donsutherland1 Posted December 11, 2010 Author Share Posted December 11, 2010 Since K&U found that KU storms were common when a a strong neg. NAO moderated, is there a similar correlation/causation when coming out of a strongly neg. AO? The experience is mixed with the AO. The January 1966, December 2000, and February 25-28, 2010 KU snowstorms commenced with the AO having been rising from severely negative levels. The February 1978 blizzard commenced with the AO at its bottom. The December 2009 and two earlier February 2010 KU snowstorms began with the AO either falling or stable at severely negative levels. Link to comment Share on other sites More sharing options...
uncle W Posted December 11, 2010 Share Posted December 11, 2010 we need a more active southern jet or this negative AO will end up giving us little snow to show for it...1954-55 had a constant -ao Jan. thru March...very dry that winter...dustings galore...1955-56 was similar but after mid March the snows finially came...the ao was negative most of that winter but was plus the end of February to the third week in March when it went negative again while we got those heavy snows...1966-67 was mostly positive starting in February when we started getting all that snow...41" in six weeks with a positive ao...One thing for sure is this -ao is making Florida cold again...Now will it help make it snow here?.. Link to comment Share on other sites More sharing options...
donsutherland1 Posted December 12, 2010 Author Share Posted December 12, 2010 we need a more active southern jet or this negative AO will end up giving us little snow to show for it... I believe that's the big problem with a La Niña setup. Unlike the combination of an El Niño-strongly negative AO, where one could count on an active southern jet to provide snowstorm opportunities, things are different this time around. Northern branch systems might phase, but opportunities for big snowstorms for the major East Coast cities are much less than they typically are during El Niño winters. Link to comment Share on other sites More sharing options...
Snow Wizard Posted December 12, 2010 Share Posted December 12, 2010 I believe that's the big problem with a La Niña setup. Unlike the combination of an El Niño-strongly negative AO, where one could count on an active southern jet to provide snowstorm opportunities, things are different this time around. Northern branch systems might phase, but opportunities for big snowstorms for the major East Coast cities are much less than they typically are during El Niño winters. Any thought when things might become more favorable for some cold in the NW? One would think it should get cold here with the Nina eventually. Link to comment Share on other sites More sharing options...
tacoman25 Posted December 12, 2010 Share Posted December 12, 2010 They can repeat. 1976-77 and 1977-78 is one case where extreme AO- episodes occurred during consecutive winters. I believe 1978-79 also had a pretty healthy -AO? Link to comment Share on other sites More sharing options...
uncle W Posted December 12, 2010 Share Posted December 12, 2010 I believe that's the big problem with a La Niña setup. Unlike the combination of an El Niño-strongly negative AO, where one could count on an active southern jet to provide snowstorm opportunities, things are different this time around. Northern branch systems might phase, but opportunities for big snowstorms for the major East Coast cities are much less than they typically are during El Niño winters. I checked the daily AO index and came up with the -4.000 or lower days...Very interesting weather surrounded most of them...I used the lowest day if there was consecutive days below -4 or the lowest for the season...s... -4.353....12/27/50... -4.330....3/8/51... -4.564....2/15/56..... -4.473....2/21/57... -4.030....3/11/58... -4.026....1/7/59... -5.896....11/18/59... -4.180....1/28/60... -3.959....12/26/61 -4.417....3/4/62... -5.010....1/21/63 -4.470....12/20/63... -3.973....1/26/65... -5.130....1/28/66... -4.334....4/5/66... -4.147....12/13/66.... -4.207....11/15/68... -4.547....12/27/68... -5.282....2/13/69... -4.421....1/8/70... -6.365....3/5/70... -5.287....12/28/76... -7.433....1/15/77... -5.291....2/5/78... -4.292....12/27/78... -4.387....1/25/79... -4.318....3/4/81... -6.226....1/19/85... -4.559....11/25/85... -4.353....12/19/95... -4.106....4/4/96... -4.269....1/10/98... -4.123....11/16/98... -4.688....12/29/00... -4.854....2/25/01... -4.202....3/24/01... -5.098....10/18/02... -4.387....1/17/05... -4.337....2/26/05... -5.821....12/21/09 -5.132....2/14/10... -4.058....11/26/10 Link to comment Share on other sites More sharing options...
NJwinter23 Posted December 12, 2010 Share Posted December 12, 2010 Thanks NJwinter23. It's unfortunate that the EUSWX archive wasn't preserved, but it is what it is. Unfortunately, extreme blocking situations haven't occurred in December with a La Niña as strong as the present one. Nevertheless, if 1950, 1995, and 2000 are representative (even as ENSO Region 3.4 was warmer), one would likely witness a return of strong blocking. 1951 saw a brief episode of strong blocking and severe cold in February and then a sustained period of strong blocking in March. In 1996, there was another period of strong blocking from late January into mid-February. 2001 saw extreme blocking from late February well into March. Interesting. After last winter forced the expansion of the charts to -6/+6, It's pretty amazing that we are once again seeing the possibility for values near -5 and -6 standard deviation (though Uncle W shows that <-4 readings were experienced in 3 straight winters in the late 70s, so I guess not unprecedented). I seem to recall a lot of your late winter return to blocking forecasts from the middle of last winter tied into the El Nino state as well (comparisons to winters like 57-58). Cant wait to see what happens in a strong La Nina if this severe block comes to fruition. Shouldnt change the fact that snowstorms will be harder to come by without a southern jet Link to comment Share on other sites More sharing options...
donsutherland1 Posted December 12, 2010 Author Share Posted December 12, 2010 For perspective, here are the daily AO records for the December 15-25 timeframe (all of which were set in 2009): 12/15 -3.890 12/16 -3.610 12/17 -3.744 12/18 -4.238 12/19 -4.651 12/20 -5.341 12/21 -5.821 *All-time December Record* 12/22 -5.503 12/23 -5.577 12/24 -5.256 12/25 -5.052 Link to comment Share on other sites More sharing options...
JBG Posted December 12, 2010 Share Posted December 12, 2010 I believe that's the big problem with a La Niña setup. Unlike the combination of an El Niño-strongly negative AO, where one could count on an active southern jet to provide snowstorm opportunities, things are different this time around. Northern branch systems might phase, but opportunities for big snowstorms for the major East Coast cities are much less than they typically are during El Niño winters. Unfortunately agreed. March 1956 may be the only strong Niña that featured a KU and even then just barely. Link to comment Share on other sites More sharing options...
Typhoon Tip Posted December 12, 2010 Share Posted December 12, 2010 Well - if nothing else it backs you into a strong suggestion that the A0 phase states may be excited from disparate physical processes. Actually, I have myself discussed those theoretically in the past, but it is still interesting to witness strong descending -AO with only modest or even negligible thermal anomalies in the stratosphere/tropopausal altitudes over/within the arctic domain. The extra-terrestrial side of the argument is always the most fascinating for me. There are several well-refereed and purchasable papers from various geophysical sources that show a sweet correlation between the Ultra Violet intensities of sun light on the phase strength, and position of the AO features, as well as the associated NAO. The very basic summary of the studies: Positive solar correlates with eastward positioning as well as a vertical extension of the mean PV depth, while negative correlates with westward positions and shallower PV intensity. Picking apart the chemistry-climate coupled model, negative solar intervals have increased visible wave lengths in the electromagnetic spectrum, whereas during positive solar intervals the reverse is true. These changes do not register to the human eye, nor show up as differentiable in biota et al, but on quantum scales this does have an effect on the decay rates of various aerosol - the residence of which have thermo-kinetic responses in free air at respective densities/SIGMA levels when interacting with sunlight. Everything we have seen last year and this cold season so far fits with this model above overall, brilliantly. What I have not seen is any direct effort to try and discretely analyze/correlate specific natures of stratospheric warming morphologies on effecting the AO response. The complete model suggests leading negative solar intervals leads to warmer stratospheric regimes, which leads to -AO propensity; *however*, is that an ambient characteristic, or is that correlated to SWEs per se - that latter being quite a bit different than the former in terms of observed behavior and subsequent time-correlated effects. The question arises because some of the more fantastic examples of SWEs in the 32 year data set at CDC took place during the more recent solar maximum. In fact, the distribution appears to be nearly even. So the "flashing" affect of the warm burst-phenomenon its self does not appear on the surface to be outright guided by the solar cycle; it appears the solar cycle is ambiance-correlated. Moreover, there does not appear to be any R-wave decay correlation (Rossby) to SWE, either. For one, when SWEs flash, in every case they begin between the 50 and 1hPa levels, well above the tropopause, the termini of ambient WAA distribution in the medium. The appearance of these events - however coincidental or not - really takes on the affect of having been inserted from above. There may still be answers existing in the chemistry-atmospheric-solar-coupled model that are just simply not yet defined. There may also be extended extra-terrestrial contribution from cosmic rays. There has been recent research showing direct connection between cosmic rays and lightning in the thunderstorms. The short and skinny on that study is that cosmic rays bombard the teetering voltage of electrons near the top of clouds, imparting a small amount of additional charge and it is that that finally overwhelms the insulation of free air, setting of a chain reaction that ripples throughout the cloud - and sometimes to the Earth's surface. If cosmic rays can have a directly measured physical connection to lighting, and considering that both electric and magnetic fields are intertwined physically, it seems entirely logical that cosmic rays could have an effect over the polar regions - if any such effect were on the stratospheric thermal fields, I am not aware of any study that connects the two, but it sure would be a fascinating journey. Lastly, In all of the 31 years of the CDC data set, there were 0 (zero) seasons that featured an SWE prior to the 15th of December. If there is about to be an SWE, perhaps the modeling might be attempting to hit that? I have seen occasional GFS ensemble system forecasts showing some impressive warming at the various sigma levels, above 60N latitude, but the consistency has not been there. I posted a discussion about this a week ago, and even annotated the output of the guidance to some degree, but the questions left of that have been difficult to answer because of this modeling consistency, and the fact that as Brian alluded any warming thus far appears beneath the threshold that would be fairly characterized as a warm burst event. But a very recent graphical depiction at CDC shows that something scary may be about to take place: J/K Anyway, for now the thermal fields appear to be neutral, and the latest guidance doesn't show anything spectacular on the horizon. What ever is guiding the mean to crash the AO to nearly -6 SD, it does not appear to fit with conventional science of SWEs, and actually even the ambient thermal field being so neutral in characteristic - it all really strongly argues that something else is guiding the AO negative. John Link to comment Share on other sites More sharing options...
Ottawa Blizzard Posted December 12, 2010 Share Posted December 12, 2010 It's been a lousy cold weather season up in Ottawa and Toronto thus far and if the AO crashes, it would likely put a fork in the rest of the winter as storms would be suppressed south, just like last year. Link to comment Share on other sites More sharing options...
NaoPos Posted December 12, 2010 Share Posted December 12, 2010 It's been a lousy cold weather season up in Ottawa and Toronto thus far and if the AO crashes, it would likely put a fork in the rest of the winter as storms would be suppressed south, just like last year. Dude, it's december 12th..... Link to comment Share on other sites More sharing options...
Snow Wizard Posted December 12, 2010 Share Posted December 12, 2010 It's been a lousy cold weather season up in Ottawa and Toronto thus far and if the AO crashes, it would likely put a fork in the rest of the winter as storms would be suppressed south, just like last year. I feel your pain. This is supposed to be a great winter for the Pacific NW and we are stuck in this horrendous blowtorch pattern which the GFS now shows no end in sight. How can we be seeing the same pattern this winter with so many indices totally opposite of last winter? Link to comment Share on other sites More sharing options...
PAblizzardlover Posted December 12, 2010 Share Posted December 12, 2010 The experience is mixed with the AO. The January 1966, December 2000, and February 25-28, 2010 KU snowstorms commenced with the AO having been rising from severely negative levels. The February 1978 blizzard commenced with the AO at its bottom. The December 2009 and two earlier February 2010 KU snowstorms began with the AO either falling or stable at severely negative levels. Thanks alot, is there a good site for historical daily AO/NAO values? Link to comment Share on other sites More sharing options...
okie333 Posted December 12, 2010 Share Posted December 12, 2010 Thanks alot, is there a good site for historical daily AO/NAO values? http://www.cpc.noaa.gov/products/precip/CWlink/daily_ao_index/history/history.shtml Link to comment Share on other sites More sharing options...
nzucker Posted December 12, 2010 Share Posted December 12, 2010 12z GFS shows a 1080mb High over Greenland: Link to comment Share on other sites More sharing options...
Kaner587 Posted December 12, 2010 Share Posted December 12, 2010 12z GFS shows a 1080mb High over Greenland: highest pressure ever recorded is 1085.6 so that'd be pretty darn impressive Link to comment Share on other sites More sharing options...
Amped Posted December 12, 2010 Share Posted December 12, 2010 highest pressure ever recorded is 1085.6 so that'd be pretty darn impressive There's Nobody up in greenland with a barometer. Link to comment Share on other sites More sharing options...
Kaner587 Posted December 12, 2010 Share Posted December 12, 2010 There's Nobody up in greenland with a barometer. and you wouldn't think there'd be somebody in mongolia either, yet thats where it was recorded Link to comment Share on other sites More sharing options...
JBG Posted December 12, 2010 Share Posted December 12, 2010 and you wouldn't think there'd be somebody in mongolia either, yet thats where it was recorded The map shows it in Greenland which is nowhere near Mongolia. Link to comment Share on other sites More sharing options...
Snow Wizard Posted December 12, 2010 Share Posted December 12, 2010 The map shows it in Greenland which is nowhere near Mongolia. I think you totally missed the point. Link to comment Share on other sites More sharing options...
Kaner587 Posted December 12, 2010 Share Posted December 12, 2010 I think you totally missed the point. LOL ...clearly he failed to read that I was talking about the highest pressure recorded on earth Link to comment Share on other sites More sharing options...
uncle W Posted December 13, 2010 Share Posted December 13, 2010 the last 14 days...Florida feeling the brunt of the neg ao again... Link to comment Share on other sites More sharing options...
A-L-E-X Posted December 13, 2010 Share Posted December 13, 2010 the last 14 days...Florida feeling the brunt of the neg ao again... Looks like the -4 anomalies extend further north, all the way to Boston. Otherwise, its a lot like last winter. I think we're ok in that lovely dark green Link to comment Share on other sites More sharing options...
okie333 Posted December 13, 2010 Share Posted December 13, 2010 Looks like the -2 anomalies extend further north, all the way to Boston. Otherwise, its a lot like last winter. I think we're ok in that lovely dark green Fixed. Link to comment Share on other sites More sharing options...
A-L-E-X Posted December 13, 2010 Share Posted December 13, 2010 Fixed. Thanks, a bit color blind here lol. I should have said -2 to -4 as I see there are some -2 to -4 anomalies up in northern VT and NH also. Link to comment Share on other sites More sharing options...
Isotherm Posted December 13, 2010 Share Posted December 13, 2010 Uncle W, that temp departure map looks very much like the composite of all -AO Decembers, with the cold corridor from the Northern Plains to the SE US, and warm in the SW US and NE New England. Don't have the map handy now but I believe it'd look similar to that. Link to comment Share on other sites More sharing options...
Organizing Low Posted December 13, 2010 Share Posted December 13, 2010 never bet against Don. Link to comment Share on other sites More sharing options...
Snow Wizard Posted December 13, 2010 Share Posted December 13, 2010 I'm not liking the looks of the longer range models. Looks like the blocking breaks down without the West ever getting a chance at something good. I'm more than a little bit worried about a bust. Link to comment Share on other sites More sharing options...
donsutherland1 Posted December 13, 2010 Author Share Posted December 13, 2010 Although I expect monthly snow figures in Montreal, Ottawa, and Toronto to increase off their depressed levels to date, it remains to be seen whether the figures will even begin to approach the lofty December 2000 amounts (Montreal: 86.5 cm; Ottawa: 108.6 cm; Toronto: 63.8 cm). More likely are figures somewhere between the December 1950 and December 1995 amounts (Montreal: 60.5 cm - 86.4 cm; Ottawa: 48.5 cm - 81.4 cm; Toronto: 5.8 cm - 30.6 cm), but probably closer to the 1950 figures. Looking ahead, the bad news is that January 2011 would probably not be a blockbuster month if those La Niña analogs are relevant. Monthly figures could be close to 45 cm - 55 cm in Montreal, 55 cm - 65 cm in Ottawa, and 15 cm - 25 cm in Toronto. Montreal and Ottawa would have the best chance at seeing one or two moderate snowstorms (15 cm or more). A lot will depend on when the current blocking episode breaks down (probably sometime during the first week in January) and how the current La Niña then impacts the overall pattern. Link to comment Share on other sites More sharing options...
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