donsutherland1

As noted earlier, IMO writing the event off completely goes beyond what can reasonably be supported by the models and their ensembles. Indeed, there has been some improvement during the 18z cycle.

A number of those were high-impact storms i.e., 12/20/2009, 12/27/2010, 2/9/2013, 1/24/2016, 1/29/2022, etc.

That was the area I was most uncertain about. I overdid the impact of the warm air aloft. Hopefully, I'll do better next time.

Unfortunately, I don't have the 6z figures.

Looking back, my errors for the 1/24-26 snowstorm:

At 12z, 8 GEFS members and 1 EPS member had 6" or more snow for NYC. The EPS member in question had 16".

Yes, I'm aware that it's time lagged. Nevertheless, its 18z data was probably reflecting the 12z suite or perhaps slightly later. At this timeframe, the details don't matter too much. I just wanted to illustrate that there are alternatives to a clean miss. I suspect that a solution that grazes the coast might currently be the most likely scenario. That would allow for a light snowfall from Philadelphia to NYC and moderate maybe larger amounts across parts of eastern Long Island into southeastern New England. The Cape could do quite well. Having said that, it's not uncommon for model tracks to vary by 50 to sometimes 150 miles over a four-day lead time. I suspect that by late tomorrow or Thursday, we should start to be able to pin down the details with some degree of confidence.

Arctic air now covers the region. Highs will be mainly in the lower 20s through Friday. One or more days could see highs in the teens. The last winter with more than one high in the teens was Winter 2018-19 when there were two such days. Moreover, New York City has the potential to see the temperature dip into the single digits for lows on one or more days during this period. Some snow flurries or snow showers are possible Thursday night into Friday morning. Additional snow is possible on Sunday. However, there remains significant uncertainty about the location of the storm's development and its track. A large storm would be historic. For reference, New York City has seen just one 10" or above snowstorm one week or less following a 10" or above snowstorm: February 3-4, 1926 (10.4") and February 9-10, 1926 (12.4"). The shortest interval between 10" or above daily snowfalls is 14 days: March 2, 1896 (10.0") and March 16, 1896 (12.0"). Records go back to 1869. Overall, January 20th-February 3rd will likely be the coldest and perhaps snowiest two-week period this winter. The forecast WPO-/EPO-/AO-/PNA+ pattern is typically the coldest pattern in January and among the coldest during the first half of February. A persistently positive PNA will have above climatological risk of moderate or significant snowfalls. For perspective, the coldest two-week period this winter prior to January 20th was January 3-16, 2026 and January 4-17, 2026 with a mean temperature of 30.3°. The snowiest two-week period was December 14-27, 2025 when 7.2" of snow fell. Already, snowfall since January 20th has surpassed that figure. The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -0.7°C for the week centered around January 14. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.48°C and the ENSO Region 3.4 anomaly has averaged -0.68°C. La Niña conditions will likely continue into at least late winter. The SOI was -2.82 today. The preliminary Arctic Oscillation (AO) was -4.601 today. That is the lowest AO value since February 16, 2025 when the AO was -4.772. Based on sensitivity analysis applied to the latest guidance, there is an implied near 100% probability that New York City will have a cooler than normal January (1991-2020 normal). January will likely finish with a mean temperature near 30.2° (3.5° below normal). Supplemental Information: The projected mean would be 2.4° below the 1981-2010 normal monthly value.

There remains potential for snowfall on Sunday in the New York City area with an even higher probability of snowfall across eastern Long Island. What's fairly certain is that a storm will develop somewhere along the Southeast coast and possibly become quite deep. What's uncertain and subject to synoptic details (the placement of vorticity maxima, 500 mb low, etc.) that the guidance can't reliably resolve at the current lead time is the exact location where the storm will develop and its ultimate track. By Thursday, the guidance should be moving into a more skillful lead time. As a result, there are varying solutions. Several models now take the storm out to sea with no impact on the New York City area. Others graze the region, possibly with several inches of snow. The 18z NBM even brings close to 0.50" QPF to New York City. This large spread reflects the degree of uncertainty that still exists. Although it looks less likely that this will be a blockbuster storm, writing the event off completely goes beyond what can reasonably be supported by the models and their ensembles. Here's the latest WPC probabilistic assessment of a moderate impact:

Let's see where the synoptic details are tomorrow. At 500 mb, there remain some important differences among the guidance.

Common theme on the 12z cycle: The GFS and GGEM have brought the precipitation farther north and west. It's too soon to write off the storm for the NYC area and especially Long Island. Details still can't be resolved reliably this far out.

Cape Hatteras has only received two 12" or above snowstorms: December 29-30, 1917 12.0" (NYC: 2.0") December 23-24, 1989 13.3" (NYC: None)

For an illustration: 0z: 6z:

Based on the forecast teleconnections, a track that leads to impacts in the northern Mid-Atlantic/southern New England regions remains plausible. The PNA+ promotes an eastern trough and the AO- block can slow the system. With the AO rising rapidly, but remaining strongly negative, the risk of suppression is reduced over what it would be were the AO to be at or below -3.000 and falling. An out-to-sea or only grazing solution remains possible, but a solution that has at least some impacts remains more likely than a purely out-to-sea solution. IMO, the 1/26 18z ECMWF-AIFS provides a plausible outcome. It also has support from the NBM's probabilities. Currently the storm and its development remain beyond the range of the models' capability to skillfully resolve the synoptic details that will lead up to the possible event. Until then, the broader longwave pattern and its evolution offer insight. At this lead time, storm formation seems to be a reasonable scenario. A coastal or out-to-sea track are both realistic possibilities with the former still looking more likely than the latter. By Wednesday or perhaps Thursday, there should be greater consensus on the outcome, especially as the guidance will be starting to resolve the all-important synoptic details. For now, a moderate- or high-impact storm remains on the table.

Central Park and JFK Airport had < 10". LaGuardia had 10".

Yes, assuming it occurs.

February 8-9, 1994 is listed as having 9.0".

New York City has seen just one 10" or above snowstorm one week or less following a 10" or above snowstorm: February 3-4, 1926 (10.4") and February 9-10, 1926 (12.4"). The shortest interval between 10" or above daily snowfalls is 14 days: March 2, 1896 (10.0") and March 16, 1896 (12.0"). Records go back to 1869.

New York City experienced its biggest snowstorm in nearly five years when 17.4" accumulated during January 31-February 3, 2021. Arctic air is now returning to the region. Highs will then be mainly in the lower 20s through Friday. Tomorrow could again see highs top out in the teens in New York City. That could happene again later in the week. The last winter with more than one high in the teens was Winter 2018-19 when there were two such days. Moreover, New York City has the potential to see the temperature dip into the single digits for lows on or more days during this period. Some snow flurries or snow showers are possible Thursday night into Friday morning. Additional snow is possible on Sunday. A number of ensemble members hint that the snowfall could be significant. It's too soon to be certain about details. A large storm would be historic. For reference, New York City has seen just one 10" or above snowstorm one week or less following a 10" or above snowstorm: February 3-4, 1926 (10.4") and February 9-10, 1926 (12.4"). The shortest interval between 10" or above daily snowfalls is 14 days: March 2, 1896 (10.0") and March 16, 1896 (12.0"). Records go back to 1869. Overall, January 20th-February 3rd will likely be the coldest and perhaps snowiest two-week period this winter. The forecast WPO-/EPO-/AO-/PNA+ pattern is typically the coldest pattern in January and among the coldest during the first half of February. A persistently positive PNA will have above climatological risk of moderate or significant snowfalls. For perspective, the coldest two-week period this winter prior to January 20th was January 3-16, 2026 and January 4-17, 2026 with a mean temperature of 30.3°. The snowiest two-week period was December 14-27, 2025 when 7.2" of snow fell. Already, snowfall since January 20th has surpassed that figure. The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -0.7°C for the week centered around January 14. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.48°C and the ENSO Region 3.4 anomaly has averaged -0.68°C. La Niña conditions will likely continue into at least late winter. The SOI was -9.93 today. The preliminary Arctic Oscillation (AO) was -3.462 today. Based on sensitivity analysis applied to the latest guidance, there is an implied near 100% probability that New York City will have a cooler than normal January (1991-2020 normal). January will likely finish with a mean temperature near 30.3° (3.4° below normal). Supplemental Information: The projected mean would be 2.3° below the 1981-2010 normal monthly value.

Totals aren't yet available for a number of locations. We'll see this evening after today's snowfall amounts are added in for some of the sites.

IMO, this remains a closer call than with the most recent storm where I believed it would not be suppressed. I still think the most likely scenarios are either up the coast (track and distance from the coast to be determined) or out-to-sea (lesser probability). The scenario of an inland cutter is probably the lowest probability right now. This is based on the forecast pattern. Synoptic details can't be resolved accurately at this timeframe. We'll see where things are by Wednesday or Thursday.

It's early, but IMO based on the modeled pattern (assuming it holds), I'd give the system nearly a 2-in-3 chance of coming far enough up the coast to impact Long Island, New York City, and at least its nearby northern and western suburbs. The exact track will be crucial to details, but at this stage the guidance cannot accurately resolve the synoptic details.

It will be a close call. A few days in early February could approach or reach freezing. Model skill that far out is low so the range of error is fairly high.

For those wondering about the location in Larchmont, the photo was taken on North Chatsworth Avenue looking toward Myrtle Boulevard (traffic light).

16 consecutive days (January 19-February 3, 1961).