donsutherland1

In most cases, December 1 to mid-February, it isn't. But when wave lengths shorten, it becomes more favorable and the snowstorm stats speak for themselves. Two thirds of snowstorms with 10" or more snow in Boston, New York City, and/or Philadelphia during the second half of February occurred with a PNA-.

Following a foggy start, tomorrow will see highs reach the lower and perhaps middle 40s. Some rain showers or a period of rain is likely later tomorrow into early Thursday as a system streaks rapidly from Minnesota across central New York State and into New England. Parts of central New York State and southern/central New England, including Boston, could see some accumulating snow. Additional precipitation could arrive Friday or Saturday. Highs will likely reach the 40s through Saturday. Numerous ensemble members and operational models continue to suggest the potential for a significant or major snowstorm some time in the February 22-24 timeframe. More evidence in the form of model consensus and support from a large number of individual ensemble members will be needed before there can be reasonable confidence in such a solution. For now, one is dealing with a low probability but high-impact scenario. An AO-/PNA- pattern, which is forecast for the timeframe involved, has seen a number of significant or major snowstorms during the second half of February. Since 1950, New York City has seen four 6" or above snowstorms during such patterns, including the 1979 President's Day blizzard (12.7") and the February 25-26, 2010 snowstorm (20.9"). In contrast, during AO+/PNA- patterns, New York City has seen just one 6" or above snowstorm. Details should start to become clearer by Wednesday or Thursday. The ENSO Region 1+2 anomaly was +0.7°C and the Region 3.4 anomaly was -0.2°C for the week centered around February 11. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.03°C and the ENSO Region 3.4 anomaly has averaged -0.47°C. Neutral ENSO conditions are now developing. Neutral ENSO conditions will develop during the close of winter. The SOI was +15.13 today. The preliminary Arctic Oscillation (AO) was -0.264 today. Based on sensitivity analysis applied to the latest guidance, there is an implied near 97% 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.

Model Debate:

Blizzard warnings are still provided. Only the watches were eliminated.

Blizzard watches were discontinued in late 2017.

Yes.

The mean temperatures for those winters were: 1995-1996: 32.2° 2003-2004: 32.4° 2010-2011: 32.7° 2013-2014: 33.0° Finally, the reference to the last winter with a mean temperature of 32° or below should be to 2014-15, as shown in past posts. Apologies for the error.

1976-77 didn't make it, because the winter was frigid (28.3° seasonal mean temperature), but seasonal snowfall was below 30.0" (24.5").

New York City remains on course for a winter season mean temperature of 32.0° or below. Much will depend on the warmup that will conclude February. The last time that happened was in 2014-2015. Some of the guidance and a number of individual ensemble members continue to suggest that the New York City area could experience a significant or major snowfall during the February 22-24 period. That's far from a done deal, despite support from the highest-ranked operational model, the ECMWF-AIFS. For now, the possible event is a low probability, high-impact scenario. The picture should become clearer later this week. To date, New York City has seen 22.3" of snow. 7.7" of additional snowfall would bring the seasonal figure to 30.0". Were that to happen, Winter 2025-2026 would be a special winter for its combination of snowfall and cold. The last five winters to see a seasonal mean temperature of 32.0° or below and 30.0" or more snowfall were 1960-1961, 1977-1978, 1993-1994, 2002-2003 and 2014-2015.

Even if I don't start the storm thread (and I hope we will have a storm to track), people can feel free to use any information I post.

Tomorrow will see highs reach the middle 40s. Some rain showers or a period of rain is likely on Wednesday into perhaps early Thursday as a system streaks rapidly from Minnesota across central New York State and into New England. Parts of central New York State and southern/central New England, including Boston, could see some accumulating snow. Additional precipitation could arrive Friday or Saturday. Highs will likely reach the 40s through Saturday. A few ensemble members (20% EPS members at 2/16 12z with 6" or more snow) and occasional operational runs (2/16 6z GFS and 12z Icon) have continued to suggest the potential for a significant or major snowstorm some time in the February 21-24 timeframe. More evidence in the form of model consensus and support from a large number of individual ensemble members will be needed before there can be reasonable confidence in such a solution. For now, one is dealing with a low probability but high-impact scenario. An AO-/PNA- pattern, which is forecast for the timeframe involved, has seen a number of significant or major snowstorms during the second half of February. Since 1950, New York City has seen four 6" or above snowstorms during such patterns, including the 1979 President's Day blizzard (12.7") and the February 25-26, 2010 snowstorm (20.9"). In contrast, during AO+/PNA- patterns, New York City has seen just one 6" or above snowstorm. Details should start to become clearer by Wednesday or Thursday. The ENSO Region 1+2 anomaly was +0.7°C and the Region 3.4 anomaly was -0.2°C for the week centered around February 11. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.03°C and the ENSO Region 3.4 anomaly has averaged -0.47°C. Neutral ENSO conditions are now developing. Neutral ENSO conditions will develop during the close of winter. The SOI was +10.90 today. The preliminary Arctic Oscillation (AO) was +0.799 today. Based on sensitivity analysis applied to the latest guidance, there is an implied near 97% 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 latest AO forecast is even more aggressive with the development of an AO+: Given the other forecast teleconnections, this implies that the late February cold shot will likely be short-lived. Temperatures could return to near normal or above normal levels in the Great Lakes Region and Northeast in the closing days of the month.

Numerous parts of Nassau County saw 2" or more of snow. Three photos from southern Westchester County where around 0.5" fell.

Overnight, New York City received 0.08" of precipitation. The 0z HRRR followed closely by the 0z GGEM did best with the final amount.

Light snow is falling in Larchmont, NY. Colder surfaces are coated.