Wednesday, October 27, 2010

Battle of the Bombs: Northwest Contests Record Storm Claim

October 29 Update: The status of the pressure record has been updated as a result of further review.

Original post:
University of Washington meteorologist Cliff Mass (h/t to American Meteorological Society's Front Page blog) is disputing claims that yesterday's storm was the most intense non-tropical system over the continental U.S. He points out that some storms in the past over the Pacific Northwest have had stronger winds, because they had stronger pressure gradients (rate of change of pressure with distance):
There has been a lot of media attention regarding the storm in the Midwest with claims it was the strongest (lowest pressure) non-tropical storm in U.S history. DON'T BELIEVE IT FOR A MOMENT. This is classic eastern U.S. media myopia....we have had the deepest and most violent storms!
He doesn't provide evidence of lower barometric pressures than yesterday's storm over land, however. Dr. Jeff Masters points out at Weather Underground:
The modern Pacific Coast record is 28.40" (962mb) at Quillayute, Washington on Dec. 1, 1987. An older reading, taken on a ship offshore from the mouth of the Umpqua River in Oregon during the famous "Storm King" event on January 9, 1880, is tied with yesterday's 28.20" (955 mb.)

The lowest non-hurricane barometric pressure reading in the lower 48 states is 28.10" (952 mb) measured at Bridgehampton, New York (Long Island) during an amazing nor'easter on March 1, 1914 (see Kocin and Uccellini, "Northeast Snowstorms; Vol. 2., p. 324, American Meteorological Society, 2004.) The lowest non-hurricane barometric pressure reading from anywhere in the United States was a 27.35" (927 mb) reading at Dutch Harbor, Alaska on Oct. 25, 1977. The lowest hurricane pressure reading was the 26.34" (892 mb) recorded in 1935 during the Great Labor Day Hurricane.

1 comment:

Anonymous said...

If it's non-hurricane pressure exclusively, let's not forget the 100mb drop (~900mb SLP range) measured by Tim Samaras' probe in the middle of an F4 tornado.

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