donsutherland1

The paper describes precisely what one would expect when the linear stability of a complex system begins to erode. The “pushing and triggering” forces are now overwhelming the Arctic’s stabilizing feedbacks. As a result, the ocean–ice–atmosphere system is reorganizing into a new regime that is defined by higher temperatures, diminished sea ice, accelerated ice-sheet loss, and increasingly frequent and intense climatic extremes. On account of of Earth-system hysteresis, once a new state emerges, atmospheric CO2 concentrations would have to fall well below current levels merely to restore the Arctic to its present state. Such a reversal appears extraordinarily unlikely in any plausible future scenario. Despite clear scientific evidence and full awareness of the consequences of amplified greenhouse forcing, humanity continues to pursue a trajectory of intensifying emissions. During the Mid-Pliocene, the Arctic was roughly 7°C to 10°C warmer than the pre-industrial baseline, even at CO2 levels comparable to today’s. This suggests that substantial additional warming lies ahead. Humanity’s climate-engineering effort, which can no longer be described as inadvertent given today's state of knowledge, has already driven the Arctic roughly one-third to one-half of the way toward a Mid-Pliocene state. In that period, Greenland’s ice sheet was drastically smaller, and the Arctic Ocean was seasonally ice-free. Given the constraints of human cognition and the deep inertia shaping collective decision-making, it is difficult to imagine this paper will meaningfully alter society’s choice to continue to dump vast amounts of greenhouse gases into the atmosphere.

For reference, model skill scores: Global Models: Ensembles: Hurricane Models:

Both dates occurred during snowfall. February 13-14, 2014 saw a storm dump 12.5" of snow (with a period of heavy windswept rain). A second system brought another 1.6" of snow. Those are Central Park figures.

The winds and stochastic variability likely contributed.

Today was the third consecutive day with a one-degree difference in high temperatures among Bridgeport, Islip, Central Park, JFK Airport, LaGuardia Airport, and White Plains. That set a new record for most consecutive such days.

A strong cold front will move across the region tonight. Parts of the region will see some showers and perhaps a thundershower. Following the frontal passage, an extended period of cooler than normal weather will follow. Highs tomorrow will top out in the lower 60s. Readings will then rise only into the middle and upper 50s through at least the coming weekend. There is a growing likelihood that the closing days of October into the opening days of November could experience a significant rain event. The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was -0.6°C for the week centered around October 15. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.15°C and the ENSO Region 3.4 anomaly has averaged -0.47°C. La Niña conditions will likely continue through mid-winter. The SOI was +15.15 today. The preliminary Arctic Oscillation (AO) was -0.870 today. Based on sensitivity analysis applied to the latest guidance, there is an implied 56% probability that New York City will have a warmer than normal October (1991-2020 normal). October will likely finish with a mean temperature near 58.4° (0.5° above normal). Supplemental Information: The projected mean would be 1.5° above the 1981-2010 normal monthly value.

Yes, some of the ECMWF runs have been wildly unrealistic. Above normal rainfall is possible, though.

I don’t think any tropical cyclone will make landfall. Some moisture could be tapped, allowing for an enhancement of rainfall.

Frontal passage possibly slowed by blocking, allowing for greater precipitation. There are some hints of a tropical moisture connection. Details remain to be resolved.

The latest CFS outlook has now shifted toward a wetter outcome for the close of October and start of November.

Yesterday saw a one-degree difference in high temperatures among Bridgeport, Islip, Central Park, JFK Airport, LaGuardia Airport, and White Plains for the second consecutive day. The last time that happened was February 14-15, 2014.

Yes. That kind of historic rainfall is very likely overdone. Not surprisingly, the 0z corrected toward lower amounts.

The idea of a potentially wet October 30-November 3 period, perhaps +/- a few days to allow for timing differences at the current forecasting range, still looks to be on track as per the latest ECMWF weekly guidance. It should be noted that the CFSv2 is still not on board. On the other hand, the 12z ECMWF has insane rainfall amounts in the Middle Atlantic Region.

Newark will probably approach or reach 70°. Most of the NYC area will probably fall just short.

Temperatures will top out in the lower and middle 60s through midweek. A stronger push of cold air could arrive afterward. Cool temperatures will likely persist through next weekend. The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was -0.6°C for the week centered around October 15. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.15°C and the ENSO Region 3.4 anomaly has averaged -0.47°C. La Niña conditions will likely continue through mid-winter. The SOI was +7.60 today. The preliminary Arctic Oscillation (AO) was -1.132 today. Based on sensitivity analysis applied to the latest guidance, there is an implied 67% probability that New York City will have a warmer than normal October (1991-2020 normal). October will likely finish with a mean temperature near 58.6° (0.7° above normal). Supplemental Information: The projected mean would be 1.7° above the 1981-2010 normal monthly value.

This is an exercise aimed at seeing if human subjectivity can be removed with an algorithm selecting analogs with a focus on the North American domain. More broadly, can analog development become an objective exercise. I don't know if that's possible right now. As noted in the discussion, I don't like one of the three that the algorithm chose (2011-12). I also include one (2024-25) that the algorithm did not choose. I will periodically post updates on this experiment. If there is merit in the algorithmic approach, one should see 500 mb patterns come more in line with the composite idea over 1- and, especially 3-month periods. The focus on this set is fall 2025 and winter 2025-26. That there is some similarity at 500 mb for winter 2025-2026 to the ECMWF forecast suggests that there's consensus on the boundary conditions and how the pattern might turn out. I don't believe the winter 500 mb idea from the experimental set precludes some intrusions of cold air into the CONUS during the winter, particularly the central U.S.

I don’t know. Probably for at least the next week or longer.

It’s unfortunate that they don’t verify their numbers before going on air. It is not a difficult task.

Analogs, because they are derived from boundary conditions, do not capture synoptic details. Thus, very short timeframes aren't great for assessing them. Periods of 1-3 months provide greater assessment value, as things essentially average out from a series of synoptic events. In theory, the better analogs should come up with a reasonable but not perfect approximation of the 1-3 month period. As North American data is available for October 12-17, I used that to make some comparisons: 2013-2024 Composite: 2011-2016-2021 Experimental Statistically-Generated Cases (discussed earlier in this thread): Actual: October 12-17, 2025: Overall, the actual 2025 data is more amplified than the composite analog cases, aside from spatial differences e.g., misaligned areas of cold and warm anomalies. These kind of differences are to be expected at the very short timeframes used, as synoptic details outweigh boundary conditions at such timeframes. If there is value in either set of analogs, that would become evident over the longer periods of time where boundary conditions outweigh synoptic details.

Under mostly sunny skies, much of the region saw temperatures reach or exceed 70° today. Highs included: Atlantic City: 72° Bridgeport: 70° Islip: 70° New Haven: 71° New York City-Central Park: 70° New York City-JFK Airport: 70° New York City-LaGuardia Airport: 71° Newark: 73° Philadelphia: 77° A cold front will move across the region tonight into tomorrow morning. Low pressure will likely form along the front and move across the region. Periods of rain and perhaps some thunderstorms are likely into tomorrow. A period of severe weather is possible. A general 0.25"-0.75" rainfall with locally higher amounts appears likely. Following the frontal and storm passage, temperatures will top out in the lower and middle 60s through midweek. A stronger push of cold air could arrive afterward. Cool temperatures will likely persist through next weekend. The ENSO Region 1+2 anomaly was -0.1°C and the Region 3.4 anomaly was -0.3°C for the week centered around October 8. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.12°C and the ENSO Region 3.4 anomaly has averaged -0.42°C. La Niña conditions will likely continue through mid-winter. The SOI was +7.60 today. The preliminary Arctic Oscillation (AO) was -0.919 today. Based on sensitivity analysis applied to the latest guidance, there is an implied 63% probability that New York City will have a warmer than normal October (1991-2020 normal). October will likely finish with a mean temperature near 58.5° (0.6° above normal). Supplemental Information: The projected mean would be 1.6° above the 1981-2010 normal monthly value.

Yes, that seems to have been an exception, prominent as it was.

Yes, there are already some studies suggesting that it erodes critical thinking skills. That's a real problem.

This is another example why I call out hypesters such as Bamwx, et al., at times: Notice his claim about the Fall NAO vs. the Winter NAO. Most of his readers likely don't know that the NAO's values can be found here: https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/norm.nao.monthly.b5001.current.ascii.table They take for granted what he says, especially as it might fit their winter preferences. But if one actually takes a look at the actual data, during 1950-2024, there were 38 cases where the fall NAO averaged < 0. From those cases, just 13 (around 34%) saw the winter NAO average < 0. So, almost the opposite of what he claims. That's a fact. It's not speculation. Hype, misleading information, and repeatedly low forecast verification from pushing extremes creates bad perceptions about the many meteorologists who do their best to provide the public with useful, actionable weather information.

I used the same AI he used to illustrate a point. I still prefer using the actual literature. AI is here to stay, how it is used or misused will have profound consequences. I take no position on whether AGI or a “singularity” will be reached anytime soon.

Far more likely, the potential tropical cyclone will approach or die as it heads toward Central America or flung NE/ENE out into the Atlantic. A lot would need to happen for the capture to play out. Models don’t have skill this far out on such details.