raindancewx

Been doing research trying to predict the PDO. Seems like the March-August PDO values (Mantua) are either "eaten away" or "reinforced" by whatever the temperature anomaly is in Nino 1.2 during October. In other words, if its a positive PDO in March-August, but Nino 1.2 is cold in October it will trend to lower values in winter. If it is a positive PDO March-August, and a warm Nino 1.2 in October, it stays positive or becomes even more positive and so on. Well anyway, we had a positive PDO in March-August 2017 (+0.62), but a cold Nino 1.2 in October - and so the general idea on my end was that Nov-Apr would trend down from Mar-Aug levels. October PDO value just came in --> +0.05 --> lowest value since December 2013. Depending on the data-set you use, the blend of Mar-Aug 2017 and Nino 1.2 implies +0.1 for the PDO in Nov-Apr, +/- 0.4, at around 90% certainty going by 1994-2016 (excluding 1997, since Nino 1.2 has never been that nearly warm since 1930)

The JAMSTEC has switched to a slightly cold winter for much of the SE / SC US. Kind of went from what I expect (cold interior West) to a blend of what cerakoter had and what I had. Very different from what it forecast last November.

It won't be of much use for this winter, but I've been working on a "Modoki" calculator for winters - will be useful if we go into an El Nino. Works fairly well using Nino 1.2, Nino 3.4, Nino 4 SSTs (raw) in October, with a recognition that each Box, Box A, B, C, must be calculated separately for the Modoki number to work correctly. The weak La Ninas and weak El Ninos seem to have their cold directly controlled by the structure of the Modoki signature, and with Box C warming quickly over time relative to the other boxes, certain types of events are becoming more likely.

My winter analogs weren't really "designed" for November, but they had everyone east of a line from Biloxi to Billings cold, and everyone west of that line warm. So far the cold has been more centered over Montana, but it does look like it will drain East for a while now.

I'm somewhat familiar with ONI/PDO/AMO/Solar values for years before 1950, but I generally forbid myself from using anything before 1931 because there is no snow data for where I live, so its kind of pointless to look at for me. But I did want to ask you...what do you like about 1917-18?

The thing about this winter is I think there are three components to the pattern: 1) Cold interior West, very warm elsewhere, wet NW, near avg moisture SW (Sept-Oct) 2) Warm SW/SE, Cold Midwest, Mild NW/NE, Wet South (June) 3) Mild/Dry SW, Very Hot NW, Coldl/Dry (MW/NE), Mild/Wet (SE)

Congrats Texans on winning the World Series - we gave you Giles & Bregman from ABQ - so pleased to see them get their rings.

One of the things I've always struggled with is trying to figure out the moisture signal in the SW in the cold season, since it is so dependent on the PDO. PDO+ seems to largely cancel out La Nina effects here except in November, April & May. But it looks like the PDO can be predicted by matching the Nino 1.2 reading in October before Nov-Apr, and also the PDO value for March-August before the Nov-Apr. There are never a whole lot of blends that allow an acceptable close blend on those two factors, but when blended correctly, you predict Nov-Apr surprisingly well, at least for the 10 years I have tested so far. Long and the short of it is that Nino 1.2 was frigid in October, which should keep the PDO somewhat negative, but it was still positive in Mar-Aug, which favors for somewhat positive. So I don't think this La Nina forces the PDO super negative just yet. Going by the Nino 1.2 weeklies, Nino 1.2 was -1.4C in October, v. +0.3C last October. (the blurred out years for 2009 are 1967, 1991, 1991, 1991) Oh and I left out 2011, which is a blend of 1952, 1971, and 1999.

Any of you use Weather Trends 360? Don't subscribe, but they linked this on Twitter yesterday - thought it might make some of you happy.

Puerto Rico isn't directly hit by hurricanes super often - but the years it has been smacked around by big time hurricanes produce a pretty good match to October for a one variable match. Hot lakes, cold ID.

I don't think this is a terrible winter for cold in TX or the SW. Might be for moisture...but it should be much colder than last year. The cold in October is displaced much deeper into the West than last October, which is what my analogs had for the winter. So its not going to be cold...we're just closer to the cold sourcing, so the cold shots will be more frequent and stronger.

I think is kind of a nuts winter personally, even though on aggregate it will probably come out relatively close to average in a lot of places. Part of me thinks TX could see some kind of fluke storm in late winter, like a blend of a Blue Norther with subtropical jet moisture. October here is directly correlated to December in La Nina, so if we end up 3-4F colder, that alone favors more cold in the SW in Dec. 2016: 75.9F (+4.6F) -->49.7F 2017: ~72.5F (+1.2F) --> ?? I put this in the MO thread, but some of the analog years I like had good snows pretty deep into the South.

I dunno if the "snow" anomalies I'm linking include sleet/freezing rain, etc, but this forum region did pretty well in terms of snow anomalies in a lot of the winters I like. If SSTs mean anything, its a good sign, since the blend is very close to current conditions. Sanity check for analogs in Oct of analog year v. Oct 22 2017:

I don't have much faith in the CFS this early, but it continues to insist on a dry NW for the winter...AND a La Nina.

Even in populated areas of New Mexico it can occasionally snow in June & September. Snow is favored precip time above 7,000 feet or so from October to May. Nice pics. Was hoping for some snow in the city this October, but not looking likely. It only happens once a decade though. Suspect my forecast will do OK, with some issues, something always comes up. Last year it was pretty good for January nationally, less so Dec/Feb. As far as I know New Mexico doesn't have any glaciers, the permanent snow/ice line here would be like 15,000 feet above sea level, but obviously the big time mountains get close - I think July is really the issue - even at 13,000 feet its rarely cold enough to snow here in July. "Beautiful Incredible Place" is how I'd describe most of New Mexico really. If you're back by June you will be able to see the white stuff on the higher peaks. Mountains will keep getting snow into mid to late May most years. Even in the city we had an inch of snow in some areas on April 29th this year. The volcanoes (5800 feet) outside the city were the lushest I had ever seen them a few days after it melted, covered in beautiful green grasses, flowers, mud, and wildlife.

I have the West pretty warm in Nov, but should be fairly cold TX to ND and east.

The JAMSTEC update agrees with what I put out - somewhat warm - but pretty wet in MO/AR etc. The run in Oct last year was pretty bad for the NW (temps) but it did have the big time warm winter right overall. Its nice to see it colder this year. It was pretty good on precip last year, except that the wetness hit CA & not the NW. But it has MO/OK/TX/AR wet - and it had them very dry last year (correctly). The Jamstec is close to what I have. I don't really buy the Temperature/Precip outlooks from the models for winter until October, but its nice to see big differences from last year.

I think so. I agree with Weatherbell and some of the other forecasters out - its kind of an ice storm pattern. I think its pretty wet in the south other than Florida.

The biggest thing the ice has going for it in the winter is that the AMO anomaly tends to end up at about 60% of its Summer values in Winter - which would be a much colder Atlantic than last winter. Last Summer was like +0.45 and went to +0.279 for Nov-Apr. This year, more like +0.325 in July-Sept, been assuming +0.15 or so for Nov-Apr, which is much less rare in terms of warmth.

We've had some really nice days here lately - down to the 30s the other night, with highs in the 60s, and then low 70s today. Some of you seem interested in skiing, and others talk about "snow fixes" so I included some snow data for the high country in winter outlook if any of you are interested. I'm expecting a pretty decent season up by Chama & Red River against their long-term averages. https://tinyurl.com/yam55n95

https://tinyurl.com/yam55n95 The link is my winter forecast, if anyone is curious. Ended up using the following for analogs, which gave a weak, slightly east-central La Nina, which isn't super far off from what the Canadian showed. Analogs: 1932 (x2), 1943 (x3), 1944 (x3), 1996 (x3), 2005 (x3), 2007 (x3), 2008 (x2), 2012 (x1). If any of you like to ski, I included some snow totals for the mountainous areas of NM as a proxy for whether ski season will be good or not.

I'm somewhat optimistic for a cooler winter than last year for the SW & SE - in my area two big early predictors both favor less warmth - the number of 87F days (we had 96!) and the AMO in July to Sept. AMO in July to Sept was 0.325 or so. Last year, 0.460. That's worth around half a degree of cooling. The increase in 87F days, fro 83 to 96, is worth about a degree of cooling. Expecting the winter here to be around 49.6F, +/-2.2F. Will put up my winter outlook tomorrow.

Part of me wonders if there will be some kind of lag in the Nina response just because it has been reversing lately - third column is Nino 3.4. 06SEP2017 20.4-0.1 24.3-0.6 26.2-0.6 28.7 0.1 13SEP2017 19.7-0.7 24.0-0.9 26.1-0.6 28.7 0.0 20SEP2017 19.3-1.1 23.9-1.0 26.3-0.4 28.7 0.0 27SEP2017 19.5-1.0 24.4-0.5 26.5-0.2 28.4-0.2 04OCT2017 19.3-1.4 24.7-0.2 26.7 0.0 28.7 0.1 I guess it could reverse in record time, but Oct 1-9 looks like it had an anomaly of -0.2C in Nino 3.4. So into Nov/early Dec it seems like a Neutral pattern would prevail. Basically, I think the Euro will trend a colder for Dec for the middle of the US when it accounts for that. I've been assuming, -1 to -2F for Dec, +/- 0.5 for Jan, and then +3 in Feb for my area. So it isn't that different from my thoughts (it has +1 for Jan and +4 for Feb for me).

Nate is almost identical to 1932 also - a tropical storm formed in the Caribbean on Oct 5 and hit LA/MS as a strong tropical storm / weak hurricane from the same direction.

I want to see what the AMO value for September was, but pending a sudden warm up / cool down from the hurricanes, I like a blend of 1932, 1943, 1944, 1996, 2005, 2007, 2008, 2012 for the winter. Tried to pick warm/neutral AMO years, with a mix of positive PDO/negative PDO years, low solar, La Ninas or Cold Neutrals after La Ninas, similar values to what I expect on the Jamstec's Modoki index which goes back to 1870. Also try to blend it all in a way that matches Summer rainfall patterns here, since we get so little rain even in the wet season. Weighting is something like: 1932: x3 1943: x2 1944: x3 1996: x3 2005: x3 2007: x3 2008: x2 2012: x1 I think it's a much colder, but still not particularly cold winter for much of interior South, South Central, and SW US. 1932-33 was one of the winters that triggered the Dustbowl so hoping it isn't that dry, but with a VEI6 volcano in the tropics, and a hurricane hitting SW FL, a four hitting Puerto Rico & TX, something is similar - whether its Nino 3.4, trade winds, or the Atlantic, its not like Puerto Rico & TX have both been hit by fours in the same year in any other year since 1850. I'm almost done writing my winter outlook, will put it out sometime between 10/7 and 10/15. Want to see how much rain we have in Oct and a couple other minor things.