bluewave

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.

Very nice to actually get a top 10 coldest record for a change. Time Series Summary for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending top 10 coldest lowest maximum temperatures 5-21 to 6-2 1 1967-06-02 48 0 2 1961-06-02 49 0 3 2021-06-02 52 0 4 2025-06-02 53 11 - 1990-06-02 53 0 - 1953-06-02 53 0 5 2005-06-02 54 0 - 1946-06-02 54 0 - 1934-06-02 54 0 6 1982-06-02 55 0 7 2003-06-02 56 0 - 2000-06-02 56 0 - 1943-06-02 56 0 - 1931-06-02 56 0 8 2015-06-02 57 0 - 1968-06-02 57 0 9 2013-06-02 58 0 - 2001-06-02 58 0 - 1950-06-02 58 0 - 1945-06-02 58 0 10 2017-06-02 59 0 - 2011-06-02 59 0 - 1973-06-02 59 0 - 1970-06-02 59 0 - 1963-06-02 59 0 - 1954-06-02 59 0

Not sure how anyone could come to that conclusion since this is a top down ocean warming process. https://www2.whoi.edu/site/argo/impacts/warming-ocean/

The warm spots topped out in the upper 80s. This delayed first 90° could mean that the warm spots like Newark could avoid a top tier summer for 90° days. The only season following a May with no 90° days to reach 40 days of 90° highs was 1983. But that was a super El Niño and this is a La Niña. If Newark can go on to avoid a very high 90° day count over 40 days, then it would probably mean a very wet and humid summer for us. Since Newark needs a dry summer for a very high number of 90° days. Data for January 1, 2025 through May 22, 2025 Click column heading to sort ascending, click again to sort descending. OCEAN COUNTY AIRPORT WBAN 89 NEWARK LIBERTY INTL AP WBAN 88 HARRISON COOP 88 Newark Area ThreadEx 88 TETERBORO AIRPORT WBAN 87 ESTELL MANOR COOP 87 TETERBORO AIRPORT COOP 87 ATLANTIC CITY INTL AP WBAN 86 LONG BRANCH-OAKHURST COOP 86 HIGHTSTOWN 2 W COOP 86 NEW BRUNSWICK 3 SE COOP 86 CALDWELL ESSEX COUNTY AP WBAN 86 BELMAR FARMINGDALE ALLAIRE AP WBAN 86 SOMERSET AIRPORT WBAN 86 All years at Newark with no 90° days in May Monthly Number of Days Max Temperature >= 90 for NEWARK LIBERTY INTL AP, NJ 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

The entire Northeast finished at 21st coldest for January 2022. It was the last time we had KU snowstorms from ACY into New England. December 26th through January 8th, 2018 was our last top 10 coldest 2 week period in NYC. It also coincided with the record 950mb benchmark blizzard. But the pattern flipped warm pretty fast in January. So the 2nd coldest December 26 to January 8 period on record couldn’t last long enough for January 2018 to finish in the top 10 for cold.

The key will be how much rain we get in early June. We probably make it back into the 80s between June 1st -10th. But we would probably need to dry out with more sun in order for the warm spots to get their first 90° of the season by June 15th. We are already running late on our first 90° day. First/Last Summary for NEWARK LIBERTY INTL AP, NJ Each section contains date and year of occurrence, value on that date. Click column heading to sort ascending, click again to sort descending. Minimum 04-07 (2010) 08-08 (2011) 69 Mean 05-18 09-09 113 Maximum 06-17 (2014) 10-02 (2019) 170 2024 05-02 (2024) 90 08-28 (2024) 95 117 2023 04-13 (2023) 92 09-08 (2023) 92 147 2022 05-21 (2022) 95 09-04 (2022) 93 105 2021 05-19 (2021) 91 09-15 (2021) 91 118 2020 06-06 (2020) 91 08-27 (2020) 93 81 2019 05-26 (2019) 90 10-02 (2019) 96 128 2018 05-02 (2018) 90 09-06 (2018) 98 126 2017 05-17 (2017) 92 09-25 (2017) 90 130 2016 05-25 (2016) 91 09-23 (2016) 90 120 2015 05-25 (2015) 90 09-09 (2015) 91 106 2014 06-17 (2014) 91 09-06 (2014) 95 80 2013 05-30 (2013) 93 09-11 (2013) 96 103 2012 05-28 (2012) 91 09-07 (2012) 90 101 2011 05-30 (2011) 92 08-08 (2011) 93 69 2010 04-07 (2010) 92 09-25 (2010) 90 170

The coldest departures have been finding a way to miss the Northeast like with a +PNA in January 2025 and a -PNA in February 2021. Our last top 10 coldest month back in February 2015 was a strong +NAO. But if the cold pools were bigger in January 2025 and February 2021, then the Northeast would have been much colder. February 1979 was one of the lowest February -PNAs at -1.82 and still stands as the coldest 2 week period since the 1960s on Long Island. Minimum 14-Day Mean Avg Temperature for ISLIP-LI MACARTHUR AP, NY Click column heading to sort ascending, click again to sort descending. 1 11.4 1979-02-06 through 1979-02-19 0 2 11.5 1979-02-07 through 1979-02-20 0 3 11.9 1979-02-05 through 1979-02-18 0 4 12.5 1979-02-08 through 1979-02-21 0 5 13.4 1979-02-04 through 1979-02-17 0 6 13.8 1979-02-09 through 1979-02-22 0 7 14.6 1967-12-31 through 1968-01-13 0 8 14.8 1967-12-30 through 1968-01-12 0 9 15.0 1979-02-03 through 1979-02-16 0 10 15.4 1979-02-10 through 1979-02-23 0

But the normal highs for the for the first week of June are still in the upper 70s.

Too bad this new wettest May on record at MPO wasn’t during the winter and all snow. Time Series Summary for Mount Pocono Area, PA (ThreadEx) - Month of May Click column heading to sort ascending, click again to sort descending. 1 2025 10.92 10 2 1989 10.58 0 3 1942 10.41 0 4 1984 9.16 0 5 1946 8.87 0 6 1919 8.32 0 7 1978 8.03 0 8 1924 7.85 0 9 1948 7.39 0 10 1988 7.33 0

The highs today will be lower than the peak highs we have been getting around the solstice in December.

Shift to warmer as we go from met spring to met summer in June . May 26 to June 2 June 2 to June 9

Yeah, still a stubborn piece of the more expansive earlier drought holding on from SE PA into nearby NJ. But nice improvement overall. Luckily, that drought which peaked last fall and winter moderated quite a bit heading into the warm season.

The storm track through the Great Lakes again greatly reduced the snowfall potential around the NYC Metro and other coastal regions. This is a great storm track for areas away from the coast as was the case with the record snows from Toronto to Montreal. The cold focusing closer to the center of the North American continent has been a repeating theme since the big step up in global temperatures in 2015-2016. My guess is that the shrinking cold pool has been limiting the geographic coverage of these Arctic outbreaks. We haven’t had a top 10 coldest month in the Northeast since February 2015.

These +5 departures will get significantly smaller with this very cool pattern to close out the month.

Yeah, but Philly to NYC Metro would have had issues with the strong easterly flow.

That’s due to you being further north closer to NEPA. SEPA from around Philly into CNJ and SNJ has had less than half the rainfall that areas further north have had. This is why drought conditions closer to I-80 have improved with lingering drought further south. Plus Eastern Long Island has had more rainfall than Newark this month.

Par for the course in recent months as the heaviest rains have been further north and east of NYC leaving lingering drought from Eastern PA into NJ.

This happens every spring once the gradient between Siberia and the WPAC relaxes. So this is the normal seasonal weakening of the Pacific Jet allowing more cutoff lows. But even if this was January there would still be mixing issues near the coast since the primary low cut to the Great Lakes before the coastal got going. This would have been a great snowstorm for the interior regions and ski resorts.We can remember the big Nor’easter back on April 4th last spring. It may also be easier to get the height rises near Iceland in the spring for more NAO dominant blocking due to the North Atlantic Jet also weakening during the spring as the gradient between the Arctic and equator weakens. Recent studies have found the North Atlantic winter jet has been getting faster. 4-4-24 Nor’easter

All our stations have a shot at the new low max record for 5-22. EWR….56° NYC…..54° LGA…..57° JFK……55° ISP……54° BDR….54° HPN….54°

The closest that we got to that was February 2021. It was actually the 19th coldest for the entire CONUS and 9th coldest in the Great Plains. But since the Northern Hemisphere was pretty mild overall, the cold was only able to occupy a narrow portion of the Central CONUS. This is why global temperatures are so important in determining what the range of winter potential here in the CONUS. Less cold means a smaller area will have the cold coverage. This is why the cold was narrowly focused into the Plains and the East Coast was just a little colder than average. If this was the 1970s the cold would have been much more extensive. What may seem like a few tenths to a degree or more globally has very large consequences locally to nationally. This is why we need to know the global to continental patterns in order to know the range of parameters for the winter forecast. The difference between a .250 and .330 batting average to someone that doesn’t follow baseball may seem trivial. But it’s the difference between an average hitter and a baseball leading batting average. Some would say that even though the winters are much warmer these days, what’s the difference since even in a warm winter I still need a coat and gloves. While the 2023-2024 winter was the warmest since 1895 in Michigan at 30.5°, it still felt cold outside. This average was still colder than every NYC winter since the 1970s. A colder winter climate like Michigan will always have more leeway. But where many of us live near the East Coast is along the margins as we warm. So a small shift in storm tracks on a global scale from just SE of I-95 near the Benchmark to west of the big cities and further into the Great Lakes makes a world of difference for our sensible weather.