Stormchaserchuck1

Here is US pattern 5 months after 5-straight months of +AO (Aug-Dec)

July will likely be the 5th straight month with +AO. How does that roll-forward, through March? Here's an animation of the next four 5-month periods.. as you can see there is a -0.3 H5 correlation over the Arctic circle, or a 57-58% chance of the +AO continuing (over the Arctic circle, north of Alaska at least). This is actually a little more +epo than +ao in technical classifications, in the roll-forward.

Thanks! Then it looks like it peaks even higher the next day.. getting close to 604dam around where that thread said the previous high was located. Interesting how much it matches the PDO composite for August.

603dm ridge over the Rockies on 18z GFS! I wonder what the US record is.

+NAO/+AO regime is really strong right now. It will be interesting to see if it lasts into the Fall. Last year it ended in September. Developing La Nina should push some cold waves into the US through the NW and Upper Midwest - I'm curious to see how much it correlates to the pattern, and if it's actually developing "from the top down" (from the deeply negative PDO). I've researched ENSO subsurface and found that it has a higher correlation to the North Pacific 500mb pattern than surface SSTs.. subsurface is Neutral right now but the central-ENSO-subsurface has been cooling the last few days, there is a -2c pocket now. My main concern for Winter prospects with this developing Weak Nina is if we dry up the STJ again.. but this year has been so wet, it's almost counter-intuitive. I would guess it wouldn't be as dry as last year. Will have to analog that.

A warm Fall, I think. Also higher chances for a -PNA pattern this Winter. The Rockies ridge if it establishes towards the end of the month may bring heat east in waves. It will be interesting to see how long the High pressure stays there.

18z GFS breaks 6000dm in the Rockies the last few days of July! Interestingly, this is the August correlation to PDO (for negative like we have now, the correlation is opposite)

7/31 years since 1994 have been ENSO Neutral (using 5-month ONI classification) Using 3-month classification, only 5/31 years since 1994 have been Neutral ENSO!

The difference between -0.4 or -0.6 ONI historically is a +10dm cold season difference in the Winter North Pacific High pressure

Thanks! I found this interesting

I'm surprised that seasonal models are so strong on a La Nina developing over the next few months, without strong negative subsurface anomalies. I guess it has something to do with 9 straight months of +SOI, as the SOI was a fantastic indicator last year, hinting that it wouldn't be a La Nina, with the index not going positive until the Fall.

With the PDO so negative, I think we can increase the chances for warmer CONUS Fall, at least Sept-Oct, and especially October - the pattern of the 2000s. This hit big time last year, with a counter-intuitive -0.5 correlation H5 +EPO in Sept-Oct. It may be a warm Pacific pattern in October.

Wonder if we'll finally break this strong +AO pattern, that has been there since May..

SOI data is reliable and goes back to the 1800s. Here's the top 9 positive SOI Fall/Winters minus negative SOI Fall Winters 1900-1950.. fits our post-1950 composite. In other words, this image below is the typical La Nina state 1900-1950. March included Here's precip

It's because it's not overpowering other forces. If we had an El Nino at +5c, there would no doubt be a trough in the North Pacific.

Daily PDO is hitting -3.4, they say that's the lowest daily they've ever seen. Last October the daily peaked at -3.0, and it resulted in a -3.8 monthly for October 2024, the lowest monthly reading on record going back to the 1800s.

Does anyone know that the top global sea-level pressure correlation during an ENSO event is actually NW of Australia and in Indonesia.. it's a total global-tropical phenomenon.. that >0.6 correlation in the equilateral-Atlantic is impressive, too.

El Nino favors cooler waters in the mid-latitudes where the Hadley Cell meets the Mid-latitude Cell... it's the opposite of what we have now from Japan to north of Hawaii

Yeah, the subsurface is weak right now. It's not a perfect predictor, but it has led by several months for the last few years.

Usually you like to see the subsurface colder if an official La Nina is to emerge

They are colder than I am for ENSO the rest of this year, but they probably have good reason with models coming within range.

I'm surprised that they favor a La Nina over ENSO Neutral for the rest of this year, just based on the ONI.. I guess they expect cooling in the coming months, along with seasonal models. SOI last year never went strong positive when a lot of things were pointing to a Moderate-Strong La Nina early in the year, and it ended up being an accurate predictor, per ONI it never even went La Nina last year. The SOI has been positive, July could be 10 months in row, although only slightly so, so I guess they are thinking it will accurately predict again.

I didn't see the post. Do you have a link?

This year, climate models seem to support a cooling of ENSO in the coming months. The SOI has been a good gauge for a few years now.. it has been positive for the last few days. A positive July would be the 10th straight month with +SOI, which would be a la nina or cold enso indicator. The subsurface was really warm in the western subsurface in the spring, but has since neutralized.. so yeah, maybe near neutral, or slightly cool for the rest of this year.

I'm starting to think the odds of an El Nino next year are lower, but higher chances 2 years from now (27-28).. maybe a Weak El Nino next year