bluewave

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.

We never really know what the warmest potential is for any winter until it actually gets underway. There were no reliable forecasts prior to December 2015 suggesting the +13 and warmer than many Novembers for the Northeast. The 2016-2017 winter also gave no early model indication of how warm it would be. Same for the 2019-2020 winter. There wasn’t a seasonal forecast issued prior to December 2021 forecasting a +13 for DFW. Plus we didn’t get any indication ahead of the 2022-2023 winter from the models that there would be such a deep trough in the West. None of the models had the magnitude of the warmth for the 2023-2024 winter ahead of time. But there were indications as early as the spring and summer I was discussing ahead of time that there were warmer risks to the forecast due to how warm the WPAC was for an El Niño. But the magnitude of the warmth became extreme since we had multiple +10 months in a row. This is because nearly every winter since 2015-2016 some portion of the CONUS has experienced a +10 or warmer month. The location and magnitude of the warmth are never forecast much in advance. Dec…2015….NYC….+13.3 JAN…2017….BTV…..+11.0 FEB….2017….ORD….+10.3 FEB…..2018…ATL….+10.6 FEB….2019…MGM….+10.5 JAN….2020…YAM….+9.8 DEC….2021….DFW….+13.2 JAN….2023….DXR….+12.3 FEB….2023…..SSI…..+9.8 DEC….2023….INL…..+15.8 FEB…..2024….FAR…..+17.5 DEC….2024…..LND…..+11.3

We haven’t had any cold and snowy winter analogs in the last 10 years which matched anything prior to the 2015-2016 global temperature jump. So that would be the main reason that 2013-2014 analog would be unlikely in this much warmer climate. We saw the same effect following the smaller jump in global temperatures in 1997-1998. Since we are yet too see a 1993-1994 or 1995-1996 repeat in the years which followed. Same goes for a replay of the 1976-1977 and 1978-1979 winters after a smaller global temperature rise in 1983. So each new global temperature jump has prevented earlier analogs from before the jumps from occurring again. We would need a major volcanic eruption not seen in hundreds or thousands of years to have a shot at one of these winters again.

Whether we get .10 or .50 most people probably won’t notice since it will be rain. Many times models are off by around .5 or more especially during the warm season when convection is involved. But everyone notices the difference between 1” and 5” when snow is involved.

The only posts I have deleted contain specific model forecast charts which can become outdated after only 1 run at times. I don’t like leaving inaccurate model information up when there is newer information available. But I never delete my forecast ideas which you can always go back and find in all the threads.

Model forecasts change which is nothing new. I was just pointing out to Liberty who enjoys the summer heat that the models were showing 85°-90° potential near JFK. Now they have a faster frontal passage so the forecast is for 80-85°. Still a warm late summer day with a dry downslope flow. Plus these warm downslope flow days usually beat guidance. So a few spots could still see some mid 80s. Back in August I was saying that the 90° potential probably wasn’t over for the warm spots in NJ which turned out to be correct this month. Maybe you should try posting some of your own ideas instead of being more concerned about trying to play gotcha games. I notice that you only chime on the few occasions that the warmest guidance doesn’t verify. But are usually silent when warmth beats guidance.

I posted yesterday that the heaviest rain would stay to our south due to the record blocking to our north which is still the case today. I didn’t mention any specific amounts since the models haven’t been very good recently in that regard beyond a few days out The big picture hasn’t changed much over most of the last year for precipitation. We have been drier than average with the heaviest amounts either completely missing our area or narrowly focusing in a small area like we have seen since May. The next few days look like more of the same. Some of the wetter models have the .50 line getting closer to NYC which would be nice. But not enough to end the drier pattern even if the wetter models closer to .50 verify. In my area along the CT Shoreline we had one of the warmest and driest summers. Vegetation has locally been on the brown side to the lack of rainfall.

You know it’s a dry pattern when the main interest is how close the .50 line gets to NYC.