El Nino 2023-2024

[GaWx]

2 hours ago, roardog said:

Doesn’t the polar vortex always strengthen this time of year?

On average, it does gradually though it will vary from year to year with ups and downs. The middle red line on the top image below is climo/normal of the mean zonal wind way up in the stratosphere (at 10 mb) at 60N. These winds correlate with the strength of the SPV. The latest EPS weeklies (from yesterday) are forecasting (mean is dark blue line) a stronger than normal SPV in late Oct, which is what @snowman19showed. However, this run then quickly weakens it to near to slightly stronger than normal for November: 

 

  With an SSW, the mean winds drop as the SPV strongly warms. If those winds were to drop to negative, that means a reversal from the normal net E to net W winds and it is called a major SSW. The last occurred last Feb.

 Looking at the image below, the yellow line is the normal temp N of 60N at 10 mb. It hits a min ~Dec 1st. That’s when the chance for a SSW starts to increase. That chance rises to a peak in Jan/Feb before tapering off in Mar. Note how the light gray area, which shows the variance surrounding the mean, stays pretty narrow through Nov. That’s largely because SSW season hasn’t started. But then it widens a lot in Dec and hits a max mid Jan through early Mar, the heart of SSW season.

 Also, check out the red line, which shows 2022 through Feb of 2023. Note that after a very cold/strong SPV Nov/Dec, it hit all-time record cold of ~196K (-77C) 1/1/23! Even that didn’t prevent a minor SSW in late Jan/early Feb, a major SSW in mid Feb, and a secondary warming/wind reversal in late Feb, which all lead to a sharp drop in the NAO from Feb to Mar:

[stadiumwave]

 

[raindancewx]

Here is a quick look at the most -PDO Nov-Apr years in October and then this year.

Looks like a decent match to me for where the month will end. The models have the PNA going negative again later in the month.

The most +PDO El Ninos are pretty cold in October in New England, where it is currently warmest relatively. Southeast tends to be warmer too.

[Terpeast]

1 hour ago, Itryatgolf70 said:

Imo, if you go to sst anomalies at tropical tidbits website, it will give you a more accurate representation of the current regions numbers every 6 hours. That's what I use and have found it pretty good https://www.tropicaltidbits.com/analysis/ocean/

Thanks, it seems they use CDAS. The one I posted uses OISST, which I think is what is used officially. 

[mitchnick]

1 hour ago, GaWx said:

On average, it does gradually though it will vary from year to year with ups and downs. The middle red line on the top image below is climo/normal of the mean zonal wind way up in the stratosphere (at 10 mb) at 60N. These winds correlate with the strength of the SPV. The latest EPS weeklies (from yesterday) are forecasting (mean is dark blue line) a stronger than normal SPV in late Oct, which is what @snowman19showed. However, this run then quickly weakens it to near to slightly stronger than normal for November: 

 

  With an SSW, the mean winds drop as the SPV strongly warms. If those winds were to drop to negative, that means a reversal from the normal net E to net W winds and it is called a major SSW. The last occurred last Feb.

 Looking at the image below, the yellow line is the normal temp N of 60N at 10 mb. It hits a min ~Dec 1st. That’s when the chance for a SSW starts to increase. That chance rises to a peak in Jan/Feb before tapering off in Mar. Note how the light gray area, which shows the variance surrounding the mean, stays pretty narrow through Nov. That’s largely because SSW season hasn’t started. But then it widens a lot in Dec and hits a max mid Jan through early Mar, the heart of SSW season.

 Also, check out the red line, which shows 2022 through Feb of 2023. Note that after a very cold/strong SPV Nov/Dec, it hit all-time record cold of ~196K (-77C) 1/1/23! Even that didn’t prevent a minor SSW in late Jan/early Feb, a major SSW in mid Feb, and a secondary warming/wind reversal in late Feb, which all lead to a sharp drop in the NAO from Feb to Mar:

Note as well all the ensemble members that fall off a cliff later in the period on the weeklies. A surprising number of the litetally off the chart weak while there are no members off the chart strong like those weak.

[Terpeast]

Ensembles showing a transitory -pna the last week of october, starting with a building ridge over aleutians/alaska.

But what’s interesting is support for a rex block in the north pac, with a low/trough replacing that stubborn nina-like ridge north/NW of hawaii. 
 

Longer range shows additional ridging over the aleutians and west thereof, with continued troughing NW of hawaii. Will be interesting to see how the PDO evolves, and I’m thinking much less negative than it is now.

[Typhoon Tip]

10 hours ago, WxUSAF said:

-EPO is cold for the east US

Need to apply a lag tho. 

-EPO peak is positively correlated with the PNA through max … Then, as it collapses the ridge signal merges into the mid latitude as a +PNA, leaving a neutral mode in the EPO.  Usually about a 3 to 5 day evolution 
 
-EPOs load cold into the west first as an “inside slider” pattern but yeah … that sets the table for the above relay into +PNA—>+PNAP which delivers it east. 

None of these correlations are one to one though. During ultra amplified scenarios, so called “cross polar“ flow types, the EPO and the PNA have merged into one very large negatively correlated mass field.  

Other times the -EPO is too transient, and/or some other mode countermands the typical relay or intervenes somehow and you may end up with split flow that remains quasi-stable and persists - they can orient a boundary spanning east with epic temperature gradients on either side … events hosting multi faceted impact types.  

[bluewave]

15 hours ago, raindancewx said:

Here is a quick look at the most -PDO Nov-Apr years in October and then this year.

Looks like a decent match to me for where the month will end.

This has been the warmest  more Niña-like -PDO pattern for Northern New England on record for the first half of October. Plenty of La Niña Octobers on the list. 
 

 

[Terpeast]

New 3.4 daily peak at +1.72

[40/70 Benchmark]

17 hours ago, raindancewx said:

Here is a quick look at the most -PDO Nov-Apr years in October and then this year.

Looks like a decent match to me for where the month will end. The models have the PNA going negative again later in the month.

The most +PDO El Ninos are pretty cold in October in New England, where it is currently warmest relatively. Southeast tends to be warmer too.

I don't think there is any doubt that this will be a -PDO DM on average....so this makes sense to me.

[so_whats_happening]

19 hours ago, Itryatgolf70 said:

Imo, if you go to sst anomalies at tropical tidbits website, it will give you a more accurate representation of the current regions numbers every 6 hours. That's what I use and have found it pretty good https://www.tropicaltidbits.com/analysis/ocean/

Unfortunately CDAS tends to be a little too cool in Nino regions where as CRW tends to be rather warm. OISST is probably the closest you will find to getting near what is reported by NOAA, which they use ERSST data. 

[so_whats_happening]

1 hour ago, Terpeast said:

New 3.4 daily peak at +1.72

I took out the 11th as it was rather erroneous and used the latter portion of the data on the 13th as it matched much better for progression of what it looked like under the surface.

Gonna be an interesting 2 weeks here.

[bluewave]

1 hour ago, so_whats_happening said:

I took out the 11th as it was rather erroneous and used the latter portion of the data on the 13th as it matched much better for progression of what it looked like under the surface.

May be the first time the subsurface cooled so much under 1+2 and increased under 4 this time of year. No real oceanic kelvin waves to speak of just sloshing back and forth. So this year continues to do its own thing.

[snowman19]

The IOD rapidly approaching +2 and the Nino is off to the races already….and the WWB just got going. IMO very likely we are above +2.0C come early next month….

[snowman19]

For those who follow it (I don’t anymore) but Siberian snowcover buildup through today has been really, really awful. This is Judah’s update from 10/10 and it hasn’t gotten any better since, looks bad for at least the next week too

[roardog]

4 minutes ago, snowman19 said:

For those who follow it (I don’t anymore) but Siberian snowcover buildup through today has been really, really awful. This is Judah’s update from 10/10 and it hasn’t gotten any better since, looks bad for at least the next week too

I always thought it was the advancement during the month of October that mattered not the overall snow cover for the month. 

[snowman19]

I always thought it was the advancement during the month of October that mattered not the overall snow cover for the month. 

Buildup would be advancement look at the chart. Its awful, the lowest out of all those years

[roardog]

49 minutes ago, snowman19 said:

Buildup would be advancement look at the chart. Its awful, the lowest out of all those years

My point is that if it advances rapidly at the end of the month like Judah hints at, you would want it to start low. 

[snowman19]

My point is that if it advances rapidly at the end of the month like Judah hints at, you would want it to start low. 

In which tweet does he “hint” that? Can you post it?

[csnavywx]

2 minutes ago, roardog said:

My point is that if it advances rapidly at the end of the month like Judah hints at, you would want it to start low. 

Still time for recovery, yes. Just not a great start. Pattern gets better in the last 7-10 days of the month, but not looking like an upper 50% type of year right now.

[roardog]

12 minutes ago, snowman19 said:

In which tweet does he “hint” that? Can you post it?

It’s the tweet you posted. lol

[snowman19]

The EPAC tropics have come alive. This is only going to positively feedback and cause further Nino strengthening (WWBs behind these tropical cyclones). The strengthening system is in place now and further coupling is coming. I predict we are at or above +2.0C in region 3.4 by 11/7.

[Daniel Boone]

35 minutes ago, snowman19 said:

The EPAC tropics have come alive. This is only going to positively feedback and cause further Nino strengthening (WWBs behind these tropical cyclones). The strengthening system is in place now and further coupling is coming. I predict we are at or above +2.0C in region 3.4 by 11/7.

Won't you just love it snowman if we get strong blocking and wind up colder and snowier than you want ala, 1968-69. 

[SnoSki14]

There is no Nino coupling. That is a full fledged Nina look on the ensembles for late October with big -PNA

[so_whats_happening]

7 hours ago, bluewave said:

May be the first time the subsurface cooled so much under 1+2 and increased under 4 this time of year. No real oceanic kelvin waves to speak of just sloshing back and forth. So this year continues to do its own thing.

Yea the ever persistent subsurface warmth under 4 is surprising for a Nino year typically this area and just west would have cooled down by now. 1+2 does continue to cool more slowly as of now but there does seem to be less overall heat to work with then just a few months ago. As for the Kelvin wave it did look like at one point there was going to be one (minor event around 10/7-10/9 time frame) but that doesn't quite seem to be happening given that we have had a couple days to watch and see if something were to evolve. Will wait a few more days to see if there is any downwelling that shows up more so than what the animation shows, which was again a minor move of 28C waters in depth and the dispersion of the cool anomalies around 150W.

[so_whats_happening]

[so_whats_happening]

On 10/15/2023 at 4:07 PM, Terpeast said:

Ensembles showing a transitory -pna the last week of october, starting with a building ridge over aleutians/alaska.

But what’s interesting is support for a rex block in the north pac, with a low/trough replacing that stubborn nina-like ridge north/NW of hawaii. 
 

Longer range shows additional ridging over the aleutians and west thereof, with continued troughing NW of hawaii. Will be interesting to see how the PDO evolves, and I’m thinking much less negative than it is now.

This should help with getting a more consistent look of an Aleutian low while waters off Japan are still cooling they are cooling much less than it has been, long ways to go it seems for destroying the -PDO but we should see a nice tick down for the monthly number.

[mitchnick]

7 hours ago, so_whats_happening said:

This should help with getting a more consistent look of an Aleutian low while waters off Japan are still cooling they are cooling much less than it has been, long ways to go it seems for destroying the -PDO but we should see a nice tick down for the monthly number.

This SSTA animation shows it nicely as well.

https://psl.noaa.gov/map/clim/sst.anom.anim.week.html

[Terpeast]

32 minutes ago, mitchnick said:

This SSTA animation shows it nicely as well.

https://psl.noaa.gov/map/clim/sst.anom.anim.week.html

Amazing, the marine heat wave off Japan is nearly gone. 

Now lets work on the ssts north/NW of hawaii. This upcoming rex block might help with that, even if it causes a -pna for us in the process. 

[bluewave]

These PDO fluctuations between -0.5 and -2.5 have been the norm this year. Notice the big up and down pattern since January. So we want to see some actual positives sustain to get a sense that the PDO is shifting. A cold pool would need to develop north and northwest of Hawaii for a true +PDO. This would be indicative of a more Nino-like Aleutian Low. But continued ridging near the Aleutians even if the PDO becomes more neutral is still problematic since it promotes a Western Trough and SE Ridge.