bluewave

Yeah, could be related. Same for the El Nino trough in the East which was much weaker in 2015-2016 and 2023-2024. I also think the much warmer adjacent off equator and subtropical oceans could be warping the response also. Those subtropical seas were so much warmer this winter that the weak La Niña ridge in the Southwest was so much stronger than the 1995-1996 weak La Niña response. It’s a bit challenging to give a specific value to just how much each individual marine heatwave is contributing. I have also been noticing discussions already taking place about the new RONI index. I went back and reread the paper on RONI and seems like most of the value was with La Ninas where the off equator warmth was masking the La Niña response. But when it comes to the strongest El Niños they can appear weaker than the past ONI. But as we saw from 2023-2024, the weaker RONI didn’t correspond to a weaker ridge over Canada and the Northern Tier and any less warmth. Plus the global temperature jump was even more impressive than past even stronger ONI higher end El Niños. But we could make an argument that the weaker RONI and warmer off equator to subtropical SST warmth could have weakened the Aleutian trough and the trough in the East under the big ridge. This could also warp the rainfall response in some way than we normally get with such strong El niños related to the Southern Stream response. This is why we should probably still use the traditional ONI for the actual El Niño intensity and incorporate the RONI for the finer details like how the Aleutian Low and other troughs are responding.

Probably related to the big expansion of the +30C warm pool in the Pacific which is several degrees warmer than we would get back in the old days with the strongest El Niños before the oceans warmed so much.

At least for the next few weeks, it looks like the warmer days will be in the 70s rather than the 90s. Plenty of blocking setting up which should cap the higher end temperature potential. These impressive temperature swings seem to have increased in frequency starting around January 2005 with how quickly the record warmth reversed to significantly colder. But the warmest temperatures during the swings most of the time is more impressive than the coldest readings. Climatological Data for NY CITY CENTRAL PARK, NY - January 2005 Click column heading to sort ascending, click again to sort descending. Sum 1160 781 - - 1035 0 4.67 15.3 - Average 37.4 25.2 31.3 -2.4 - - - - 3.5 Normal 39.5 27.9 33.7 - 970 0 3.64 2005-01-01 60 40 50.0 14.8 15 0 0.00 0.0 0 2005-01-02 50 37 43.5 8.5 21 0 0.00 0.0 0 2005-01-03 58 49 53.5 18.7 11 0 0.45 0.0 0 2005-01-04 51 46 48.5 13.8 16 0 0.06 0.0 0 2005-01-05 46 35 40.5 6.0 24 0 0.28 T 0 2005-01-06 41 34 37.5 3.1 27 0 0.62 0.0 0 2005-01-07 42 36 39.0 4.8 26 0 T T 0 2005-01-08 41 35 38.0 3.9 27 0 0.59 T 0 2005-01-09 40 33 36.5 2.6 28 0 0.00 0.0 0 2005-01-10 48 39 43.5 9.7 21 0 0.00 0.0 0 2005-01-11 40 35 37.5 3.8 27 0 0.25 T 0 2005-01-12 39 35 37.0 3.4 28 0 0.12 0.0 0 2005-01-13 59 38 48.5 15.0 16 0 0.00 0.0 0 2005-01-14 66 34 50.0 16.6 15 0 1.03 0.0 0 2005-01-15 34 26 30.0 -3.4 35 0 0.00 0.0 0 2005-01-16 31 27 29.0 -4.3 36 0 0.00 0.0 0 2005-01-17 28 18 23.0 -10.3 42 0 0.03 0.5 T 2005-01-18 18 9 13.5 -19.7 51 0 T T 0 2005-01-19 26 9 17.5 -15.7 47 0 0.03 0.8 0 2005-01-20 30 20 25.0 -8.2 40 0 0.00 0.0 0 2005-01-21 20 9 14.5 -18.6 50 0 0.00 0.0 0 2005-01-22 25 6 15.5 -17.6 49 0 0.93 8.5 0 2005-01-23 26 9 17.5 -15.7 47 0 0.25 5.3 13 2005-01-24 24 8 16.0 -17.2 49 0 T T 14 2005-01-25 33 20 26.5 -6.7 38 0 0.00 0.0 13 2005-01-26 37 17 27.0 -6.2 38 0 0.01 T 13 2005-01-27 18 9 13.5 -19.8 51 0 0.00 0.0 13 2005-01-28 22 5 13.5 -19.9 51 0 0.00 0.0 11 2005-01-29 34 15 24.5 -8.9 40 0 0.00 0.0 11 2005-01-30 38 24 31.0 -2.5 34 0 0.02 0.2 11 2005-01-31 35 24 29.5 -4.1 35 0 0.00 0.0 11

This was a record breaking April temperature drop spanning around 5 days. These charts are just for hourly reports and miss highs or lows recorded between hours. Spots that radiate well dropped more than 60°. https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=169&network=NJ_ASOS&zstation=EWR&v=tmpf&hours=111&month=apr&dir=cool&how=exact&syear=1900&_r=t&dpi=100&_fmt=png

FWIW, the April dynamical mean came in at 2.06 for the ONI. This is significantly ahead of 2023 and 2015 at the same point. 2023 was at 1.54 and 2.10 verified. April 2015 was at 1.30 and 2.80 verified. So for the two most recent El Niños reaching an ONI of 2.0 or greater, the spring predictability barrier resulted in too weak a forecast. https://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/ April 2026 Average, Dynamical models 0.764 1.120 1.438 1.709 1.763 1.951 2.060 1.856 1.810 April 2023 Average, Dynamical models 0.460 0.785 1.098 1.328 1.406 1.481 1.547 1.473 1.386 April 2015 Average, dynamical models 0.8 1 1.2 1.3 1.4 1.3 1.3 1.3 1.1

Yeah, would be nice for some improvement of the lower soil moisture to get at least one major storm system while the blocking and STJ is in place.

I try not to get too far ahead of things and just say at this point the temperatures next winter will probably be warmer than last winter was in the Northeast. Just hoping we can keep some semblance of a benchmark track going especially as we approach late January and February. I wouldn’t mind a mild winter at all if we could get a least one nice backloaded style event. The difference between 2015-2016 and 2023-2024 was that we got a great blocking pattern one winter and not so great the other winter. Even 2023-2024 had a good one week period in February with 2 events. But they were narrowly focused into portions of NJ and SNE really couldn’t cash in as much. We did get that record STJ in February associated with the larger event. Obviously, we would want to avoid a 97-98 outcome where we really didn’t get much snow at all. Unfortunately, we just don’t have the technology to forecast snowfall and blocking so many months in advance. Climate Reanalyzer has the 500mb reanalysis maps. But they are delayed a bit to around the 8th of the following month. https://climatereanalyzer.org

As we saw back in 2023-2024, the atmospheric response from the El Nino Ridge parked just north in Canada and the Northern Tier of the CONUS was one of the strongest on record. But the El Niño trough expression through the Aleutian Low and trough across the south to the Mid-Atlantic was much weaker than usual for such a strong Nino ridge which lead to the record warmth with that event. So even the ONI reaching 2.1 really didn’t do that event justice since it failed to incorporate the record Nino 4 +30C warm pool which was the warmest on record. You will notice that the MEI and SOI responses were also much weaker than usual for such a strong event. It will be interesting to see as this one develops whether the SOI, MEI, and RONI lag behind again. All I can say at this early juncture is that the WWB atmospheric component from March and April was much stronger than in 2023 near all time record values leading to the very impressive OKW beneath the surface.

Looks like the STJ really becomes active as we head into May with the rapidly developing El Niño.

We are seeing elements of the spring 2023 pattern with how early and strongly this El Niño is developing. That year had a shift to stronger blocking in late April following early record 90 warmth. Notice the 2 matching dates from 2023 and how close in time the record warmth was. So it’s possible that this week will turn out to be the warmest we see for a while. But rainfall has been generally disappointing. Maybe the developing STJ can allow for some better rainfall opportunities especially by the early summer like we saw in 2023. Newark Area, NJPeriod of record: 1893-05-01 through 2026-04-16DateHighest maximum temperatures (degrees F)Top Record 2nd Record 3rd Record 4/13 92 in 2023 86 in 1977 84 in 2018+ 4/14 93 in 2023 89 in 2026 88 in 2022+ 4/15 91 in 2026 88 in 1960 87 in 1941 4/16 92 in 2002 90 in 2026 89 in 1896

I am curious to see how much rain we actually get vs just low clouds and onshore flow.

Yes, we have had numerous 90°+ events in the Northeast during developing El Niños in April. But the 500mb forecast most closely matches 2023 with a shift to strong blocking. Makes sense since this one is coupling with the atmosphere and is much stronger early on like 2023.

Yeah, the atmosphere seems to be following the April 2023 developing El Niño script. Both April 2023 and 2026 have featured early record 90°+ warmth in the Northeast. Then a reversal to cooler and strong blocking to close out the month.

Yeah, we may get one of our famous spring cut-off low patterns.

The STJ near the Baja is forecast to become more active with the developing El Niño. So it’s looking like more rainfall chances in late April. But the individual storm details will probably have to wait.