raindancewx

The PNA is supposed to flip 1/20 or so. That makes sense given that we have real storms in the forecast again down here, which tends to happen when it flips. The other result is the cold should start to bleed into the Northeast. The long-term correlation of a +SOI December = Warm South February also appears to be setting up now as get near February following a +16 SOI reading in December (top five last 90 years).

The time frame supported by the big system southeast of Kamchatka in late December and the recent large SOI crashes does look like it will have a big storm. Already looks like Albuquerque might get screwed by a big East wind with that system. It is only 4.5 - 6.5 days out though, and the GFS & Euro both show a lot of moisture with it. It looks like a strong system from the Gulf of Alaska so maybe it is pulling in subtropical moisture. I don't really look in detail until we're within 3.5 days of the entire event.

It's interesting looking back at the +NAO in November. The value was +2.54, and then -0.30 in December. So far, the winter correlations are far closer to what you'd get from looking at +NAO Novembers rather than -NAO December or January years. You can see that the cold in the interior West and warm east look shows up after a +NAO November on the correlations map (blue = neg correlation to positive NAO, i.e. cold). That wasn't perfect for December, with Florida pretty cold and a lot of the South near average, but it's not bad for a map generated from one variable. CPC has the West heavily favored cold in the 6-10 day period, and it's already been cold in some places in the West for January to date. The new incoming cold may focus on the Northwest though, which again is consistent with the +NAO November.

The storms in Sept-Oct came through when the WPO was in the opposite phase. Some hints it may flip back by the end of the month. I'd imagine it will be easier for the bigger cold/wet Fall storms in an otherwise warm pattern to recur if the WPO does flip. The subtropical tap may also open up a bit for storms if the pattern really does flip as much as it is supposed to in a week or two. The PNA is forecast to go negative for the first time in what...two months? The GFS has been showing something around a week from now, but it does look moisture starved.

The time frame I mentioned above (1/14-1/18) for the Bering Sea Rule is now supported by the recent SOI crashes too (1/18-1/19). The theme this year has been moisture starved northern branch systems, so no reason to deviate from that until proven otherwise. 9 Jan 2021 1011.86 1006.35 4.25 19.34 10.60 8 Jan 2021 1013.12 1005.30 15.13 19.56 10.69 7 Jan 2021 1014.99 1004.95 25.58 19.23 10.68

Keep your eye on that cold spot in the North Pacific. With some additional eastern Nino zone weakening and the north Pacific look, we could go to a Jan-Apr 2017 pattern fairly quickly. The PNA is forecast to go negative for the first time in a while, so there do seem to be changes coming with Nino 4 taking over as the coldest Nino zone compared to averages. It is interesting to see the PNA (projected) flip coinciding perfectly with the Bering Sea Rule and then also the recent big SOI crash. Some kind of big system is coming I think.

Nino 4 has emerged as the coldest zone on the weekly data. Pretty neat to see that after it's warmth for the past decade. Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 09DEC2020 22.4-0.1 24.3-0.8 25.4-1.2 27.7-0.8 16DEC2020 22.0-0.8 24.3-0.8 25.6-0.9 27.8-0.7 23DEC2020 22.1-1.1 24.5-0.7 25.7-0.9 27.6-0.8 30DEC2020 22.2-1.3 24.4-0.9 25.4-1.2 27.3-1.1 06JAN2021 23.1-0.8 24.7-0.8 25.5-1.1 27.1-1.2 For all the hype about this event ending up a strong La Nina in the Fall, it's not even close to recent big La Ninas like 1988, 1999, 2007 or 2010. It's really a bit behind 2011 overall. 07DEC2011 21.4-1.0 23.9-1.2 25.5-1.1 27.5-1.0 14DEC2011 21.5-1.2 24.1-1.0 25.6-1.0 27.4-1.1 21DEC2011 22.1-1.0 24.5-0.7 25.6-1.0 27.2-1.3 28DEC2011 22.6-0.9 24.4-0.9 25.5-1.1 27.1-1.3 04JAN2012 22.7-1.1 24.6-0.8 25.5-1.0 27.2-1.2 Part of why I used 2007-08 as a major analog for winter is because it does get very cold - eventually - in Nino 4 that event. But it's much slower than in 2010-11. We're still pretty close to 2007-08 in Nino 4 even as the other areas drift away from. In 2011-12, the La Nina didn't really drop Nino 4 below 27.0C - I think this event may still briefly get significantly under that threshold. We've been running 0.2C or so above 2007-08 Nino 4 readings pretty consistently. 26DEC2007 21.9-1.4 23.7-1.6 24.9-1.6 27.0-1.4 02JAN2008 22.6-1.1 23.9-1.5 25.0-1.6 26.8-1.6 09JAN2008 23.3-0.8 24.0-1.5 24.8-1.8 26.6-1.7 16JAN2008 24.1-0.4 24.0-1.6 24.6-2.0 26.6-1.7 23JAN2008 24.1-0.7 24.1-1.7 24.4-2.2 26.4-1.8 30JAN2008 25.1-0.1 24.7-1.3 24.9-1.7 26.5-1.7 06FEB2008 25.9 0.3 24.8-1.4 24.6-2.1 26.4-1.8 13FEB2008 25.9-0.1 24.7-1.7 24.5-2.2 26.4-1.7 20FEB2008 26.7 0.6 25.1-1.4 24.9-2.0 26.4-1.7 27FEB2008 27.2 0.9 25.8-0.9 25.3-1.6 26.3-1.8 05MAR2008 27.3 1.0 26.3-0.6 25.7-1.3 26.6-1.5 12MAR2008 27.2 0.7 26.5-0.5 26.0-1.1 26.7-1.4 19MAR2008 27.3 0.9 26.7-0.5 26.2-1.1 26.8-1.4

I mentioned this in the winter thread, but there is a theory in long-range forecasting that North Pacific (Bering Sea) patterns will show up in the US in 17-21 days. The big storm by Kamchatka over 12/28 is now supported by the SOI thing I use to pass over the SW - somewhere - in about 10 days given the recent big crash in the SOI. The 12/28 storm supported 1/14-1/18 for a storm passage, and now it looks like 1/17 or so using the SOI rule. Over the past few weeks the eastern Nino zones have really been getting their asses kicked by warming even as the western zones remain quite cold. Nino 3 and Nino 1.2 are already close to not being in "La Nina territory".

I really can't see Northern New England ending up as the only cold spot in the US as you have it for January. Utah is the place that has been consistently cold this winter and you had it solidly warmer than average this month. It really doesn't look that warm out there in the long range, you'll keep seeing inversions with cold lows even if there is high pressure and little moisture. The -NAO doesn't really favor cold in northern New England in January, so your idea never really made any sense to me. By the time we get to March, it's actually a warm signal for a lot of the Northeast, and even by January it's kind of Neutral. It favors storms more than cold really. You've got a lot of places up there in Northern New England 10+ above normal so far this month. My guess is they'll cool off later in the month with more normal warmth and snow, and still finish 3-8 above normal in some spots. It's also going to be real hard to get big systems for Northeast snow until the SOI dies off, the +20 ish readings of late will keep the subtropical jet weak and way south of where it would be in an average year. You were looking in the winter thread when I posted that a -NAO never follows a sufficiently high SOI in December, so you seem on board with that. You missed the WPO & NAO combination for December, which is why you couldn't see the cold in the West from what I can see. It's not like the PNA favored cold in Utah, it doesn't do that. Your forecast this year was actually pretty strange, its pretty rare to have Missouri as the hottest place in the US in a winter. If you think the South will be warm, the warmest areas in a La Nina will almost be the Southeast coast, south Texas, or the southern areas of the Southwest.

There is now support from a big SOI crash for a system over the Southwest in the time frame you'd expect from the North Pacific timing I mentioned above. Date Tahiti (hPa) Darwin (hPa) Daily Contribution 30 day Av. SOI 90 day Av. SOI 8 Jan 2021 1013.12 1005.30 15.13 19.56 10.69 7 Jan 2021 1014.99 1004.95 25.58 19.23 10.68

The snow/precip shield has been trending west on the model runs. I think we'll get some snow in the city. You can see the snow in NW NM on the 3 km-NAM now It's gone way west on the GFS too - The Euro has had some precip in the Rio Grande Valley for a while -

MEI finally updated after close to two months. https://psl.noaa.gov/enso/mei/ YEAR DJ JF FM MA AM MJ JJ JA AS SO ON ND 2007 0.6 0.4 -0.2 -0.4 -0.4 -0.9 -0.8 -0.9 -1.1 -1.1 -1.1 -1.2 2020 0.3 0.3 0.2 -0.1 -0.2 -0.7 -1 -1 -1.2 -1.2 -1.1 -1.2

SOI has really kicked into high gear recently. Over +19 for the past 30 days. Historically, the top SOI values in January don't actually favor a La Nina the next winter though. The winters after a +10 SOI in January for the prior 90 years have tended to see warmer conditions in Nino 3.4. I think the push for the SOI now reflects the fairly quick cooling we've seen in Nino 4 more than anything.

The GFS seems to be caving to the Euro a bit.

This looks pretty good for New Mexico up to about Denver now? Timing is certainly lined up with the big SOI crash 12/31 to 1/1. Trend is our friend hopefully.

Euro still has Nino 4 cooling off through January. The end of the La Nina could be as soon as March - most of the ensembles are above -0.5C in April as they were last month. Nino 4 is still forecast to be very cold this month before slowly warming. It should still be below average in Spring & early Summer if the Euro is right. If we see a cold Nino 4 verify for winter and spring it is a fairly strong cool signal in the Summer for the US in some areas.

The Euro has a lot of light snow still, Canadian is kind of similar. GFS very different. I'm inclined to think this storm will happen, it's just the track. It has the "SOI support" I look for with a big crash 12/31 to 1/1, which is 9-10 days ahead of the precip below as the theory goes.

For anyone who remembers, there were several very powerful lows in the North Pacific late in December. One long-range forecasting theory is that lows in the Bering Sea/Gulf of Alaska area will 'appear' in the US 17-21 days later. If you buy that, the 938 mb low over southern Kamchatka is believed to correspond to about 35N over the Rockies (Albuquerque essentially), and will move east as a developing or rapidly strengthening storm. "Albuquerque lows" are often quite good snow storms for Colorado, but not necessarily where I am. I'm attaching an image from late December and how it is supposed to correspond in the US spatially. We'd be looking at 1/14 to 1/18 for the Rockies, a day early West Coast if it comes west to east, and then around 1-2 days later for the Midwest/Northeast. I'm not a huge fan of this method. It does work quite well sometimes though.

QBO now appears to be in decline. It's been very similar to 2010 for four months, but not close for actual US weather. https://psl.noaa.gov/data/correlation/qbo.data 2010 -16.02 -16.98 -19.68 -23.57 -26.28 -25.05 -9.84 1.45 6.58 10.83 12.16 10.97 2020 -2.51 -3.20 -4.36 -5.03 -4.86 -2.78 0.34 4.78 7.95 10.80 11.15 10.37

Nino 4 in 2007 looks like it is still behaving pretty similarly to 2020. But Nino 3.4 is really starting to fall behind the pace. That's not super surprising to me, I had other years in my winter blend to warm up 2007-08. It is worth noting in December, the 2017-18 event was colder/stronger in Nino 1.2 and Nino 3 in December, but warmer to the West. This is what I get for the four zones compared to 1951-2010 averages and some recent events in December. The closest match to December is easily 2011, within 0.2C in all zones, and then 1974 and 1983 are close outside Nino 1.2. These are all standardized against 1951-2010 averages. If you look at what the CFS / Canadian tried to do for US temperature anomalies in January, the models look a lot like January 1975, 1984, 2012 as a blend.

The weeklies had a bit of a rebound this week. I think you see that for another week or two before the real weakening push starts. The monthly data was the most different from the weeklies it has been in a while too. Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 02DEC2020 21.8-0.5 24.4-0.7 25.5-1.1 27.6-1.0 09DEC2020 22.4-0.1 24.3-0.8 25.4-1.2 27.7-0.8 16DEC2020 22.0-0.8 24.3-0.8 25.6-0.9 27.8-0.7 23DEC2020 22.1-1.1 24.5-0.7 25.7-0.9 27.6-0.8 30DEC2020 22.2-1.3 24.4-0.9 25.4-1.2 27.3-1.1 https://origin.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/detrend.nino34.ascii.txt 2020 10 25.46 26.75 -1.29 2020 11 25.30 26.75 -1.45 2020 12 25.43 26.65 -1.22 Even so, the monthly data warmed quite a bit. Against the 1951-2010 standard that I like, the December reading is -1.03C

I actually wrote it wrong up there - it's more like 17-21 days. I did have the timing right though, 12/28, +17 to 21 days is about 1/14 to 1/18. There are some hints of the SOI reversing sharply for a day and the MJO waking up a bit, both of which would probably help. This is what comes up when you Google the timing. I'm not a huge fan of Bering Sea stuff for New Mexico a lot of our storms are essentially clippers or weak cold fronts. https://www.weatherboy.com/tag/bering-sea-rule/#:~:text=Bering Sea Rule Suggests Warmth%2C Severe Storms Returning in March&text=Meteorologists look at weather patterns,United States come mid-March

About time. Most of January 2008 the MJO was in phase 7 to phase 2. Second half of that month is very cold after a warm start. That's been the main analog of my outlook for three months now. That month is not super cold though with the first half offsetting the colder second half pretty effectively.

One of the long-range theories is that US patterns tend to repeat what happens in the Bering Sea in 14-18 days. I've been real curious for a while now if that 938 mb low SE of Kamchatka in late December is going to be a big storm over New Mexico around 1/14-1/18. I'm mentioning it in this thread because I think the idea is the southern tip of Kamchatka is supposed to correspond to 35N - so this would be an "Albuquerque low", which is often quite good for Colorado.