Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.
By: Dr. Jeff Masters , 3:04 PM GMT on November 27, 2013
The busiest travel day of the year in the U.S. is at hand this Wednesday, and Winter Storm Boreas continues to slow travel over much of the Eastern U.S. with a nasty mix of snow, sleet, freezing rain, heavy rain, and high winds. Dangerous snowy and icy travel will continue to cause trouble in many of the high elevation areas from the Smoky Mountains to Maine Wednesday. The greatest snows of 6+ inches will fall in the Adirondack Mountains of New York, and strong northwest winds will bring lake effects of 2 - 4" to Rochester, NY and much of the south shore of Lake Ontario.
Figure 1. Winter Storm Boreas heads up the Eastern U.S. on Tuesday, November 26, 2013. Image credit: NASA Earth Observatory.
A very wet and windy storm for the U.S.
Boreas has tapped into an "Atmospheric River" of very moist air from the Gulf of Mexico, and the amount of water vapor available to make rain (the "Precipitable Water") was near record highs (for November) along the East Coast Tuesday night and Wednesday morning. The high elevation areas of South Carolina, North Carolina, and Virginia received more than 3" of rain in a 24-hour period ending at 8 am EST Wednesday, and both New York City and Philadelphia got more than 2". The heavy rains, combined with cloud ceilings as low as 500 feet and wind gusts as high as 40 mph, have slowed air traffic landing at New York's La Guardia airport and in Philadelphia. The FAA web site warned of 1 hour delays for flights arriving in Philadelphia, and 2 hours at La Guardia, on Wednesday morning. However, none of the other 38 major airports in the U.S. was reporting delays in excess of over 15 minutes Wednesday morning, and Winter Storm Boreas has been more of a nuisance than a travel disaster.
Accompanying Boreas' heavy rains along the coast have been high winds; a Wind Advisory for sustained winds of 20 - 30 mph, with gusts up to 60 mph, is in place along much of the coast from New Jersey to Maine. While the rains will be gone on Thursday in time for the Macy's Thanksgiving Day Parade in New York City, winds will still be strong, making conditions potentially too dangerous for the balloons used in the parade. These balloons are not allowed to fly if the city experiences sustained winds of 23 mph with gusts of 34 mph. The forecast calls for sustained winds of 15 - 25 mph gusting to 40 mph on Thursday.
Figure 2. Observed precipitation for the 24-hour period ending Wednesday, November 27, 2013. Image credit: NOAA.
Lehar weakens to a tropical storm; threat to India lessens
Cyclone Lehar has met up with dry air and strong upper level winds that have torn into the storm, reducing it to a tropical storm with 65 mph winds at it heads west-northwest at 17 mph towards India's Bay of Bengal coast. Satellite images show that Lehar is much less organized than before, with a much diminished area of heavy thunderstorms. Cooler waters near shore and continued dry air and wind shear as the storm nears landfall will keep Lehar below hurricane strength until landfall. Landfall is expected to occur between 06 - 12 UTC Thursday, November 28, in the Andhra Pradesh state of India.
Have a great Thanksgiving, everyone, and I'll be back Friday with a new post.
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