Franken-storm On Course for Historic Destruction

With apologies to Steve Sisco of the HPC who coined the term in passing and is now getting credit for the hilarious name all over the interwebs.

Hurricane Sandy is beginning to acquire a post-tropical look in satellite presentations due to SSW wind shear aloft (which is expected to weaken after tomorrow afternoon) and some dry air from Mexican high plateau (which is temporarily feeding into the storm from the SW), but it still has a full warm core and a closed circulation, and will thus remain tropical for some time.  It has, for the time being, weakened a touch to a 80 mph category 1 storm and is expected to weaken still further in the next day or two as it lifts NWW and then NE, strafing North Carolina with heavy rain and wind before stalling over the Gulf Stream.  While near NC, it may regain a bit of strength or it may remain a category one hurricane, but don’t be fooled.  The real trouble begins as it feels the effects of the approaching arctic trough.

Models have converged some over the last day of forecast cycles with only the ECMWF/NOGAPS (European/US Navy) insisting on a southern track that takes the storm closer to DC and Baltimore and only the CMC (Canadian) taking the storm far enough north to blunt the damaging impacts a bit.  The SREF (short range ensemble forecast), NAM (North American Mesoscale), UKMet and GFS (US Medium Range) take the storm near or over Long Island.

If the core consensus among US generated models is any indication, and the storm really does track from off Hatteras to off Montawk, to NY Bight, or even just south of there as many of the SREF members are suggesting, it spells utter and complete disaster for NY City.  A description of the likely impacts:

  • Subways flooded as storm surge exceeds 8 feet in the bight and on the batteries.  Lower Manhattan under water.
  • Long Island’s beaches take a pounding, as to those in S CT, RI and MA and in NJ.  Many areas lose multiple feet of beach and storm surges in some places exceed 10 feet.
  • Prolonged sustained winds to 50 mph begin late Sunday and last through early Tuesday with peak sustained winds of over 60 mph over much of Long Island and coastal New jersey.  Gusts reach 90 mph in convective/heavy rainfall.  Wind damage to trees, power lines and even windows in the city creates power outages and injures many.
  • Excessive rainfall, especially in New Jersey and Long Island, floods the traditionally prone areas very quickly.
  • Heavy SNOW! impacts the high terrain of the Adirondacks and Catskills in NY and Shenandoah (far W VA, WV, and PA) as the storm winds down and cools at all levels.  With leaves still on the trees in many of these places, this could lead to tree damage.
  • Tornado impacts east of the track with such severe temperature contrasts and such explosively favorable dynamics aloft could be greater than normal for a tropical impact.
  • Seas could reach 25-50 feet above normal in swells making shipping impossible.
The saving grace is that this thing will not have the staying power of the Perfect Storm.  That beast hammered the coasts while staying just offshore and holding its intensity for nearly 3 days.  This will begin impacting our coasts Sunday and by Tuesday afternoon it will be weakening rapidly and the winds will by dying down.
Nonetheless, I now believe the probability of 10-digit (> 10 billion dollar) damage now exceeds 70% and the probability of a coastal impact is now near 100%.  So…batten down the hatches.  And hope your power doesn’t go out for longer than a few days.  Hope…because that might actually be unlikely.

2 thoughts on “Franken-storm On Course for Historic Destruction

  1. Can you describe the likely impacts for the DC area based on the consensus landfall? The reports I'm reading say the high winds and rain will cover a very large area — including the family homestead here in Woodbridge.

    I mean, we obviously won't lose power for that long or suffer much damage based on this neighborhood's history with these sorts of events, but still…

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  2. The rain is going to be the big story for you. The model mean rainfall from the short range ensemble forecast is printing out 6-10 inches of rain in the DC area…you will get some rain from the front-facing outer band of Sandy as it approaches the Carolinas, and then a bigger blast of rain from a wrap-around band that backs in from the NE as the storm spreads out and retrogrades westward near Long Island.

    In the heaviest rain, you'd be looking at 25-30 mph winds with higher gusts…nothing overly frightening. So…in short…roughly similar to the effects felt in the DC area by Hurricane Floyd, minus a little bit of wind over DC and a good 20-25 mph worth of wind in the Delmarva (where Floyd produced widespread 50-60 mph winds but this storm will be more like 30-40).

    Floyd produced 11.5 inches of rain in the Woodbridge area…this storm will be a little less but still very large rainfall totals.

    Up by me in Long Island, we're far more worried about widespread wind damage, storm surge and tornadoes and far less worried about flooding.

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