RodneyS Posted November 1, 2011 Share Posted November 1, 2011 October 2011 saw a drop-off in precipitation from the nearly nine inches each in August and September to 3.91 inches, placing it 40th for October precipitation (out of 141 years). However, the total for the last three months is 21.67 inches, which places them 3rd on the all-time list, behind only August-October 1934 (23.41 inches) and August-October 1942 (22.43 inches). Link to comment Share on other sites More sharing options...
Ian Posted November 1, 2011 Share Posted November 1, 2011 Heh, just pulled this up yesterday myself for filler on a CWG post. Obviously mostly Aug/Sep related but pretty solid. 1934 again. Link to comment Share on other sites More sharing options...
Bob Chill Posted November 1, 2011 Share Posted November 1, 2011 1934 seems to be matching up with alot of your thoughts. I may dig deeper myself just for fun. I wish their was satellite data back then though. Things like handwritten records, sparse obs, tree rings, and data interpolation just don't make me feel too confident. How are the enso, pdo, nao, etc indexes figured out pre-satellite? I read an article about tree rings and they do seem like they can tell some of the story with precip and solar stuff but it just seems so outdated compared to what we do now with satellites. Link to comment Share on other sites More sharing options...
RodneyS Posted November 1, 2011 Author Share Posted November 1, 2011 Heh, just pulled this up yesterday myself for filler on a CWG post. Obviously mostly Aug/Sep related but pretty solid. 1934 again. Great minds, etc. As I'm sure you know, September 1934 recorded the all-time high precipitation amount for any month in DC history, at 17.45 inches (second highest is 14.41 inches in August 1928). However, October 1934 recorded only 0.75 inches, which places it as the 15th driest October in DC history. So, not much of an analog there with this October. Link to comment Share on other sites More sharing options...
Ian Posted November 1, 2011 Share Posted November 1, 2011 Great minds, etc. As I'm sure you know, September 1934 recorded the all-time high precipitation amount for any month in DC history, at 17.45 inches (second highest is 14.41 inches in August 1928). However, October 1934 recorded only 0.75 inches, which places it as the 15th driest October in DC history. So, not much of an analog there with this October. Yeah the Sept # skews it so much it's not necessarily meaningful tho I'd still hold we ran into at least a 30 day pattern or so that was indeed quite similar -- just earlier this yr. I doubt we'd ever get a 'perfect' match down the months anyway. I have hit the 1930s quite a bit over the past 6 mo or so looking at climo stuff. Link to comment Share on other sites More sharing options...
Deck Pic Posted November 1, 2011 Share Posted November 1, 2011 1934 seems to be matching up with alot of your thoughts. I may dig deeper myself just for fun. I wish their was satellite data back then though. Things like handwritten records, sparse obs, tree rings, and data interpolation just don't make me feel too confident. How are the enso, pdo, nao, etc indexes figured out pre-satellite? I read an article about tree rings and they do seem like they can tell some of the story with precip and solar stuff but it just seems so outdated compared to what we do now with satellites. I also am unsure how reliable reconstructed data is....but by most accounts it was a +PDO winter with a ridge in Western Canada and a trough over the east..not a big blocking winter...ENSO was probably not a factor....maybe a bit of a NIna hangover, but basically neutral...and there was probably a southern stream....It was not a cold winter...more normalish or slightly below....I think it is a loose analog, though ENSO should be more of a factor this winter and the PDO will be negative...more blocking too.... Link to comment Share on other sites More sharing options...
RodneyS Posted November 1, 2011 Author Share Posted November 1, 2011 I also am unsure how reliable reconstructed data is....but by most accounts it was a +PDO winter with a ridge in Western Canada and a trough over the east..not a big blocking winter...ENSO was probably not a factor....maybe a bit of a NIna hangover, but basically neutral...and there was probably a southern stream....It was not a cold winter...more normalish or slightly below....I think it is a loose analog, though ENSO should be more of a factor this winter and the PDO will be negative...more blocking too.... FYI, the 1934-35 winter (December 1934-February 1935) in DC averaged 35.3 degrees, ranking it 47th coldest of 140 years. Snowfall was 3.0 inches in December, 24.4 inches in January, 3.5 inches in February, and 0.5 inches in March, for a total of 31.4 inches, ranking that season the 19th snowiest of 123 years. 1935 was the second snowiest January in DC, next to 1922, when the Knickerbocker storm contributed to a record 31.5 inches. Link to comment Share on other sites More sharing options...
Bob Chill Posted November 1, 2011 Share Posted November 1, 2011 I think it is a loose analog, though ENSO should be more of a factor this winter and the PDO will be negative...more blocking too.... Pretty much agree with that. Looking at historical pdo/nao/ao data it all points towards the potential for a long term negative cycle for all 3 indexes. Especially the PDO. I love looking at this chart: We've had back to back winters with good blocking too. If we have a 3rd then it would sorta confirm a negative cycle for those indexes too but they're a bit volitile. It's been a while when the ao and nao averaged negative for 3 consecutive winters. Just briefly looking at the monthly tabular stuff, the NAO hit 3 in a row a couple times in the late 50's - 60's. The AO is more common. 50's and 60's featured alot of negative winters. Most recently was 85-87. The last time we had a combined negative ao & nao winter 3 years in a row was the 60's. It will be interesting looking back on this upcoming winter and seeing how the indexes shake out. Link to comment Share on other sites More sharing options...
RodneyS Posted November 30, 2011 Author Share Posted November 30, 2011 October 2011 saw a drop-off in precipitation from the nearly nine inches each in August and September to 3.91 inches, placing it 40th for October precipitation (out of 141 years). However, the total for the last three months is 21.67 inches, which places them 3rd on the all-time list, behind only August-October 1934 (23.41 inches) and August-October 1942 (22.43 inches). November precipitation looks as if it's finalized at 1.94 inches, which makes it only the 91st wettest November in DC history. However, the four-month total is now 23.61 inches, which keeps August-November 2011 precipitation in the same relative position -- third on the all-time list behind 1934 (26.99 inches) and 1942 (24.35 inches). Link to comment Share on other sites More sharing options...
RodneyS Posted December 31, 2011 Author Share Posted December 31, 2011 November precipitation looks as if it's finalized at 1.94 inches, which makes it only the 91st wettest November in DC history. However, the four-month total is now 23.61 inches, which keeps August-November 2011 precipitation in the same relative position -- third on the all-time list behind 1934 (26.99 inches) and 1942 (24.35 inches). December precipitation appears to be finalized at 4.90 inches, making it the 16th wettest December in DC history. The five-month total is 28.51 inches, which keeps August-December 2011 precipitation in the same relative position -- third on the all-time list behind 1934 (29.90 inches) and 1942 (28.60 inches). Link to comment Share on other sites More sharing options...
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