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Preliminary Outlook for Winter 2011-12


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Thanks everyone! Yes, a frigid January does have a good amount of support. If I were to choose analogs for January, I'd say 1963, 1994, and 2009. I include 1994 for it's strong resemblance to the stratospheric preset, and anticipated evolution.

I hope you're right but the NAO is a lot more negative these years than 1994. Also we're in PDO cold phase.
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Strongly disagree. There is likely going to be a very tight gradient this winter, similar to past winters that are close analogs (and typical of weak Nina/-neutral ENSO). I think DC may pull out one decent month (and DC will still see the cold), but it's not going to be pretty for people south of the M/D line, especially as you head south of DC.

Weak la nina is our second snowiest ENSO signal, however, there may be other signals at play this winter (like QBO) that will play a more prominent role than ENSO.

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Thanks! I think you did a great job putting everything together, and are certainly holding yourself accountable with those detailed departure maps. I also think the throwing out dates for storms is something fun to do, even if it has a low chance of verifying, it's a good learning experience. With that said I don't know if I'll be adding that to my outlook this year. :lol:

I know we've been talking about this in our subforum-- but second and third year la ninas tend to be colder than first year ones. Of course, it can easily be colder and snow less-- at least two of our three big snowstorms last winter involved extremely delicate set ups that were thread the needle type scenarios.

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I an curious what methods you used in pinning down exact time-periods of focus with a seemingly high level of confidence?

Also wondering with the general analog selection if using active sun activity years is perhaps a bad move? Active solar periods seem to have some sort of impact on the upper atmosphere near the polar regions, too complicated/many abbreviations to type on my iPhone right now though!

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Looks very similar to 2008-09. Nice presentation.

Given that 2008-09 was +QBO and this winter will almost certainly be -QBO, you don't see that being a significant factor in bringing different patterns? Obviously, the ENSO progression appears to be pretty similar, and the North Pacific looks quite similar to 2008 at this time as well.

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I an curious what methods you used in pinning down exact time-periods of focus with a seemingly high level of confidence?

Also wondering with the general analog selection if using active sun activity years is perhaps a bad move? Active solar periods seem to have some sort of impact on the upper atmosphere near the polar regions, too complicated/many abbreviations to type on my iPhone right now though!

Started out by analyzing fourier components of current tropical wave progression. Took the resultant forcing on top of the preset to dictate the pattern evolution and storm opportunities. Any level of confidence expressed in the write up is entirely artificial ;)

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Looks very similar to 2008-09. Nice presentation.

Given that 2008-09 was +QBO and this winter will almost certainly be -QBO, you don't see that being a significant factor in bringing different patterns? Obviously, the ENSO progression appears to be pretty similar, and the North Pacific looks quite similar to 2008 at this time as well.

I avoided the explicit use of analogs in this forecast, but if I had to say, 2008-9 would definitely be on the list for a very good match to current SSTs. But yes, we're in a nearly opposite QBO state, which will certainly make an impact. So despite similarities, the forecast definitely doesn't exactly mirror 2008-9.

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  • 1 month later...

Very nice writeup, Sam. Solid reasoning brought forth with as good chance as any that I've seen to verify. I hope you're right! I'm intrigued by the 1993-94 analog because I agree in many ways. However, as mentioned earlier in the thread, the Pacific, notably the NPAC if different and NAO signal may be in opposition.

Thanks for the hard work on this and good luck!

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Thanks Jerry and Wes!

Yeah Jerry, I'm a little wary of the some of the cooling in the GOA recently. I gotta say though, some of the similarities in mid latitude SSTs with 2008 are uncanny. Primary difference is in the equatorial Pacific and Indian Ocean. Definitely a more pronounced (and Nino-esque) IOD right now. Also continue to see cooling in the east Pacific. I think this trend continues with the descending QBO easterlies. Starting to see the associated temp changes in the stratosphere.

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Wow, You had some solid reasoning, and great great information on your prediction, thanks alot man! This forum has taught me so much, from the professionals!

I gotta say, January looks to be absolutely FRIGID here in illinois if that verifys. -6,-10 degrees below normal?!?! January is always fairly bone chilling in these parts, but my goodness that's absurd.

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Wow, You had some solid reasoning, and great great information on your prediction, thanks alot man! This forum has taught me so much, from the professionals!

I gotta say, January looks to be absolutely FRIGID here in illinois if that verifys. -6,-10 degrees below normal?!?! January is always fairly bone chilling in these parts, but my goodness that's absurd.

Thanks! Yes, this forum is excellent!!

Still see plenty of support for a significant dump of arctic air in the first half to middle of January. -6 to -10 is certainly significant, though nothing unprecedented. I never make any half-hearted forecasts ;)

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In short - Somewhat cooler than normal in DCA.

99 percent probability of normal climo snowfall in DCA; however I lean toward 3 to 9 inches total snowfall for the winter in Dale City.

If you want snow, move to the Sierra Nevada, the Lake Effect snowbelts or the northeast.

That forecast for the DCA area could be in major jeopardy in January. One big Miller A could put DCA in the plus for snow ... just saying

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--- REVIEW ---

--- JANUARY ---

The first half of the month will feature a major arctic outbreak across the eastern two thirds of the nation, accompanied by a number of snow and ice threats. A thaw is likely for the second half of the month across much of the nation, while still maintaining stormy conditions in the northern tier.

Developing highly amplified quasi-stationary pattern across the North Pacific and Canada, crossing the Rockie Mountains, supports upward planetary wave propogation, and given preset of the stratosphere, a major stratospheric warming is possible to end the month of December. Following typical time scale, the NAM should respond by the end of the first week. Combined with favorable forcing in the Pacific as high amplitude MJO progresses eastward, this will trigger a rapid displacement of the Canada vortex south into the already established long wave trough in the Plains. This fits the recipe for a major Miller A storm for the eastern half of the nation around Jan 4-9.

Clipper track and Miller A track will be predominant following this event, keeping much of the nation, outside the Gulf and east coast, on the dry side. Given the expected forcing on top of the preset, should see strong blocking that will support storm tracks through the Mid Atlantic and off the New England coast through week 2.

I agree with the previous poster, it sounds like an above normal snowfall season for much of the east with this forecast.

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One last consideration for the preset is snow and ice cover, which is near all-time minimums right now. However, meaningful statistical correlation to the NAM and winter midlatitude temp anomalies is usually limited to October during snow and ice recovery. Intra-annual cycle (period ~195 days) in the NAM would suggest a high index state for the fall, which would promote a fast recovery. Also of note, the intra-annual cycle will be in a low index state for the winter...

It appears at least in the short term that this is working out pretty well. The AO has become predominantly positive in the last three weeks. There will certainly be higher frequency oscillations, but it should average generally positive through the next couple months. And this has helped bring about a colder and stormier regime over the arctic, with expanding snow cover, and ice cover now turning the corner ... earlier than past years

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It appears at least in the short term that this is working out pretty well. The AO has become predominantly positive in the last three weeks. There will certainly be higher frequency oscillations, but it should average generally positive through the next couple months. And this has helped bring about a colder and stormier regime over the arctic, with expanding snow cover, and ice cover now turning the corner ... earlier than past years

Copypasted from my post on And We Begin Part Deux

Current (2 days ago... FSU uses a delayed dataset) snow/ice cover vs average... notice especially that ice is well below average, yet snow is hugely above average:

nhmap.png

Past year's graph... last year had more ice than this year, and it had a particularly early snow cover recovery... looks like we're crossing average even earlier this year, even with much less ice... snow cover is amazing right now:

nhtime1year.png

35-55N snow cover... notice it's non-zero currently:

3555time4month.png

35-55N snow cover for the past year... notice that last year (which had a record-early start on the FSU dataset) started LATER than this year:

3555time1year.png

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In short - Somewhat cooler than normal in DCA.

99 percent probability of normal climo snowfall in DCA; however I lean toward 3 to 9 inches total snowfall for the winter in Dale City.

If you want snow, move to the Sierra Nevada, the Lake Effect snowbelts or the northeast.

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