Phil

It had quieted down a bit as of 30mins ago, but since then clouds have thickened and are preventing me from seeing anything.

Brightest aurora I’ve ever seen. And it was directly overhead! Sucks it was 90% cloudy but caught a few glimpses thru gaps in the cloud deck and even that was enough to take my breath away. Hoping for more!

Lmao. Fine. Cold December, warm February, below average snowfall. And lots of dry wind.

Out east as in Asia? Or eastern US? Either case, I have no idea. Depends how quickly and cleanly ENSO transitions, and the structure of the Indo-Pacific Warm Pool. Also how quickly westerly shear/+QBO downwells.

Woah

I’m not sure the GFS is finished caving.

I think that was largely due to other factors. The effects on winter patterns are state dependent because the manner(s) in which the stratosphere and troposphere interact vary substantially from year to year. However, it’s theoretically possible that the major geomagnetic storming in 2003 and 2005 contributed to the seasonal evolution of the annular mode/PV during those winters via the destruction of ozone augmenting the thermal wind.

Depends on ENSO and time of year. But the only clear-cut Niña/+IOD winter was 1999/00, which had a warm/zonal mean state (intraseasonal variability notwithstanding). Though I suppose 2007/08 and 2020/21 were borderline cases, and were more blocky/meridional overall, though the latter probably wouldn’t have been absent the SSW in February. But we’re getting ahead of ourselves a bit, as the IOD usually flips negative in late summer or autumn during developing niñas. If it’s still positive come Oct/Nov, then it’s worth a closer look (IMO).

The aurora is pretty looking, but I’m more concerned with effects on stratospheric photochemistry. Too much geomagnetic storming could hurt high latitude blocking prospects..

+IOD with developing niña would be unusual. Happened during second year niñas such as 2008 and 1999, but no first year cases that I can find in the last 30 years at least. Could very well end up flipping to -IOD sooner than projected and all this will be moot. 2010 flipped like that.

00z will probably come around even more. This run still looks like it’s digging the Bering Sea trough too far south.

NPAC digging/ULL bias strikes again.

18z GFS looks like a cave to the Euro.

Latitude of the 4CH is important. If it’s centered too far south it inhibits moisture advection.

That seems about right to me. There might not be much of a SW monsoon this summer, though.

We’re supposed to root for La Niña, though. Right?

This would be wild.

To simplify it, the poleward transport of westerly momentum (culminating as a stronger/poleward northern jet) can “abandon” components of middle latitude waves. Which under certain wavenumbers (and other seasonal boundary conditions) can guide those waves into a state of quasi-resonance and/or amplifying constructive interference. The timing of all elements has to be absolutely perfect for an outcome like June 2021. The probability of that happening is so low that it almost never happens.

I’m not as confident as you w/rt the downstream/PNW ridge, but agree the GFS solution near/south of the Aleutians is BS. That’s a classic GFS failure mode (phasing/deepening ULLs). The operational CMC shows how a big western ridge could legitimately happen. Very different than the GFS over the NPAC.

Actually looks like more GEFS and GEPS ensemble members moved towards an ECMWF-like solution (though not necessarily all the way). The CMC may look similar in the PNW but upstream it couldn’t be more different than the GFS. That’s an entirely different universe.

I don’t know if y’all remember but my idea for summer 2017 was an epic fail of monumental proportions. It was the worst seasonal prediction I’ve ever made. That was the year of the fluky niño-costero that developed during the second half of winter, before collapsing and reversing to an EPAC niña during the summer. Perfect reversal inside 3 months. It was an unprecedented evolution in the post WW-II era, and it threw me through flaming hoops upside down and butt-naked. Will never forget that one. Learned a lot from it, though.

Indeed. But tropical forcing (both intraseasonal and low frequency/ENSO) was structured very differently that year. And to be fair, I was predicting a massive 4CH that summer with lots of western heat centered over the Interior West/inland PNW, but that got overshadowed by that fluky 4-day aberration that was a 1-in-500 year wave entrapment event (we might not see it again in our lifetimes). My misfire on the most prolific heatwave in PNW history is especially annoying because everything else that summer I nailed to a tee. But that’s not what people will remember. Story of my life, haha.