uncle W Posted November 10, 2012 Share Posted November 10, 2012 The Ash Wed. storm had some blocking also... Link to comment Share on other sites More sharing options...
bluewave Posted November 10, 2012 Author Share Posted November 10, 2012 ^The January 1992 Nor'easter, which caused alot damage over the Delmarva region, had block a huge block over SE Canada: The December 1992 Nor'easter, also had a block over SE Canada. It's seems that the most damaging storms for Mid-Atlantic and Northeast, come with strong blocks that develop somewhere over SE Canada: October 1992 had some blocking that month has well: The March 2010 windstorm also had a similar SE Canada blocking pattern to December 1992, but the blocking was stronger and longer duration. There was also record New England flooding for the end of March 2010 with the blocking still in place over the pole. March 2010 December 1992 Link to comment Share on other sites More sharing options...
Dsnowx53 Posted November 10, 2012 Share Posted November 10, 2012 Nate, I tried to quote your post but my phone wouldn't let me. I think he's arguing that weaker jet = more meridional jet instead of a more zonal jet. Weaker jets tend to dip/"rise" more. The mid and upper level winds in the North Atlantic are much weaker in a -NAO than a +NAO. Link to comment Share on other sites More sharing options...
LocoAko Posted November 12, 2012 Share Posted November 12, 2012 This does not make any sense. The lack of a gradient would make the jet weaker, and that would make storms weaker. Strong storm systems occur because of the phasing of powerful shortwaves in an amplified mid-latitude jet stream. If you have less of a temperature differential between the arctic and the tropics, there would be less energy in the jet to phase and yield mid-latitude cyclones. You also can't argue that a warming climate leads to more +NAO states and more -NAO states. There is no physical mechanism that makes the NAO both more positive and more negative at the same time. What you could argue is that the lack of arctic sea ice is causing wave transfer to the stratosphere, as in the propagation of Rossby waves. This theory seems contradictory to the idea of increased Siberian snow cover leading to the warmer stratosphere, but some papers have theorized that the declining arctic sea ice leads to a more -NAO/-AO. You might check out the Fang and Wallace paper from 1994, printed in Journal of Climate. The only problem is that winters following historic sea ice minimums, such as 07-08 and 11-12, had a very positive NAO and AO, so the correlation cannot be that strong. 2007 had the 2nd lowest sea ice on record, and 2011 had the third lowest sea ice on record, yet neither winter had a significant degree of high-latitude blocking. Jennifer Francis has done (and continues to do) a lot of work at this at Rutgers. A weaker jet allows for more meridional flow and more stagnant patterns, as Doug said. Here are some videos about it from AMS and other presentations: (I haven't watched this one and it is very long, but likely very informative: More resources from her on her research: http://marine.rutger...pubs_10-05.html It makes a very convincing case that IMO is hard to argue with, especially with what we've been seeing in recent years... Link to comment Share on other sites More sharing options...
LocoAko Posted November 12, 2012 Share Posted November 12, 2012 Also, here is the published paper version of the above presentation, if this is more your style. http://marine.rutger...L051000_pub.pdf 3. Conclusions[14] In summary, the observational analysis presented in this study provides evidence supporting two hypothesized mechanisms by which Arctic amplification – enhanced Arctic warming relative to that in mid-latitudes – may cause more persistent weather patterns in mid-latitudes that can lead to extreme weather. One effect is a reduced poleward gradient in 1000-500 hPa thicknesses, which weakens the zonal upper-level flow. According to Rossby wave theory, a weaker flow slows the eastward wave progression and tends to follow a higher amplitude trajectory, resulting in slower moving circulation systems. More prolonged weather conditions enhance the probability for extreme weather due to drought, flooding, cold spells, and heat waves. The second effect is a northward elongation of ridge peaks in 500 hPa waves, which amplifies the flow trajectory and further exacerbates the increased probability of slow-moving weather patterns. While Arctic amplification during autumn and winter is largely driven by sea-ice loss and the subsequent transfer of additional energy from the ocean into the high-latitude atmosphere, the increasing tendency for highamplitude patterns in summer is consistent with enhanced warming over high-latitude land caused by earlier snow melt and drying of the soil. Enhanced 500-hPa ridging observed over the eastern N. Atlantic is consistent with more persistent high surface pressure over western Europe. This effect has been implicated as contributing to record heat waves in Europe during recent summers [Jaeger and Seneviratne, 2011]. [15] Can the persistent weather conditions associated with recent severe events such as the snowy winters of 2009/2010 and 2010/2011 in the eastern U.S. and Europe, the historic drought and heat-wave in Texas during summer 2011, or record-breaking rains in the northeast U.S. of summer 2011 be attributed to enhanced high-latitude warming? Particular causes are difficult to implicate, but these sorts of occurrences are consistent with the analysis and mechanism presented in this study. As the Arctic sea-ice cover continues to disappear and the snow cover melts ever earlier over vast regions of Eurasia and North America [brown et al., 2010], it is expected that large-scale circulation patterns throughout the northern hemisphere will become increasingly influenced by Arctic Amplification. Gradual warming of the globe may not be noticed by most, but everyone – either directly or indirectly – will be affected to some degree by changes in the frequency and intensity of extreme weather events as greenhouse gases continue to accumulate in the atmosphere. Further research will elucidate the types, locations, timing, and character of the weather changes, which will provide valuable guidance to decision-makers in vulnerable regions. Link to comment Share on other sites More sharing options...
thewxmann Posted November 12, 2012 Share Posted November 12, 2012 I don't at all believe that man is the cause of climate change, but I'm not stupid. Something is definitely changing. Something is different that is making our storms stronger. Katrina and Rita, sub 900 mb hurricanes. Sandy phasing with a nor'easter and polar jet stream. The tornado outbreak two years ago.... the hurricane season where we had like 30 named storms. I don't know what the cause is, but something is definitely happening that's making our weather more violent. Nah, not necessarily. Have a look at the late 1800's. We had, within a span of <15 years: -The Blizzard of '88 -An exceptionally deadly hurricane season in 1893 (NYC hurricane, Sea Islands hurricane, Cheniere Caminada hurricane) -Perhaps the most violent tornado week in history in late May 1896 (which ended in the St. Louis tornado that killed over 250 people) -The Galveston Hurricane of 1900. ...not to mention numerous other major events in this period (indianola hurricane, New Richmond tornado, etc.) So I would say there is precedence to the high frequency of extreme weather we've had as of late. Link to comment Share on other sites More sharing options...
LongBeachSurfFreak Posted November 12, 2012 Share Posted November 12, 2012 Nate, I tried to quote your post but my phone wouldn't let me. I think he's arguing that weaker jet = more meridional jet instead of a more zonal jet. Weaker jets tend to dip/"rise" more. The mid and upper level winds in the North Atlantic are much weaker in a -NAO than a +NAO. Thanks that's exactly what I meant. Link to comment Share on other sites More sharing options...
uncle W Posted February 25, 2013 Share Posted February 25, 2013 lowest daily winter ao value since 1950...I hope I didn't miss a date...Weather at the time for NYC...season.......value.....date.....1949-50......-2.854.....3/15/50......1.4" 3/14...record cold the beginning of the month...1950-51......-4.353.....12/27/50....3" snow 12/27 and 9 degrees...the biggest snow and coldest temperature of the winter...1951-52......-3.805.....3/4/1952....4" snow 3/2...1952-53......-3.766.....12/27/52....12 degrees is the coldest temp. of the season...4" snow 12/31...1953-54......-3.495.....1/30/54......cold continues...Cold snowy January...1954-55......-3.064.....1/4/55........cold continues...1955-56......-4.564.....2/15/56......1.4" 2/17 and 2/22...Big March snows......1956-57......-4.473.....2/21/57......2.6" snow 3/1...1957-58......-4.030.....3/11/58......snow storms 3/14 and 3/21......1958-59......-4.026.....1/7/59........cold continues...1959-60......-4.108.....1/28/60......18 degrees 2/3 is the coldest temp for Feb...Big March cold and snow.....1960-61......-2.719.....1/10/61......greatest snowy and cold period followed 1/15-2/12.....1961-62......-4.417.....3/4/62........record cold 3/2 and the Ash Wednesday storm 3/6...1962-63......-5.010.....1/21/63......Near record cold 1/23 and 4" snow 1/26...Biggest snow of the season...1963-64......-4.470.....12/20/63....1.4" 12/18...6.6" 12/23-24...11 degrees 12/20 coldest for that month...January Blizzard....1964-65......-3.973.....1/26/65......ice storm 1/24 and continued cold...1965-66......-5.130.....1/28/66......8 degrees is the coldest temp. of the season 1/28...7" on 1/30...1966-67......-4.147.....12/13/66....wet snow and rain 12/13-14 is the start of two weeks of snow and cold...7" snow 12/24-25...1967-68......-3.490.....2/7/68........8 degrees 2/11...Cold and dry continues...1968-69......-5.282.....2/13/69......17 degrees 2/17 is the coldest temp for the month...15" of snow 2/9-10......1969-70......-6.365.....3/5/70........20 degrees 3/10 coldest temp for the month...4" of snow 3/29...1970-71......-2.821.....2/6/71........12 degrees max 2/2...1972-73......-2.044.....12/17/72...24 degrees max 12/17...1973-74......-2.792.....12/19/73...big ice storm 12/16-17...17 degrees 12/19 is the coldest temp of the month...1974-75......-1.695.....12/18/74...some minor cold in a mild month...one of the few times the weather was benign at the ao minimum...1975-76......-3.262.....1/24/76......-1 degrees 1/23 is the coldest temp of the winter...1" of snow 1/23...1976-77......-7.433.....1/15/77......-2 degrees on the 17th is the coldest temp of the winter...5" snow 1/14-15...1977-78......-5.291.....2/5/78........10 degrees 2/5 is the coldest temperature of the season...18" snow 2/6-7......1978-79......-4.387.....1/25/79......Very cold and snowy February......1979-80......-3.705.....1/24/80......continued cold and dry...longest stretch of cold that winter...1980-81......-4.318.....3/4/81........largest snowfall for the winter...8.6" 3/5...1981-82......-3.804.....12/30/81...January 1982 was very cold and snowy...1982-83......-3.410.....2/6/83........4" of snow 2/6 and 18" 2/11-12......1983-84......-3.706.....3/13/84......record cold 3/10...7" snow 3/8-9...1984-85......-6.226.....1/19/85.....-2 degrees 1/21 is the coldest temperature that winter...1985-86......-3.894......2/6/86.......4.5" of snow 2/7 and 2/11...Snowiest period of the winter...1986-87......-3.507.....3/9/87........2" snow 3/12...Near record cold 3/10...1987-88......-2.314.....2/28/88......0.6" 2/27 is the last measurable snow...Thawing after...1988-89......-0.318.....3/4/89........2.5" 3/6 and near record cold 3/7...1989-90......-3.482.....12/10/89...One of the coldest Decembers on record...1990-91......-3.381.....3/9/91.......24 degrees 3/12......1991-92......-2.597.....12/4/91.....0.7" 12/5......1992-93......-2.228.....3/2/93.......Super storm 3/13...Near record cold followed......1993-94......-3.503.....2/24/94.....2.6" 2/23...12 degrees 2/27...Feb KU...1994-95......-3.116.....3/9/95.......20 degrees 3/10 is the coldest temp for the month......1995-96......-4.353.....12/19/95...8" of snow during a very cold period...January blizzard.....1996-97......-3.377.....12/30/96...11 degrees New Years Day....1997-98......-4.269.....1/10/98.....14 degrees New Years day...Coldest of the winter...1998-99......-3.856.....3/10/99......5" snow 3/14-15...17 degrees 3/8 is the coldest temp for the month...1999-00......-2.118.....2/18/00......3" snow and ice 2/22......2000-01......-4.854.....2/25/01......6" snow 2/22 and 17 degrees...coldest for the month...2001-02......-3.293.....12/28/01...Coldest period of the winter followed but benign...2002-03......-3.575.....1/22/03......7 degrees 1/24 is the coldest for the winter... blizzard in February...2003-04......-4.387.....1/17/04......1 degree 1/16 is the coldest temp of the season...6" of snow 1/15...Dec. ...2004-05......-4.337.....2/26/05......6" of snow 2/25 and 8" 2/29...blizzard in January...2005-06......-3.569.....12/5/05......2" snow 12/4...1" 2/6 and 6" 12/9...14 degrees 12/14 is the coldest temp of the season......2006-07......-2.184.....2/4/07........8 degrees 2/5 is the coldest for the winter...2007-08......-2.468.....1/2/08........12 degrees 1/3 second coldest of the winter...2008-09......-3.178.....2/3/09........4.3" 2/5 12 degrees...2009-10......-5.821.....12/21/09...11" snow 12/19-20......16 degrees 12/18 is the coldest for the month...2010-11......-5.172.....12/18/10...20" of snow 12/26-27...23 max on 12/14...2011-12......-3.451.....1/28/12...4.3" of snow 1/21... largest snowfall of the season... 2012-13......-4.802.....3/19/13...3.0" of snow 3/18..... the AO was at its lowest point on 12/8...It is one of the few times we didn't see any real winter weather when the AO was at its lowest...We still have time for it to drop below that number...The AO has been mostly negative this year but the nao was slightly positive... 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bluewave Posted February 25, 2013 Author Share Posted February 25, 2013 ^^^^^^^^^^^^^ Great research as always, Uncle. It's interesting how the October to winter AO relationship worked out again this winter. http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/monthly.ao.index.b50.current.ascii.table Link to comment Share on other sites More sharing options...
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