raindancewx

The models haven't been loading today, but the 3-km NAM is in through Saturday at least, and at this range it should be quite good. More decent snows for Western Colorado and Northern New Mexico.

Very close to 1959 so far, although colder in TX, NM and the interior NW. These are the totals from the SW storm - a lot of the SW is now running well above average for precipitation totals winter to date.

12/10 system definitely had some juice with it. GFS is fairly optimistic for Saturday too.

The fetch of subtropical moisture with the current system over the Southwest ended a 110 day rainless period in Phoenix, and a 242 day rainless period in Yuma. There were periods of long dry weather over the Southwest in the 2017-18 La Nina, but it was centered more over Texas & New Mexico, rather than Arizona and Southern California. Amarillo went close to five months without measurable precipitation in 2017-18, and Albuquerque went 96 days without precipitation in that event. A lot of Arizona and New Mexico are now running near average for December precipitation totals, and I'd expect more systems by the end of the month.

That next system on 12/12 looks a bit more promising than it did yesterday along the NM/CO border. Still in the time frame of the most recent early December SOI crash. There should be something around 12/19 too - GFS already has a storm in that time frame, it's +10 days from the SOI crash recently.

The models now say the MJO is in phase five more than neutral. It seemed like there was a strong wave before but with multiple points of strength (which got interpreted by the RMM method as Neutral), and now it is more phase five alone. The Euro has weak progression in phase five for a while now. You can see the emergence into phase five more clearly on the Canadian side of the image.

I got some more snow today. Very light. The local NWS has a lot of trouble estimating lows, but they do real well for highs. But with subtropical moisture initially moving over dewpoints of 5-10, it isn't surprising we hung out in the low 30s for a while with some snow. This La Nina is infinitely better than the 2017-18 La Nina, when the city had three days with 0.1" or more from Oct-May. We're already at three for 10/1-12/10. No rain or snow in the whole state that December, this is already storm two, and I'd imagine there will be another around 12/19 given the SOI drop, and something will probably come through 12/26-12/30 too.

If you guys want a reason to be optimistic - I had the NAO negative in December. But the Isotherm guy thought it would be negative in January. It looks like December is at least partially right on my end, but that doesn't actually mean his January call is wrong.

I find the 3-km NAM is a pretty good model at short ranges, unlike it's exaggerating cousin the 12-km NAM. Pretty good snows depicted for Western Colorado and Northern New Mexico.

At this point - and I don't expect this to happen - the winter of 1959-60 may be a best case scenario for what 2020-21 can do. You can see a similar look to early December, with a warm NE Pacific, similar north Atlantic, and cold Nino zones - although not a La Nina. The 1959-60 winter gets very cold in 1960. That said, the Indian Ocean, waters by Australia, La Nina, and Western Pacific, not to mention solar activity (very high in 1959-60) and the cold November 1959 - are all very different even if December finishes similarly. The rest of December 1959 does look like what CPC is showing generally for later in the month. I think a warmer version of the January map is possible, but I wouldn't bet on it either.

I went with 0.1-0.4 inches of precipitation for Albuquerque with the coming system. Pretty decent snows are likely for the mountains. There was another SOI crash last night of 10 points, so I'll be on the lookout for a system around 12/19. Something tends to come through in the 12/26-12/30 time frame in NM/CO, so I'd expect two more decent storms after this one as a minimum, so we'll have a shot a wetter than average December.

Next shot at something down here is likely around 12/19. Date Tahiti (hPa) Darwin (hPa) Daily Contribution 30 day Av. SOI 90 day Av. SOI 9 Dec 2020 1013.79 1009.05 5.29 9.93 8.11 8 Dec 2020 1015.26 1010.05 7.73 9.84 8.05 7 Dec 2020 1015.79 1009.15 15.15 10.02 7.90 CPC is pretty confident in a warm period starting 12/17. Texas had near to record warmth in a lot of spots today. Going forward, you'll see some days like that in other parts of the south to help burn off the cold.

Whenever there is some huge surge of subtropical moisture, my default is the 3-km NAM and Euro will eventually have the right sense of the totals, but not until within 48 hours of the event finishing. Until then, I just assume 0.2"-0.6" of liquid equivalent for the NM valleys for each full day of precipitation until proven otherwise, higher or lower.

https://www.weatherbell.com/final-winter-2020-21-forecast Weatherbell updated their winter outlook. This image from above was right, they just labelled it wrong. Weatherbell analog blend changed the from winters starting in 1973, 1988, 2010 (x2), to winters starting in 1973 1974 1975 1995 (x2) 1998 (x2) 1999 2005 2007 (x2) 2010 2017 It's a warmer look. But would support a cold West / hot Southeast in Jan-Feb.

Make it happen Chinook. You guys in Colorado will get at least some snow out of this Thu-Sat period.

The 12-km NAM, Euro, GFS and Canadian now have a pretty big precipitation event out here 12/10-12/12, in the correct time frame after the big SOI crash around 12/1. 3 Dec 2020 1013.45 1007.55 11.31 8.63 7.78 2 Dec 2020 1014.81 1008.05 15.78 8.74 7.73 1 Dec 2020 1014.91 1007.10 21.23 8.99 7.70 30 Nov 2020 1013.51 1006.20 28.18 9.24 7.69 This map from WPC looks pretty good to me. I'd go 0.20-0.60" for most of New Mexico, higher mountains and SW, lower SE (nothing to 0.20"). Arizona could easily get a winter of precipitation in the SE part of the state. This is what the Euro has for days 2-4 (Thursday-Saturday). For a lot of places in the SE AZ / SW NM zone, these totals would be a winter of precipitation if they verified. The 12-km NAM is a lot more optimistic, but I don't really buy these totals, yet.

That's probably the most moisture I've seen a model show in Arizona in at least six months. Not thrilled to see the Euro changing the location of the moisture every 12 hours, but the trend in increasing moisture is nice to see. A lot of it will likely be snow.

I am pretty optimistic for you guys for March. My NAO indicator seems to have worked at least a little bit for December, with the index at least nominally negative. I think the blend I had said -0.2 for December. It had March more negative than December. Nino 4 has been following 2007 (but warmer) all year. If it continues to do that, you do have a strong wet signal for the Ohio Valley in February, and then a weak wet signal for New England. Should still be cold enough for a lot of snow. Nino 4 is likely to finish Dec/Jan the coldest it has been in 5-10 years, maybe more. The warm signal from a cold Nino 4 January doesn't really extend into all of New England either in February. It took until Dec/Jan but the 2007-08 La Nina did see Nino 4 eventually drop below 27.0C, which is very cold for that area, even by 1951-2010 averages. It should happen in the next six weeks. You'll know the effect has kicked in if you see a big snowstorm in say, Kentucky, in mid-January or February. Also a cold signal for you guys in Spring. The correlations aren't super strong, but with Nino 4 set to run ~2C colder in the next few months compared to last year, it should have a big imprint on the patterns. We're not getting jack out here once the Spring correlations kick in, winter is less of an issue though

We're open for business for your skiing and snow needs.

The GFS run from Tuesday was honestly better for this time frame than runs of the recent days. This is the most recent five day period depiction on the GFS and the Canadian: The Canadian is probably too optimistic but I like to use it as a "bust up" ceiling for the high end of what is possible. A lot of this is Thursday-Saturday, so not exactly in la-la model land anymore, but the details are still going to change.

I'm a bit surprised there hasn't been more snow in the red circled area. That's my guess for the next area to fill in a lot.

Nino1+2 Nino3 Nino34 Nino4 Week SST SSTA SST SSTA SST SSTA SST SSTA 07OCT2020 19.5-1.2 23.4-1.5 25.5-1.2 27.8-0.8 14OCT2020 19.6-1.2 23.6-1.3 25.3-1.4 27.8-0.9 21OCT2020 19.9-1.1 23.8-1.2 25.3-1.4 27.8-0.8 28OCT2020 20.0-1.1 23.5-1.5 24.9-1.7 27.9-0.7 04NOV2020 20.3-1.0 23.6-1.3 25.1-1.5 27.8-0.8 11NOV2020 21.2-0.3 24.1-0.9 25.7-1.0 27.9-0.7 18NOV2020 21.0-0.7 23.6-1.4 25.2-1.5 27.9-0.7 25NOV2020 21.0-1.0 23.7-1.3 25.3-1.3 27.9-0.7 02DEC2020 21.8-0.5 24.4-0.7 25.5-1.1 27.6-1.0 We're going to a Modoki La Nina event if the structure of this week keeps up. You have Nino 4 likely to take over as the coldest zone by anomaly as soon as the next few weeks, as Nino 1.2/3/3.4 warm (probably aren't really as weak as this week on a monthly basis though). If you look at early Dec 1997, there is at least a passing resemblance to the early Dec 2020 look in the US, with Nino 1.2 much warmer (relatively) than the western zones.

GFS and Canadian are different, but the NAM looks like the Euro to some degree. The northern stream system is more of a mess at this point, but still expect some snow for Colorado.

You're the one who has been expecting an east-based La Nina. Good luck with that. Trends have been running opposite for weeks now. The plume moves from majority -0.5C or lower through March, to majority above -0.5C in April. That's the end of the La Nina on the Euro. Whether it's fast by a month, or slow by a month, doesn't really matter. I had the event peaking in Nov/Dec at the surface, Oct/Nov at the subsurface, that's still at least possible.