donsutherland1 Posted November 20, 2017 Share Posted November 20, 2017 This morning parts of the New York City area saw snow flurries. Although the temperature was well above freezing, the flurries offered a reminder that November 2017 has had a greatly different meteorological character than the record warm October that preceded it. Based on the latest guidance, there is an implied 71% probability that November will finish with a colder than normal monthly temperature in New York City. The most likely range would be 44.9°-46.4°. That would represent a 17.7°-19.2° drop from October. That would represent the biggest October-November change in temperature since the monthly mean temperature fell 18.2° in 2007 (and possibly since 1947 when the monthly mean temperature fell 19.4°). This morning, the Arctic Oscillation stood at a preliminary -2.953. That is the lowest November figure since November 4, 2016 when the AO was -3.137. It is also the 3rd lowest figure on record for November 20, surpassed only in 1965 (-3.230) and 1950 (-3.041). The ensembles continue to indicate that the AO will fall below -3.000 in coming days. The downstream response should ensure that November will wind up with a colder than normal anomaly. Going forward, I still believe there is a somewhat higher probability that December will wind up colder than normal in the Northeast and parts of the Great Lakes region. Much of Canada should be colder than normal. The first 7-10 days could average somewhat cooler than normal in the Northeast and eastern Canada, although there remains substantial uncertainty concerning whether or not there will be blocking. However, all things considered, typically the presence of an SOI+ during the first 10 days of December (common in La Niña conditions) is cooler than an SOI- situation. The forecast temperature anomaly on the EPS for the 12/1-5 period lends support to this idea. Link to comment Share on other sites More sharing options...
Isotherm Posted November 20, 2017 Share Posted November 20, 2017 I disagree with a relaxation until mid+ December. I think the temperature moderation is very transient prior to the reload. As mentioned last week, the wave 1 event will significantly weaken the SPV such that zonal winds are about 50% of their previous intensity in 10 days. This will downwell, subsequently inducing a renewed -NAM regime beginning later in the first week of December. Contemporaneously, weak LF forcing will be propagating back toward the Maritime continent, and the retracted jet / poleward -AAM transport will redevelop. All of these factors will lead to a cold to much colder than normal December across parts of the Central and Eastern US. Once the pattern sets up, I expect the first meaningful opportunity for coastal snow to appear thereafter (as stated in the outlook, I am expecting the Dec 15-30 period to offer potential for significant or major). This is the most interested I have been in the winter pattern in a few years, and since 2013 for December. Link to comment Share on other sites More sharing options...
psv88 Posted November 20, 2017 Share Posted November 20, 2017 1 hour ago, bluewave said: First official flurries of the season here in SW Suffolk. Add NW Suffolk to the list, flurries here. Link to comment Share on other sites More sharing options...
uofmiami Posted November 20, 2017 Share Posted November 20, 2017 2 hours ago, psv88 said: Add NW Suffolk to the list, flurries here. Had fluries at my house in Syosset as well before. And again by East Norwich while driving back to Great Neck. Link to comment Share on other sites More sharing options...
snowman19 Posted November 20, 2017 Share Posted November 20, 2017 17 hours ago, Neblizzard said: The PDO is neutral ( actually +0.4) so you’re wrong about that. No, that was last month’s (October’s) number. And secondly, that is not “the blob” reappearing. That warm water out by the Aleutians and west of there is in a classic -PDO position. Look at the chart I posted comparing a -PDO signature to a +PDO signature. Here are maps of the blob; note the difference: Link to comment Share on other sites More sharing options...
Brian5671 Posted November 20, 2017 Share Posted November 20, 2017 ^^^ where's all the warmth you predicted? Link to comment Share on other sites More sharing options...
snowman19 Posted November 20, 2017 Share Posted November 20, 2017 2 minutes ago, Brian5671 said: ^^^ where's all the warmth you predicted? Don’t change the subject. The info you posted was wrong. It shows how little knowledge you have of basic weather. Do your research next time before you post inaccurate proclamations Link to comment Share on other sites More sharing options...
Brian5671 Posted November 20, 2017 Share Posted November 20, 2017 10 minutes ago, snowman19 said: Don’t change the subject. The info you posted was wrong. It shows how little knowledge you have of basic weather. Do your research next time before you post inaccurate proclamations What's the latest figure then if it's not +.04? That's certainly not a "robust" -PDO as you have opined in the past. You also argued for warmth this week, this week will be anything but warm around here and the next 10-15 days also look BN. Looks like you should study up on the subject of "basic weather" Link to comment Share on other sites More sharing options...
donsutherland1 Posted November 20, 2017 Share Posted November 20, 2017 4 minutes ago, snowman19 said: No, that was last month’s (October’s) number. And secondly, that is not “the blob” reappearing. That warm water out by the Aleutians and west of there is in a classic -PDO position. Look at the chart I posted comparing a -PDO signature to a +PDO signature. Here is are maps of the blob; note the difference: The PDO SSTA region is bounded by 30°N-50°N and 145°E to 150°W (see area enclosed in the black box) courtesy of: https://link.springer.com/article/10.1007/s00382-014-2364-5: Link to comment Share on other sites More sharing options...
snowman19 Posted November 20, 2017 Share Posted November 20, 2017 9 minutes ago, donsutherland1 said: The PDO SSTA region is bounded by 30°N-50°N and 145°E to 150°W (see area enclosed in the black box) courtesy of: https://link.springer.com/article/10.1007/s00382-014-2364-5: Thanks Don. For comparison: Link to comment Share on other sites More sharing options...
MJO812 Posted November 20, 2017 Share Posted November 20, 2017 Mike Ventrice on the - NAO on the Euro https://mobile.twitter.com/MJVentrice/status/932694429361635329 Link to comment Share on other sites More sharing options...
MJO812 Posted November 20, 2017 Share Posted November 20, 2017 Monster negative NAO on the Euro Link to comment Share on other sites More sharing options...
IntenseBlizzard2014 Posted November 20, 2017 Share Posted November 20, 2017 1 hour ago, snowman19 said: Thanks Don. For comparison: It's still a slightly +PDO. The western part of the PDO region is cooling off BTW. Link to comment Share on other sites More sharing options...
psv88 Posted November 20, 2017 Share Posted November 20, 2017 3 hours ago, Brian5671 said: What's the latest figure then if it's not +.04? That's certainly not a "robust" -PDO as you have opined in the past. You also argued for warmth this week, this week will be anything but warm around here and the next 10-15 days also look BN. Looks like you should study up on the subject of "basic weather" Wow. When you argue against warmth you know its going to be cold. Link to comment Share on other sites More sharing options...
Brian5671 Posted November 21, 2017 Share Posted November 21, 2017 1 hour ago, psv88 said: Wow. When you argue against warmth you know its going to be cold. Yep, I am seeing a lot of cold. Reminds me of Nov/Dec 2010...Good blocking, plenty of cold on our side of the globe. Last few years Canada was so warm it too forever to route out the warmth. Link to comment Share on other sites More sharing options...
MJO812 Posted November 21, 2017 Share Posted November 21, 2017 Euro weeklies say game on Looks great moving forward Link to comment Share on other sites More sharing options...
gravitylover Posted November 21, 2017 Share Posted November 21, 2017 9 minutes ago, bluewave said: We may also get a record low sea ice feedback boost to the blocking like we did with the record Kara to the North Pole block in January 2016. Here's the current (Nov 17) Bering Sea ice extent in the 40 year passive microwave perspective. Friday had the lowest extent for the date in the satellite record, but as importantly, look at the past five years! Data from @NSIDC #akwx #Arctic @Climatologist49 @ZLabe@DaveSnider pic.twitter.com/U5sPLxjt8f As I scrolled down a ways he says that the low sea ice levels are due to excessive storminess rather than warm temps. There was another panel that showed some temps 10-20* above avg but that's still cold considering that the average is in the single digits. Link to comment Share on other sites More sharing options...
frd Posted November 21, 2017 Share Posted November 21, 2017 10 minutes ago, bluewave said: We may also get a record low sea ice feedback boost to the blocking like we did with the record Kara to the North Pole block in January 2016. Here's the current (Nov 17) Bering Sea ice extent in the 40 year passive microwave perspective. Friday had the lowest extent for the date in the satellite record, but as importantly, look at the past five years! Data from @NSIDC #akwx #Arctic @Climatologist49 @ZLabe@DaveSnider pic.twitter.com/U5sPLxjt8f Great point, if I may ask a question. Did this prior feedback boost in Jan. 2016 lead to, or contribute anyway to the blizzard in the Mid Atlantic and Northeast regions ? Link to comment Share on other sites More sharing options...
uncle W Posted November 21, 2017 Share Posted November 21, 2017 winters with an ao near or lower than -5... winter.......AO min. date...............weather just before or after date... 1976-77...-7.433...01/15/1977...record cold with snow... 1969-70...-6.365...03/05/1970...cold all month with late snows... 1984-85...-6.226...01/19/1985...record cold with snow... 2009-10...-5.821...12/21/2009...snowstorm... 2012-13...-5.688...03/20/2013...snow... 1977-78...-5.291...02/05/1978...blizzard... 1968-69...-5.282...02/13/1969...blizzard... 2010-11...-5.172...12/18/2010...blizzard... 1965-66...-5.130...01/28/1966...record snow with cold... 1962-63...-5.010...01/21/1963...record cold... 2015-16...-4.916...01/17/2016...blizzard... 2000-01...-4.854...02/25/2001...snow... Link to comment Share on other sites More sharing options...
MJO812 Posted November 21, 2017 Share Posted November 21, 2017 Snow showers possible Sunday Maybe more if the ull can dig further south Link to comment Share on other sites More sharing options...
WeatherFeen2000 Posted November 21, 2017 Share Posted November 21, 2017 That low pressure is forming earlier and more west with each run. I think temps may be a problem but if it catches the vort early and more west, dynamic cooling and evaporative cooling will cool the column and produce wet snow. Each run the accumulated precipitation has been drifting west. Let’s see how early that low forms and how west in the future runs. Definitely something to keep an eye on! Link to comment Share on other sites More sharing options...
WeatherFeen2000 Posted November 21, 2017 Share Posted November 21, 2017 Not sure how warm it is but ukmet shows an interesting scenario at 120hrs http://meteocentre.com/numerical-weather-prediction/map-explorer.php?lang=en&map=na&run=00&mod=ukmet&stn=PNM&comp=1&run2=00&mod2=ukmet&stn2=PNM&hh2=144&fixhh=1&stn2_type=prog&mode=latest&yyyy=latest&mm=latest&dd=latest&hh=120 Link to comment Share on other sites More sharing options...
CIK62 Posted November 21, 2017 Share Posted November 21, 2017 Next 8 days averaging 44degs., or just about Normal. Link to comment Share on other sites More sharing options...
Brian5671 Posted November 21, 2017 Share Posted November 21, 2017 1 hour ago, LurkerBoy said: How does the long range pattern look How about you read the discussion? Link to comment Share on other sites More sharing options...
LurkerBoy Posted November 21, 2017 Share Posted November 21, 2017 23 minutes ago, Brian5671 said: How about you read the discussion? I have been... Link to comment Share on other sites More sharing options...
dmillz25 Posted November 21, 2017 Share Posted November 21, 2017 13 minutes ago, LurkerBoy said: I have been... Brother it’s ok to ask but you literally ask every single day. Right now it looks below normal for the foreseeable future except maybe a day or 2. No snow chances for a few weeks at least. Link to comment Share on other sites More sharing options...
SnowGoose69 Posted November 21, 2017 Share Posted November 21, 2017 14 minutes ago, bluewave said: There's an interesting correlation between La Nina Novembers and strong blocking near the Bering and Aleutians. All 9 La Novembers since 1950 with this pattern were followed by a -AO December. This would match the long range guidance shifting the primary NH blocking from the Bering and Aleutians to the North Pole or Greenland. This November so far has seen record 500 mb blocking near the Bering and Aleutians. La Nina Novembers with a strong Bering and Aleutians block since 1950 and December AO. 2010...-2.631 1996...-1.721 1995...-2.127 1985..-1.948 1973...-0.181 1970...-0.399 1966...-1.401 1955...-0.444 1950..-1.928 Never realized December 96 had such a negative AO given it was so warm Link to comment Share on other sites More sharing options...
bluewave Posted November 21, 2017 Share Posted November 21, 2017 8 minutes ago, SnowGoose69 said: Never realized December 96 had such a negative AO given it was so warm It could have been a great December if the Pacific wasn't so unfavorable. Link to comment Share on other sites More sharing options...
nyblizz44 Posted November 21, 2017 Share Posted November 21, 2017 2 minutes ago, bluewave said: It could have been a great December if the Pacific wasn't so unfavorable. Doesnt this make the point that a -NAO , while a good thing to have, is far from the only factor to drive cold & snow to the coast? Link to comment Share on other sites More sharing options...
uncle W Posted November 21, 2017 Share Posted November 21, 2017 1996 was one of the exceptions that had a negative ao and nao in December with nothing to show for it...November 1996 was cold... Decembers with an ao and nao -1 or lower... year.....ao.....nao..... 1950...-1.928.....-1.02...snow 12/27... 1961...-1.668.....-1.48...snow 12/24 1963...-1.178.....-1.92...snow 12/23 1976...-2.074.....-1.60...snow 12/26 1995...-2.127.....-1.67...snow 12/20 1996...-1.721.....-1.41...no snow... 2009...-3.413.....-1.93...snow 12/20 2010...-1.749.....-1.85...snow 12/27 1996 was the only December that was mild without measurable snow in NYC... Link to comment Share on other sites More sharing options...
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