cbmclean

As you have mentioned many times it is likely that there are at least two additive factors at play in our recent snow woes 1. The perma-SER courtesy of the -----PDO 2. Pack puke episodes which are more frequent, stronger, and longer in duration due to pac warm pool/hadley cell expansion/Babar The PDO flipping should hopefully help with factor 1 but I don't know of any reason why it would help with factor 2. So when the PDO flips it's a matter of do we get 80% back or 20% back (or whatever). I think 100% is out of reach sadly.

Can you stop by Wilson, NC on the way down, pick up their snow climatology and take it back to them? I don't want it here.

I know I take things literally but I was not being serious about the infinitesimally slow decrease in rotation rate causing climate impacts on a decadal scale. I was just poking a bit of fun at those mocking Chuck.

He's correct, at least about the slowing part. https://www.science.org/content/article/ancient-eclipses-show-earth-s-rotation-slowing

Now that we have established that @psuhoffman is a stalker, I propose we just start a PDO watch, sort of like how Nightline started specifically to follow the Iran hostage crisis.

Meh, you might care too much about what they think.

That would make sense to me if the arctic cold pool was "standing its ground" as it were, but since the high latitudes are warming faster, I would expect arctic/polar jets to retract faster then than the STJ, thus lessening the latitudinal temperature gradient and leading to weakening of the jets.

I hope you're right...

That was what made it worse than 2019 to me. That year the epic look hovered just outside d16. But this year it was moving nicely up in time and then.... Just so frustrating.

Do you find that unexpected or surprising?

RDU record is 1,164 days from December 1989 to Feb 1993: https://abc11.com/north-carolina-snow-nc-drought-last-time-it-snowed/14449555/

Sure, but I was more referring to the fact that a +PDO might not have saved the Jan 6-7 event. But perhaps it might reduce the probability of such events because the cold wouldn't have to constantly fight against SER and thus it might take only 1 - 2 weeks for thermals to recover from pac puke instead of 3 - 4. It's all speculation of course. We simply watch and wait.

And I fear that this one is one we're not getting back because even when/if the PDO flips we'll still have the pac puke. This wasn't primarily a SER fail but the fact that the entire continent was taking weeks to recover from the near-record pacific onslaught that almost completely eliminated snow in the CONUS outside the high elevations. I think it is the tag-team effect of the PNA/SER and Pac Puke which has made this last period so hostile. A pac puke comes along and scours the cold out. Then once it shuts off the source regions begin to recover, but the PNA/SER tendency constantly fights against the cold making it to the eastern conus. It takes weeks to slowly push the thermal boundary back over us and then it just gets wiped out by another pac attack and the whole things starts over. I have hope that a PDO flip can improve the PNA/SER tendency, but I don't see how it can help much with the jet stream/Hadley cell problem. So at best we'll hopefully be able to recover faster from the pac attacks. I hope I'm just being pessimistic.

But is it a "reflection event" or an "absorption event"? Because if we have the "wrong" one it's just dookie.

One of my hobbies is now researching the nature of the PDO. Laugh at me but I usually start research on Wikipedia(it's a great place to get an overview!) and I came across mention of an "Interdecadal Pacific Oscillation". Anyone ever heard of that one before? https://en.wikipedia.org/wiki/Interdecadal_Pacific_oscillation

I'll have to see some studies on that; until then I see it as just idle speculation.

I've been told I'm a literalist.

I didn't really get the impression that the PDO was the number one villain this year. Sure it didn't help, but if I had to pick my number failure mechanism it could be the frequency/strength/duration of pacific trough jet extensions. The first event took out four weeks of good climo and was primarily the cause of the failure of the otherwise promising early January period. The second event killed late January and early Feb. Likewise the collapse of the modeled epic pattern in late Feb was due to the failure of the advertised HL blocking. Is that connected to the PDO?

Just curious, what is the risk?

They are definitely already working on this. Several AI or AI/physics hybrid models have been posted on the site this winter. They have the potential to be powerful but one thing to remember is that many AI methodologies (e.g. artificial neural networks) have to by definition "learn" by using past data. As has been mentioned many time here past data may have limited relevance in a changing climate. That may limit their effectiveness going forward.

I try to be open-minded. I agree that we probably place too much confidence in modeling in d10+. And I understand that human knowledge can do a lot from simple analysis roll forward say to ~ day 3. But from day 3 through day 10 I truly don't see any alternative to model-based forecasting. If you have a different alternative to propose I would honestly like to hear you out.

What, in detail, is your proposed alternative to model-based forecasting?

Maybe at some point we can max out the register and cause it to roll over into colds again.