bluewave Posted January 23, 2012 Share Posted January 23, 2012 The milder winter pattern since the AMO switched positive in 1995 has been a dramatic change for our area. The previous -AMO period from 1977 through 1994 featured colder winter temperatures in our region. The January pattern in the Arctic looks much different from 1995 through the current day. The colder years featured more blocking north of Alaska than we have been seeing lately. The recent blocking near Greenland created the pattern necessary for the record snowfall since then. January 1994 was the last temperature reading in NYC below zero. We came close in January 2004 but the arctic outbreak was weaker than we saw back in 1994. The January block was in place during both those months north of Alaska. I put together some NYC winter temperature stats since 1994. Winter....Days below 32...Lows below 10 degrees...Lows below 5 degrees...Lows below zero 93-94...25...9..5...1 94-95...8.....2..0...0 95-96...25...4..0...0 96-97...6.....2..0...0 97-98...2.....0..0...0 98-99..9......1..0...0 99-00..17....4..1...0 00-01..11....0...0..0 01-02..2......0...0..0 02-03..22....6...0..0 03-04..25....8...3..0 04-05..15....8...0..0 05-06..6......0...0...0 06-07..16....1...0...0 07-08..5......0...0....0 08-09...20...2...0....0 09-10...15...0...0....0 10-11...18...1...0....0 11-12....3....0...0.....0...* so far Link to comment Share on other sites More sharing options...
Brian5671 Posted January 23, 2012 Share Posted January 23, 2012 Excellent discussion-when would the AMO switch back? also interesting that since 1995, the snowfall has increased dramatically for the area especial this decade...(due to the block as you point out) Link to comment Share on other sites More sharing options...
uncle W Posted January 23, 2012 Share Posted January 23, 2012 here are some more temperature stats for NYC...days with a max in the teens...the coldest max...days with a max 32 or lower...consecutive days with a max 32 or lower... more stats here...NYC hasn't seen a max in the teens since 2009... http://www.americanwx.com/bb/index.php/topic/30291-nyc-winter-climate-stats/ Year..... days max...days max 32 or below/consecutive days... 2011-12...0....27.............5............2 2010-11...0....23...........22............4 2009-10...0....20...........17............3 2008-09...1....16...........22............3 2007-08...0....20.............6............2 2006-07...1....18...........18............9 2005-06...0....24.............9............2 2004-05...2....18...........18............9 2003-04...4....15...........26............9 2002-03...1....15...........31..........12 2001-02...0....31.............3............2 2000-01...0....25...........20..........13 1999-00...1....19...........18............7 1998-99...0....25...........13............3 1997-98...0....29.............3............2 1996-97...1....17...........11............3 1995-96...3....17...........30............9 1994-95...0....20...........11............5 1993-94...5....10...........31............5 1992-93...0....27.............7............3 1991-92...0....23.............9............2 1990-91...0....20.............7............1 1989-90...1....18...........19............9 1988-89...0....20...........19............3 1987-88...1....17...........19............7 1986-87...1....19...........11............5 1985-86...0....22...........19............4 1984-85...1......9...........18............5 1983-84...3....13...........29............8 1982-83...0....21...........13............4 1981-82...6....15...........20............6 1980-81...3....14...........30..........11 1979-80...0....21...........19............5 1978-79...6....13...........26..........11 1977-78...0....21...........42..........12 1976-77...5....12...........45............9 1975-76...2....15...........20............3 1974-75...0....27.............8............2 1973-74...0....22...........23............3 1972-73...1....18...........13............4 1971-72...1....15...........17............5 1970-71...4....12...........25............5 1969-70...3....14...........27............6 1968-69...0....22...........18............3 1967-68...4....13...........22............9 1966-67...1....16...........25............6 1965-66...1....19...........14............2 1964-65...3....16...........22............5 1963-64...0....22...........18............7 1962-63...1....13...........29............7 1961-62...0....24...........16............4 1960-61...2....19...........27..........16 1959-60...0....23...........15............3 1958-59...0....22...........26..........10 1957-58...2....10...........21..........12 1956-57...1....12...........13............6 1955-56...1....18...........20............4 1954-55...1....17...........16............4 1953-54...0....21...........13............4 1952-53...0....29.............2............1 1951-52...0....20...........13............3 1950-51...0....20...........14............3 1949-50...0....22...........12............3 1948-49...0....22.............9............4 1947-48...2....18...........32..........10 ...................................................................... 1942-43...2......8............28...........5 1935-36...4....16...........39..........12 1934-35...5....16...........24............6 1933-34...6......8............38...........9 1917-18.12......2............45.........10 ......................................................................................................................................... Link to comment Share on other sites More sharing options...
bluewave Posted January 23, 2012 Author Share Posted January 23, 2012 Excellent discussion-when would the AMO switch back? also interesting that since 1995, the snowfall has increased dramatically for the area especial this decade...(due to the block as you point out) Thanks, you can see how long the AMO phases have been in the past. The other thing is that the changes have been occurring against a general long term warming trend . January NYC temperatures Winter NYC temperatures The overall pattern has been getting warmer, but you can see that the last long stretch without below zero readings in NYC happened during the last +AMO era through the 40's and 50's. I guess the much colder climate made it easier to go below zero especially back before 1940. http://www.erh.noaa....ow0degdays.html here are some more temperature stats for NYC...days with a max in the teens...the coldest max...days with a max 32 or lower...consecutive days with a max 32 or lower... more stats here...NYC hasn't seen a max in the teens since 2009... http://www.americanw...-climate-stats/ Thanks for adding those. Link to comment Share on other sites More sharing options...
Isotherm Posted January 23, 2012 Share Posted January 23, 2012 The milder winter pattern since the AMO switched positive in 1995 has been a dramatic change for our area. The previous -AMO period from 1977 through 1994 featured colder winter temperatures in our region. The January pattern in the Arctic looks much different from 1995 through the current day. The colder years featured more blocking north of Alaska than we have been seeing lately. The recent blocking near Greenland created the pattern necessary for the record snowfall since then. January 1994 was the last temperature reading in NYC below zero. We came close in January 2004 but the arctic outbreak was weaker than we saw back in 1994. The January block was in place during both those months north of Alaska. I put together some NYC winter temperature stats since 1994. Winter....Days below 32...Lows below 10 degrees...Lows below 5 degrees...Lows below zero 93-94...25...9..5...1 94-95...8.....2..0...0 95-96...25...4..0...0 96-97...6.....2..0...0 97-98...2.....0..0...0 98-99..9......1..0...0 99-00..17....4..1...0 00-01..11....0...0..0 01-02..2......0...0..0 02-03..22....6...0..0 03-04..25....8...3..0 04-05..15....8...0..0 05-06..6......0...0...0 06-07..16....1...0...0 07-08..5......0...0....0 08-09...20...2...0....0 09-10...15...0...0....0 10-11...18...1...0....0 11-12....3....0...0.....0...* so far Chris, I think that first map you posted is probably heavily skewed by the 1977-1980, which occurred at the tail end of the -PDO phase, when we reached the "tank" so to speak in terms of cold air globally. US January 1977-1980: US January 1981-1994: Thus I think the PDO being negative 1977-1979 then positive thereafter was by far the most important factor in warming winters up. But don't get me wrong I do believe the AMO certainly plays a role in enhancing colder winters. But the cold of the 60s/70s was largely due to the -PDO and -AO/NAO in my opinion. I tend to think the AMO is a more influential index for the warm season months, although it does have an impact on the winter. Re the current AMO -- note how the atlantic has really cooled over the past year: Last year Now Current AMO value is actually slightly negative. 2011 values. 2011 0.182 0.144 0.092 0.128 0.181 0.215 0.136 0.189 0.192 0.103 -0.035 -0.010 It's probably not long term as the AMO decadal warm phase should last another 10 years, but the cooler Atlantic has implications for our spring, summer weather and the hurricane season. Link to comment Share on other sites More sharing options...
bluewave Posted January 23, 2012 Author Share Posted January 23, 2012 Chris, I think that first map you posted is probably heavily skewed by the 1977-1980, which occurred at the tail end of the -PDO phase, when we reached the "tank" so to speak in terms of cold air globally. US January 1977-1980: US January 1981-1994: Thus I think the PDO being negative 1977-1979 then positive thereafter was by far the most important factor in warming winters up. But don't get me wrong I do believe the AMO certainly plays a role in enhancing colder winters. But the cold of the 60s/70s was largely due to the -PDO and -AO/NAO in my opinion. I tend to think the AMO is a more influential index for the warm season months, although it does have an impact on the winter. Re the current AMO -- note how the atlantic has really cooled over the past year: Last year Now Current AMO value is actually slightly negative. 2011 values. 2011 0.182 0.144 0.092 0.128 0.181 0.215 0.136 0.189 0.192 0.103 -0.035 -0.010 It's probably not long term as the AMO decadal warm phase should last another 10 years, but the cooler Atlantic has implications for our spring, summer weather and the hurricane season. Nice post. I like using the AMO a bit more than the other indices although it's one piece of the puzzle. Yes, the late 70's did skew it toward colder, but they would skew any grouping due to the execptional nature of the cold. The PDO actually went positive in 1977 after the long really low readings of the early 70's. I think that those weak back to back Ninos also played a role along with the great blocking patterns. http://jisao.washing.../pdo/PDO.latest http://www.esrl.noaa...on.us.long.data You can still see the ridge north of Alaska from the 1980-1994 time frame. The super +AO of the late 80's and early 90's skewed it lower until the very cold and snowy winter of 93-94. We were still able to manage the really cold December of 1989 during that era. Link to comment Share on other sites More sharing options...
Isotherm Posted January 24, 2012 Share Posted January 24, 2012 Nice post. I like using the AMO a bit more than the other indices although it's one piece of the puzzle. Yes, the late 70's did skew it toward colder, but they would skew any grouping due to the execptional nature of the cold. The PDO actually went positive in 1977 after the long really low readings of the early 70's. I think that those weak back to back Ninos also played a role along with the great blocking patterns. http://jisao.washing.../pdo/PDO.latest http://www.esrl.noaa...on.us.long.data You can still see the ridge north of Alaska from the 1980-1994 time frame. The super +AO of the late 80's and early 90's skewed it lower until the very cold and snowy winter of 93-94. We were still able to manage the really cold December of 1989 during that era. Good points, I agree. The weak ninos of the late 70s coupled with strongly negative NAO/AO and the backdrop of the PDO signal yielded a perfect storm of factors which led to the historic 1976-1979 winters. Link to comment Share on other sites More sharing options...
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