Post Tropical Super Storm Sandy was an epic storm. It could very well be the
worst storm that ever hit New Jersey,
southern New England, Long Island,
and New York City. It will take awhile
to assess the total cost of the damage of the storm, but it will be in the
billions. It cost dozens of lives and left millions in the dark. The transit
system of New York City was
crippled like never before.
Our forecast warning area was spared the worst of Sandy.
That said, we certainly had issues to deal with, mainly with wind damage as
well as tidal river flooding, one storm related fatality, but nothing like our
neighbors to the south and east.
On October 22nd, the 18th Tropical System of the year, Sandy,
formed south of Jamaica
in the Caribbean Sea. It intensified fairly quickly into
a Category 2 hurricane as it slammed into portions of Jamaica
and Haiti. It
then tracked north into the southeastern Cuba,
after which it weakened to a low end Category 1 hurricane/high end tropical
storm due to land interaction. It brushed the Bahamas
and its outer bands of rain hit sections of the east coast of Florida,
as well as North Carolina. An
anomalous ridge of high pressure in the mid levels of the atmosphere forced the
storm to track mainly due north very slowly, as its center remained off the
southeast coast. Meanwhile, a high amplitude trough was located west of the
entire Appalachian chain with surface highs anchored over Hudson Bay,
as well as across Newfoundland.
The tropical system continued to track in a mainly northerly fashion October
26th through October 29th. At the same time, a significant upper level
disturbance, including a very strong upper-level jetlet, took aim toward the
mid-Atlantic states, poised to interact with Sandy.
The high to the northeast strengthened, which ultimately prevented Sandy
from heading out to sea. As the strong energy from the mid-Atlantic interacted
with Sandy, it pulled Sandy
back to the northwest, over the Gulf Stream, well off
the Delmarva Pennisula. Sandy actually strengthened with core winds clocked to
90 mph before it made landfall near Atlantic City, New Jersey about 800 PM EDT
on October 29th. At this point, it has lost some of its tropical
characteristics but packed a stronger punch than a regular high end category 1
hurricane would have, due to the fact it had become fully absorbed into the
mid-Atlantic system. A few hours prior to landfall, it had a central pressure
of only 940 mb, one of the lowest on record. It became embedded within a very
large mid latitude low pressure area which, in combination with the full moon
occurring on the 29th, and the trajectory of the storm approaching from the
east southeast, likely contributed to the record storm surge. Once it made
landfall, post tropical system Sandy
tracked west northwest across southern Pennsylvannia, then turned northward
into western New YorkState
on October 31st. It weakened considerably after landfall, and as dry air in the
mid layers of the atmosphere worked into it.
While our region escaped the worst impacts from Sandy,
record flooding from a tidal surge worked up the Hudson River,
at Poughkeepsie. The reading at Poughkeepsie
crested at 9.54 feet. The NYC Battery crested at 13.88 feet. Tidal flooding was
noted all the way north to Albany.
Minor flooding occurred on Lake George as water from a
strong northerly fetch piled up into the village
of Lake George. A few river gages
in the Catskills came close to flooding but no points went above flood stage as
rainfall amounts were not that heavy. In fact, much of region in the HudsonValley saw rainfall amounts under
an inch due to valley shadowing as easterly winds helped dry out the air, as it
descended down off the Berkshires and Taconics. Also, drier air from the
Canadian Maritimes was injected into the right side of Sandy,
which helped mitigate rainfall amounts everywhere in our region which was on
the right side of the storm track. The maximum rainfall amounts were a little
over 3 inches in western GreeneCounty.
The winds were forecast to be the worst impact from Sandy.
While they did not quite reach the destructive levels as feared or forecast, we
did have reported gusts 60-77 mph in our region, mainly across the higher
elevations. A trained weather spotter located near Hancock,
MA in the Berkshires, reported the highest
wind gust reaching 77 mph. Most of our area had peak wind gusts in the 50-59
mph range. The official high wind gust at AlbanyInternationalAirport
was 49 mph, lower than the peak wind from Irene. Nevertheless, there were minor
damage reports, mainly downed trees and wires, especially across the higher
elevations and south of Albany, as
well as isolated to scattered power outages. There was one storm-related
fatality in our forecast area, a woman was killed in Kerhonkson,
NY in UlsterCounty when a large section of
roofing blew into her windshield. The worst of the effects of Sandy
happened late Monday afternoon (Oct 29) through much of the night. By Tuesday,
October 30th, as Sandy was well
inland to our southwest, the wind initially decreased and so did the scattered
rain bands. However, gusty southeast winds of 40 to 50 mph took place again Tuesday as good mixing developed after
the sun came out, and temperatures remained very mild. These winds quickly
diminished by dark.
The Operational ECWMF honed in on this storm from 10 days out, even before Sandy
formed. That forecast model initially had the storm hitting Cape Cod
on Day 10, a day too late. However, for subsequent runs after 00Z Tuesday
October 23rd, the ECMWF had the storm tracking into the northern mid-Atlantic
coast or New York City, with
central pressures as low as 927 mb. Although the track wobbled a little during
run to run, with one run considerably further east and others slightly to the
south, making landfall at the mouth of the Delaware Bay, the operational ECMWF
was superior to any other long-range forecast model. However, many other ECMWF
ensemble packages, at least about a week out, still had the storm hooking to the
east, so the operational European model was on the western side of its ensemble
envelopes. The operational GFS initially tracked Sandy
well out to sea, missing the east coast by a thousand miles! Many ensemble
members in the early days (about a week before the event) did have the storm
hooking back into Maine or Cape
Cod. Several earlier runs of the GFS did produce an interesting
trowal feature that would have brought a stripe of heavy rain to our region,
but still kept Sandy well to our east. Within five days of the event, the GFS
latched onto the event, with an increasing number of ensemble members hooking
it westward into the region, mainly from Cape Cod
northward. Slowly, the GFS honed in on taking Sandy
into southern New Jersey.
Overall, the GFS operational model was on the eastern side of its ensemble
envelopes. Initially, the Canadian Global Model also had the storm hitting New
Jersey, but later runs "lost" it to sea,
before honing back in on it about five days out. The NAM
ultimately did hone in on southern New Jersey
within several days of the event. The United Kingdom Model (UK) initially had
the storm tracking well out to sea, before ultimately tracking it into the Jersey
shore in the shorter-term.
Six hourly balloon launches were mandated from 18Z Thursday October 25th
through 06z Tuesday October 30th. This was the first time in history that ALL
upper air stations in the United States
were required to do six hourly balloon launches. Two staff members were
deployed to the NY State Office of Emergency Management starting over the
weekend of October 27 and 28th, 24/7 Saturday through Tuesday.
Above: Loops of 500 hPa heights and vorticity from (left to right)
the GFS, ECMWF, CMC and GFSEnsemble, initialized 0000 UTC 25 October.
Above: Loops of MSLP and vorticity from (left to right) the GFS,
ECMWF, CMC and GFSEnsemble, initialized 0000 UTC 25 October.
Above: Loops of 850 hPa winds from (left to right) the GFS, ECMWF,
CMC and GFSEnsemble, initialized 0000 UTC 25 October.
Above: Loops of 925 hPa temperatures from (left to
right) the GFS and ECMWF initialized 0000 UTC 25 October.
Above: Sandy track forecasts from the National
Hurricane Center displayed on AWIPS (left and middle) at 1500 UTC 29 October and
2100 UTC 29 October, and from 2100 UTC October 29 displayed in Hurrivac with the
cone of uncertainty (right).
Above: Loop of forecasted track of Sandy from the
National Hurricane Center beginning 2100 UTC 29 October (left) and loop of the
GFS and ECMWF MSLP beginning 0000 UTC 22 October valid 0000 UTC 30 October
Above: Loop of MSLP, 700 hPa heights and 850-700
hPa 2-D frontogenesis from the 1800 UTC 29 October GFS.
Above: Loop of MSLP from the 1800 UTC GEFS.
Above: Loops of 1800 UTC 28 October GEFS 850 hPa
winds and anomalies (left) and 1500 UTC 28 October SREF 850 winds and anomalies
Above: Loops of 850 hPa winds from
the 1800 UTC 29 October GFS (left) and NAM (right).
Above: Loops of 925 hPa winds from
the 1800 UTC 29 October GFS (left) and NAM (right).
Above: Loops of cross sections of
frontogenesis between the southern New England coast to Lake Ontario from the
1200 UTC October 29 NAM (left) and 1800 UTC 29 October GFS (right).
Above: Graphic of the wind impacts of
Above: Precipitation totals from 3
Above from left to right: Dual Pol
precipitation estimates, legacy Doppler radar precipitation estimates and
Vermont and northern NY precipitation totals.
Above: Displays of river levels from
assorted points in the forecast area.
Above: Displays of river levels from
assorted points in the forecast area and graphic of the flood warning for