griteater

40/70 - thing is, at 500mb, a composite of the last 2 winters (below) looks like La Nina instead of El Nino with NPac ridge and -PNA. So, when I composited the last 4, it came out to kind of what I had in my head for this winter in the big picture. +QBO this winter would favor a more poleward NPac ridge. That composite of mine does have a poleward ridge (no negative anomalies in Alaska), but it's biased to the NW. 4 of the last 5 mod-strong Ninas with a poleward NPac ridge were biased to the NW ('56, '71, '74, '11) . '89 is the lone exception. One thing that would support the idea of a suppressed NPac ridge would be a strong +AO. The seasonal models favor a suppressed ridge at the moment. AO/NAO are always a challenge to figure out. Anyway, those are some thoughts on it...hope I will have time to put more into it the next 2 weeks...my work has been busier than normal of late.

My first guess on winter...

raindance - is this your SOI 10 point drop storm?

Yes. It will end up being classified as east-based or hybrid/mix. If it were west-based (Central Pacific), the max cool anomalies would be centered roughly along 160W thru the fall/winter.

Monthly 500mb anomaly forecasts from the Oct release of the seasonal models via Oct Copernicus ECMWF update (via twitter @SimonLeeWx). Overall theme from the models is high latitude blocking in Dec, transitioning to -PNA / +NAO in Feb

The Met Office prides itself on its predictions of the NAO with its seasonal model. I looked at the NAO prediction from prior October seasonal model output back to Oct 2009 (this is the oldest date in the archive on the seasonal model site - https://www.metoffice.gov.uk/research/climate/seasonal-to-decadal/gpc-outlooks/ens-mean). In looking at the charts, I would say that in 9 of the 11 years, the October prediction of the NAO on the model was a good one. The 2 misses were in Oct 2013 and 2015. Here was the Oct seasonal output from 2010 and 2011 - both quite good with the NAO prediction (-NAO in 2010-2011 / +NAO in 2011-2012), with both of those being La Nina winters. Finally, here is a chart from the Met Office showing hindcasts for their prediction of the NAO with the GloSea5 seasonal model for the winters of 1993 to 2012. The results are pretty good. Note: this is the NAO prediction from the Nov1 release each year - https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2014GL059637

^ Other somewhat similar years to these 2 model outputs are: 2011-2012, but the +EPO/+NAO was even stronger in the analog year 2007-2008, but the negative height anomaly extended much farther south (down into the southern plains) in the analog year 1999-2000, but the negative height anomaly was farther north from Alaska to northern Canada

The October release from the Euro Seasonal (ECMWF SEAS5) and Met Office / UKMet Seasonal (GloSea5) are similar for Dec-Feb with +EPO and +NAO, and lots of zonal flow. They are most similar to the winter of 1998-1999. Are they correct? Time will tell, but they paint a grim picture for cold and snow across the lower 48. Euro and UKMet Seasonals... 1998-1999 500mb, Temperature, and Snowfall Anomalies...

Opening up this thread for cross regional discussion prior to and during the winter of 20-21 One of the well-known 'problem areas' in recent winters has been the highly positive AO & NAO. Here is a map showing how the 500mb pattern from the winters of 11-12 to 19-20 (last 9 winters) has compared to the winters of 02-03 to 10-11 (12-20 minus 03-11). Getting the AO/NAO even back to neutral would be a step in the right direction. Last winter alone, the AO numbers were kind of astounding. The AO was +2.42 / +3.42 / +2.64 for Jan / Feb / Mar. That's the highest on record for Jan-Mar going back to 1950 The October release of the Euro Seasonal predicts the greatest potential for a -NAO to be in December, with higher values predicted for Jan-Mar. The purple covers the range of ensemble members on the Euro Seasonal (purple line is the median). The gray area is the model climatology. The yellow and orange is from the analysis in the 24-year hindcast period

psu - enjoyed your write-up. Regarding the orientation of the North Pac High during cool Enso winters, I wrote a bit about this in an outlook from winter 17-18. Take a look at the section titled "North Pacific Pattern" https://www.americanwx.com/bb/topic/50432-griteaters-winter-outlook-17-18/

It was 1046 over NW Iowa Thursday at 7AM - https://www.wpc.ncep.noaa.gov/dailywxmap/index.html

I ended up with a Trace

It's tough getting that high in just the right spot. If it's up over the NE, it can want to slide out too quick too, as you know. Going back to that post I made the other day, it was in the mid-80's today in South Florida....so, I was OK with where the high was located - the bigger issue to me was the subtropical ridge was putting up a strong resistance to allowing the cold air to sink south.

Just pulled an HRRR sounding for 4pm right around Greenville and it shows a very shallow warm layer at the surface and a warm nose that's maybe +0.5 C deg at 800mb

It really is....everything just has to fall right when it's like that. Things like, snow hard to get temps to crash and get that first layer down, snow when the sun is down, etc.

The RGEM kept showing 0.2, 0.2, 0.2 for precip, but no, I ignored it

South of a line from Chattanooga to Cape Hatteras, the radar has looked straight horrid....guess it'll get going down east NC later on, but dang. Where's the "What did we learn" thread?

Winter forecast still on track

Ground temps guy has arrived...we are ready now for the storm!

"Can you take me high enough?!"...from the band "Damn Yankees"

What brought you back? An offer you couldn’t refuse?

^ Stronger +IOD look too, which makes sense (I think it will linger thru winter because of how strong it’s been )

You can get SST reanalysis maps back into the late 1800's here - https://www.esrl.noaa.gov/psd/cgi-bin/gcos_wgsp/printpage.pl