Powerful Nor'easter poised to hammer Eastern U.S.

An intense and very wet Nor'easter is gathering strength over the Gulf of Mexico, and stands poised to generate heavy snow and possible blizzard conditions tonight through Saturday from the Smoky Mountains to New England, including the major cities of Washington D.C., Philadelphia, and New York City. The storm has already dumped up to three inches of snow in western North Carolina, and a foot or more of snow is likely over the mountains of North Carolina, Virginia, and Tennessee. Flooding from the storms' heavy rains will be a problem in Mississippi and Alabama, where up to six inches have fallen (Figure 1).


Figure 1. Total rainfall from the Dec 18 - 19 Nor'easter, as estimated by Birmingham, Alabama radar.

Tornadoes threaten Florida
Severe thunderstorms capable of generating tornadoes have developed along the storm's cold front, which is advancing over Florida today. The Storm Prediction Center has placed most of Florida in its "Slight Risk" area for severe weather, and tornado warnings have already been issued for Homestead and Naples this morning, though no confirmed tornadoes have resulted from the warnings thus far. The threat of tornadoes will continue through mid-afternoon over Florida, then gradually decrease late this afternoon as the low-level winds align with the upper-level winds, creating less of the change of wind direction with height typically needed to create tornadoes.

You can track today's storm with our interactive tornado map and severe weather map.

Copenhagen
Our Climate Change expert, Dr. Ricky Rood, has left Copenhagen's COP15 climate change talks to resume his slightly saner life as a professor at the University of Michigan. His latest post, called The Party is Over: Copenhagen Devolved presents a fascinating look at what it was like to be at the conference, and what was (and was not) accomplished there. I'll be posting my own summary of the legacy of the Copenhagen talks early next week.

Jeff Masters