Time-lapse animation of Sandy Oct-28 from geostationary orbit, 1 frame per minute, 11 hours of daylight. Although “only” a category 1 hurricane, this superstorm has enormous size. Tropical storm force winds extend out over an area 900 miles in diameter.
Living in South Florida makes you alert to tropical storms during hurricane season from May to November. Exactly 7 years ago, at the end of October 2005, the eye of category 3 hurricane Wilma swept over our home in West Palm Beach in South Florida – the most powerful natural weather event I have ever witnessed. After avoiding a direct hit since then, we got a massive rain event from Isaac earlier this year, but again avoided a direct hit. To be sure, often the flooding associated with hurricanes is worse than the wind damage. For example, when hurricane Katrina hit New Orleans in August 2005, most of the devastation came from flooding after the levees were breached. But the first question is always where the storms will make landfall and how strong they are when they hit your area.
Tropical storms are being tracked and forecast in great detail, in particular by the National Hurricane Center of the National Weather Service. There are many great visualizations illustrating the path, windspeed, rainfall, extent of tropical storm force winds, etc. Due to the convenience for browsing, I have almost completely switched to following hurricane or weather updates from the iPad. (In this case I’m using the Hurr Tracker app from EZ Apps.)
Last week a new tropical storm emerged in the Carribean and was named ‘Sandy’. A few days ago with Sandy’s center over the Bahamas, the path looked like this:
Note the use of color for wind speed and the cone of uncertainty in the lower segment, as well as the rings around the center indicating the size of the area with storm-force winds.
Naturally curious whether South Florida was likely to get hit, another image gave us some relief:
Now a few days later, while we did get some strong northerly winds and pounding surf leading to beach erosion, Sandy was not a particularly disturbing event for South Florida. At the same time, however, Sandy is forecast to make landfall on the Jersey shore within about 24 hours during the night from Monday to Tuesday.
One interesting set of maps with a color code displaying the probability of an area experiencing winds of a certain speed, say at least tropical storm force winds (>= 39 mph). The following map was issued this afternoon and indicates the very large area (mostly offshore) with near 100% probability of exceeding tropical storm force winds in purple.
This indicates how large Sandy is – an area the size of Texas with tropical storm force winds! Meteorologists are concerned for the Northeast due to Sandy converging with two other weather events, a storm from the West and cold air coming down from the North. This is expected to intensify the weather system, similar to the Perfect Storm of 1991. Due to the timing around Halloween this is why Sandy was also called a ‘Frankenstorm’.
One of the most chilling pictures is this animated GIF from WeatherBELL. A story in the Atlantic earlier today writes this:
Dr. Ryan Maue, a meteorologist at WeatherBELL, put out this animated GIF of the storm’s approach yesterday. “This is unprecedented –absolutely stunning upper-level configuration pinwheeling #Sandy on-shore like ping-pong ball,” he tweeted. It shows how cold air to the north and west of the storm spin Sandy into the mid-atlantic coastline.
(Click the image if the animation doesn’t play in your browser.)
Understandably this forecast of superstorm Sandy has the authorities worried. The full moon tomorrow exacerbates the tides and New York City is expecting up to 11 ft storm surge. Cities across the Northeast are taking precautions as of this writing. For example, the New York City subway metro transit system is shutting down tonight and several hundred thousand people in low-lying coastal areas are under mandatory evacuation order. More than 5000 flights to the area on Monday have been cancelled. Take a look at the expected 5 day precipitation forecast in the Northeast. Some areas may get up to 10 inches of rain and/or snow!
The first priority is to use such visualizations to communicate the weather impact and allow people to take necessary precautions. One can use similar hurricane charts to visualize other uncertain events, such as the future outcomes of development projects. We will look at this in an upcoming post on this Blog.
Addendum 11/4/12: The NYTimes has provided some interactive graphics detailing the location and size of power outages caused by superstorm Sandy in the New York and New Jersey area. The New York City outages have been summarized in this chart, normalized to the percentage of all customers. As can be seen, the efforts to restore power over the first 6 days have been fairly successful, especially in Manhattan and Staten Island, less so in Westchester.