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Hurricane Sandy

Category 2 hurricane (SSHWS/NWS)
Formed	October 22, 2012
Dissipated	October 31, 2012 (extratropical after October 29)
Highest winds	1-minute sustained: 110 mph (175 km/h)
Lowest pressure	940 mbar (hPa); 27.76 inHg
Areas affected	Greater Antilles, Bahamas, most of the eastern United States (especially the coastal Mid-Atlantic States and New England), Bermuda, eastern Canada
Part of the 2012 Atlantic hurricane season
Part of a series on Hurricane Sandy
History Meteorological history Effects Greater Antilles United States Maryland and Washington, D.C. New Jersey New York New England Canada Other wikis Commons: Sandy images Wikinews: Sandy stories

The meteorological history of Hurricane Sandy included the largest size for an Atlantic hurricane and the lowest recorded pressure in Atlantic City, New Jersey and Philadelphia, Pennsylvania.

Origins

A tropical wave was moving westward through the eastern Caribbean Sea on October 19, 2012. It had an extended low pressure area, and conditions were expected to gradually become more favorable for development. On October 20, the system became better organized, and the U.S. National Hurricane Center (NHC) assessed a high potential for it to become a tropical cyclone within 48 hours, giving it the Invest number of 99L. By the next day, the associated convection, or thunderstorms, had become minimal, although barometric pressure in the area remained low, which favored development. The thunderstorms gradually increased, while the system slowed and became nearly stationary over the western Caribbean. At 1500 UTC on October 22, the NHC initiated advisories on Tropical Depression Eighteen about 320 mi (515 km) south of Kingston, Jamaica. This was based on surface observations and satellite imagery, which indicated the system had developed enough organized convection to be classified.

When the tropical depression formed, it was in an area of weak steering currents south of a ridge extending eastward from the Gulf of Mexico. Low wind shear and warm sea surface temperatures were conducive to strengthening and rapid deepening. Late on October 22, a Hurricane Hunters flight observed winds of 40 mph (64 km/h) in a rainband, which prompted NHC to upgrade the depression to Tropical Storm Sandy. Outflow increased, while moist atmosphere helped the convection organize further. NHC noted that "remaining nearly stationary over the warm waters of southwestern Caribbean Sea is never a good sign for this time of year." Still, the cloud pattern initially remained largely the same. Early on October 24, an eye began developing. By that time, Sandy was moving steadily northward, drawn by a trough approaching from the northwest. At 11 a.m. EDT (1500 UTC) on October 24, the NHC upgraded Sandy to hurricane status after the Hurricane Hunters observed flight-level winds of 99 mph (159 km/h). At the time, Sandy was about 65 mi (105 km) south of Kingston, Jamaica.

Caribbean landfalls and The Bahamas

At about 3 p.m. EDT (1900 UTC) on October 24, Sandy made landfall near Kingston with winds of about 80 mph (130 km/h). Just offshore Cuba, Sandy rapidly intensified into a Category 2 hurricane on the Saffir-Simpson scale with 110 mph (175 km/h) winds. Shortly thereafter at 1:25 a.m. EDT (0525 UTC), the hurricane struck Cuba just west of Santiago de Cuba. At landfall, Sandy had a well-defined eye of over 23 mi (37 km) in diameter, and flight-level winds reached 135 mph (216 km/h). While over land, the structure deteriorated and the eye was no longer visible. After Sandy exited Cuba, dry air and increasing shear restricted the outflow and caused the structure to become disorganized. A mid-level low over Florida turned the hurricane toward the north-northwest.

By early October 26, most of the convection was located to the north of the center due to wind shear and dry air to the southwest of the hurricane; by this time, the size of the storm had increased greatly. As the day progressed, the storm continued moving slowly to the north, and the strong wind sheer caused the storm's intensity to decrease. By the next day, the NHC remarked that Sandy was "showing characteristics of a hybrid cyclone... like a large occluded frontal low." However, the system maintained a warm thermal core, and despite strong 60 mph (95 km/h) wind shear, the hurricane continued to develop thunderstorms due to good divergence from a nearby trough; the same trough turned Sandy toward the northeast. On October 27, Sandy briefly weakened to a tropical storm, after dry air became fully ingested into the mid- and upper-level circulations. Later that day, however, wind reports from the Hurricane Hunters indicated that Sandy had re-intensified into a hurricane.

Post-tropical transition and final landfall

By late on October 27, Sandy was moving steadily northeastward ahead of an approaching trough. Although it maintained winds of hurricane force, the entrainment of dry air caused the inner area of convection to diminish. On October 28 however, thunderstorms increased over the center, and Sandy's upper-level circulations were stronger than 24 hours prior. As the day progressed, the wind shear decreased, and a banded eye began redeveloping while the hurricane was still over the Gulf Stream. The convection organized further early on October 29. Around the same time, Sandy began transitioning into an extratropical storm early on October 29 after the western periphery of the circulation began interacting with a cold front. The storm revolved around an upper-level low over the eastern United States, and also to the southwest of a ridge over Atlantic Canada that the NHC described as "highly anomalous"; this caused Sandy to turn to the north and northwest.

Maintaining an eye and deep convection, the hurricane intensified, reaching a secondary peak of 90 mph (150 km/h) by 1500 UTC on October 29 while moving over a small area of the Gulf Stream with waters of 81º F (27º C). Around that time, Sandy had a wind field of over 1,000 nautical miles (1,150 mi, 1,850 km) in diameter. Both a warm and cold front were located near the storm's center, and the storm was predicted to become extratropical before landfall. The convection diminished while the hurricane accelerated toward the New Jersey coast, due to it becoming involved with the low to the west. The pressure continued to drop, which indicated the system was intensifying due to baroclinic instability. In its advisory issued late on October 29, the NHC noted, "all of these considerations lead us to conclude that the most appropriate classification at advisory time is extratropical." The agency declared Sandy post-tropical at 2300 UTC that night just offshore southern New Jersey, and about an hour later the storm made landfall about 5 miles (8 km) southwest of Atlantic City. The intensity at landfall was estimated at 90 mph (150 km/h), although the strongest winds were located east and southeast of the center.

Dissipation

After moving ashore, Sandy continued to the west, weakening below hurricane force by the time it reached Pennsylvania. The Hydrometeorological Prediction Center (HPC) continued issuing advisories on the system after it became post-tropical. The system continued to weaken as it moved across Pennsylvania, and by 0300 UTC on October 31, the system's movement had shifted to the northwest. By 0900 UTC on October 31, the circulation degenerated into a trough of low pressure, with no discernible circulation. Later that day, the remnants of Sandy spread into the Great Lakes, and the HPC issued its last advisory.

Predictions

As early as October 23, while Sandy was developing in the Caribbean, the European Centre for Medium-Range Weather Forecasts (ECMWF) predicted the storm would strike the East Coast of the United States, while most other tropical cyclone forecast models anticipated the storm would move out to sea. By the next day, various computer models agreed that Sandy would interact with a trough over the eastern United States and turn to the west. About five days before landfall, the ECMWF, Geophysical Fluid Dynamics Laboratory (GFDL), and Navy Operational Global Prediction System (NOGAPS) models predicted Sandy would strike the Delmarva Peninsula, while the American Global Forecast System (GFS) model anticipated the hurricane would move out to sea; the remaining models were between the two scenarios. By four days before landfall, the NHC was forecasting a landfall on New Jersey, as were most of the computer models. In general, the European computer models performed better than the United States ones, due to the European models being on stronger computers and with higher resolution. MIT professor Kerry Emanuel used the moment to call attention to the under-performance of US models and to recommend a "dedicated effort" to reverse it.

Records

The storm surge, which occurred at high tide, pushed water to 13.88 feet (4.23 meters) at Battery Park, New York, beating the previous record of 10.02 feet (3.05 m) set by Hurricane Donna in 1960 in the same place. However, a storm surge of 13 feet (during low tide) was also reported at Battery park during the 1821 Norfolk and Long Island hurricane, which was before records were officially kept. Storm tide records were also broken in Sandy Hook, New Jersey and Philadelphia, Pennsylvania, with peak tides of 13.31 ft (4.06 m) and 10.62 ft (3.24 m), respectively. The tidal gauge in Sandy Hook lost power while the tide was still rising, meaning the tide crested higher than the recorded peak.

Sandy was the second largest tropical cyclone since 1988, according to Weather Underground. The only storm to beat it was Hurricane Olga in 2001.

Sandy was second to 1938 New England hurricane for the most intense storm, at 946 millibars, to hit land in the United States north of Cape Hatteras, North Carolina. (The 1938 storm was 941 mbar at landfall.) The barometric pressure hit a record low of 948 mbar (28.0 inHg) over Atlantic City, New Jersey, breaking the previous record of 961 mbar (28.4 inHg) low set in 1938. Sandy also broke the record for producing the lowest pressure in Philadelphia, with a minimum of 954 mbar (28.2 inHg); this broke the 962 mbar (28.4 inHg) record set during the 1993 Storm of the Century.

A buoy in New York Harbor reached a record level when it measured a 32.5-foot wave on October 30 that was 7.5 feet taller than a 25-foot wave registered by Hurricane Irene in 2011.

Global warming effect

Climate scientists are divided on the exact role global warming plays in strengthening hurricanes like Hurricane Sandy, but have agreed that climate change likely leads to stronger and wetter storms, though possibly fewer of them. Tropical storms derive their energy from warm waters, and warmer water generally mean stronger storms. Climate change has caused sea levels to rise, which made the storm surge and coastal flooding caused by Sandy a lot more devastating. Since the overall sea level has risen by 20 cm (and is accelerating), the rise in sea level increases the risk for major floods to occur every time a storm hits. A 2012 paper in Nature projected that climate change could lead to floods that should occur only once a century to happening every three to twenty years.

In the case of Hurricane Sandy, two major factors contributing to the size and strength of the storm were unusually warm ocean surface temperatures and an increase in blocking patterns, both of which are expected to occur more frequently due to global warming. Mark Fischetti of Scientific American proposed a more explicit link, arguing that the melting of Arctic ice caused a negative North Atlantic Oscillation, which fueled the expansion of Sandy by pushing the jet stream South. Meteorologist Kerry Emanuel stated in an interview that no individual weather event such as Hurricane Sandy can be attributed to climate change since weather events are variable, but the overall events may be attributed to climate change.

Rep. Henry Waxman (D-Calif.), the top Democrat of House Energy and Commerce Committee, wants Republicans to hold a hearing in the lame duck session on links between climate change and Hurricane Sandy. "Hurricane Sandy is exactly the type of extreme weather event that climate scientists have said will become more frequent and more severe if we fail to reduce our carbon pollution. That is why we are writing to request that you hold a hearing on the storm and its relation to climate change in the lame-duck session," he and Rep. Bobby Rush (D-Ill.) wrote.

See also

• 2012 Atlantic hurricane season
• List of New Jersey hurricanes

References

1. Todd Kimberlain (2012-10-19). Tropical Weather Outlook (TXT) (Report). National Hurricane Center. Retrieved 2012-10-23.
2. Stacy Stewart (2012-10-19). Tropical Weather Outlook (TXT) (Report). National Hurricane Center. Retrieved 2012-10-23.
3. Eric Blake (2012-10-20). Tropical Weather Outlook (TXT) (Report). National Hurricane Center. Retrieved 2012-10-23.
4. Deitra Tate (2012-10-21). "Great Start to Week...Watching Tropics". Local15TV. Retrieved 2012-11-01.
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6. Robbie Berg (2012-10-21). Tropical Weather Outlook (TXT) (Report). National Hurricane Center. Retrieved 2012-10-23.
7. Stacy Stewart (2012-10-22). Tropical Weather Outlook (TXT) (Report). National Hurricane Center. Retrieved 2012-10-23.
8. ^ Robbie Berg; Lixion Avila (2012-10-22). Tropical Depression Eighteen Discussion Number 1 (Report). National Hurricane Center. Retrieved 2012-10-23.
9. Richard Pasch (2012-10-22). Tropical Storm Sandy Discussion Number 2 (Report). National Hurricane Center. Retrieved 2012-10-23.
10. Stacy Stewart (2012-10-23). Tropical Storm Sandy Discussion Number 3 (Report). National Hurricane Center. Retrieved 2012-10-23.
11. Daniel Brown (2012-10-23). Tropical Storm Sandy Discussion Number 4 (Report). National Hurricane Center. Retrieved 2012-10-24.
12. Jack Beven (2012-10-24). Tropical Storm Sandy Discussion Number 7 (Report). National Hurricane Center. Retrieved 2012-10-24.
13. ^ Michael Brennan (2012-10-24). Hurricane Sandy Discussion Number 9 (Report). National Hurricane Center. Retrieved 2012-10-24.
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15. Stewart, Stacy (October 25, 2012). "October 25 12:30 a.m. EDT (0430 UTC) Update". National Hurricane Center. Retrieved October 25, 2012.
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17. ^ Stacy Stewart (2012-10-25). Hurricane Sandy Discussion Number 12 (Report). National Hurricane Center. Retrieved 2012-10-26.
18. Michael Brennan (2012-10-25). Hurricane Sandy Discussion Number 13 (Report). National Hurricane Center. Retrieved 2012-10-26.
19. ^ Michael Brennan (2012-10-25). Hurricane Sandy Discussion Number 14 (Report). National Hurricane Center. Retrieved 2012-10-26.
20. Jack Beven (2012-10-26). Hurricane Sandy Discussion Number 15 (Report). National Hurricane Center. Retrieved 2012-10-26.
21. Michael Brennan (2012-10-26). Hurricane Sandy Discussion Number 16 (Report). National Hurricane Center. Retrieved 2012-10-26.
22. Richard Pasch (2012-10-26). Hurricane Sandy Discussion Number 18 (Report). National Hurricane Center. Retrieved 2012-11-01.
23. Jack Beven (2012-10-27). Hurricane Sandy Discussion Number 19 (Report). National Hurricane Center. Retrieved 2012-10-27.
24. Jack Beven (2012-10-27). Tropical Storm Sandy Discussion Number 20 (Report). National Hurricane Center. Retrieved 2012-10-27.
25. Daniel Brown (2012-10-27). Hurricane Sandy Discussion Number 21 (Report). National Hurricane Center. Retrieved 2012-10-27.
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33. Richard Knabb; James Franklin (2012-10-29). Hurricane Sandy Discussion Number 30 (Report). National Hurricane Center. Retrieved 2012-10-31.
34. Daniel Brown; Dave Roberts (2012-10-29). Post-Tropical Cyclone Sandy Tropical Cyclone Update (Report). National Hurricane Center. Retrieved 2012-10-31.
35. Daniel Brown; Dave Roberts (2012-10-30). Post-Tropical Cyclone Sandy Tropical Cyclone Update (Report). National Hurricane Center. Retrieved 2012-10-31.
36. Daniel Brown (2012-10-30). Hurricane Sandy Discussion Number 31 (Report). National Hurricane Center. Retrieved 2012-10-31.
37. Daniel Petersen (2012-10-30). Post-Tropical Cyclone Sandy Advisory Number 32 (Report). Hydrometeorological Prediction Center. Retrieved 2012-10-30.
38. Mary Beth Gerhardt; Jason Krekeler; Bruce Sullivan (2012-10-30). Post-Tropical Cyclone Sandy Advisory Number 34...Corrected (Report). Hydrometeorological Prediction Center. Retrieved 2012-11-01.
39. Daniel Petersen; Allison Monarski; Bruce Sullivan; Andrew Orrison (2012-10-31). Post-Tropical Cyclone Sandy Advisory Number 35...Corrected (Report). Hydrometeorological Prediction Center. Retrieved 2012-11-01.
40. Daniel Petersen; Andrew Orrison; Bruce Terry (2012-10-31). Remnants of Sandy Advisory Number 36 (Report). Hydrometeorological Prediction Center. Retrieved 2012-10-31.
41. Mary Beth Gerhardt (2012-10-31). Remnants of Sandy Advisory Number 37 (Report). Hydrometeorological Prediction Center. Retrieved 2012-10-31.
42. ^ Dan Vergano (2012-10-30). "U.S. forecast's late arrival stirs weather tempest". USAToday. Archived from the original on 2012-11-01. Retrieved 2012-11-01.
43. Pagano, Thomas, "Today Show Coverage of ECMWF Forecasts and other Sandy Links", The River Seers blog, October 31, 2012. Pagano was a visiting scientist at ECMWF in October 2012. Retrieved 2012-11-01.
44. "British meteorologists predicted Sandy's course - Video on TODAY", video.today.msnbc.msn.com, October 31, 2012. Retrieved 2012-11-01.
45. Emanuel, Kerry, "Why America Has Fallen Behind the World in Storm Forecasting", Wall Street Journal Speakeasy blog, October 28, 2012. Retrieved 2012-11-01.
46. Aaron Naparstek (2005-07-20). "The Big One for New York City". The New York Press. Archived from the original on 30 December 2007. Retrieved 2012-10-31. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
47. ^ Public Information Statement (Report). Mount Holly National Weather Service. 2012-10-31. Retrieved 2012-11-01.
48. "How Hurricane Sandy compares to the worst U.S. natural disasters". Mother Nature Netwok. Retrieved 31 October 2012.
49. "Hurricane Sandy breaks records: death toll and amount of damage unknown". Iowa State Daily. Retrieved 31 October 2012.
50. "How Sandy stacked up: the storm in statistics".
51. "Hurricane Sandy a record-breaker".
52. ^ Walsh, Bryan (12 November 2012). "Outsmarting the Surge". 180 (20). Time magazine. Retrieved 4 November 2012. {{cite journal}}: Cite journal requires |journal= (help)
53. Trenberth, Dr. Kevin. "Hurricane Sandy mixes super-storm conditions with climate change". The Conversation. Retrieved 2012-10-29., "The sea surface temperatures along the Atlantic coast have been running at over 3C above normal for a region extending 800km off shore all the way from Florida to Canada. Global warming contributes 0.6C to this. With every degree increase, the water holding of the atmosphere goes up 7%, and the moisture provides fuel for the tropical storm increases its intensity and magnifies the rainfall by double that amount compared with normal conditions."
54. Marshall, Michael (2012-10-29). "Slow-moving hurricanes such as Sandy on the rise". New Scientist. Retrieved 2012-10-29. Kerry Emanuel at the Massachusetts Institute of Technology said that Sandy is expected to linger for days due to blocking patterns that make weather systems move slowly, and that climate change will cause more situations similar to this to occur.
55. Fischetti, Mark (October 30, 2012). "Did Climate Change Cause Hurricane Sandy?".
56. Palmer, Lisa (October 29, 2012). "Hybrid Hell".
57. "Rep. Waxman seeks lame-duck hearing on Sandy, climate change links". The Hill. Retrieved 4 November 2012.

v t e Hurricane Sandy
Meteorological history Political impact
Effects by region	Greater Antilles United States Maryland and Washington, D.C. New Jersey New York New England Canada
Other	Bounty John B. Caddell Chris Christie Lorenzo Langford Hurricane Sandy: Coming Together Occupy Sandy 12-12-12: The Concert for Sandy Relief 14th Street Tunnel shutdown

• Hurricane Sandy
• Meteorological histories of individual tropical cyclones