bluewave

I agree with most of what you just said. But I have a partial disagreement with you on what constitutes a sensible mid latitude response. The response has two components. The first is the strength of the 500mb ridge across Canada and the Northern Tier of the CONUS. During the 2023-2024 super El Niño this ridge was more expansive than the 1997-1998 super El Niño pressing further south toward the mid-Atlantic and enhancing the warmth. So this wasn’t reflected in the RONI only peaking at 1.5. But the RONI was more representative of the weaker Aleutian low and Mid-Atlantic to Southeast low. We can also see the RONI inconsistency with the 2015-2016 super El Niño in another way. While it was better matched with the ONI than 2023-2024, the Aleutian low was still much weaker than 1997-1998. Plus the rainfall response was much less in places like CA along with more of a ridge in the Eastern CONUS than past super El Niños.

It’s a bit like relying on temperature departures rather than absolute rankings in a warming climate. But the global temperatures will respond to the absolute Nino 3.4 SSTs rather than the departures which update to reflect the warming baseline each decade. The value of RONI is probably more for La Ninas where the WPAC warm pool has been defining La Nina’s more than the Nino region cold pool of the past. But the absolute strength of La Niña measured through Nino 3.4 SSTs has been shrinking since we haven’t had a strong La Niña by actual SSTs since 2010-2011.

Hopefully, the clouds and convection can prevent another run on 100° so soon after the one in May. The only model with upper 90s in our area is the Euro. But it has less clouds and convection than the other models. It could be correct if the convection underperforms with the ongoing drought. The model forecasts highlight the big temperature divide as early as Thursday.

Ultimately El Niños are ranked by their jump in global temperatures. 2023-2024 had a larger rise in global temperatures than previous super El Niño events. So relying on the RONI metric is inadequate to describe these much stronger events. Even the authors of the paper which RONI is based on said the scale may need to be reevaluated in the future. So I view it as an experimental index which should be used alongside the traditional ONI scale. It can be used for assessing features like El Niño rainfall and the strength of the Aleutian Low. But ONI was closer to reality on temperatures during 2023-2024 than RONI. Plus the 500 mb ridge over North America was more in line with ONI. 2023-2024 was the warmest winter on record for the CONUS which none of the models beyond 15 days forecast. The warmth across the Northern Tier even exceed some of the previous super El Niño events. Seasonal models don’t have the ability to see extremes. Extreme warmth has been greatly exceeding extreme cold. So the long range models miss extreme warmth much more often since extreme cold has become so rare. About the only thing I use the seasonal models for are the Nino plumes once we get past the spring predictability barrier in early June. But we knew something really big was coming months ago with the record WWBs and kelvin waves. https://journals.ametsoc.org/view/journals/clim/37/4/JCLI-D-23-0406.1.xml As they previously cautioned, in the future, if there are significant divergences between the tropical mean state and trends in the Niño indices, then this index will need to be re-evaluated. We hope this work motivates additional studies and simulations of these indices in a changing climate.

Those seasonal model 2m temperatures typically run way too cool especially with super El Ninos like we saw in 2023-2024 and 2015-2016. This has been the case with all the seasonal models. Even the forecasts issued in November were still too cool NMME DJF 2023-2024 long range forecast issued August 2023 Verification DJF 2015-2016 long range forecast issued August 2015 Verification

More traditional June El Niño 500 mb pattern forecast for next week as this record El Niño continues to intensify.

Looks like some cooler and hopefully wetter weather is on the way for next week following more unusual warmth this week for a developing El Niño. A ridge out West and a trough near the Great Lakes is a closer match to El Niño June expectations. It’s forecast to occur right as this event is setting records for the warmest Nino 3.4 SST on record for early June.

This past November was in 2025. Part of the reason this El Niño is becoming record breaking so early on is due to the accumulation of record SST warmth in the WPAC. The WWBs beginning in November 2025 started the kelvin waves and warm push eastward. These are record breaking WWBs that we haven’t seen since the late 1990s. So a record WPAC warm pool initiation plus record WWBs equal a record El Niño. Also note how Nino 1+2 never fully cooled off after the last super El Niño in 2023-2024. So it’s no surprise that this event is becoming so strong given the much warmer background state that it’s originating in. Past climate reconstructions along with modeling support the idea that it’s normal for El Niños to become more frequent and stronger as the world warms. So the 2020s will be the first decade with super El Niños over +2.0° occurring only 3 years apart. https://apnews.com/article/4379af505f994766a4fa332e9c7a923a https://www.colorado.edu/today/2024/09/25/1-2-el-nino-events-could-be-extreme-mid-century https://www.science.org/doi/10.1126/science.354.6317.1210

Looks like there could have been some small hail near the Jones Beach West End.

Yeah, we can go back to last November to see the very beginning of this record El Niño event for so early in the season. The WWB over the Maritime Continent was essentially tied for the strongest on record during the month of November. It began to give that record warm pool a nudge to the east with the record WWBs expanding eastward in the following months.

Nino 3.4 getting to 29.27 is really impressive so early in this event. The all-time record was 29.82 back on 11-17-15. They may need to extend the scale since the current forecast peak over is 30°C.

The NJ warm spots away from the sea breeze are tied for the most 90° days by June 6th. Time Series Summary for SOMERSET AIRPORT, NJ Click column heading to sort ascending, click again to sort descending. 1 2026-06-06 6 0 - 2021-06-06 6 1 2 2023-06-06 4 0 - 2000-06-06 4 13 5 2022-06-06 3 0 Time Series Summary for HARRISON, NJ Click column heading to sort ascending, click again to sort descending. 1 2026-06-06 8 1 2 2018-06-06 7 0 - 2010-06-06 7 15 3 2021-06-06 5 0 - 2013-06-06 5 0 - 2002-06-06 5 5 - 2001-06-06 5 7 Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. 1 2026-06-06 8 0 - 1991-06-06 8 0 - 1986-06-06 8 0 2 2010-06-06 7 0 3 2021-06-06 6 0 - 2002-06-06 6 0 - 1936-06-06 6 0

Similar recent theme of the wind gusts being more impressive than the actual rainfall amounts. Another very warm with below average rainfall pattern coming up this week. Hopefully, the models are correct about the wetter pattern with the Great Lakes trough during week 2 approaching the summer solstice.

Warm spots away from the sea breeze influence like Harrison and Newark are currently in 1st and 2nd place for the most 90° days by June 5th. Time Series Summary for HARRISON, NJ 90° days by June 5th Click column heading to sort ascending, click again to sort descending. 1 2026-06-05 8 0 2 2018-06-05 7 0 3 2010-06-05 6 15 Time Series Summary for NEWARK LIBERTY INTL AP, NJ 90° days by June 5th Click column heading to sort ascending, click again to sort descending. 1 1991-06-05 8 0 - 1986-06-05 8 0 2 2026-06-05 7 0 3 2010-06-05 6 0 - 2002-06-05 6 0 - 1936-06-05 6 0

Yeah, we could have active forcing from the WPAC and CPAC over to the EPAC with how extensive the warm pool is forecast to become. Notice how the pattern from the Great Lakes to the Northeast wasn’t all that different between 1997-1998 and 2023-2024. Forcing either focused near the EPAC in 1997-1998 or more split like 2023-2024 between the WPAC and CPAC along with the EPAC yielded roughly similar results for the Great Lakes and Northeast.