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Wes Junker's Presentation - 2012 AmWX conference


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My Summary/Paraphrasing - Great Presentation

Wes Summary (My Paraphrasing)

- For Big snow seasons, El Nino becomes less and less important as you go north

- 500 MB NH anomaly for DC biggest seasonal snowfall years shows much more blocking and southern stream than Boston and NYC for their top 10

- +PNA for DC needed, not as much needed for BOS..which has big snow seasons with a -PNA and a ridge over the Aleutians

- For all I-95 cities, the worst Snow seasons have a very +AO composite, so much more similar for BAD winters

- need Tropical forcing near dateline versus over the Indian ocean for a tendency toward Blocking, but usually there in Ninos anyway

- Midwest big snow years has massive dominant northern stream

- for Big snow, especially near DC, need forcing near dateline versus Indonesia, for strong STJ and usually biases toward -NAO

- FEB best for Southern stream in Mod/Strong Nino, backloaded winter...don't worry if NOV/DEC suck

- Southern CA often wet with the stronger ninos, mudslides

- weaker Ninos, less southern stream, even some ridging in deep south/FL, often Cold Anomaly in west that spreads toward the northeast

- for DCA, region 3.4 anomaly, bullseye is 1.2 to 2.2, with an exception or 2

- Big statistical difference in Ninos for DC is median closer to the mean, 50-50 above versus below snow which is much better than usual

- AO so important too, even though Nino and AO probably work in synchronicity

- Crappier DCA nino years tend to have -PNA, suppressed southern stream and blocking over Baffin Island versus central/east based NAO...see 72-73 for the 1st 2 factors...another crappy year 91-92 had same thing...no cold air, +AO...97-98 another example...strong STJ but too warm...trough in west...everything sheared out when it comes across the south...often blocking over Europe

- So +PNA, -AO, -NAO best combination

- We need the cold air to be held in by high latitude blocking....need it for the big storms

- AO probably more important for big snowstorms and winter than NAO which is smaller scale

- very hard to tell where tropical forcing is most important since it usually sets up over the dateline in a Nino anyway

- 1/27/98 example of easterly component, closed off too far north, couldnt hold sfc high in place, no 50-50 low/NF trough/Confluence, same as Randy infamous MLK storm

- 2006-07..not enough southern stream, too strong PAC jet, nasty vortex over GOA

- Big Boston snows, Ridge further east over Central Conus, need it further west for DCA

- Sample Size so small, hard to say must be a certain way with a nino....just tendencies

- Hard to forecast AO/NAO much in advance even though folks have their different methods, but some methods that MAY help - SSW's (more common in Nino, but misunderstood, Autumn snow cover, Westerlies, MJO, ATL SST's (tripole - chicken/egg), Solar Flux, Geomagnetic Field, 30mb zonal winds in November...but weak correlation with each on their own...Wes not a big fan of any on their own

- SSW's misunderstood, especially last winter

- Wes wants to roll the dice with strong Nino...97-98/72-73 not a foregone conclusion

- Funny References to 53, Mitchnick, JI, CT blizz, Bethesda Boy

- Easterly QBO/Solar Min plays a role...more tropical convection, earlier SSW's, lower GLAAM

- Wes wants to see strong -AO in November

- MJO much less impact in Nino than Nina because of default forcing in same place

- Models break down strong AO patterns too early....much more stable patterns than models suggest...hard to dislodge and flip so very important in early season

THE END, great presentation

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Awesome! Thanks for this. More great presentations ahead and I wish the O's weren't playing so that I could be there. I hope everyone, especially the out-of-towners, have a great time in Bmore.

The heck with the Os they play 162 games. Great summary Matt. Well done and easy to understand

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Matt, Good summary. I'd say I want to see the Ao be strongly negative 3 standard deviations or so early in the winter, December or even early Jan would also be good. About the stratospheric warming events. They do sometimes make a difference and can drive the pattern but you need the warming to propagate downward and to get that you want something called the EP flux to be pointed at the pole rather than the equator. It was nice seeing everyone at the conference.

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If your PPT slides are still on my laptop, can we have your consent to post them here?

I was going to modify them and use some of them for CWG articles which might lead to copyright issues. Therefore, I'd like to hold off on posting all the slides from the presentation. I'll post some of the stuff I know I won't use in the NYC and New England Forums. Later this fall, once the CWG articles have been posted, them the slides can be posted, until then, it would be better if they were not posted.

Wes

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