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.