bluewave

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.

The 30 year means keep going up every 10 years so it takes a smaller departure to finish near the top. https://www.ncei.noaa.gov/access/us-climate-normals/#dataset=normals-monthly&timeframe=30&location=NY&station=USW00094728 https://www.ncdc.noaa.gov/IPS/lcd/lcd.html;jsessionid=ED181C50757CEAA76F64228C9949C424?_page=0&state=NY&_target1=Next+> Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Apr Click column heading to sort ascending, click again to sort descending. Rank Year Mean Avg Temperature Departure 1 2010 57.9 +5.4 2 2023 57.6 +3.9 3 2017 57.2 +4.2 4 1941 56.8 +6.7 5 2002 56.1 +3.6 - 1981 56.1 +4.1 - 1921 56.1 +6.1

Heaviest thunderstorms in a while here.

Yeah, need the trades to relax near the Dateline for the El Niño to fully develop. Unusually warm SSTs from IO to WPAC may be playing a role. So still a big disconnect between Nino 3.4 and 1.2. When Nino 1.2 first warmed to +2 to +3 in 1997, Nino 3.4 was +0.5 to +1.0. This time, Nino 3.4 is still neutral due to the stronger trades and a much less impressive subsurface.

Yeah, pretty far west for a developing El Niño this time of year. So the subsurface below Nino 3.4 is much less impressive than the super years like 97-98 and 15-16. But Nino 1+2 is near record levels for April. Sustained Nino 1+2 values above +2 usually are accompanied by more warming in 3.4 than we have currently seen. So no analogs at all for this type of El Niño evolution both in regard to the WWB activity and faster 1+2 warming. Tough to guess how this will ultimately end up in terms of strength and location of warmest anomalies. https://psl.noaa.gov/enso/dashboard.html https://www.cpc.ncep.noaa.gov/data/indices/

Very close..

Near record upper low for this time of year.

January 15th to February 15th 2016 was probably the closest we got to super modoki forcing with the record Nino 4 SSTs. But it wasn’t as far west as the 09-10 true modoki. 97-98 was our last super El Nino with east based forcing.

Tough to verify day 10 snowstorms during the winter when that warm pool ridge east of New England keeps popping up the closer in we get. Someone at one of the weather model centers should come here and discuss this frequent model error. The GFS has had even more of a cold bias than the Euro at day 10. So the long range GFS has even more virtual snow than the Euro.