Finally, Virginia Hippie mentions the LRC above. It has been reliable. Some folks complain the LRC is a black box; however, I figure they do have a system that they just can't overwhelm the casual viewer with. Notice the LRC cycle period is about the same length as the average MJO cycle. Plus I like the persistence background of the LRC with the cycles on top.
I looked into the LRC a bit and from what I've seen, though anecdotally it seems to have some correlation with the upper-level patterns, the surface weather during these cycles can be quite different when patterns are forecast to be repeated. Lezak's winter forecast for last winter did not fare too well for most of Canada and the eastern half of the US temperature-wise (his precip was also quite off): http://lrcweather.co...:blog&Itemid=29
His summer 2012 forecast ended up doing well... towards the end of May he predicted a hot summer across the US. However, by that time a hot summer seemed fairly obvious, regardless of whether or not people used the LRC to make their forecasts.
I have a few issues with the LRC, one being that there has been no formal analysis to determine how strong a correlation the LRC has. Second, some/most of the advocates of LRC are quick to show you successful forecasts of the LRC, but analyses on where the LRC fails and why it failed are sparse at best. Later in his blog (linked above), Lezak does a post-analysis of why 2011-12 was "the winter that wasn't" via the AO, NAO and jet stream, but he failed to analyze why the LRC method failed WRT the winter forecast. I'm all for creating and testing new theories, but if you can't perform a rigorous analyses to find statistical correlations (say with 500mb heights), then it's just hearsay. Another issue is there has been no published research paper discussing the LRC (of any kind... not just peer-reviewed) since Lezak started to develop his theory in the 1980s. That's over 20 years for him or someone else to do a formal, statistical analysis on the LRC, and there's nothing.
Maybe I just haven't dug deep enough, but those have been my observations on the LRC since someone told me about it last winter. I would like to hear other opinions about the LRC from those who have actually studied and used the LRC in their forecasting to get a better idea of just how good or bad this theory actually is. There's no doubt that there are natural cycles in the atmosphere on all sorts of different time scales, and the LRC may be on to one of them, but the science behind why the LRC works or doesn't work and its correlation to North American weather just isn't fleshed out enough (which is concerning considering how long it's been around).
You mentioned that the LRC has a similar time scale as the MJO... why not just use the MJO to make the forecast instead of the LRC then? Is one more accurate than the other?
Of course, some of the points mentioned above have been discussed already in years past (I'm sure you'll recognize this thread: http://www.stormtrac...es-with-weather
Apologies for the long and skeptical post, but I just can't fathom why some mets utilize it in their forecast given the lack of research and verification of it. If the theory by itself does add value over climo more so than the conventional teleconnections and forecasting tools, why are so few mets using it and why have many mets not even heard about it? Why hasn't a rigorous analysis and verification of the LRC been done? I'm not trying to confront you individually with all of these questions... I'd like to hear all mets' opinions on the matter.