Weak La Nina Winter

[AfewUniversesBelowNormal]

Global SSTs have really cooled. Earlier La Nina not getting strong was I think a lot to do with ridiculously warm Global temperatures. Maybe this changes in the next few weeks. In other words, if this were the 1980s, Nino 3.4 could be about -0.5c cooler. The variation I think is more important if you take year-to-year global warming into account. 

[AfewUniversesBelowNormal]

Nice development of warm pocket in western subsurface, meaning consistency of the event is establishing. With only a cold pool, you get a lot of surface fluctions, with warm-cold pool variation, it becomes a gradual steady movement into Moderate La Nina.

[raindancewx]

Just for reference for anyone curious, here is a look at SSTs for cold ENSO years in the 1930s and 1940s v. 2007 (a pretty strong/cold La Nina even against 1951-2010 means). I focused on the low-solar La Ninas, so no 1947-48, 1948-49, but threw in 1946-47. 1942-43 is generally considered to have a similar ONi value 2007-08 in its era, -1.4 for 1942-43 vs. -1.5 for 2007-08, however in absolute terms, I think 1942-43 today would be akin to an anti 1997-98, super super cold waters in Nino 1.2, and an ONI value of perhaps -2.0 against 1986-2015.

Here is 1973-74, the coldest La Nina since 1950, v. 1942-43 - pretty similar overall, but 1973-74 was -1.9C against 1951-2010, while the 1927-1956 ONI ONI for 1942 was only -1.4 or so.

[raindancewx]

1999 remains a terrible analog to this La Nina - close to perfect opposite, which may be useful for consideration in future months.

 

[40/70 Benchmark]

1 hour ago, raindancewx said:

1999 remains a terrible analog to this La Nina - close to perfect opposite, which may be useful for consideration in future months.

 

Ding, ding, ding....we have a winner.

Its like likening a poodle on a german Shepard because they are both dogs.

La nina events on opposite ends of the spectrum.

[Paragon]

3 hours ago, raindancewx said:

1999 remains a terrible analog to this La Nina - close to perfect opposite, which may be useful for consideration in future months.

 

You mean an anti-log rather than an analog? I tend to agree!

[Paragon]

1 hour ago, 40/70 Benchmark said:

Ding, ding, ding....we have a winner.

Its like likening a poodle on a german Shepard because they are both dogs.

La nina events on opposite ends of the spectrum.

Still it may be useful in the sense that it's so diametrically opposite that whatever happened in 1999, you expect the exact opposite to happen this winter.

People forget that weak la ninas are our second snowiest winters (after weak el ninos).

 

[Paragon]

On 11/8/2017 at 5:50 PM, raindancewx said:

Just for reference for anyone curious, here is a look at SSTs for cold ENSO years in the 1930s and 1940s v. 2007 (a pretty strong/cold La Nina even against 1951-2010 means). I focused on the low-solar La Ninas, so no 1947-48, 1948-49, but threw in 1946-47. 1942-43 is generally considered to have a similar ONi value 2007-08 in its era, -1.4 for 1942-43 vs. -1.5 for 2007-08, however in absolute terms, I think 1942-43 today would be akin to an anti 1997-98, super super cold waters in Nino 1.2, and an ONI value of perhaps -2.0 against 1986-2015.

Here is 1973-74, the coldest La Nina since 1950, v. 1942-43 - pretty similar overall, but 1973-74 was -1.9C against 1951-2010, while the 1927-1956 ONI ONI for 1942 was only -1.4 or so.

1942-43- wasn't that among a group of super-cold WW2 winters? I remember one of those winters in the 40s (42-43 I think) had multiple lows below zero at NYC including one -6 that was the last time they ever got below -2.

[raindancewx]

I'm really conflicted on how this event evolves, right now, the SSTs look like a Weak, Eastern La Nina, or Peru La Nina/Cold Neutral, with a positive Modoki value, which is pretty similar to 1996. Historical La Ninas have ALL seen <0 modoki values, and become more "central" based as they age and weaken, but this event may collapse from the East. The current look is not a bad match to my analogs (I'm using ERSST V.5 for Oct 2017 as it goes back to 1950 until the data that goes back to 1870 comes for Oct 2017):

Analog	Nino 1.2	Nino 3.4	Nino 4	Weight
1932	21.28	26.75	28.54	x2
1943	21.47	26.29	28.19	x3
1944	20.87	26.51	28.58	x3
1996	20.26	26.46	28.49	x3
2005	20.01	26.59	28.77	x3
2007	19.41	25.33	27.90	x3
2008	20.89	26.43	28.27	x2
2012	20.67	26.96	29.00	x1
Mean	20.55	26.34	28.42	x20
2017	20.20	26.22	28.62

The analogs produced a (slightly) cold East / pretty warm West November, which is what I think is evolving, but then the cold gradually moves West, as the years in aggregate are all very warm Atlantic years with low solar (except 2012), and no dominant NE Pacific PDO signal. I sincerely believe that the "cold interior West" pattern present in October 2017, winter 1932-33, winter 1943-44, winter 1996-97, winter 2007-08, winter 2012-13 is part of this pattern and will return occasionally, transiently, in Dec, Jan and Feb.

My analog system says these are the closest Nino 1.2, 3.4, 4 matches to October 2017 against 1931-2016:

Those years have big time cold pouring down the middle of the US on aggregate in November, similar to my analogs. Cold also moves West somewhat in December as my analogs had. Worth noting 7/10 years are in warm AMO years.

[40/70 Benchmark]

7 hours ago, Paragon said:

Still it may be useful in the sense that it's so diametrically opposite that whatever happened in 1999, you expect the exact opposite to happen this winter.

People forget that weak la ninas are our second snowiest winters (after weak el ninos).

 

I often remind folks of that.

We do have some weak la nina events that are very warm, though......just not sure I would advise folks to expect that over the majority of the winter this season.

[Paragon]

13 minutes ago, 40/70 Benchmark said:

I often remind folks of that.

We do have some weak la nina events that are very warm, though......just not sure I would advise folks to expect that over the majority of the winter this season.

Ray I think the last 8 weak la ninas have gone 50/50 here, a true crap shoot lol.

 

[Paragon]

6 hours ago, raindancewx said:

I'm really conflicted on how this event evolves, right now, the SSTs look like a Weak, Eastern La Nina, or Peru La Nina/Cold Neutral, with a positive Modoki value, which is pretty similar to 1996. Historical La Ninas have ALL seen <0 modoki values, and become more "central" based as they age and weaken, but this event may collapse from the East. The current look is not a bad match to my analogs (I'm using ERSST V.5 for Oct 2017 as it goes back to 1950 until the data that goes back to 1870 comes for Oct 2017):

Analog	Nino 1.2	Nino 3.4	Nino 4	Weight
1932	21.28	26.75	28.54	x2
1943	21.47	26.29	28.19	x3
1944	20.87	26.51	28.58	x3
1996	20.26	26.46	28.49	x3
2005	20.01	26.59	28.77	x3
2007	19.41	25.33	27.90	x3
2008	20.89	26.43	28.27	x2
2012	20.67	26.96	29.00	x1
Mean	20.55	26.34	28.42	x20
2017	20.20	26.22	28.62

The analogs produced a (slightly) cold East / pretty warm West November, which is what I think is evolving, but then the cold gradually moves West, as the years in aggregate are all very warm Atlantic years with low solar (except 2012), and no dominant NE Pacific PDO signal. I sincerely believe that the "cold interior West" pattern present in October 2017, winter 1932-33, winter 1943-44, winter 1996-97, winter 2007-08, winter 2012-13 is part of this pattern and will return occasionally, transiently, in Dec, Jan and Feb.

My analog system says these are the closest Nino 1.2, 3.4, 4 matches to October 2017 against 1931-2016:

Those years have big time cold pouring down the middle of the US on aggregate in November, similar to my analogs. Cold also moves West somewhat in December as my analogs had. Worth noting 7/10 years are in warm AMO years.

An interesting list of winters.  There is quite a bit of variance in sensible weather there between individual winters- especially from very cold winters like 1943-44, 1960-61, 1978-79, and 2000-01 to bookend winters like 1992-93, 1996-97, 2005-06, 2008-09 and 2012-13.  The bookend winter of 1959-60 didn't make your list.  

[raindancewx]

I could never fully match any year since 1930 to conditions in the Pacific last year, but 1931 was the closest overall (almost identical in Nino 1.2, Nino 3.4, but too cold in Nino 4). Best blend I've been able to come up with, in terms of of matching SSTs in Nino 1.2, Nino 3.4, and Nino 4 to 2016-17 is this:

1931 (x6)

1941 (x8)

1998 (x5)

Anomalies are against 1951-2000 means from NOAA, for Nino 1.2, Nino 3.4, Nino 4 respectively in DJF.

1941	0.87	0.8	0.58
1931	0.54	-0.30	-0.37
1998	0.04	-1.48	-1.39
2016	0.57	-0.29	-0.07

Actually very difficult to get a cold Nino 3.4, somewhat cold Nino 4, and pretty warm Nino 1.2, even with 80+ years to blend. The Atlantic was warmer in the analogs than last year, so everything go shoved to the NW. But its still close. Only way to get something like last year was to blend two years after a super-East El Nino and a year after a big Modoki El Nino (since it is cold in some areas that aren't cold in the East El Ninos) - and my blend is still too warm in Nino 3.4 and too cold in Nino 4, but its all w/in 0.15C.

 

[AfewUniversesBelowNormal]

Check this out...

 

[raindancewx]

Strongest weekly departure for the event as of the weekly update - third column is Nino 3.4 and its departures

 07JUN2017     23.1-0.1     26.9 0.3     28.1 0.4     29.3 0.5
 14JUN2017     22.9 0.0     26.7 0.2     28.2 0.5     29.4 0.6
 21JUN2017     22.9 0.3     26.7 0.4     28.3 0.7     29.5 0.7
 28JUN2017     22.8 0.4     26.5 0.4     28.1 0.7     29.4 0.6
 05JUL2017     21.7-0.3     26.1 0.2     28.0 0.6     29.4 0.6
 12JUL2017     21.8 0.0     26.1 0.4     27.8 0.5     29.3 0.5
 19JUL2017     21.4-0.1     25.7 0.2     27.6 0.4     29.2 0.4
 26JUL2017     21.3 0.0     25.5 0.1     27.1 0.0     28.9 0.2
 02AUG2017     20.9-0.1     25.4 0.1     27.2 0.2     28.9 0.2
 09AUG2017     20.5-0.3     25.1 0.0     26.7-0.2     28.7 0.1
 16AUG2017     19.9-0.7     24.5-0.5     26.4-0.5     28.8 0.1
 23AUG2017     19.6-1.0     24.6-0.4     26.7-0.1     28.9 0.2
 30AUG2017     20.3-0.2     24.5-0.4     26.5-0.2     28.8 0.2
 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
 11OCT2017     19.5-1.3     24.4-0.5     26.2-0.5     28.5-0.1
 18OCT2017     19.5-1.4     23.9-1.1     25.9-0.8     28.3-0.4
 25OCT2017     19.6-1.4     24.2-0.8     26.2-0.5     28.5-0.2
 01NOV2017     20.4-0.8     24.4-0.6     26.3-0.4     28.7 0.1
 08NOV2017     20.2-1.2     23.8-1.2     25.6-1.1     28.3-0.3

[AfewUniversesBelowNormal]

It will be La Nina through March.

[raindancewx]

In this area of the world, the "warm over cold" feature, i.e. warm waters off Mexico/Central America north of cold waters in Nino 3 / Nino 1.2 often predates a dip in the storm track as major thunderstorms kick up on the boundary of the anomalies. Will be interesting to see if that happens in December. It seems like February is the protected month in the NE, January is the protected month in the SE/Midwest, and here in the West its December. "Protected" meaning no warming in high temperatures long-term over most areas. March in the West and December in the East seem to have the opposite tendency, with very fast warming.

I wasn't completely sure when I did my winter outlook if this feature would show up (it wasn't there even two weeks ago), but I thought it might - some of my winter analogs had it. December tends to be cold in the West when that feature shows up.

Look at 1943, 1996, 2008, 2012 - the boxes are warm over cold.

[AfewUniversesBelowNormal]

^I was going to comment on that. How close the gradient is, I don't think any recorded ENSO event has had such a short width. More ridging propagating the poles and all over the place vs holding steady over the Azores for 3 months is my guess on effect.

[raindancewx]

This is the best match I could get for the Pacific / Atlantic, while maintaining the "warm" north of cold Nino 1.2/Nino 3 in November. Believe it or not 1943 is the best match since 1930.

[AfewUniversesBelowNormal]

I think the warmer SSTS so close to the equator will favor a completely different La Nina pattern - blocking moving northeast into NW Canada and the Gulf of Alaska and the Poles, more trough off the west coast, and just an overall always-moving pattern. There could also be some juicy US storm systems. Global water vapor is also at top 5% on record right now. 

[raindancewx]

One of the reasons I like the Jamstec is it catches features like this - look at the October update a few weeks back - it had the warmth north of the cold Nino 1.2/3 for the winter. It's quite good picking those features out. 

My idea for this winter since October (https://www.scribd.com/document/361349089/Winter-2017-18-Outlook) has been that the PDO would end up near 0 for Nov-Apr, and the GOA low will strengthen/weaken throughout the period and that would lead to different areas going into the freezer from Nov-Apr. My winter analogs had the East cold in Nov, which looks good. Broadly speaking, three alternating areas where the cold will be centered:

Nevada (45%)-->Montana (40%) -->Michigan (15%)

October had the cold by the ID/NV border, cold has been centered on MT since, seems like MI will be the center now/next. Then it begins to migrate Westward again. The winter progressions often mirror Summer - June, like Nov was stupid hot in the West, but July, Aug, Sept were all near average with some heat and also incredible cold shots. Cities in the West had record early frosts in September - would expect some of that level of cold to return later in winter. Low solar activity is also a big deal in the West, since it makes the upper levels of storms colder, and we're fairly high up, with thin air, relatively low gravity, away from the moderation of the oceans in many areas.

[raindancewx]

New Jamstec is out for November - slightly stronger peak ONI (-0.7C?)

Modoki structure very different from last year (-0.48) - since the Nino 1.2 / Box B area is colder.

Nice to see parts of the West trending wetter. The trend to wetter in the coastal SE is interesting.

South Central & SE US have trended colder, with warmer expectations on the West coast.

Last year, the model correctly had the East Coast dry - this year it has it wet. Has CA very dry, but Rockies wet.

Model is much colder nationally than last year.

Some major differences in the Indian Ocean and Pacific Ocean expected v. last winter too.

 

[Wow]

For the SE, November is looking quite a bit colder compared to the last couple of years and there is some correlation to that for the following DJF season.  It's more likely we'll end up colder (and wetter) than the past few winters.  The increased high lat blocking seems to be a big factor this year.

[raindancewx]

The PDO - by Mantua/JISAO anyway - fell to its lowest value (+0.05) since Dec 2013 in Oct 2017.

http://research.jisao.washington.edu/pdo/PDO.latest.txt

[raindancewx]

Nino 3.4 may finally be colder year over year - but its still kind of a close call since it is warmer than last year from the Equator to 5N in Nino 3.4. The y/y change looks like a classic cold PDO horseshoe, even though we're not really in a negative PDO regime yet, still neutral.

[40/70 Benchmark]

56 minutes ago, raindancewx said:

Nino 3.4 may finally be colder year over year - but its still kind of a close call since it is warmer than last year from the Equator to 5N in Nino 3.4. The y/y change looks like a classic cold PDO horseshoe, even though we're not really in a negative PDO regime yet, still neutral.

There are some pretty seasoned mets who don't think the ssts are that reflective of a neg PDO.

The latest PDO reading confirms.

[raindancewx]

It's not negative, its all mixed up if you look at the images for canonical warm/cold phases. But it is trending negative. The PDO spiked to +1.88 last November, so it makes sense that it looks much more negative y/y. It's probably going to be around 0 again on the JISAO index.

[40/70 Benchmark]

I called for around neural...hair below 

[AfewUniversesBelowNormal]

So we're in Moderate Nina now. ONI is 3-months, but that will likely peak at Weak because the SSTs just outside of equator are so warm. Strong Nina effects are being felt...

[raindancewx]

The PDO is really an imbalance between the NE & NW Pacific, and the corresponding pressure pattern. If both are warm, but the NE is +2 and the NW is +1, that's positive, and the reverse follows. If both are cold, but the NE is -1, and the NW is -2, that's positive too. The cold tongue = warm PDO, warm tongue = cold PDO.

Last year, you had a very warm NE Pacific coast and the cold tongue, and the NW Pacific coast was colder. That's pretty classically positive. This year, you have slightly the WARM tongue off the NE Pacific coast, and only slightly warmer conditions on the NE Pacific coast v. on the NW Pacific coast. The warm tongue is associated with the negative PDO, the rest with a slightly positive PDO. So its mixed up. It really does seem like whatever the base state for the PDO is in March-August, Nino 1.2 anomalies in October will indicate whether that base state goes towards the warm PDO or cold PDO phase. We had a warm PDO base state from March-August (+0.62) so its taking a while for Nino 1.2 to break the positive phase, but the trend is down.

Here in the SW, October, November, April and May (for precipitation) are very sensitive to the PDO base state, so the drop off is consistent with the weather here - basically no moisture this November (not that unusual) v. near record moisture last November. ENSO seems to have the most power over January-March here, with the Atlantic in charge of December. Solar and ENSO influence here both seem to peak in March, while the PDO influence kind of peaks in Nov and then May (haven't had a warm or even normal May here since the PDO was negative in 2013).