I want to give a couple examples of significant conflicting signals- both short and long-term. The end result is a situation where long range, climate, and seasonal models are likely to have a very tough time not only in the medium to long range (2-4 week period), but thinking seasonally, as well (winter and next spring).
Short-term
To start, let’s look at the EPO. While strongly positive at present, both the EPS and GEFS pictured below take the EPO, or East Pacific Oscillation, negative in the coming couple of weeks.
A negative EPO pattern favors a trough across the eastern portion of the country, especially here in our neck of the woods, with western ridging.
All well and good, right? WRONG. The MJO, or Madden Julian Oscillation, is forecast to stall out into early October in Phase 1.
This time of year, Phase 1 argues strongly for eastern ridging and well above normal warmth while the western portion of the country can experience early wintry conditions.
Talk about contradiction! That’s what makes weather so fun and fascinating. Expect to be humbled often and to always learn! At various times of the year, select teleconnections can mean a lot more than other times of the year. For example, during the summer and fall, we lean heavily on the EPO, PNA, and MJO (if amplified). During the winter and spring, it’s important to take into account what the AO and NAO have to say. It’s important to know when to “pick and choose” when to use particular teleconnections… Furthermore, the various MJO phases (1-8) mean drastically different things at different times of the year. While lovers of chilly fall conditions have grown to hate an amplified Phase 1, they have to love it come winter (shown below). Just look at that difference!
Before jumping ahead to another example of “contradicting signals,” we’re confident the amplified MJO Phase 1 will carry the day through the short to medium range period. Note the strong agreement between the EPS and GEFS below with respect to temperature anomalies in the 6-10 day period.
With that said, there will be challenges within (the big difference as early as this weekend between the GFS and European operational data). A lot of that has to do with the “fight” between the EPO and MJO to take control.
As all of this unfolds across the East, the west will begin to cash in on early winter. Well below average cold and snowy conditions will begin to make headlines over the weekend into next week across not only the Rockies, but some of the low ground, as well. Should the MJO swing into Phase 2 (and I think it will towards mid-Oct), then watch out. We’ll be looking at a rather significant shift towards a much colder feel- and it’ll sting even more so with the late season heat over the better part of the next couple of weeks.
Flipping the page to winter (remember, our prelim. winter outlook will be posted later this week) and the contradiction continues. Upon looking at the current SST configuration, one could easily argue we’re talking about a La Nina winter unfolding ahead.
Meanwhile, the current SOI would suggest we’re in a moderate El Nino.
If you think this can’t wreck havoc even on the short-term forecast pattern, think again…
To close, while the conflicting data can create headaches at times, it’s more fascinating than ever trying to sift through the data and build our forecast(s). It’d be wise to expect more wild swings ahead- leave it to us to try and minimize the impacts of those swings in your day-to-day personal and professional lives. Accordingly, it’s also ultra-important to factor in additional items, such as solar and PDO into the equation for the upcoming winter.
Speaking of, without giving too much away, if I’m a winter weather fan (and I am), I wouldn’t worry in the least about the current warmth… 😉
What makes seasonal forecasting so challenging (and fun :-)) are the multiple features that can impact a forecast. We’ve talked about the importance of ENSO (various types of Nino and Nina events) in past updates, as well as low solar and QBO. All of these moving parts and pieces are coming together in a manner that seems to be favoring more of a cold, wintry regime, locally, this year. Is that us saying another blockbuster 2013-2014 winter awaits? Absolutely not (there are other differences noted above with the SST configuration). However, it is suggesting that this winter will be absolutely nothing like the past couple…
In addition to the central PAC anomalies, we also are keying in on some other items of interest in the overall SST configuration:
The SST CA model is quickly becoming one of our more trusted seasonal forecast models. We note how it becomes increasingly bullish on a central and eastern trough as winter wears on (by the way, this is likely to go deep into spring this year, too).
Cold overwhelms the pattern and when you combine it with the active storm track (noted by the green hues, suggesting above normal precipitation through our neck of the woods), confidence is continuing to grow for an above normal snow season.
The SST configuration on the JAMSTEC would suggest a cold, stormy set-up, locally. That said, while it sees the above average precipitation, it’s awfully warm at the surface.
The NMME (to no surprise…) would suggest a very warm, wet winter.
As a reminder, our complete and final annual winter outlook will be posted here during the second half of October. That will include additional model data, along with several other points behind our reasoning for our winter forecast. As we always do, we’ll put “pen to paper” when it comes to our winter forecast, including our expected temperature and snowfall anomalies. Given the data above, including the warm JAMSTEC and NMME, it’s going to be very, very hard to see a warm winter here. In fact, our idea is for the exact opposite, given the SST configuration, and lines up more closely with the SST CA idea at this point. We’re also in the camp of a very, very active storm track through the Ohio Valley. “Big-hitter” potential is present from a winter storm perspective, especially given that we are likely to see resistance from the SE ridge.