bluewave

Tomorrow looks like a bigger Ambrose Jet day than today.

We were still a very solid +PDO SST signature through the winter of 16-17. Just look at that big cold pool south of the Aleutians and warm crescent along the West Coast. Then in 17-18 you could see the beginning of a shift with lingering warm pool near the Baja and cold pool still north of Hawaii. Still plenty of warmth up in the Bering Sea for a weaker +PDO than 16-17. But this is when the first hint of warming began to the east of Japan. Though not to the point of being overpowering yet which began in 18-19 flipping the PDO negative and preventing the El Niño from coupling in 18-19 and 19-20.

This one long range climate model initialized in 2013 did a great job forecasting the +PDO shift in 2014 that lasted through 2018. So we always have to evaluate on a case by case basis. Plus it’s tough to know when the model is just in repeater mode or actually seeing a shift until we see the verification. https://www.nature.com/articles/ncomms11718 The negative phase of the Interdecadal Pacific Oscillation (IPO), a dominant mode of multi-decadal variability of sea surface temperatures (SSTs) in the Pacific, contributed to the reduced rate of global surface temperature warming in the early 2000s. A proposed mechanism for IPO multidecadal variability indicates that the presence of decadal timescale upper ocean heat content in the off-equatorial western tropical Pacific can provide conditions for an interannual El Niño/Southern Oscillation event to trigger a transition of tropical Pacific SSTs to the opposite IPO phase. Here we show that a decadal prediction initialized in 2013 simulates predicted Niño3.4 SSTs that have qualitatively tracked the observations through 2015. The year three to seven average prediction (2015–2019) from the 2013 initial state shows a transition to the positive phase of the IPO from the previous negative phase and a resumption of larger rates of global warming over the 2013–2022 period consistent with a positive IPO phase.

Looks like the warmest readings today will be following the over the top pattern we have been getting since around 2018. Onshore flow for the south facing beaches. The warmest downslope flow in the Northeast will be found in Mass and NH. So the warmest departures and perhaps actual temperatures will be heading to our north today.

While these climate models forecasts through NDJFM 2030 could just be repeating the 2025 initialization, the winter forecast is still in -PDO mode. It could also be related to the western ocean basins warming fastest to the east of Japan and New England with mean ridges in those positions. I am just putting this forecast out there since it was recently issued. But don’t have any info on how reliable it is or whether the next run will show some type shift later in the 2020s. There is also that cool spot south of Greenland and Iceland which could be related to the more +NAO winters we have seen continuing. https://hadleyserver.metoffice.gov.uk/wmolc/

My guess is that the duration of this current -PDO interval, which emerged around 18-19, will linger as long as the WPAC stays this warm. May had multiple areas near and west of the Dateline ranking near the warmest on record. We probably would have continued the +PDO which emerged around 13-14 right into the 2020s if it wasn’t for that rapid increase in WPAC 500mb heights which warmed the WPAC leading to the -PDO. Hopefully, the changes in the WPAC at 500mb and the surface don’t permanently load the dice for more -PDOs with only intermittent +PDOs. In the old days, the -PDO defined more by the cold pool off the West Coast. Now, the warm pool and 2nd EOF of the PDO in the WPAC are running the show. It would be nice to get monthly real time 2nd EOF updates. But the the ranking charts below can be used in place of the formal 2nd EOF numbers. 2019 to 2025 -PDO 2014 to 2018 +PDO

Yeah, NJ has done a good job of keeping the heat during the 2020s. The enhanced onshore flow has lead to quite a 90° gradient. The last 5 seasons have averaged 41 days reaching 90 west of the sea breeze front in NJ. Here along the CT Shore we have only been around 12 days. Monthly Number of Days Max Temperature >= 90 for HIGHTSTOWN 2 W, NJ Click column heading to sort ascending, click again to sort descending. Mean 0 1 6 19 12 2 0 41 2024 1 1 11 17 11 0 0 41 2023 0 0 2 18 5 6 0 31 2022 0 3 3 22 19 2 0 49 2021 0 3 10 14 13 1 0 41 2020 0 0 5 23 13 1 0 42 Monthly Number of Days Max Temperature >= 90 for NEW HAVEN TWEED AP, CT Click column heading to sort ascending, click again to sort descending. Mean 0 0 2 5 4 1 0 12 2024 0 0 2 3 4 0 0 9 2023 0 0 0 4 0 4 0 8 2022 0 1 1 6 9 0 0 17 2021 0 0 4 3 5 0 0 12 2020 0 0 1 7 4 0 0 12

While the pattern is warming up from late May, it’s still staying wet. So even though the temperatures are above average, the high end potential is limited. Would need to see things really dry out for major mid 90s to around 100° as the month progresses.

Early next week looks cooler and wetter than the earlier forecasts as another cutoff low is forecast to develop over the Great Lakes. New run Old run

Most of the rain appears to be from Friday into Saturday. But the Euro and CMC have some lingering showers into early Sunday. Hopefully, we can some breaks of sun during the afternoon on Sunday.

Yeah, the warm up this week turned into more of an over the top one than the models were showing last week. So the warmest departures will be up in Canada like we have been seeing so often. The usual warm spots will see their first 90° potential. But the onshore influence remains east of NYC. June 2 to 9 new run June 2 to 9 old run

The global temperatures that I am citing are directly related to the ones experienced across the CONUS. The days are long past when the concept of a warming climate remains an abstraction. Now it dictates the ranges of winter temperatures and patterns along with other seasons.This is why the winters across the globe and the CONUS are much warmer with each new jump in global temperatures. The idea is that these baseline jumps in temperatures are permanent across the globe. But the door is always open for very high end volcanic activity which would shift us back temporarily to colder regimes of the past. Though after a number of years we would revert warmer again. This storm track shift to warmer and further north is still a work in progress after 7 seasons with the record low snowfall totals. I think it’s possible the there could be some shift in the way the Pacific is warming which could lead to benchmark snowstorm tracks returning from time to time. But I don’t think it’s very likely the record 2010-2018 with the 50 to 100 year concentration of KU Benchmark tracks will return absent major volcanism. Through the 1970s the world was still in a much colder climate. This allowed the CONUS to have the #1 coldest winter since 1895 in 1978-1979. The CONUS also experienced their 7th coldest winter in 1977-1978 and 12th coldest in 1976-1977. The Northeast recorded their #5 coldest winter in 1976-1977 and 11th coldest in 1977-1978. Our first baseline jump in temperatures across the world occurred in 1982-1983. Across the CONUS the coldest winters of this era were 1983-1984 at #18 and 1984-1985 at #19 coldest. For the Northeast the coldest winter of this era was 1993-1994 which ranked as #13 coldest since 1895. The next global baseline jump in temperatures occurred in 1997-1998 and was much larger than 1982-1983. So the coldest CONUS winter of this era was 2009-2010 which ranked at #22 coldest since 1895. The coldest Northeast winter of this era was 2014-2015 which ranked as #22 coldest. Another major baseline temperature jump happened in 2015-2016. So the coldest winter of this era was 2018-2019 at #84 coldest for the CONUS. The most recent even larger baseline jump in temperatures started in 2023-2024. Our coldest CONUS winter so far was 2024-2025 at #104 coldest. This past winter was also the 27 warmest on record for the CONUS even with the coldest temperatures in the Northern Hemisphere focusing into the CONUS in January. But December was so warm for the CONUS at #4 warmest that is balanced out the winter average to much warmer.

Yeah, looks like a brief warm up this week before we get another cooler weekend with onshore flow and rain. So a continuation of the May theme into June. The upper low keeps returning to the Northeast.

My analysis isn’t contingent on whether folks here are receptive or not. My only focus is getting the pattern correct. You will notice how we haven’t had a single analog for any winter forecast issued in the last 30 years verify if that analog was in the prior base state. Base state number 1 was from the late 1800s into the late 1970s. Base state 2 was 1984 to 1997. Base state 3 occurred from 1998 to 2015. Base state 4 was from 2016 to 2022. The new warmest base state 5 only began in 2023. I have begun using this forecast and analysis technique with great success in recent years. But there are some overlapping features which have continued through the varying base states. Such as La Niña mismatch winters which I identified for the recent winter forecast last October. The mismatch replayed during the recent 24-25 winter leading to the strong -EPO and +PNA. But this base state was so much warmer that a 13-14 analog couldn’t be supported. This is what I pointed out last December. I first began using this technique back in the 2010s. There were numerous instances during this decade when some outlets were going with 1970s analog packages . But I pointed out how this new base state couldn’t support that type of cold. So in effect each new warmer base state had been producing weaker reflections from prior eras. Such as the 24-25 winter very weakly reflecting the strong +PNA -EPO of 13-14 and 14-15. But the much warmer Pacific and faster Pacific Jet eroded the ridge from the west leading to frequent jet extensions which knocked the ridge down. The other feature was the lack of a strong cold trough to the east. I also pointed out last fall how warm Canada was compared to those earlier years. Which continued into last winter. So the amount of Arctic air in North America was much more limited compared to 13-14 and 14-15. Since we are only a few years into this new warmer 2023 base state, there will probably be more weak reflections of winters from the past to come. But getting the levels of cold and snow and cold will struggle compared to earlier eras. The other thing to observe is that we still haven’t had a +7 winter and higher warm departure like occurred in 2001-2002 in this new much warmer climate from Philly to Boston. The departures in 23-24 and 24-25 have come in just below those levels with smaller departures than 01-02. So 22-23 was only about .5° cooler in the actual temperatures than 01-02 with a smaller departure in a much warmer base state. If we get a +7 in this new much warmer base state, then the 01-02 winter record for warmth will be easily eclipsed. But it’s uncertain as to whether or when we would see a +7 winter in this much warmer climate. Something that extreme would probably only become obvious once we’re were into the actual pattern. As it’s not easy to predict a +7 winter ahead of time. But my guess is that there is at least some chance we see a winter that would exceed the warmth experienced in 22-23 and 23-24 from Philly to Boston by 2030. The one caveat is a major volcanic eruption such as the earth hasn’t seen in hundreds or perhaps thousands of years to temporarily shift us back into a colder base state.

Not seeing a 1983 type pattern as we head into June. That summer featured a strong ridge over the Great Lakes with a trough near New England. So a strong westerly flow summer. The summer pattern coming up this week is the same one we have been experiencing the last decade. Elongated ridge to the north and east of New England and plenty of onshore flow. So NJ gets their first 90° of the season which is delayed while JFK and the South Shore gets a very strong Ambrose Jet.

May was a rare month for us when we were all over +5 around the 20th and only a little above average to close out the month. EWR….+1.0° NYC….-0.9° LGA…..-0.5° HPN….+0.7 BDR….+0.2 JFK…..+2.1° ISP…...+1.9° AVG…..+0.7°

The lack of 90° heat this May in the past for the warm spots like Newark has resulted in summers which haven’t exceeded 40 days going over 90°. So this early spring signal would suggest that top tier years for 90° days like 2010 and 2022 when Newark approached 50 days reaching 90° won’t occur this summer. So we are probably in for more onshore flow again this summer with areas west of NYC seeing the strongest heat and cooling sea breezes further east. The only year in the past to reach 40 days with no 90° temperatures at Newark in May was 1983. But that was a much different super El Niño pattern. It was also in the more westerly flow era. These days we have been seeing more summer onshore flow with the elongated ridge to the north and east of New England. All years with no 90° heat at Newark in May Annual and Monthly Number of Days Max Temperature >= 90 for NEWARK LIBERTY INTL AP, NJ following no 90° days in May Click column heading to sort ascending, click again to sort descending. 2025 0 0 M M M M M 0 2020 0 0 5 17 9 0 0 31 2014 0 0 2 8 2 3 0 15 2009 3 0 0 1 10 0 0 14 2008 0 0 6 11 2 3 0 22 2005 0 0 10 11 12 4 0 37 2003 0 0 5 8 7 0 0 20 1997 0 0 7 10 3 0 0 20 1990 2 0 5 9 9 1 0 26 1989 0 0 4 12 8 3 0 27 1984 0 0 8 6 8 0 0 22 1983 0 0 7 15 11 7 0 40 1982 0 0 1 10 1 0 0 12 1976 2 0 7 2 4 0 0 15 1973 0 0 5 9 12 5 0 31 1972 0 0 0 16 4 1 0 21 1971 0 0 6 7 7 2 0 22 1968 0 0 4 9 9 1 0 23 1967 0 0 5 1 1 0 0 7 1966 0 0 10 14 8 1 0 33 1963 0 0 6 11 3 0 0 20 1961 0 0 4 13 8 9 0 34 1960 1 0 3 2 8 1 0 15 1958 0 0 2 11 6 2 0 21 1954 0 0 5 10 3 0 0 18 1952 0 0 8 17 2 4 0 31 1950 0 0 8 6 3 1 0 18 1946 0 0 5 5 2 0 0 12 1940 0 0 2 11 1 1 0 15 1938 0 0 4 4 9 0 1 18 1935 0 0 1 11 2 0 0 14 Years at Newark with 40-50 days reaching 90° with multiple days over 90° in May Monthly Number of Days Max Temperature >= 90 for NEWARK LIBERTY INTL AP, NJ from April to October Click column heading to sort ascending, click again to sort descending. 2010 1 2 13 21 11 6 0 54 2022 0 4 6 20 18 1 0 49 1993 0 3 9 22 11 4 0 49 1988 0 1 10 15 17 0 0 43 2021 0 4 12 11 13 1 0 41 2002 4 1 5 16 14 1 0 41 1991 0 8 10 9 12 2 0 41 2016 0 3 3 16 13 5 0 40 1983 0 0 7 15 11 7 0 40 1959 0 5 5 8 15 6 1 40 Recent years with 50 days reaching 90° at Newark had demonstrated the major heat potential in May. This year Newark only made it to 88° in May. 2022 made it to 98° in May. 2010 reached 95° in May Monthly Highest Max Temperature for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. 2025 87 88 M M M M M 88 April to October Monthly Highest Max Temperature for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. 2022 88 98 96 102 101 93 76 102 April to October Monthly Highest Max Temperature for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. 2010 92 95 98 103 98 98 79 103

The climate across the globe has significantly shifted from the mean state we were in back in 09-10. The base state was fairly stable from the late 1800s into the early 1980s. The first temperature jump out of this much colder era occurred in 82-83. So none of the winters which have occurred since then have been as cold as the late 1970s. We saw a much more significant rise in temperatures during 97-98. So we have not experienced a winter as cold as we saw from the mid 80s up to 1994. Plus this is when the all or nothing snowfall pattern began around NYC Metro after being stable from the early 60s to early 90s with many moderate snowfall seasons in the middle of the range. It’s also why the 95-96 snowfall season hasn’t been rivaled around NYC. The next significant rise in global temperatures occurred in 15-16. This is why we haven’t seen a repeat of winters like 09-10, 10-11, 13-14, and 14-15 since then. The planet has recently experienced a much greater rise in temperatures to a new higher baseline with the 23-24 winter. So this is why we were not able to see a repeat this past 24-25 winter of the 13-14 analog which was being discussed back in December. This new warmer base state was significantly higher than the 13-14 winter. The only way for the climate system to return to a colder baseline would be through major to historic volcanism. But unfortunately such an event in this modern world would be extremely disruptive. Absent any major volcanism, we will just keep shifting the baselines higher with every new periodic global temperature jump. So a whole series of winter analogs prior to 15-16 become out of reach for the new warmer baseline.

We can add May 2025 to the list for the 10.00+ amounts in the northern sections of the OKX forecast zones. Monthly Data for May 2025 for Upton NY NWS CWA Click column heading to sort ascending, click again to sort descending. NJ WEST MILFORD TWP 2.5 SSE CoCoRaHS 12.73 CT PROSPECT 1.9 ENE CoCoRaHS 12.67 NY PORT JERVIS 2.9 ESE CoCoRaHS 11.47 NY NEW WINDSOR 3.3 W CoCoRaHS 10.98 CT PROSPECT 0.5 SW CoCoRaHS 10.79 NY WARWICK 3.2 WNW CoCoRaHS 10.54 NY WARWICK 3.9 W CoCoRaHS 10.25 NJ RINGWOOD 3.0 SSE CoCoRaHS 10.09

It would be very difficult in this much warmer climate for a 09-10 repeat during an El Niño. First, we get more Southeast Ridge link ups with the -NAOs during the 2020s. So New England wouldn’t have to worry about -NAO suppression and confluence like they had in 09-10. The STJ riding too far north would be more of a risk for mixed precipitation from Philly to Boston. Since a stronger Southeast Ridge or Western Atlantic Ridge would probably mean plenty of cold rain from DC to Philly. But I would still take my chances from around NYC Metro into Southern New England that at least one system would really connect for a major snowstorm.

While this doesn’t meet the formal definition, this has some sting jet-like features. Very strong W to NW winds next few hours behind the system with the steepening low level lapse rates. So some spots could gust past 50mph next several hours as models have been underestimating the wind gusts here this year.

The location of the upper low holds the key to our first 90°. If it gets out of the way like the 12z run today, then we’ll have our first 90° next week at the usual warm spots. More of a 0z solution then we’ll top out in the 80s. This is a pretty big jump in just one run. But models usually struggle with closed low solutions. 12z 0z

Yeah, this is why we were +5 a few weeks ago for May and now down to 0 to +2.

Still quite a bit of inshore flow with the cutoff low lingering nearby. The usual warm spots will probably get back to the 80s. But the first 90° still looks delayed to beyond the first week of June.

The record high pressure east of Japan in association with the record warmth has shifted the timing of the rainy season there.