Ridiculously Resilient Ridge

[morganism]

Daniel Swain of weather west fame.

Remote linkages to anomalous winter atmospheric ridging over the northeastern Pacific

http://onlinelibrary.wiley.com/doi/10.1002/2017JD026575/full

"Severe drought in California between 2013 and 2016 has previously been linked to the persistence of atmospheric high atmospheric pressure over the Pacific Ocean (nicknamed the "Ridiculously Resilient Ridge"), which prevented winter storms from reaching the coast over several consecutive years. "

[Neven]

I couldn't find a separate thread for this, so I'll let it stand. But I've changed the title as separate threads on papers coming out will clog the forum very fast (and the title contained a typo).

[morganism]

New insights into the Ridiculously Resilient Ridge & North American Winter Dipole

http://weatherwest.com/archives/5982

1) Atmospheric pressure patterns similar to the Triple R are now occurring more frequently than they did in previous decades.

2) The unprecedented magnitude and persistence of recent West Coast ridging can be traced (at least in part) to regionally-accentuated warming of the lower atmosphere.

As is often the case in scientific endeavors, these early findings raised more questions than answers. These lingering questions motivated us to continue our analyses, which resulted in the two new scientific papers discussed below. (And additional work remains in progress.)

[Jim Hunt]

Stefan Rahmstorf is "tweeting" about this topic:

https://twitter.com/rahmstorf/status/938686201065811968

California drought linked to sea ice loss in the Arctic via Rossby waves in the atmosphere.

[A-Team]

California drought linked to sea ice loss in the Arctic via Rossby waves in the atmosphere.

The focus of the forum seems too narrow. Perhaps something about rapid onset of climate change on the exquisitely sensitive western margin of North America with the ocean affected as much as the air. No need to wait for 2020 much less 2100, it's here now.

The Cvijanovic 2017 article is open source, quite readable and light years ahead of weather west (correlation is not causation; see also p-hacking: https://en.wikipedia.org/wiki/Data_dredging).

There's a LATimes piece about it too. It is a different notion from the J Francis papers, being a two-stage teleconnection from Arctic ice loss to tropical convection to stationary North Pacific geopotential ridge development which blocks Californian and indeed Southwestern precip.

(As in the Southwest summer monsoon was disrupted, it hasn't rained since Aug 3rd and temperatures have averaged 8-20ºF too high since March, attributable to a stationary high over the Great Basin when the NWS dares step out of their daily weather trivia box.)

https://www.nature.com/articles/s41467-017-01907-4
http://www.latimes.com/politics/la-na-pol-climate-california-20171205-htmlstory.html

[morganism]

Starting up again, lots of cold waves headed for the NE

New insights into the Ridiculously Resilient Ridge & North American Winter Dipole

https://weatherwest.com/archives/5982

"Other work has suggested that unusually warm ocean conditions in the “extratropical” Pacific (i.e. the so-called “Warm Blob” in the Gulf of Alaska) may also be linked to the persistent ridge—though there’s considerable evidence that the atmospheric Triple R caused the oceanic Blob, rather than the reverse"

[morganism]

The Ridiculously Resilient Ridge returns…again

https://weatherwest.com/archives/8692

"In the past, I’ve cautioned that the existence of a “Ridiculously Resilient Ridge”-like feature is really only discernible in retrospect, when we can be certain that there was actually multi-month persistence of anomalously high mid-tropospheric pressure (geopotential heights). Well, I just looked back at the dismal 2020-2021 season, and…it’s back. "

It’s worth noting that this persistent North Pacific ridging and subsequently very dry California winter was well predicted by the seasonal models this year (which is not always the case!). It’s a predictive success that will unfortunately have seriously implications for the deepening drought across California and the broader West."

[morganism]

"SST Blob in the eastern pacific responsible for oppressive heat in NW. Once the cool SSTs off the west coast warm up, it is game on for major heat everywhere. Stay tuned and cool!

https://twitter.com/realwxforecast/status/1411776147579457539

"A 600dm ridge (recently called a "heat dome" in the media) is beginning to show up in the models across California and desert Southwest. Another extreme western U.S. heat wave is looking probable later next week.

[morganism]

Strong, persistent West Coast ridge developing; warmer and much drier for most of CA

https://weatherwest.com/archives/12616

In the coming days (and probably for the next 2-3 weeks), a persistent ridge of high pressure will set up shop just west of the West Coast–effectively blocking the jet stream and bringing an end to the December parade of cold storms across California. There is strong multi-model ensemble agreement regarding the overall persistence and (more importantly) positioning of this ridge, which will very likely keep most or all of California somewhat warmer and much drier than average for mid-January over the next 2 weeks. 2-week dry spells are not unusual in California, and indeed seem to have a slight climatological preference for the month of January. So this multi-week ridge, in and of itself, is not especially unusual for this part of the world. How long it persists into late Jan, Feb, and beyond is more important from a seasonal and drought-busting (or not) perspective (more thoughts on that below). All in all, though, it appears this will be a prolonged period of fairly benign weather across California and much of the rest of the West. After the December deluge, and enormous Sierra Nevada snow accumulations, this pattern will cause statewide snow water equivalent “percents of average” for the date to fall precipitously–from about 133% of average for the date (as of today) to around or perhaps even below 100% of average for the date by late Jan."

[morganism]

(...)"it looks very dry and warmer than average essentially statewide. The reason? Well, it’s the same old story: an increasingly resilient ridge of high pressure keeps re-developing and re-strengthening just west of the West Coast, in a perfect position to deflect the Pacific storm track. This is, of course, a familiar refrain: it’s highly reminiscent of the Ridiculously Resilient Ridge pattern of recent years. While I’m not quite ready to pull the adverbial modifier trigger yet, we’re almost there if this thing persists through much of February (as appears likely). "

https://weatherwest.com/archives/12924