After another full day of investigation regarding the potential for setting a CONUS record low pressure during the event on Tuesday 26 October 2010, which has involved contributions from staff at WFO Duluth, MN, WFO Twin Cities/Chanhassen, MN, NWS Central Region Headquarters, the NWS Communications Office, and the National Climatic Data Center, here is where we stand:
We still are confident in the 955.2 mb (28.21 inches of mercury) recorded at Bigfork, MN at 513 PM (2213 UTC) 26 October 2010 as the lowest pressure with this storm. This value/location also establishes a new record for the state of Minnesota.
As you are aware, there continues to be intense interest regarding this event and whether this value establishes a new continental lower 48 states record low pressure for a non-tropical weather system as recorded at a land-based observing station in the CONUS. After a long investigation, and with input from the National Climatic Data Center, the 955.2 mb value does NOT set a new record low pressure for the lower 48 United States.
NCDC has verified two east coast storms with lower pressure as published in their Climate Data Publication:
955.0 mb (28.20 inches of mercury) 13 January 1913 at Canton, New York
955.0 mb (28.20 inches of mercury) 7 March 1932 at Block Island, Rhode Island
NCDC has also verified this pressure reading:
956.3 mb (28.24 inches of mercury) 16 December 1916 at Eastport, Maine
Thus, it appears that the 26 October 2010 storm will have the second lowest recorded pressure at a land-based observation station for CONUS non-tropical low pressure system. It is, without question, the lowest recorded pressure for any storm of record in the central part of the United States (i.e. east of the Sierra Mountains and west of the Appalachians)
WFO Duluth has created a webpage regarding the pressure records that can be accessed here with more information: