Hurricane/Hybrid Sandy Timing and Impacts
If you have been watching The Weather Channel for coverage of Hurricane Sandy, you may have noticed the two different computer models they keep showing. These two models, the EURO and GFS, are just two of many solutions meteorologists use to forecast the weather. However the EURO and GFS are two medium range global models and over time have proven to be the best. The EURO is run by the European Centre for Medium-Range Forecast (ECMWF) and is usually the most reliable model. The GFS is an American model run by the National Center for Environmental Prediction (NCEP). Weather models solve the known equations that govern atmospheric physics. It is for that reason meteorologists study years of calculus and physics in school. Thank god we developed computer models to solve these equations.
The models use data collected by upper air measures (balloon launches, satellite data, observed data) to input into these equations to start the process. These measurements are usually taken twice a day, at 8 NAM/PM during Daylight Savings time and at 7 AM/PM when it ends. They run on Coordinated Universal Time (UTC) which begins at 00z at midnight on the Prime Meridian (0 degrees longitude, border West/East Hemisphere) . This is done so all balloon launches are done at the same time. In a rare move the government ordered balloon measurements 4 times a day until Sandy passes. This is an impressive step by the government and shows they are taking the storm very serious.
Now on to the weather.
I've zeroed in a New Jersey impact. I am going to support a northern NJ landfall although that doesn't change the forecast for New England all that much. I apologize in advance for the length of this post; I promise that when the weather is normal I will be much more brief.
|Bottom Right is Sandy, Blue arrow pointing to cold front, yellow highlight is energy that will combine with Sandy|
|Red X's my track|
|X's are energy on Satellite, Lots of moisture for Sandy to work with|
|Not only will this field expand, it will intensify|
|Valid Sunday 8 am-Monday 8 am|
|Valid Monday 8 am-Tuesday 8 am|
|GFS six hour snowfall accumulations. I think DC sees some flakes|
A long duration of onshore winds will force significant storm surge into the the beaches of Long Island, Northern New Jersey and Southern New England. Even Northern New England will see moderate water rises. Waves offshore are forecast to on the order of 40 feet. Throw in a high tide and coastal residents have a disaster on their hands. There is a Weather Channel program called "It Could Happen Tomorrow" on New York City being hit from the Southeast by a major Hurricane. This system might be as close as it gets to that scenario.
|Click to enlarge. Red circle shows where worst coastal flooding will be. Everywhere sees awful beach erosion|
There is a full moon so tides will already be 20% higher. Even worse is that the October full moon (Harvest Moon) has the strongest effect on tides. Coastal communities must seriously consider evacuations. If you live on Cape Cod and want to leave do so ASAP.
Finally the wind speeds. Residents along the coast will have to deal with dangerous winds and major surge. Further inland the wind speeds are the major issue. When compared to Hurricane Irene last year, she does not compare to Sandy. I lost power for 5 days during Irene. Our trees have been weakened by Irene and the October Snowstorm last year. Further this will produce winds of Tropical Storm force for 24-36 hours. Hurricane force gusts (or sustained in some areas) will be felt for roughly 12 hours. We didn't see a single Hurricane force gust in MA during Irene. Block Island gusted to 79. I think Block Island or Blue Hill gust well over 100. I set the over/under at 115 mph. Here is my support for this forecast
|GFS 900 mb winds Sunday morning 2 am, maps from Dr. Ryan Maue and Weatherbell|
|Sunday 8 PM. Tropical Storm force gusts begin|
|Very similar set up. Look at the size of this storm.|
|Slowly moving, so water just piling up offshore, waves building|
|GFS Monday 8 PM.|
|EURO Monday 8 pm|
Finally GFS Tuesday at 2 am.
|Still Hurricane force gusts for SNE|
Tuesday will still be windy as its unknown how exactly Sandy reacts once over land. Some model guidance suggest a loop over NY state and then back out to sea. We can fine tune that later today or tomorrow. Folks I expect power to be out for a significant period of time. The stores will be mobbed today but get what you need. Take loose furniture inside, tie down anything you do not want to blow away. If you sleep in a bedroom in which a large tree could fall on, move to a safer place in the house. I think thats all. Any questions leave a comment here, on facebook, or tweet me @zgreenwx. Thank you for your time.