Sandy Aftermath…October 30th, 2012 at 8:45 pm by Tony Petrarca under General Talk, Tony's Pinpoint Weather Blog
After a very busy 5 Days ( we started to get concerned in the weather center last week), things are calmer now. Wind gusts were impressive with the storm, as high as 86 mph on south shore in gusts. At one point the wind was sustained at 64 mph in Westerly.In the weather center, our meteorologist were looking at wind speed forecast data from various computer models. While the computer wind speed forecasts near the ground were modest for the south shore, what really caught our attention was zone of very strong winds along the coast at 1500 meters above ground….115 mph….wow! It was our thinking that,while not all of that 115 mph wind magnitude would reach ground level, at least 50-70% of it would. This is why we went with a forecast of hurricane fore winds on the south shore.
What had me most concerned was the storm surge potential….this why we were using the following forecast graphic below very often on our broadcast, (and we don’t use this depiction often unless its absolutely necessary)
Based on an already astronomically high tide (full moon), the wind speeds we were forecasting along and offshore, plus the trajectory of the wind (becoming onshore)…this was all pointing to a serious surge potential. Other factors for determining surge include the duration of the wind, the approach angle of the storm (from southeast to northwest), past surge history, and lastly the geography of our coastline and Narragansett bay. All of this was factored by our weather team to come up with our early warning forecast for the coastal surge.
The photo below is along the south shore the next day…evidence of the water surge.
Photo from Providence Journal Staffer G. Wayne Miller