donsutherland1

The ECMWF-AIFS is moving into it s high-skill range, where it continues to outperform the non-AI guidance. It continues to show very little prospect for the kind of occasional snowy solution that has popped up from time to time on some of the guidance. At 500 mb, its map tells the story about the low probability of phasing. The northern energy is well in front of the southern energy. This limits the risk of interaction, much less phasing. Not surprisingly, the other guidance now appears to be in line with the AIFS, with none showing a snowy solution for the NYC area. If one looks at the EPS ensembles, 16% showed 6" or more snow and fewer than 6% of members showed 10" or more snow during the 2/12 0z cycle vs. the respective 22% and 12% during the 2/11 0z cycle (in which the operational ECMWF showed a phased solution). Although it's premature to suggest that precipitation, should it arrive, cannot start as a little snow, sleet or mixed precipitation, the idea of a phased solution with significant snowfall appears unlikely. As has been the case much of this winter, should that outcome verify, the ECMWF-AIFS will again have led the way at an impressive lead time. Finally, the ECMWF-AIFS map 36 hours later shows a distinct failure to phase.

It will turn somewhat cooler to close the week. Temperatures will mainly top out in the middle to upper 30s on Thursday and Friday. The weekend will see highs in the upper 30s and lower 40s. It could become even milder with highs in the lower to perhaps middle 40s next week. Precipitation could arrive on Sunday or Monday. The ENSO Region 1+2 anomaly was +0.3°C and the Region 3.4 anomaly was -0.5°C for the week centered around February 4. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.25°C and the ENSO Region 3.4 anomaly has averaged -0.52°C. La Niña conditions will likely continue into at least late winter. The SOI was -1.20 today. The preliminary Arctic Oscillation (AO) was -1.676 today. Based on sensitivity analysis applied to the latest guidance, there is an implied near 91% probability that New York City will have a cooler than normal February (1991-2020 normal). February will likely finish with a mean temperature near 31.5° (4.4° below normal). Supplemental Information: The projected mean would be 3.8° below the 1981-2010 normal monthly value. Overall, Winter 2025-2026 is on track for a seasonal mean temperature of 31.9°. That would be the lowest winter mean temperature since Winter 2014-2015 when the mean temperature was 31.7°. Winter 2025-2026 would only become the fourth winter of the 21st century with a mean temperature of 32.0° or below.

The April 1841 snowstorm was a really big one from parts of the Mid-Atlantic region into New England. Philadelphia received at least 8”. NYC picked up a foot. Some parts of New England saw 20”.

I agree. I think it's a statistical artifact, but can't rule out other factors being involved e.g., an increase in baroclinicity in early April that allows for occasional big storms even as the weather is warming. Interestingly enough, one finds a similar dearth of 6" or above daily snowfalls during March 23-31 in Newark where records go back even farther to 1843.

The operational ECMWF abandoned its call for a big snowstorm, but its AI cousin maintained continuity from its earlier cycles with its call for a lack of snow. FWIW, I've seen some complaints on social media concerning the EC-AIFS. They concern the model's being a "black box." At this point, given what I've seen, it's probably better that the AIFS is, in fact, a "black box," as it limits the ability of those who don't like what they see from injecting their own biases into the mix; a lot of that occurs when the non-AI model solutions are pulled apart (often yielding incorrect solutions from the injection of subjectivity). The AIFS has done quite well this winter, especially within four days. It has sometimes seen changes, but its run-to-run continuity is generally better than its non-AI counterparts, aside from its accuracy. This allows for longer lead time without compromising accuracy.

And its AI cousin says:

From last night's light freezing rain:

The persistent and often severely cold pattern is now breaking. Tomorrow will be even milder with the temperature topping out in the upper 30s. A few places could reach 40°. A cold front will likely cross the region, possibly touching off a few snow flurries or rain showers. It will turn somewhat cooler into the weekend. By early next week highs will mainly be in the upper 30s and lower 40s with lows in the lower 30s. 20s are possible outside New York City. Precipitation could arrive on Sunday or Monday. The ENSO Region 1+2 anomaly was +0.3°C and the Region 3.4 anomaly was -0.5°C for the week centered around February 4. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.25°C and the ENSO Region 3.4 anomaly has averaged -0.52°C. La Niña conditions will likely continue into at least late winter. The SOI was +5.72 today. The preliminary Arctic Oscillation (AO) was -2.407 today. Based on sensitivity analysis applied to the latest guidance, there is an implied near 91% probability that New York City will have a cooler than normal February (1991-2020 normal). February will likely finish with a mean temperature near 31.3° (4.6° below normal). Supplemental Information: The projected mean would be 4.0° below the 1981-2010 normal monthly value. Overall, Winter 2025-2026 is on track for a seasonal mean temperature of 31.9°. That would be the lowest winter mean temperature since Winter 2014-2015 when the mean temperature was 31.7°. Winter 2025-2026 would only become the fourth winter of the 21st century with a mean temperature of 32.0° or below.

While I believe it could still turn colder to end February as per the ECMWF weeklies, I tend to agree that the risk of a return of severe cold in the East is probably largely over.

If one takes off about 2.5°, they'd be about as common as they once were.

The world is warmer than it has been and is continuing to warm largely due to anthropogenic greenhouse gas emissions. Extreme cold periods are becoming warmer and less frequent than they once were. Nevertheless, that does not mean that such cold, when it occurs regionally, should be dismissed out-of-hand. The kind of sustained deep cold that has occurred in the Great Lakes Region and Northeast is uncommon today. It is not trivial. It is one of this winter's highlights. For example, New York City saw a 16-day mean temperature below 20° for the 125th time since record-keeping began in 1869. However, it was the first such occurrence since 1982. That was 44 years ago. That rarity makes it noteworthy. Moreover, it's plausible that at least some of us might not see such sustained and deep cold again during our lifetimes given how infrequent it has become. That places like Phoenix are on course for their warmest winter on record does not minimize the cold that has just occurred elsewhere. That it has occurred in a warmer and warming world makes it all the more remarkable.

The snow was blinding at times.

The persistent and often severely cold pattern is poised to break. However, exceptional warmth appears unlikely through at least mid-February, even as milder readings return. After mid-month, highs could begin to reach the lower 40s. Tomorrow will see the temperature reach or exceed freezing. Wednesday will be even milder with the temperature topping out in the upper 30s. A cold front will likely cross the region, possibly touching off a few snow flurries or showers. It will turn somewhat cooler into the weekend. The ENSO Region 1+2 anomaly was +0.3°C and the Region 3.4 anomaly was -0.5°C for the week centered around February 4. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.25°C and the ENSO Region 3.4 anomaly has averaged -0.52°C. La Niña conditions will likely continue into at least late winter. The SOI was +4.66 today. The preliminary Arctic Oscillation (AO) was -2.895 today. Based on sensitivity analysis applied to the latest guidance, there is an implied near 90% probability that New York City will have a cooler than normal February (1991-2020 normal). February will likely finish with a mean temperature near 31.2° (4.7° below normal). Supplemental Information: The projected mean would be 4.1° below the 1981-2010 normal monthly value. Overall, Winter 2025-2026 is on track for a seasonal mean temperature of 31.9°. That would be the lowest winter mean temperature since Winter 2014-2015 when the mean temperature was 31.7°. Winter 2025-2026 would only become the fourth winter of the 21st century with a mean temperature of 32.0° or below.

That's incorrect. The opposite is true. Winter/early spring is cold; it flips later spring/summer. Here are 500 mb anomalies and temperature anomalies for March Greenland blocks: Here are mean temperatures for NYC (1980-2025): March 1-15: NAO -0.50 or below: 39.3°; NAO +0.50 or above: 41.5° March 16-31: NAO -0.50 or below: 43.3°; NAO +0.50 or above: 46.4° Finally, what does AI say about the posted map under discussion? Here's ChatGPT 5.2's response: Gemini's Output:

That's quite worrisome, especially when it comes to science. Science is truly at the cutting edge of knowledge creation and, if expertise is watered down, it will have an adverse impact on that outcome.