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Hurricane Sandy: 1 in 100 Year Storm For New York City?

28 Oct 2012, 7:25 am
An Historic Storm



Prediction: you’ll be hearing about the implications of “Sandy” for many weeks to come. This sprawling, historic hybrid mash-up of hurricane and fierce Nor’easter may even impact the 2012 Election.



Just a hunch.



Most of the (60+) weather models we study show Sandy pinwheeling just south of Long Island & New York City; sustained 60-90 mph winds funneling water into the “New York Bight”, where New Jersey meets the Hudson River Valley. A full moon complicates matters Monday afternoon, the worst day.



NOAA “Slosh” model simulations show an 8-9 foot storm surge pushing across Long Island Sound into parts of Brooklyn & Queens. Runways at La Guardia Airport may be under 2 feet of water Monday.



In a tornado you want to be below ground, in a basement – but hurricanes call for “vertical evacuations”; 3rd or 4th floor of a well-constructed building. Inland flooding and week-long power outages may impact an almost unprecedented swath of the northeast, from DC to Philly, New York & Boston.



A quiet week is shaping up here; dry for Halloween – 50 F. will feel surprisingly good by Thursday. A cold rain next Monday may end as a few wet snowflakes; skies clear for Election Day 2012.







Still On Track. The 00z NAM shows extra-tropical Nor’easter passing very close to New York City by 10 pm Monday night, capable of a very damaging storm surge over Long Island and even pushing into New York Harbor, with hurricane-force winds extending inland as far as Hartford, Albany, Wilkes-Barre and Philadelphia Monday night.



Sandy: second largest tropical storm in the Atlantic since 1988; tropical storm-force winds extending 450 miles from the center of the storm (northeast quadrant). Source: Weather Underground. Future Radar (WRF-NMM) model courtesy of Ham Weather.



60 million Americans may be impacted by Sandy – with implications for the 2012 elections, according to the BBC.



Unprecedented? From the Saturday night Baltimore, MD/Washington D.C. NWS discussion: “I cannot recall ever seeing model forecasts of such an expansive areal wind field with values so high for so long a time. We are breaking new ground here.




Monday Morning Storm Surge. NOAA models are hinting at a 5 foot storm surge Monday morning along the Jersey shore – map above valid 7 am Monday.




What Keeps Us Up At Night? The same NOAA “Slosh” model is hinting at a 6-10 foot storm surge for Long Island Sound by 7 pm Monday; the combination of sustained 60-80 mph. winds and low pressure (and a full moon) carving out a “dome” of water, pushed along by Sandy – water literally piling up north of Long Island – pushing toward LGA, JFK and lowland areas of Brooklyn and Queens. Not sure why they’re not moving people.





8-12 Foot Storm Surge? Here is the NOAA forecast for Kings Point, New York, east of La Guardia Airport, showing a steady rise in water levels, peaking Monday night – the combination of storm surge, high tide (and full moon) creating a possible 10+ rise in water levels in Long Island Sound.




Major Flooding For Lower Manhattan? Here is the NOAA forecast for water levels at The Battery – showing some potentially jaw-dropping rises in water levels. A storm surge of 4-5 feet, superimposed high tide (and full moon) may have some very unpleasant consequences for low-lying areas of Manhattan, Brooklyn, Queens and Staten Island.



Why No Hurricane Watches or Warnings? Because Sandy is transitioning from a warm-core (ocean-powered) hurricane into an extra-tropical low pressure system, a classic Nor’easter, fed by powerful temperature extremes and swirling jet stream winds aloft to amplify and focus the storm’s fury. More details on the transition and terminology from NHC, via Facebook: “…thus, once Sandy loses its tropical cyclone status it will be know as “Post-tropical Cyclone Sandy” in NWS products. Some aspects of this transition are already occurring, and NWS forecasts of storm impacts are based on this expected evolution. Regardless of when this transition occurs, Sandy is expected to bring significant wind, surge, rainfall and inland flooding hazards over an extremely large area, and snowfall to more limited areas. Because Sandy is expected to make this transition before reaching the coast, the NWS has been using non-tropical wind watches and warnings, issued by local NWS Weather Forecast Offices (WFO’s), to communicate the wind threat posed by Sandy in the Mid-Atlantic States and New England (this is why NHC’s tropical storm warnings extend only into North Carolina). The NWS plans to continue using non-tropical watches and warnings issued by local offices in the Mid-Atlantic States and northward throughout this event. By using non-tropical warnings in these areas from the start, we avoid or minimize the significant confusion that could occur if the warning suite changed from tropical to non-tropical in the middle of the event.”



Forecast: Big Surf. Photo details: “Store workers Fletcher Birch, right, and Jay Kleman finish boarding up the windows on a surf store in Ocean City, Md. on Saturday, Oct. 27, 2012 as Hurricane Sandy approaches the Atlantic coast.” (AP Photo/Jose Luis Magana)




NOAA HFIP – Experimental Real-Time High Resolution Forecasts. Forecast track courtesy of NOAA AOML.




New York City’s Most Destructive Storms Since 1821. File photo credit here.




Perspective. If a storm surge forecast of 4-9 feet verifies in the New York City area it would be the worst flooding since Gloria in 1985, possibly since ex-Tropical Storm Agnes merged with an extra-tropical low pressure system to produce massive flooding in late June, 1972. Source:


National Weather Service: “A Storm Like No Other”. Details (and video) from The Associated Press: “The National Weather Service says Hurricane Sandy is an extremely unique storm that will hit the U.S. with strong winds and rain, potentially causing massive damage.


Frankenstorm 2012: Sandy “Hybrid” To Hit Northeast. We’re seeing a higher amplitude weather pattern in recent years, weather systems deeper, moving slower. Could record Arctic ice melt this summer be having an impact, helping to generate fewer (but stronger) storms like Sandy’s spawn? Details from Huffington Post; here’s an excerpt: “Hurricane Sandy has already slammed Cuba, bringing heavy rain and winds around 110 miles per hour on Thursday, as it moved north. By Friday morning, the death toll had already risen across the Caribbean. Climate Central reported that the jet stream winds boxing in Sandy and creating a “Frankenstorm” are part of “blocking patterns [which] have appeared with greater frequency and intensity in recent years.” Some scientists have suggested the patterns could be linked to 2012’s record Arctic sea ice loss, which exposes more open water to absorb the sun’s energy. Representative Ed Markey (D-MA) released a report Thursday, saying, “If climate change continues unchecked, Hurricane Sandy won’t be our October surprise, it could be the new normal for New England….”


Hurricane Preparation. Details from FEMA’s web site:

  • To begin preparing, you should build an emergency kit and make a family communications plan.
  • Know your surroundings.
  • Learn the elevation level of your property and whether the land is flood-prone. This will help you know how your property will be affected when storm surge or tidal flooding are forecasted.
  • Identify levees and dams in your area and determine whether they pose a hazard to you.
  • Learn community hurricane evacuation routes and how to find higher ground. Determine where you would go and how you would get there if you needed to evacuate.
  • Make plans to secure your property:
  • Cover all of your home’s windows. Permanent storm shutters offer the best protection for windows. A second option is to board up windows with 5/8” marine plywood, cut to fit and ready to install. Tape does not prevent windows from breaking.
  • Install straps or additional clips to securely fasten your roof to the frame structure. This will reduce roof damage.
  • Be sure trees and shrubs around your home are well trimmed so they are more wind resistant.
  • Clear loose and clogged rain gutters and downspouts.
  • Reinforce your garage doors; if wind enters a garage it can cause dangerous and expensive structural damage.
  • Plan to bring in all outdoor furniture, decorations, garbage cans and anything else that is not tied down.
  • Determine how and where to secure your boat.
  • Install a generator for emergencies.
  • If in a high-rise building, be prepared to take shelter on or below the 10th floor.
  • Consider building a safe room.

Image credit above: “Beachgoers venture out to the end of Minutemen Causeway in Cocoa Beach, Fla., around lunchtime to see the waves, getting sandblasted from the wind and sand, due to the effects of the outer bands of Hurricane Sandy.” Friday, Oct. 26, 2012. (AP Photo/Florida Today, Malcolm Denemark)



Here is an edited version of what I sent our corporate Alerts Broadcaster clients Saturday PM:



Alerts Broadcaster Update: Hurricane Sandy is still on track to become a record storm for much of the Mid-Atlantic and Northeast; as many as 50-75 million Americans may be impacted by high winds, coastal flooding and extensive inland flooding by Tuesday. A few headlines:

* Conditions deteriorate during the day Sunday, from south to north across the Mid-Atlantic region. Accelerate preparations to secure facilities and safeguard staff early in the day Sunday.



* The storm peaks Monday and Monday night; conditions slowly improve by Tuesday afternoon as the center of Sandy moves inland and slowly dissipates.



* New York City officials are discussing evacuation plans and even closing the subways at the height of the storm (Monday). “SLOSH” simulations are predicting as much as 6-9 feet of water pushing across Long Island Sound into parts of Queens and Brooklyn. A storm surge coming up New York Harbor may flood Lower Manhattan and Battery Park. Areas within 5 feet of sea level are threatened. My hunch: La Guardia Airport and JFK may see runway inundation Monday, with as much as 1-3 feet of standing water on some runways.



* NBC in New York reports that MTA officials are considering shutting down subways, bridges and commuter rails by 7 pm Sunday. No final decision has been made as of 10 pm eastern time, but I anticipate that this will, in fact, happen. Don’t wait until the last minute.



* A 4-8 foot storm surge is possible over coastal New Jersey and the southern coastline of Long Island. Communities that have a history of severe flooding during hurricanes and severe Nor’easters can expect widespread flooding from Sandy.



* Many coastal highways within 3-4 feet of sea level will be closed by Sunday night. Again, if you plan to evacuate away from the coast/sea level, the time to do it is now, or Sunday morning at the latest.



Minimal Hurricane – Maximum Punch. Don’t be fooled by Sandy’s Category 1 ranking. A powerful contrast in pressure between this deepening storm, and a blocking ridge of high pressure to the north, will create a vast area of 50-90 mph winds late Sunday into Tuesday morning, as much as 250 miles wide as the storm “hooks” westward, probably passing just south of Long Island and New York City.Map: Ham Weather.


Latest Model Ensemble. A majority of weather models bring Sandy’s path south of New York City and Long Island. Keep in mind that the most extreme storm surge will take place north of wherever Sandy comes ashore. We are placing special emphasis (as is NHC) on the GFS and ECMWF (European) solutions.Map: Ham Weather.


European (ECMWF) Model. The ECMWF was the first model to turn Sandy inland – back on Monday we predicted that Sandy would, in fact, impact the northeastern USA. So I’m putting a little additional weight on this model, which shows landfall just north of Atlantic City Monday night. Map above valid 1 am Tuesday morning. The purple-shaded area designates the most extreme rains, with as much as 1-2” of rain falling every 3 hours from the Delaware Valley to Washington D.C. The greatest impact of inland flooding comes Monday afternoon into Tuesday morning.Map: WSI Corporation.


GFS Model. Underscoring and validating the ECMWF simulation, the latest GFS run also shows a landfall near Atlantic City Monday evening at 7 pm (00z GFS run). This could be close to a worst-case scenario for Manhattan: sustained east/southeast winds, coupled with extremely low pressure, carving out a dome of water, a “storm surge”, as much as 5-10 feet above normal high tide. A full moon Monday increases the risk of historic flooding, possibly comparable to the June 22, 1972 flood, which was sparked by Tropical Storm Agnes fusing with another storm, resulting in 122 deaths and $6 billion in damage ( Map: Weather Bell.


Canadian Model Solution. The GEMS model from Environment Canada shows a vaguely similar left-hand turn for Sandy late Monday into Tuesday morning, with the core of the storm passing almost directly over New York City by 1 am Tuesday morning. I want to stress that Boston, Cape Cod, Martha’s Vineyard, Nantucket, Providence and coastal Long Island will also experience potentially historic flooding,  due to the combination of a powerful differential in air pressure, slow movement and a full moon late Monday.Map: Weather Bell.


Sprawling Wind Field. This is a map showing the huge swath of hurricane-force winds at 1 pm Monday, stretching from near Boston and Cape Cod to coastal Rhode Island, Connecticut and Long Island. These are wind predictions for 900 mb, about 1,500 feet above the ground, but I expect surface winds to be in the 70-95 mph range from midday Monday into early Tuesday morning. Data: NAM-WRF.


Dangerous Storm Surge. NOAA’s “Slosh” models are showing a storm surge as high as 6-10 feet above mean sea level Monday evening at 7 pm over the westernmost tip of Long Island Sound – pushing water into Queens and Brookyn. Both JFK and LGA may see runways inundated by rapidly rising water as Sandy tracks just south of Long Island.Map above: NOAA.

Summary: Sandy is still on track to deliver a punishing blow to much of the northeast, the slow speed, extreme pressure gradient and full moon on Monday making this historic Nor’easter equivalent to a Category 1-2 hurricane. It’s still impossible to pin down where the most severe storm surge will take place – the level of water hinges on the precise track Sandy takes as it passes south of Long Island and New York City Monday.



Consider accelerating your preparations to safeguard life and property. Remember the impact of inland flooding – many towns will lose power for several days, perhaps longer. If you live within 5-7 feet of sea level, in an arc from New Jersey to New York to Long Island and southern New England, have a Plan B, well inland. The best advice if you can’t reach higher ground in time: vertical evacuations. Find shelter on the third or fourth floor of a well constructed building (office complex or hotel), well away from outer walls and windows to safeguard yourself from flying debris and broken glass.



Sandy may be a hybrid hurricane – Nor’easter by the time it pushes ashore Monday night; but there’s little doubt this will be an historic storm.




Remembering Irene: Don’t Underestimate Risk of Inland Flooding. NOAA HPC is predicting a wide swatch of 4-8″ rains from Sandy, with some 10″ amounts over the Delmarva Peninsula.



Experts: Team Obama Should Root For Hurricane Sandy To Interrupt Election. And what a mess that would be; U.S. News and World Report has an intriguing story – here’s an excerpt: “…Pastor says a natural disaster that impacts the election would “stretch the fabric of American Democracy to the point of being torn” because, in many cases, local disputes over voting “would be addressed in an area where one party is largely dominant and the rules are extremely weak.” So far, American elections have been fairly natural disaster-free. Hudak says there have been some “small scale issues” with blizzards in the upper plains and Rocky Mountain states in previous elections. With any luck, that streak will continue in 2012. But even if Sandy isn’t catastrophic, inclement weather throughout the country could have a more predictable impact on the election…”

* Election In Sandy’s Shadow. reports on the implications of Hurricane Sandy complicating the 2012 Election; details here.



Election Day Weather. Here is the updated GFS (very extended) Outlook for Tuesday evening, November 6. Overall the forecast looks drier than it did yesterday, the only rain over northern New England, Louisiana, Texas and the Pacific Northwest, a few light showers from Grand Forks to Duluth and the Twin Cities.



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Welcome to the WeatherNation blog. Every day I sift through hundreds of stories, maps, graphics and meteorological web sites, trying to capture some of the most interesting weather nuggets, the stories behind the forecast. I’ll link to stories and share some of the web sites I use. I’m still passionate about the weather, have been ever since Tropical Storm Agnes flooded my home in Lancaster, PA in 1972. I’ve started 5 weather-related companies. “EarthWatch” created the world’s first 3-D weather graphics for TV stations – Steven Spielberg used our software in “Jurassic Park” and “Twister”. My last company, “Digital Cyclone”, personalized weather for cell phones. “My-Cast” was launched in 2001 and is still going strong on iPhone, Android and Blackberry. I sold DCI to Garmin in 2007 so I could focus on my latest venture: WeatherNation. I also write a daily weather column for The Star Tribune And if you’re on Twitter, you’ll find me @pdouglasweather

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