bluewave

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

NYC metro will approach the lowest late May pressures on record tomorrow. We will probably come in about 5mb above the all-time May and June lows. 987 mb is a record for May 31st and just above the monthly lows in the low 980s. So people will be looking at their home barometers and asking what month is this.

This looks like it will be the deepest low in the Northeast near the end of May since 2003. Models now have pressures dropping below 985mb. The last storm this strong at this time of year was a 981mb low on Cape Cod on June 1st 2003. https://www.wpc.ncep.noaa.gov/ncepreanal/

Yeah, the heat builds in CA and goes up into Canada. This time of year in 2023 was when we had the record air pollution from the Canadian wildfires. That had to be some if the worst air quality we ever saw.

The rapid expansion of the WPAC warm pool over the last decade becoming the most extreme since 2019 is largely the result of the record 500mb to surface ridging in that region leading to clear skies and light winds warming the SSTs below. The interesting thing is how deep below the surface the warming extends. While the 500mb pattern can shift for a few months leading slightly cooler SSTs, the SSTs rapidly rebound when the ridge returns like we have seen this spring following a brief winter hiatus. The challenge is that we are adding so much heat to the system evidenced by the record global temperature jumps in 15-16 and 23-25, that we don’t really understand why the WPAC has been warming more rapidly than the other parts of the Pacific. So it’s uncertain whether an extreme EPAC warming leading to an El Niño event event even bigger than 23-24 would even shift the STJ for more than a season before the Northern Stream of the Pacific Jet takes over again the next year. That’s why my comments were that I would just be grateful to see some semblance of a STJ and benchmark track pattern. Obviously a high end volcanic event could shift the pattern and storm track back colder for a period of time, but it would only be transient until the effects wear off and the warming resumes. Remarkable Changes in the Dominant Modes of North Pacific Sea Surface Temperature https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2022GL101078

We started seeing record heat and drought well north into Canada since around 2021. May 2023 was pretty extreme with the record 500mb blocking leading to the worst wild fires on record especially in Eastern Canada. So this current over the top warming is just a continuation of the same theme.

All this low pressure in the Northeast could continue to have a say. While it does look like we will see a warm up first week of June, the higher end heat potential may remain capped since models are now coming around to an upper low lingering nearby. So we probably see a return back to 80s. But not sure if the first 90s of the season will occur if there is too much onshore flow. Perhaps, the interior sections of NJ would have the best shot. This is looking like another over the top warm up. The most impressive temperature departures may go to our north again. Upper low lingering nearby first week of June

I know that people around here don’t like all the milder winters, but we may need a really strong El Niño like 15-16 to bring back at least some semblance of a STJ. Weak El Niños or warm neutrals such as 18-19 and 19-20 have been struggling against the La Niña background state. The primary driver has been the WPAC warm pool. Would much rather take my chances getting a very strong to super El Niño as long as the storm track is close to the benchmark. Really don’t care at this point if it’s near 60° before or after the storms or how long the snow stays on the ground. Just want to see some great snowstorms again. But as we saw in 23-24, the La Niña background combined with the very strong El Niño to pull the forcing too far west in the Pacific near the Maritime Continent. So really not sure if even a very strong El Niño can shift the marine heatwaves around which have been associated with the record WPAC warm pool. There is very little we can do from Philly to south coastal side Boston when the Northern Stream of the Pacific Jet is so strong. With Great Lakes cutters, I-95 to I-84 huggers, and suppressed Southern Stream storm tracks. The default position becomes milder winters with below to well below normal snowfall. Even the marginally colder winter this year was still around 40° near the coast on the days that .25 or more of precipitation fell. Perhaps, we can score a decent MJO 8 like we last saw in January 22 in the coming winters. Even one good month can make the winter passable. But we have seen in recent winters how we haven’t been able to get a clean MJO 8 response due to the competing marine heatwaves and multiple areas of forcing.

Very strong recent south based -NAO especially at 500mb warming the seas below with clear skies and strong high pressure. https://s2s.worldclimateservice.com/climatepanel/

Yeah, really comfortable temperatures for this time of year. These late May deep upper lows have been a regular feature here over the years. The Euro has been hinting at a usually strong phaser this weekend. Very rare to see a 984mb low in the Northeast at the end of May. The GFS just came on board for a deep Northeast low also and phasing between the two streams.

Very comfortable temperature pattern for this time of year continuing right into early June over the next 10 days. Very familiar over the top warmth into Canada. So the first 90° of the season is running late.

Yeah, this spring has featured the same very strong La Niña background 500mb pattern which has dominated since around 2019. Pretty much being driven by the WPAC warm pool and 500m ridge pattern. Notice how amplified the Aleutian Ridge has been along with the Southeast or Western Atlantic Ridge. We can also see the Aleutian Ridge continuing to extend back very close to Japan. This is the 2n EOF of the -PDO which has been at record levels since 2019. Spring 2025 similar to the pattern since 2019

Yeah, NYC was able to reach 106° back in 1936 when the weather equipment wasn’t underneath a dense stand of trees which grew up around and over the site. Our last series of summers without marine influence was back in 2010-2013. It’s when Newark to parts of Long Island reached 108° with strong westerly downsloping offshore flow. Now that the global background temperatures have jumped much higher than 2010 twice in 15-16 and 23-24, we have been getting onshore summer flow due to the ridge expanding more to the east of New England. While our summers have still been well above average temperatures with record dew points, drought feedback is necessary to set an all-time high in the warm season. All of our new monthly maximum temperatures have occurred in the winter and fall since 15-16. We set an all-time winter max of 80° in February 2018 which beat the previous record of 76° by 4°. The new all-time October high of 96° back in 2019 beat the old record by 3°. That inky took a brief flash drought which emerged in September. But nothing like the record droughts further back in the past. The most extreme summer heatwave in the CONUS since 2020 was in the Pacific Northwest back in 2021. Stations best their all-time summer high by 6°. So if our 108° summer heat back in 2010 was ever exceeded by 6°, then it would be 114°. But there isn’t any present indication in the new much wetter climate with more onshore flow that that type of scenario would be likely anytime soon here.

All our summer heat over the last decade had come with onshore flow and record high dew points. This is a result of the big ridge setting up east of New England. So the 100° heat has been mostly found over NJ with only occasional instances into Queens. It has also been a pretty rainy summer pattern. From 2010 to 2013 the ridge was to our west over the Great Lakes. So we got frequent westerly flow downsloping events. Even though the dry patterns were modest compared to earlier times, we still maxed out at 108°. Parts of the Pacific Northwest had highs 6° above the all-time levels back in 2021. The result of the much warmer climate in the 2020s and the historic droughts out West. So if this area ever saw a 1960s style drought with 2020s temperatures and westerly flow, then the max temperature potential would probably be 112° to 114°. The good news is that it’s very difficult to meet these conditions in this new climate. Since it’s uncertain how well our power grid would function with widespread temperatures that high.

Pretty wild how JFK has had the 7 lowest spring high temperature at only 82° while the average high temperature has been 3rd warmest. Time Series Summary for JFK INTERNATIONAL AIRPORT, NY - Mar through May Click column heading to sort ascending, click again to sort descending warmest spring temperature 1 1983 75 0 - 1967 75 0 3 1968 78 0 - 1958 78 0 4 2008 79 0 - 1984 79 0 - 1966 79 0 5 2005 80 0 6 1961 81 0 - 1950 81 0 7 2025 82 7 - 2004 82 0 - 1997 82 0 - 1982 82 0 - 1972 82 0 - 1971 82 0 - 1951 82 Time Series Summary for JFK INTERNATIONAL AIRPORT, NY Click column heading to sort ascending, click again to sort descending average spring high temperature 1 2010 64.0 0 2 2012 63.1 0 3 2025 62.6 7 4 2024 62.5 6 - 1985 62.5 0 5 1991 61.8 0 6 1986 61.3 0

These late season upper cold pools are great if you like higher elevation snows.

New England has been very lucky since their last Hurricane Bob way back in 1991. This has been related to the 500 mb heights rising faster north and east of New England relative to the Gulf Coast. The last major U.S. hurricane major landfall north of Jacksonville occurred in 1996. This is a new record for the U.S. Coastline relative to the total U.S. major landfalling hurricanes over a 30 year period. It’s part of the reason that there have been so many high impact major landfalling hurricanes in and around the Gulf Coast recently. Even Sandy was driven west into SNJ near ACY and avoided a New England landfall. This is why it was so damaging around the NY Bight. https://www.aoml.noaa.gov/hrd/hurdat/All_U.S._Hurricanes.html

A +7.2° F warming of the Gulf Stream in only 40 years is a big deal and is related to the rise in 500mb heights associated with the Southeast Ridge and Western Atlantic Ridge. But 500 mb heights are on the rise everywhere. So there could also be more remote teleconnections involved spanning all the ocean basins. We have seen the subtropical ridge expansions simultaneously across the entire planet.

Yeah, the usual warm spots could avoid a big year like 2022 and 2010 for 90° days since we haven’t had any 90° days yet. Monthly Number of Days Max Temperature >= 90 for NEWARK LIBERTY INTL AP, NJ all years with 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

We knew something was up as early as June 2009. Record -NAO -AO pattern emerged with solid trough development underneath. Was actually the 6th coldest June and July on record for the Northeast going back to 1895. It was a beautifully refreshing summer that year. Then the CONUS scored their 4th coldest October on record since 1895 from coast to coast. So in some ways it was a warmer mirroring of the 1976-1977 historic cold pattern which emerged during in the summer of 1976. But it didn’t have the extreme level of cold in 1976-1977. Most on here were fine with that since the snowfall pattern was so much better than in 1976-1977. The STJ during the 2009-2010 winter was one of the most beautiful the East has ever seen. I would take my chances any time with a STJ like that even in a very mild winter. Most would be happy even getting a smaller snowfall version of 2009-2010. I wouldn’t even care if it was 60° a few days later.

Haha..JFK has had 12 top 3 low makes since 2000 from 5-21 to 6-2. But I know this would be preferable for many during the winter. These late May cutoffs have been very persistent over the period. Top 3 coldest finishes since 2000 at JFK New York-Kennedy Airport Area, NYPeriod of record: 1948-07-17 through 2025-05-23 Lowest maximum temperatures (degrees F)Top Record 2nd Record 3rd Record 5/21 51 in 1990 52 in 1967 56 in 2000 5/22 55 in 2025 55 in 1967 56 in 2003 5/23 56 in 2003 56 in 1982 56 in 1967 5/24 55 in 1956 56 in 1967 57 in 1969 5/25 47 in 1967 54 in 2005 55 in 1973+ 5/26 52 in 1967 56 in 2003 59 in 1992+ 5/27 50 in 1961 53 in 1973 57 in 1987+ 5/28 59 in 1996 59 in 1950 60 in 1968 5/29 52 in 2021 57 in 1967 59 in 1996 5/30 52 in 2021 57 in 1953 60 in 2017 5/31 60 in 1953 61 in 2000 61 in 1992 6/1 63 in 2015 63 in 1964 63 in 1959 6/2 56 in 2015 62 in 2005 62 in 1997

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.

My point is that any winter month when some portion the coldest departures in the Northern Hemisphere are found in the CONUS is becoming less frequent. Plus when you add a less intense cold pool like last January centering in the U.S. the results aren’t as extensive or intense as past instances. The cold pool departures last January were much less impressive than the last time the coldest departures were in the CONUS like February 2021 and February 2015. Getting a replica of 2015 has several challenges that I can see. First, the planet has had two tremendous baseline jumps in background temperature during 2015 into 2016 and an even greater jump the last 2-3 years. So this naturally weakens the cold pool. Second, the more extensive warming of the WPAC has been associated with a faster Northern Stream of the Pacific Jet. The faster jet keeps sending pieces of energy into the NEPAC blocking causing it to weaken. So we haven’t able to reach the blocking levels there we saw in 2013-2014 and 2014-2015. This was the case over the recent 2024-2025 winter. Third, getting a weak Modoki El Niño like February 2015 has been a challenge with the WPAC warm pool expansion. So the attempts in 2018-2019 and 2019-2020 didn’t work out.

The patterns we get are the function of the warmer temperatures and higher overall 500 mb heights. So the ridging potion at 500mb occupies more real estate than the troughs. Smaller troughs or cold pools have less overall cold. The Northern Hemisphere cold pool was near the lowest on record this past winter. This is why even though the coldest temperatures on the planet in January were located in the CONUS, amount of cold was so limited that the monthly cold ranking for the CONUS was only the 33rd coldest January. It’s also why Canada was so warm with a record low sea ice on Hudson Bay. The cold into the Northeast was very limited relative to other times the coldest temperatures in the Northern Hemisphere were in the CONUS.

I would have to disagree with you. The shrinking cold pool makes it difficult for any combination of teleconnection indices to deliver the coldest departures into the Northeast during top 20 monthly and seasonal Arctic outbreaks for the CONUS and Northeast. Getting a so called right combination of teleconnections becomes statistically more difficult. The closest we came was January 2022 at the 21st coldest January in the Northeast since 2015. If the Arctic outbreak from late December into January 2018 lasted longer than we could have pulled it off. But this diesnt mean that it’s impossible, just statistically more difficult. We’ll see if we can sneak one in during the coming years. Obviously, it could require a major volcanic event.