for a longer duration. Stock up and please be prepared to go without power for awhile. My biggest concern is that the beating trees all across the Northeast and Mid Atlantic have taken (from Irene, the October blizzard of 2011, and the derecho of June) have weakened them and may allow them to be more apt to tumble, given the right circumstances. So just be prepared…and try and remove any leaves that are blocking any drainage.


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