In this post I want to focus solely on the winds. I'd really like to take a step back and point out the magnitude and duration of the wind that we're going to be dealing with across the Northeast tomorrow.
Throughout the post I will be referring to the high resolution NAM computer model, which is a U.S. based model that is very accurate in "short range" forecast periods of 48 to 60 hours into the future.
The first image is valid 8am EDT tomorrow morning and is zoomed in on the NYC sector:
The wind scale in knots is shown at the right of each image. You take knots (kts) and multiply by 1.15 to reach miles per hour (mph). The model is looking just above the surface level, so I will be rounding down by 10 mph in the estimates that will be provided below to better reflect the surface level wind estimates.
Here are some wind speed forecasts by major city based on the above model and valid at 8am EDT Monday (as shown in the first image):
New York City: 50-55 mph
Islip (Long Island): 60-65 mph
Atlantic City: 60-65 mph
Philadelphia: 45-50 mph
Baltimore/Washington: 35-40 mph
Providence: 55-60 mph
Boston: 45-50 mph
The next image is valid 3 hours later, 11am EDT:
Here are the wind speed forecasts for the same locations for 11am EDT:
New York City: 60-65 mph
Islip (Long Island): 70-75 mph
Atlantic City: 60-65 mph
Philadelphia: 60-65 mph
Baltimore/Washington: 40-45 mph
Providence: 70-75 mph
Boston: 55-60 mph
By 2pm EDT, hurricane force winds are forecast at NYC, with very strong winds spreading along the adjacent coast and Long Island:
Here are the wind speed estimates for 2pm EDT:
New York City: 65-70 mph
Islip (Long Island): 85-90 mph
Atlantic City: 55-60 mph
Philadelphia: 55-60 mph
Baltimore/Washington: 50-55 mph
Providence: 80-85 mph
Boston: 70-75 mph
Keep in mind, at this point we haven't even had landfall of the center yet, and winds have been 50+ mph at multiple locations for 6 hours or more!
Jumping ahead to 8pm EDT, this model is forecasting the center to be very nearly landfall along the middle Jersey coast:
Here are the wind speed estimates for 8pm EDT, 12 hours after we began:
New York City: 75-80 mph
Islip (Long Island): 90-95 mph
Atlantic City: 55-60 mph
Philadelphia: 55-60 mph
Baltimore/Washington: 55-60 mph
Providence: 70-75 mph
Boston: 65-70 mph
The video clip below pulls the model imagery together into a loop for the period 8am EDT Monday to 11am EDT Tuesday:
Keep in mind that we haven't covered gusts with any of the above, so you can add an additional 20 mph, and we haven't accounted for the stronger winds in high rise buildings. You can add about 20 mph for every 30 floors of a building. So, take the NYC estimate of 75-80 mph at 8pm. That would yield 95-100 mph winds at the 31st floor of a building, and 115-120 mph winds at the 61st floor of the same building. Thus, the widespread potential for window breakage that we've been talking about for some time now.
I hope this will give everyone in the path of Sandy a clear picture of just how strong, damaging and long lasting the winds will be. You should rush your preparations to completion in this area, because as you can see, strong winds will spread into the region shortly after sunrise tomorrow, and will last for 12-24 hours in most places. As a result, wind damage will be widespread:
...which will lead to widespread power outages, some of which are likely to last for weeks due to the widespread nature of this storm:
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