bluewave

Nino 1+2 didn’t get above +2 until the summer in 1972 and 3.4 was at +1.0 borderline moderate. So there have been no known El Niño evolutions with 3.4 lagging so far behind 1+2. The WPAC didn’t have the record warm pool like we have now. So this event is technically starting out more east based than any other year. How this plays out later on is still to be determined. 7th week of Nino 1+2 first going above +2 this year minus 1972.

Maybe one last freeze for some interior spots.

Nino 1+2 has been above +2 for 7 weeks and 3.4 is only +0.4. By the 7th week in 2015 of 1+2 going above +2 Nino 3.4 was +1.2. At the same point in 1997 it was +0.9. So an unusually long lag in Nino 3.4 warming with the trades staying active near the Dateline.

We could have used the upcoming record +PNA 590 DM ridge last winter.

That’s a good question. My guess the actual PDO will be contingent on how long it takes the atmosphere to have a more Nino-like response. Those PDO forecasts are a function of how the El Niño atmospheric pattern develops.

Yeah, the WPAC warm pool was warmest on record for the month of April. The trades are much stronger now near the Dateline than in 2015 and 1997. The Central Pacific is much cooler with 3.4 lagging well behind 1+2. So we don’t really have any past instances of an early El Niño evolution like this.

You are in a unique spot where you can get a top 5 warmest and snowiest in the same season due to less ice and warmer Lakes.

I know that these seasonal forecasts aren’t great. But they are forecasting the -PDO to weaken a bit in the coming months. This would be expected if some of the stronger forecasts for the El Niño worked out. Still a tough call as to how strong in 3.4 it will get since the WWBs are still pretty far west of the Dateline. This will be a learning experience on how long it takes 3.4 to warm when the current subsurface still favors 1+2 and 3. Never had 1+2 this much warmer than 3.4 in the early development phases before. 3.4 was usually closer to +1 in past years when 1+2 was over +2 for this long. So not sure what this means going forward.

Spatially using that composite as to where the departure centers lined up wasn’t bad. But the magnitude of the warm departures was way beyond. I have noticed various seasonal forecasts sometimes getting where the departures were located correct but ultimately having a cold bias. April was 7° warmer than the composite is some spots. So not sure how much a forecaster would know ahead of time to warm an older composite. Several spots had their warmest April on record. https://www.nrcc.cornell.edu/services/blog/2023/05/02/index.html

After dipping below -2 recently the more +PNA let it rise a bit. https://s2s.worldclimateservice.com/climatepanel/

I know that we both understand that. I have done the same thing. But posters on this forum hear a specific year mentioned and then aren’t happy when the snowfall or temperature forecast isn’t exactly like that year. So I had to lean more on recent year composites rather than the specifics. I guess it’s just the way people hear things and relate to their favorite winters from the past.

Tough to say when. There was a great recent paper on the topic. Gives new meaning to persistence forecast.

When you use specific analogs from an earlier era you raise expectations among your readers. It’s probably better to just draw up the maps without references to pre 2010 analogs. The only winter forecast which has been reliable since 15-16 has been some version of the SE Ridge or WAR. This feature has been present whether we had El Niño, La Niña, neutral, or uncoupled El Niño.

The changes have been what made each of the winters unique. Haven’t seen any seasons since 2010 match earlier analogs. We went from historic Atlantic blocking in 09-10 and 10-11 to record Pacific blocking in 13-14 and 14-15. We had the 11-12 non winter in between. Plus some could argue Nemo in 12-13 was one of their greatest snowstorms. The 15-16 super El Niño seems to have resent the winters warmer with a dominant SE Ridge or WAR. We actually got our strongest monthly SE Ridge in December 2015 during an El Niño when we went +13 for the month. That was probably related to the interaction with the strongest Mina-like MJO 4-6 during a super El Niño.

6 out of the last 9 El Niño winters have been warmer than average during the most recent 30 year climate normals era. The only 3 colder ones with much above normal snowfall were modokis in 02-03, 09-10, and 14-15. 5 of the warner 6 were basin wide or east based. Really hesitant to even look at El Niños before 1990 for specifics since the climate base state has warmed so much since then. 2 out of the 6 warmer winters had above normal snowfall. But the other 4 were well below average on the snowfall. 04-05 was a modoki with extensive warmth west of New England and a snowier outcome. The record warm 15-16 had a snowy end when the forcing became more west based from late January into early February.

The early evolution suggests east based or east based transitioning to basin wide. So that would probably favor another warmer than average winter. Could be looking at a record 9 warmer winers in a row since 15-16. Don’t think we ever had a cold modoki El Niño with well above normal snowfall begin this east based before. But moderate to stronger basin wide or east based El Niño’s have had variable snowfall. Generally below normal to normal with a few snowier seasons in the mix. A higher end El Niño could have a big impact on global climate after the 15-16 super El Niño represented a big step up in global temperatures.

The only certainty with our winters since 09-10 has been no specific analogs from before this era have been useful for a seasonal forecast due to changes in the global climate.

It also looks like the anomalous warm pool south of Hawaii may have played a role. Notice the classic La Niña VP anomalies north of Australia. But the forcing south of Hawaii has more of a Nino-like look. So the trough and STJ near California were enhanced producing a local Nino-like effect. But SE Ridge in the Eastern US was pure La Niña.

April finished 3 warmest behind 1998 and 1983. But those months were at the tail end rather than the beginning of the event. So this is the first time Nino 1+2 was this warm during a spring ahead of an El Niño. https://psl.noaa.gov/enso/dashboard.html

They had more breaks of sun than some of the surrounding sites. You can see them running close on the high for the month so far. Each day has been slightly different with cloud over from station to station with the cold pool. Data for May 1, 2023 through May 4, 2023 Click column heading to sort ascending, click again to sort descending. Name Station Type Highest Max Temperature ESTELL MANOR COOP 65 NEWARK LIBERTY INTL AP WBAN 64 HARRISON COOP 64 Newark Area ThreadEx 64 HIGHTSTOWN 2 W COOP 64 PHILADELPHIA/MT. HOLLY WFO COOP 63 Atlantic City Area ThreadEx 63 EB FORSYTHE NEW JERSEY RAWS 63 PENNSAUKEN 1N COOP 63 New Brunswick Area ThreadEx 63 MARGATE COOP 63 MILLVILLE MUNICIPAL AIRPORT WBAN 63 ATLANTIC CITY INTL AP WBAN 63 SEABROOK FARMS COOP 63 LONG BRANCH-OAKHURST COOP 63 FREEHOLD-MARLBORO COOP 63 NEW BRUNSWICK 3 SE COOP 63

The April Central Pacific Trade wind index still came in positive. So we are closer to the El Niño years which took longer for the trades to relax. Developing El Niño Aprils https://www.cpc.ncep.noaa.gov/data/indices/cpac850 850 MB TRADE WIND INDEX(175W-140W)5N 5S CENTRAL PACIFIC ANOMALY 2023….+1.1 2018…..+1.7 2015….-1.6 2014….-0.1 2009….+1.2 2006…+1.5 2004…..+1.2 2002….+0.4 1997….-1.8 1994...+0.5 1991…+0.5 1986….+0.9 1982….-1.5.

Maybe some more small hail today with the near record cold 850mb temperatures.

The subsurface favors this remaining east based warming for the current time. So 1+2 should probably remain near or above +2. Models really can’t reliably forecast long range whether this remains east based or becomes more basin wide. Trades would need to relax near the Dateline for 3.4 to begin to warm above neutral. That’s why Nino 3.4 is still neutral while 1+2 is over +2. The 16 and 97 events were approaching moderate in 3.4 when they first went above +2 in 1+2. Since 1+2 is such a small area, need Nino 3 to also warm closer to +2 to impact the actual forcing. East based forcing usually takes 1+2 and 3 to be in tandem. Still to early to know how this plays out since we haven’t seen the trades relax near the Dateline yet. That’s what is needed for 3.4 to get to moderate to strong levels by the fall. The subsurface below 3.4 is weaker than the last 2 super events in 2015 and 1997. Those years were already producing strong WWBs near the Dateline by March. But the upper ocean temperature anomalies from 180-100W are still impressive for this time of year. https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/index/heat_content_index.txt Equtorial Upper 300m temperature Average anomaly based on 1981-2010 Climatology (deg C) YR MON 180W-100W April 2023…+1.20 April 2015….+1.74 April 2014…..+1.41 April 1997……+2.17

Looks like a small hail sounding with some CAPE and low freezing level.