Geos Posted December 13, 2012 Share Posted December 13, 2012 Thought I'd start a discussion on how the QBO trends seem to affect our winters across the region and across the continent. Be interesting to hear different thoughts on this. I plotted the 30mb QBO values (source: http://www.cpc.ncep....s/qbo.u30.index ) against the ONI values since the beginning of 1998. I figured that was a good place to start because we had such a slow start to the winter of 1998-1999. Underneath each double axis graph of the QBO and ENSO values I plotted the PNA and NAO values for reference. (Plan to plot AO values on another chart to see what the shows - if anything) For anyone who doesn't know what the QBO is: http://www.geo.fu-be...t/produkte/qbo/ Referring to the chart below: The positive values correlate to westerly winds, and the negative are easterly winds (equatorial). Both sides of the scale represent winds the start at the top of the lower stratosphere and migrate down to the tropopause. A couple things I noticed - the slow start to winter of 1998-1999, the QBO was coming out of a deep negative run (like it is now). The torch of January 2006, the same. Deep negative values seem to correlate strongly with a raging Pacific jet. Will post some more thoughts in the morning. Link to comment Share on other sites More sharing options...
Geos Posted December 13, 2012 Author Share Posted December 13, 2012 December of 2000 you can see we were coming off positive values with weak ENSO conditions. The next January bascially shut off the snow until the very end of the month. The steady QBO around -15 could be partly to blame, but also the NAO went positive that month along with an increasing PNA. The frigid month of February 2007 saw a +QBO, near neutral PNA and -NAO. Around the GHD Blizzard, we had a +QBO going for quite some time, -ONI, PNA was going down, with a slightly +/neutral NAO. From what I can see the build up of the -QBO over time is worst case scenario for winter weather in the region (particularly south part of the subforum), especially in terms of getting cold air in. The Pacific jet has had time to strengthen and gets set in its pattern. Couple that with unfavorable NAO, PNA, and AO - things are even worse. So low negative values and positive values have a good chance at turning things around here during this winter. Can't wait to see what the new values for this month will end up being. Predicted to be about -10. Link to comment Share on other sites More sharing options...
LakeEffectOH Posted December 14, 2012 Share Posted December 14, 2012 Geos, check out Dave Tolleris' (DT) website at WxRisk.com. He has an interesting discussion about the effects of the - QBO on this month and the possible effects it will have in Jan & Feb. The video is This Week in Weather Part 2. Scroll down a little and you will see the videos. http://www.wxrisk.com/ Link to comment Share on other sites More sharing options...
turtlehurricane Posted December 14, 2012 Share Posted December 14, 2012 December of 2000 you can see we were coming off positive values with weak ENSO conditions. The next January bascially shut off the snow until the very end of the month. The steady QBO around -15 could be partly to blame, but also the NAO went positive that month along with an increasing PNA. The frigid month of February 2007 saw a +QBO, near neutral PNA and -NAO. Around the GHD Blizzard, we had a +QBO going for quite some time, -ONI, PNA was going down, with a slightly +/neutral NAO. From what I can see the build up of the -QBO over time is worst case scenario for winter weather in the region (particularly south part of the subforum), especially in terms of getting cold air in. The Pacific jet has had time to strengthen and gets set in its pattern. Couple that with unfavorable NAO, PNA, and AO - things are even worse. So low negative values and positive values have a good chance at turning things around here during this winter. Can't wait to see what the new values for this month will end up being. Predicted to be about -10. I think there's something to this. The thing that matters with the QBO is the vertical wind shear through it, since that drives vertical motion via the thermal wind equation. We currently have a descending easterly QBO with westerlies descending above that. There must be rising motion from the upper troposphere to the center of the easterlies to maintain thermal wind balance, and subsidence from the center of the westerlies near 5 hPa to the center of the easterlies at 30-40 hPa. This results in converging vertical motion at the center of the easterlies, resulting poleward flow to conserve mass. This poleward flow is torqued into westerlies by the Coriolis force, which could enhance the jet. Of course there are probably alot of other things going on, the QBO is complicated. Link to comment Share on other sites More sharing options...
Geos Posted December 14, 2012 Author Share Posted December 14, 2012 Geos, check out Dave Tolleris' (DT) website at WxRisk.com. He has an interesting discussion about the effects of the - QBO on this month and the possible effects it will have in Jan & Feb. The video is This Week in Weather Part 2. Scroll down a little and you will see the videos. http://www.wxrisk.com/ Yeah I watched those clips. Actually twice, in order grasp everything he was saying. The QBO seems to be a good gauge on the strength of the Pacific jet. Here's the exact values over the last 3 months: Sept: -26.61, Oct: -24.51, Nov: -18.95 at the 30mb level. Link to comment Share on other sites More sharing options...
Geos Posted January 4, 2013 Author Share Posted January 4, 2013 QBO update! Average value for December was -10.03. We are getting into good territory now regarding the relaxing of the Pacific jet. http://www.cpc.ncep.noaa.gov/data/indices/qbo.u30.index'>http://www.cpc.ncep.noaa.gov/data/indices/qbo.u30.index Link to comment Share on other sites More sharing options...
Harry Posted January 5, 2013 Share Posted January 5, 2013 December of 2000 you can see we were coming off positive values with weak ENSO conditions. The next January bascially shut off the snow until the very end of the month. The steady QBO around -15 could be partly to blame, but also the NAO went positive that month along with an increasing PNA. The frigid month of February 2007 saw a +QBO, near neutral PNA and -NAO. Around the GHD Blizzard, we had a +QBO going for quite some time, -ONI, PNA was going down, with a slightly +/neutral NAO. From what I can see the build up of the -QBO over time is worst case scenario for winter weather in the region (particularly south part of the subforum), especially in terms of getting cold air in. The Pacific jet has had time to strengthen and gets set in its pattern. Couple that with unfavorable NAO, PNA, and AO - things are even worse. So low negative values and positive values have a good chance at turning things around here during this winter. Can't wait to see what the new values for this month will end up being. Predicted to be about -10. Nice discussion.. Check this out and note the phase/direction during some of our most famous bombs.. Jan 67, 78, 79, 99, GHD etc.. http://www.esrl.noaa.gov/psd/data/correlation/qbo.data'>http://www.esrl.noaa.gov/psd/data/correlation/qbo.data +QBO offers up our best shot for the big bomb. Heck even March 93 super bomb was during +QBO.. Link to comment Share on other sites More sharing options...
Geos Posted January 6, 2013 Author Share Posted January 6, 2013 Nice discussion.. Check this out and note the phase/direction during some of our most famous bombs.. Jan 67, 78, 79, 99, GHD etc.. http://www.esrl.noaa.gov/psd/data/correlation/qbo.data +QBO offers up our best shot for the big bomb. Heck even March 93 super bomb was during +QBO.. Nice link. I think the QBO value for January will be pretty close to 0 and that should bode well for another major storm in the subforum somewhere. - As long as we don't have an overwhelming west based block that drives storms to the east! The Pacific jet is going to relaxing. Link to comment Share on other sites More sharing options...
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