asthut Posted January 1, 2012 Share Posted January 1, 2012 Raise your hand if your winter forecast is busting. This winter has proven a difficult long-range forecast for many of us.. especially in the east and midwest. If you told me in September or October winter temperatures would start off well-above average, I would have a hard time believing you. Of course the reason for the bust is largely coming down to a positive AO and NAO. I was banking on a negative AO and NAO this winter. If anyone forecasted a pro-longed period of a positive NAO I would love to hear your explanation... This topic may have been discussed in previous posts but I would like this thread to be geared toward predicting teleconnections with an emphassis on AO and NAO. I have seen correlations between NAO and sun activity in the past. I have also heard theories that Siberian snowpack may be an indicator. Any comments would be great to hear. Busting the winter forecast is upsetting. Link to comment Share on other sites More sharing options...
donsutherland1 Posted January 1, 2012 Share Posted January 1, 2012 This topic may have been discussed in previous posts but I would like this thread to be geared toward predicting teleconnections with an emphassis on AO and NAO. I have seen correlations between NAO and sun activity in the past. I have also heard theories that Siberian snowpack may be an indicator. My winter thoughts weren't posted until 11/28 (warm, less blocking). In part, I had concern about the AO and that led to holding off on any ideas. First, statistically, only once did three consecutive winters have strong blocking (seasonal average AO -1 or below). Second, an AO+ regime had set in on August 28. Since then, periods of blocking were short and infrequent. Third, in November an extreme AO+ regime set in and was likely to continue into at least part of December. The consequences of such situations are discussed quite a bit in the AO +3.5 thread. Fourth, autumn had seen no SSW events. SSW events can sometimes lead to a displacement or splitting of the polar vortex, leading to an AO-. As for the solar-AO connection, I haven't seen much in the literature to suggest anything beyond a weak correlation. I don't use it. I reserve judgment on the Siberian snowpack-AO connection. There is some promise there. Link to comment Share on other sites More sharing options...
usedtobe Posted January 1, 2012 Share Posted January 1, 2012 I can't say I expected the positive AO before mid November but once the AO really spiked I thought i might last a couple of months as that suggested that the northern annular mode was strongly positive. The slide below shows the impact on the northern annular mode. You can see two composites in the right hand corner of the figure, one for when the NAM is negative (the red one) and one when it is positive. Note neither go way quickly. In Dec 2009 the NAM went negative early in the month and pretty much stayed that way until Jan when there was a short positive spike but then another warming event shoved the AO and NAO negative and it stayed that way through Feb. This year, the NAM went strongly positive in November suggesting it would last through Dec (I even posted a CWG article on it). The problem with trying to forecast the NAO or Ao months in advance is that none of the correlations are real strong (ie, solar, qbo) and actually act differently based on each other. Therefore, most climo people will tell you the AO is only predictable a week or two in advance. Anyway, those are my thoughts. Link to comment Share on other sites More sharing options...
Rainshadow Posted January 1, 2012 Share Posted January 1, 2012 Raise your hand if your winter forecast is busting. This winter has proven a difficult long-range forecast for many of us.. especially in the east and midwest. If you told me in September or October winter temperatures would start off well-above average, I would have a hard time believing you. Of course the reason for the bust is largely coming down to a positive AO and NAO. I was banking on a negative AO and NAO this winter. If anyone forecasted a pro-longed period of a positive NAO I would love to hear your explanation... This topic may have been discussed in previous posts but I would like this thread to be geared toward predicting teleconnections with an emphassis on AO and NAO. I have seen correlations between NAO and sun activity in the past. I have also heard theories that Siberian snowpack may be an indicator. Any comments would be great to hear. Busting the winter forecast is upsetting. You'd probably find that for this season outlooks that were made in November or later in November are having a leg up over outlooks that were issued earlier, because at least as far December was concerned it became more apparent that it was not going to be cold. Wes's comments are right about the lower skill in outlooking the AO and NAO, kind of the northeastern conus "holy grail" sort of speak. This winter is obviously not in the books yet, but the two previous winters nh and eurasian snowcover averaged above normal for the month of October, this fall it was below. We (as in PHL area) do better with snowfall (didn't correlate temps) with the former, but its not close to being absolute. Happy New Year everyone! Link to comment Share on other sites More sharing options...
uncle W Posted January 1, 2012 Share Posted January 1, 2012 I had a list of analogs with some snowy/cold and some not...Once the AO sky rocketed in November I knew a cold December forecast was in trouble...I still think we will see a storm like we saw in late October...Hopefully it comes before Spring arrives...If it happens late January or February we will get a blizzard...... Link to comment Share on other sites More sharing options...
donsutherland1 Posted January 1, 2012 Share Posted January 1, 2012 ...most climo people will tell you the AO is only predictable a week or two in advance. I tend to agree. Having a good idea as to what level the AO will be is not possible from very far out. At this time, I don't believe one can have high confidence in seasonal AO predictions. Statistics offer some insight, but sample sizes are small. The Siberian snowcover increase might also lend some insight, but that's still a work in process, as encouraging as that work has been. Link to comment Share on other sites More sharing options...
donsutherland1 Posted January 1, 2012 Share Posted January 1, 2012 Happy New Year everyone! Happy New Year to all. Link to comment Share on other sites More sharing options...
donsutherland1 Posted January 1, 2012 Share Posted January 1, 2012 You know the thread is going to be a depressing one when Don S posts in it and Wes follows. Perhaps AmericanWx should consider using some of the funds raised beyond the targeted amount to hire a psychologist to post following Wes' and my messages to help members cope with any adverse issues our dismal messages might cause? Hopefully, in the not-too-distant future, the pattern will change. Link to comment Share on other sites More sharing options...
winterymix Posted January 1, 2012 Share Posted January 1, 2012 Perhaps AmericanWx should consider using some of the funds raised beyond the targeted amount to hire a psychologist Naw...you can blame it one me! Link to comment Share on other sites More sharing options...
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