Wednesday, November 12, 2014

Bering Sea Superstorm Among the Strongest Extratropical Cyclones on Record

The Bering Sea Superstorm has developed and is now weakening, but not after becoming one of the strongest extratropical cyclones on record in the North Pacific.
Partially derived from former Super Typhoon Nuri, the typhoon's remnants joined up with the polar jet stream and a very strong disturbance in the mid-latitude belt of westerly winds, leading to explosive development of low pressure.
As a result, the Bering Sea storm whipped up hurricane-force winds in parts of Alaska's Aleutian Islands as well as giant waves in the Bering Sea over the weekend.
On Saturday morning, U.S. time, the low was analyzed by NOAA to have a pressure of 924 millibars. The National Weather Service in Anchorage said the storm may be one of the five deepest extratropical (non-tropical) low pressure systems on record in the North Pacific, as determined by minimum pressure.
However, the 924-millibar analysis is an estimate. The lowest pressure directly measured in this storm was 929.8 millibars at a buoy northwest of Attu in the far western Aleutians. This is not as low as the pressures measured in a similar storm on October 25, 1977, when a record-setting 925-millibar pressure reading was recorded on a ship docked at Dutch Harbor, Alaska. Two other storms have produced directly-measured pressures lower than 929.8 millibars over the extratropical North Pacific.
The buoy measurement this past weekend was not right in the center of the storm, based on wind speeds and directions measured at the buoy. Hence, NOAA estimated the central pressure at 924 millibars.

http://www.weather.com/news/weather-hurricanes/bering-sea-superstorm-alaska-aleutians-20141105

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