Carbin - NOAA Federal Thu, Jan 29, 2015 at 3:31 PM Reply-To: Gregory Carbin - NOAA Federal To: MAP@listserv.albany.edu Hello Mappers, While watching the atmospheric events unfolding over the Northeast this week, I began to wonder how to rank the 2015-01-26/27 Blizzard/Nor’easter with archived hourly surface observations and the duration of wind and snow events from those obs. Using SPC’s surface observation archive starting in 1970, I gathered all available DJF hourly surface observations from NY, NJ, CT, RI, MA, VT, NH, and ME where the following conditions were met: sustained wind speed > 25 mph (blizzard is defined as ~35 mph and ~¼ mile visibility) AND any intensity of falling/blowing snow Additionally applying visibility and/or gust criteria to the search filter would be preferable but the archived observations available prior to 1999 do not include these two parameters. I wrote a Python routine to squeeze out the starting date and duration (in hours) when the above conditions were met at any observation site for two or more consecutive hours. Once a time series was established for at least two consecutive hours at any site, I allowed for one hour gaps in the series to account for missing hourly observations, or a brief lull in higher observed wind speeds. Caveats for these results include not accounting for manned vs. ASOS-era observations, part-time stations, and missing data. Keeping these issues in mind, it still appears there were at least a few locations where extreme winter conditions lasted longer for this event than other significant prior events, especially across southeast New England. Here are some of the new “storm duration” records established on 2015-01-27, along with the earliest duration event for this station in the record: #1 ACK 026-hours starting: 2015-01-27 00:00:00, earliest duration event date: 1993-02-28 #1 HVN 008-hours starting: 2015-01-27 03:00:00, earliest duration event date: 1978-01-09 #1 HYA 009-hours starting: 2015-01-27 12:00:00, earliest duration event date: 1973-02-11 #1 PVD* 012-hours starting: 2015-01-27 02:00:00, earliest duration event date: 1973-02-11 PVD, at 12-hours, tied with two other events (see below). For comparison, here are a few “storm duration” records at stations a bit to the southwest of those shown above, for the Great Blizzard of February 1978: #1 BDR 014-hours starting: 1978-02-06 19:00:00 #1 GON 013-hours starting: 1978-02-06 15:00:00 #1 JFK 019-hours starting: 1978-02-06 14:00:00 #1 NZW 013-hours starting: 1978-02-06 19:00:00 For the new duration record holders (HVN, HYA, and PVD), here are the previous duration records, and the duration and rank (not accounting for ties) of the Great Blizzard of February 1978 at those locations: #2 HVN 007-hours starting: 2010-12-26 21:00:00, 1978-02-06 002-hours, ranked 4th #2 HYA 008-hours starting: 2003-01-02 09:00:00, 1978-02-06, 004-hours, ranked 6th #2 PVD 012-hours starting: 2005-01-23 08:00:00 #2 PVD 012-hours starting: 2003-12-06 17:00:00, 1978-02-06, 006-hours, ranked 4th For the major airports (BOS, JFK, LGA), with relatively long records, here are the top ranked duration events, and the rank for the 2015-01-27 event: #1 BOS 025-hours starting: 1981-12-06 14:00:00, 2015-01-27, 002-hours, ranked 14th #1 BOS 025-hours starting: 1978-02-07 01:00:00 (tie) #1 JFK 019-hours starting: 1978-02-06 14:00:00, 2015-01-27, 000-hours NO EVENT #1 LGA 012-hours starting: 2003-02-17 07:00:00, 2015-01-27, 000-hours NO EVENT Mount Washington, AKA “The Rock Pile”, provides a great frame of reference with respect to long duration extreme winter weather. Here are the longest stretches (in excess of 26 hours) at 6,288 feet above sea level for DJF. Interestingly, the Great Blizzard of February 1978 does not make the MWN list (again, some data may be missing), but the Great Blizzard of January 2015 does, at only one hour more than the duration experienced at Nantucket (ACK)! 060-hours starting: 2010-02-24 08:00:00 040-hours starting: 2003-12-12 05:00:00 040-hours starting: 2003-12-08 10:00:00 040-hours starting: 2003-12-06 13:00:00 037-hours starting: 1979-01-25 11:00:00 036-hours starting: 2003-01-03 21:00:00 034-hours starting: 1975-01-29 17:00:00 034-hours starting: 1975-01-27 05:00:00 034-hours starting: 1975-01-25 14:00:00 033-hours starting: 2012-02-27 23:00:00 033-hours starting: 2012-02-24 19:00:00 033-hours starting: 1985-01-22 08:00:00 032-hours starting: 2005-02-10 06:00:00 031-hours starting: 1979-01-29 14:00:00 029-hours starting: 2010-12-22 10:00:00 029-hours starting: 2010-12-06 10:00:00 027-hours starting: 2015-01-27 07:00:00 027-hours starting: 2010-12-26 22:00:00 027-hours starting: 1995-02-28 20:00:00 027-hours starting: 1995-02-27 14:00:00 -Greg