bluewave

This summer was much drier in New England than 2010 was leading to the record low streamflows that some areas are experiencing.

Mid to perhaps upper 80s Tuesday as the models are slowing the front down. New run Old run

The recent summer pattern across the U.S. is a reversal of the Dust Bowl. The record heat has been located in the West and East with cooler and wetter in the middle. This is the opposite of the Dust Bowl with record heat and drought focused in the middle. https://journals.ametsoc.org/view/journals/clim/36/20/JCLI-D-22-0716.1.xml Abstract A cooling trend in summer (May–August) daytime temperatures since the mid-twentieth century over the central United States contrasts with strong warming of the western and eastern United States. Prior studies based on data through 1999 suggested that this so-called warming hole arose mainly from internal climate variability and thus would likely disappear. Yet it has prevailed for two more decades, despite accelerating global warming, compelling reexamination of causes that in addition to natural variability could include anthropogenic aerosol–induced cooling, hydrologic cycle intensification by greenhouse gas increases, and land use change impacts. Here we present evidence for the critical importance of hydrologic cycle change resulting from ocean–atmosphere drivers. Observational analysis reveals that the warming hole’s persistence is consistent with unusually high summertime rainfall over the region during the first decades of the twenty-first century. Comparative analysis of large ensembles from four different climate models demonstrates that rainfall trends since the mid-twentieth century as large as observed can arise (although with low probability) via internal atmospheric variability alone, which induce warming-hole-like patterns over the central United States. In addition, atmosphere-only model experiments reveal that observed sea surface temperature changes since the mid-twentieth century have also favored central U.S cool/wet conditions during the early twenty-first century. We argue that this latter effect is symptomatic of external radiative forcing influences, which, via constraints on ocean warming patterns, have likewise contributed to persistence of the U.S. warming hole in roughly equal proportion to contributions by internal variability. These results have important ramifications for attribution of extreme events and predicting risks of record-breaking heat waves in the region.

Still looks pretty warm to me since the Atlantic is currently the 5th warmest on record for the date. We also have to remember that this is the warmest 1991-2020 climo. So the actual historical ranking is pretty high. The cold pool west of Ireland is from the locally stronger winds there with the deep low pressure.

I had 1.78 spread out over 3 days. My wettest single day was only .76. The last 1.02” in a day was way back on May 5th. 3-23-24 was my last 2.92” in one day. This was my 5th driest summer at only 4.99”. It was also my 4th warmest summer here. So all the vegetation and grass was on the brown side. But July 99 back on the South Shore of LI still holds the record for the brownest vegetation that I have seen. Nearly all the lawns and the parkways were completely brown.

Hoping the cutoff low to the SW can finally end the 13th longest daily streak with under 1.00” here since early May. Number of Consecutive Days Precipitation < 1.00 for NEW HAVEN TWEED AP, CT Click column heading to sort ascending, click again to sort descending. 1 244 2014-12-10 through 2015-08-10 2 240 1964-12-05 through 1965-08-01 3 200 2001-10-10 through 2002-04-27 4 194 1965-08-03 through 1966-02-12 5 171 2013-06-09 through 2013-11-26 6 160 1971-02-09 through 1971-07-18 7 159 1960-11-02 through 1961-04-09 8 151 2015-08-12 through 2016-01-09 9 148 1962-04-02 through 1962-08-27 10 146 1957-05-15 through 1957-10-07 11 142 2007-09-12 through 2008-01-31 - 142 1955-03-23 through 1955-08-11 12 138 1966-10-20 through 1967-03-06 13 137 2025-05-06 through 2025-09-19 14 132 1955-11-05 through 1956-03-15 15 131 2009-01-29 through 2009-06-08

Yeah, from the 60s to early 90s within a few inches of 25” was very common. There were a few seasons of near 30”+ and a few 20” and below. So a very balanced snowfall pattern during that stable colder era. The snowfall became all or nothing since 93-94. Most seasons have been over 30” or under 20” since then as the winters have continued to warm. The storm tracks remained cold enough to our south for many 30”+ seasons from 09-10 to 17-18. The warmer storm tracks since 18-19 have resulted in most seasons ending up with under 20” of snow. So it has been challenging to get a 30”+ season. Plus NYC hasn’t had a season near 25” since 12-13. So losing the higher end 30”+ seasons and continuing the decline in the near 25” seasons has resulted in the under 20” season becoming most common. NYC snowfall seasons near 25” 12-13….26.1” 08-09…27.6” 92-93…24.5” 90-91….24.9” 86-87….23.1” 84-85….24.1” 83-84….25.4” 82-83…..27.2” 81-82……24.6” 78-79…..29.4” 76-77…..24.5” 73-74…..23.5” 71-72…..22.9” 69-70….25.6” 64-65….24.4”

The lowest 10 year for JFK was 18.0” from 83-84 to 92-93. So this 7 year stretch has been lower that 10 year. The 7 year got down to 15.8” vs the current 14.5”. The key difference is that snow drought ended with 93-94 and 95-96 since the climate was so much colder than our modern 2020s climate. Unlikely we see a 50”+ season and a 70”+ season during the remainder of the 2020s within 2 years apart to break this snow drought without the greatest volcanic eruption in hundreds to thousands of years. Unfortunately, we don’t have a reliable long range volcanic forecast system.

Record heat to our west yesterday with temperatures only missing 90° by 1°. This is why I have been discussing the potential for 85°-90°heat since late August even when models weren’t showing it. Models often underestimate the heat potential during flash droughts. 443 CDUS41 KCTP 190624 CLIIPT CLIMATE REPORT NATIONAL WEATHER SERVICE STATE COLLEGE PA 224 AM EDT FRI SEP 19 2025 ................................... ...THE WILLIAMSPORT PA CLIMATE SUMMARY FOR SEPTEMBER 18 2025... CLIMATE NORMAL PERIOD 1991 TO 2020 CLIMATE RECORD PERIOD 1895 TO 2025 WEATHER ITEM OBSERVED TIME RECORD YEAR NORMAL DEPARTURE LAST VALUE (LST) VALUE VALUE FROM YEAR NORMAL ................................................................... TEMPERATURE (F) YESTERDAY MAXIMUM 89R 351 PM 88 1964 75 14 78

Will be intersting to see if Walpack, NJ actually has a colder August monthly minimum temperature than September. They made it down to 37° on 8-31. The lowest so far this month has been 38°. After some cooler temperatures this weekend the pattern warms up again next week. Walpack NJ 2025-08-31 Mesonet 79 37 Walpack NJ 2025-09-09 Mesonet 75 38

I think the warm blobs can begin to exert some influence on the pattern when they become anchored to the subsurface like we are seeing now across most of the WPAC to North of Hawaii. Last winter we had one of the deepest troughs for the last 20 years emerge to the east of Japan. The surface SSTs didn’t cool very much compared to past deep trough instances since the subsurface had accumulated to much heat. So the strong gradient remained between the area east of Japan and Siberia. This lead to frequent jet extensions. Plus when the record SSTs are located near the Kuroshio Current in the WPAC and Gulf Stream in the Atlantic, they can help to initiate Rossby wave breaking which have a big influence on hemispheric circulation patterns. https://www.cpc.ncep.noaa.gov/products/GODAS/ocean_briefing_gif/global_ocean_monitoring_current.pdf

It’s pretty wild how fast we dried out after that record deluge last August.

The 1980s snowfall averaged about 6” higher than the last 7 seasons. Monthly Total Snowfall for JFK INTERNATIONAL AIRPORT, NY Click column heading to sort ascending, click again to sort descending. Mean T 0.1 2.6 8.2 5.9 2.7 1.0 20.4 1979-1980 T 0.0 2.5 3.0 2.3 3.2 T 11.0 1980-1981 0.0 0.2 1.7 7.7 T 6.9 0.0 16.5 1981-1982 0.0 T 3.1 12.5 0.8 0.3 8.2 24.9 1982-1983 0.0 0.0 4.8 1.0 24.7 0.1 1.5 32.1 1983-1984 0.0 T 1.2 9.9 T 10.9 T 22.0 1984-1985 0.0 T 5.5 12.4 9.0 0.4 T 27.3 1985-1986 0.0 T 2.8 3.0 13.5 T T 19.3 1986-1987 0.0 0.4 1.0 11.8 7.9 2.0 0.0 23.1 1987-1988 0.0 0.4 3.0 15.7 0.5 0.1 0.0 19.7 1988-1989 0.0 0.0 0.7 4.7 0.1 2.7 0.0 8.2 Monthly Total Snowfall for JFK INTERNATIONAL AIRPORT, NY Click column heading to sort ascending, click again to sort descending. Mean 0.0 0.7 1.8 3.7 7.3 1.0 T 14.5 2024-2025 0.0 0.0 3.0 2.5 6.5 0.0 0.0 12.0 2023-2024 0.0 T T 2.4 10.4 T 0.0 12.8 2022-2023 0.0 T T T 1.7 0.4 0.0 2.1 2021-2022 0.0 T 0.2 17.8 3.2 0.5 0.0 21.7 2020-2021 0.0 0.0 7.2 0.9 26.4 T T 34.5 2019-2020 0.0 T 1.9 1.9 T T T 3.8 2018-2019 0.0 4.8 T 0.7 3.1 6.1 0.0 14.7

The subsurface is very impressive also.

Top down drought with all the record warmth and blocking in Canada forced this system too far to our south. Places like JFK have had their 7 driest September to September period. They are down 11.3” of precipitation over the last year at only 31.99”. Time Series Summary for JFK INTERNATIONAL AIRPORT, NY Click column heading to sort ascending, click again to sort descending. 1 1966-09-16 27.41 0 2 1985-09-16 29.11 0 3 1965-09-16 30.62 0 4 1970-09-16 30.92 0 5 1995-09-16 31.41 0 6 2022-09-16 31.84 0 7 2025-09-16 31.99 0 8 2002-09-16 33.14 0 9 1954-09-16 33.40 19 10 1981-09-16 33.42 0

Yeah, still too early to know if it’s just a default or the models are onto something.

Top 10 driest September to September period for many stations in the Northeast.

That is the trend which is independent of the different regimes. It could be why the seasonal models are defaulting to it. I am not really interested in what the seasonal models are showing this early.

The blended model ensemble mean is defaulting to the full trend diagram.

They really need to change their opposition to air conditioning since Europe has some of the fastest summer warming on the planet. https://www.cnn.com/2025/07/02/climate/europe-air-conditioning-heat-wave-intl-latam

Yeah, it’s funny that most of the seasonal model forecasts for this winter are defaulting to figure 1 full trend.

Having this happen two falls in a row makes me think something might have changed at least for the near term precipitation around here. But it has only been a year and things can flip back to wetter again. This top down warming and drying from Canada is something new for us though.

I will give the EPS weeklies credit for starting to pick up on March 2012 record warmth during mid-February. https://fox12weather.wordpress.com/2012/02/16/ecmwf-weekly-maps/

Portions of the Northeast could see more drought expansion with the update tomorrow.

Friday could be the warmest day at JFK since 8-25 since we are finally getting an offshore flow. Moderate dewpoints and steep low level lapse rates. So mid 80s are possible from the forecast soundings.