On Wednesday morning Tropical Storm Arthur was still gaining strength off the east coast of Florida. It is forecast to gain hurricane strength by midday Thursday while moving to the north over the warm waters of the Gulf Stream.
An approaching cold front from the Midwest combined with strengthening high pressure over the subtropical Atlantic will steer Arthur northward then off to the northeast on Friday while increasing its forward speed.
On this track the center of then Hurricane Arthur will pass near or just off the Outer Banks of North Carolina late Thursday and out to sea on the Fourth of July. Heavy surf, beach erosion and locally heavy rainfall are the expected impacts along the East Coast.
This year the National Hurricane Center has begun issuing storm surge forecast graphics showing the possible extent and depth of flooding due to the storm. The shaded blue area in the graphic shows areas along the coast that have a 10 percent chance of up to three feet of water over the land. A few spots of shaded yellow indicate a 10 percent chance of flooding in excess of three feet.
While that may sound like a small probability, the force and damage due to storm surge can be devastating even at relatively low water heights. This product will give decision makers and us citizens a visualization of the threat we face from an approaching storm.
Six years ago when we faced Ike, storm surge information was provided as a line or two in the text of the Hurricane Advisory, usually several paragraphs from the top. We've come a long way since then in being able to communicate the threat.
A year or two from now NHC plans to begin issuing Storm Surge Warnings to further highlight the threat to life from this aspect of the hurricane.
For more education on storm surge, check this out: http://noaanhc.wordpress.com/2014/06/17/storm-surge-plain-and-simple-part-1/
And a video can be seen here: https://www.youtube.com/watch?v=Mm4m1kNPS-M&feature=youtu.be