donsutherland1

Overnight, colder air rushed into the region. Rain changed to wet snow for a time even in nearby suburbs where there was a slushy coating of snow in many places. White Plains picked up 2" of snow. The highest amount in the region was 20.0" at High Point, NJ, but that figure was from 8:30 am. The departing storm will likely be followed by a short period of below normal but not exceptionally cold temperatures before it turns milder early next week. A stronger shot of cold could arrive late in the month. The first week of December will likely feature generally below normal temperatures. The NAO fell to a preliminary -2.751 on September 24th (all-time September record: -2.371, September 12, 1971). That was the 9th lowest value on record. La Niña winters following September cases where the NAO fell to -1.900 or below featured a predominantly positive NAO. The most recent such winters were 2016-2017 and 2022-2023. The mean temperatures for those winters in New York City were 39.3° and 41.0° respectively. The 1991-2020 normal value is 36.2°. A warmer to much warmer than normal outcome is favored by the November run of the ECMWF for Winter 2024-2025. The ENSO Region 1+2 anomaly was +0.2°C and the Region 3.4 anomaly was 0.0°C for the week centered around November 13. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.20°C and the ENSO Region 3.4 anomaly has averaged -0.30°C. Neutral ENSO conditions may evolve into a La Niña event during the late fall. Uncertainty as to whether a La Niña will develop has increased. The SOI was +12.40 today. The preliminary Arctic Oscillation (AO) was -0.976 today. Based on sensitivity analysis applied to the latest guidance, there is an implied 97% probability that New York City will have a warmer than normal November (1991-2020 normal). November will likely finish with a mean temperature near 51.2° (3.2° above normal).

From Milford, PA from my sister:

Three photos from this morning. White Plains: West Harrison:

Larchmont, NY:

Discussion New York City has seen its biggest rainfall since August 18th when 2.29" fell. Periods of rain will continue overnight and through much of tomorrow. The rain will likely end as a period of wet snow or flurries on Friday morning in the distant northern and western suburbs, especially hilly sections where some accumulations are possible. A heavy wet snowfall is likely in the higher elevations of the Catskills and Poconos. The departing storm will likely be followed by a period of below normal but not exceptionally cold temperatures. A stronger shot of cold could arrive to end the month or start December. The first week of December will likely feature generally below normal temperatures. The NAO fell to a preliminary -2.751 on September 24th (all-time September record: -2.371, September 12, 1971). That was the 9th lowest value on record. La Niña winters following September cases where the NAO fell to -1.900 or below featured a predominantly positive NAO. The most recent such winters were 2016-2017 and 2022-2023. The mean temperatures for those winters in New York City were 39.3° and 41.0° respectively. The 1991-2020 normal value is 36.2°. A warmer to much warmer than normal outcome is favored by the November run of the ECMWF for Winter 2024-2025. The ENSO Region 1+2 anomaly was +0.2°C and the Region 3.4 anomaly was 0.0°C for the week centered around November 13. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.20°C and the ENSO Region 3.4 anomaly has averaged -0.30°C. Neutral ENSO conditions may evolve into a La Niña event during the late fall. Uncertainty as to whether a La Niña will develop has increased. The SOI was +14.12 today. The preliminary Arctic Oscillation (AO) was -1.097 today. Based on sensitivity analysis applied to the latest guidance, there is an implied 98% probability that New York City will have a warmer than normal November (1991-2020 normal). November will likely finish with a mean temperature near 51.4° (3.4° above normal).

I have seen no information about specific impacts. I suspect follow-up research will aim to provide more insight into regional impacts.

The 1z NBE shows 1.1" snow for New York City on Friday with a daily minimum temperature of 38°. If that winds up being the low, the odds are very strongly against measurable snowfall, even if some snow mixes with the rain. Below is the historic data:

A soaking rain will arrive overnight. The rain will likely continue into Friday morning with the heaviest rainfall occurring overnight into tomorrow morning. A general 1.00"-2.00" rainfall with some locally higher amounts is likely. The rain will likely as a period of wet snow or flurries on Friday morning in the distant northern and western suburbs, especially hilly sections where some accumulations are possible. That rain will likely be followed by a period of below normal but not exceptionally cold temperatures. A stronger shot of cold could arrive to end the month or start December. The first week of December could feature generally below normal temperatures. The NAO fell to a preliminary -2.751 on September 24th (all-time September record: -2.371, September 12, 1971). That was the 9th lowest value on record. La Niña winters following September cases where the NAO fell to -1.900 or below featured a predominantly positive NAO. The most recent such winters were 2016-2017 and 2022-2023. The mean temperatures for those winters in New York City were 39.3° and 41.0° respectively. The 1991-2020 normal value is 36.2°. A warmer to much warmer than normal outcome is favored by the November run of the ECMWF for Winter 2024-2025. The ENSO Region 1+2 anomaly was +0.2°C and the Region 3.4 anomaly was 0.0°C for the week centered around November 13. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.20°C and the ENSO Region 3.4 anomaly has averaged -0.30°C. Neutral ENSO conditions may evolve into a La Niña event during the late fall. Uncertainty as to whether a La Niña will develop has increased. The SOI was +16.99 today. The preliminary Arctic Oscillation (AO) was -1.706 today. Based on sensitivity analysis applied to the latest guidance, there is an implied 98% probability that New York City will have a warmer than normal November (1991-2020 normal). November will likely finish with a mean temperature near 51.5° (3.5° above normal).

It will mild tomorrow with temperatures topping out mainly in the middle and upper 50s. The dry weather will continue through most of tomorrow. Rain is likely late tomorrow night into Friday morning. Models have grown wetter in recent cycles. A storm total of 1.00"-2.00" is likely with a few locally higher amounts. There is a chance that distant northern and western suburbs, especially hilly sections, could see the rain end as a period of wet snow or flurries. That rain will likely be followed by a period of below normal but not exceptionally cold temperatures. The NAO fell to a preliminary -2.751 on September 24th (all-time September record: -2.371, September 12, 1971). That was the 9th lowest value on record. La Niña winters following September cases where the NAO fell to -1.900 or below featured a predominantly positive NAO. The most recent such winters were 2016-2017 and 2022-2023. The mean temperatures for those winters in New York City were 39.3° and 41.0° respectively. The 1991-2020 normal value is 36.2°. A warmer to much warmer than normal outcome is favored by the November run of the ECMWF for Winter 2024-2025. The ENSO Region 1+2 anomaly was +0.2°C and the Region 3.4 anomaly was 0.0°C for the week centered around November 13. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.20°C and the ENSO Region 3.4 anomaly has averaged -0.30°C. Neutral ENSO conditions may evolve into a La Niña event during the late fall. Uncertainty as to whether a La Niña will develop has increased. The SOI was +15.46 today. The preliminary Arctic Oscillation (AO) was -1.178 today. Based on sensitivity analysis applied to the latest guidance, there is an implied 97% probability that New York City will have a warmer than normal November (1991-2020 normal). November will likely finish with a mean temperature near 51.5° (3.5° above normal).

It will turn somewhat cooler tomorrow with temperatures topping out mainly in the middle 50s. The dry weather will continue through the middle of the week. Rain is likely Wednesday night and Thursday. A storm total of 0.50"-1.00" is likely with some locally higher amounts of 1.50". That rain will likely be followed by a period of below normal but not exceptionally cold temperatures. With the remainder of November potentially becoming mainly dry following the rainstorm, parts of the region could challenge records for their driest fall and driest season on record. Select records are below: New York City: Driest fall: 4.00", Fall 1908; Driest season: 3.92", Summer 1999 Newark: Driest fall: 4.21", Fall 1931; Driest season: 4.21", Fall 1931 Philadelphia: Driest fall: 2.37", Fall, 1922; Driest season: 2.37", Fall 1922 Wilmington, DE: Driest fall: 3.17", Fall 1922; Driest season: 3.17", Fall 1922 The NAO fell to a preliminary -2.751 on September 24th (all-time September record: -2.371, September 12, 1971). That was the 9th lowest value on record. La Niña winters following September cases where the NAO fell to -1.900 or below featured a predominantly positive NAO. The most recent such winters were 2016-2017 and 2022-2023. The mean temperatures for those winters in New York City were 39.3° and 41.0° respectively. The 1991-2020 normal value is 36.2°. A warmer to much warmer than normal outcome is favored by the November run of the ECMWF for Winter 2024-2025. The ENSO Region 1+2 anomaly was +0.2°C and the Region 3.4 anomaly was 0.0°C for the week centered around November 13. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.20°C and the ENSO Region 3.4 anomaly has averaged -0.30°C. Neutral ENSO conditions may evolve into a La Niña event during the late fall. Uncertainty as to whether a La Niña will develop has increased. The SOI was +9.29 today. The preliminary Arctic Oscillation (AO) was +0.012 today. Based on sensitivity analysis applied to the latest guidance, there is an implied 96% probability that New York City will have a warmer than normal November (1991-2020 normal). November will likely finish with a mean temperature near 51.4° (3.4° above normal).

Tomorrow will be another mild day with temperatures topping out in the lower to perhaps middle 60s across much of the region. The dry weather will continue through the middle of the week. Rain is likely Wednesday night and Thursday. The potential exists for 0.50"-1.50" of rain. That rain will likely be followed by a period of below normal but not exceptionally cold temperatures. With the remainder of November potentially becoming mainly dry following the rainstorm, parts of the region could challenge records for their driest fall and driest season on record. Select records are below: New York City: Driest fall: 4.00", Fall 1908; Driest season: 3.92", Summer 1999 Newark: Driest fall: 4.21", Fall 1931; Driest season: 4.21", Fall 1931 Philadelphia: Driest fall: 2.37", Fall, 1922; Driest season: 2.37", Fall 1922 Wilmington, DE: Driest fall: 3.17", Fall 1922; Driest season: 3.17", Fall 1922 The NAO fell to a preliminary -2.751 on September 24th (all-time September record: -2.371, September 12, 1971). That was the 9th lowest value on record. La Niña winters following September cases where the NAO fell to -1.900 or below featured a predominantly positive NAO. The most recent such winters were 2016-2017 and 2022-2023. The mean temperatures for those winters in New York City were 39.3° and 41.0° respectively. The 1991-2020 normal value is 36.2°. A warmer to much warmer than normal outcome is favored by the November run of the ECMWF for Winter 2024-2025. The ENSO Region 1+2 anomaly was -0.2°C and the Region 3.4 anomaly was -0.3°C for the week centered around November 6. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.32°C and the ENSO Region 3.4 anomaly has averaged -0.35°C. Neutral ENSO conditions may evolve into a La Niña event during the late fall. The SOI was +8.52 today. The preliminary Arctic Oscillation (AO) was +0.241 today. Based on sensitivity analysis applied to the latest guidance, there is an implied 90% probability that New York City will have a warmer than normal November (1991-2020 normal). November will likely finish with a mean temperature near 51.2° (3.2° above normal).

No worries. I thought my discussion might have been unclear. Hopefully, things will turn out better than what I expect.

Tomorrow will be another mild day with temperatures topping out in the lower 60s across much of the region. The dry weather will continue through the middle of next week. Rain is likely Wednesday night and Thursday. The potential exists for 0.50" or more of rain. That rain will likely be followed by a period of below normal but not exceptionally cold temperatures. With the remainder of November potentially becoming mainly dry following rainsform next week, parts of the region could challenge records for their driest fall and driest season on record. Select records are below: New York City: Driest fall: 4.00", Fall 1908; Driest season: 3.92", Summer 1999 Newark: Driest fall: 4.21", Fall 1931; Driest season: 4.21", Fall 1931 Philadelphia: Driest fall: 2.37", Fall, 1922; Driest season: 2.37", Fall 1922 Wilmington, DE: Driest fall: 3.17", Fall 1922; Driest season: 3.17", Fall 1922 The NAO fell to a preliminary -2.751 on September 24th (all-time September record: -2.371, September 12, 1971). That was the 9th lowest value on record. La Niña winters following September cases where the NAO fell to -1.900 or below featured a predominantly positive NAO. The most recent such winters were 2016-2017 and 2022-2023. The mean temperatures for those winters in New York City were 39.3° and 41.0° respectively. The 1991-2020 normal value is 36.2°. A warmer to much warmer than normal outcome is favored by the November run of the ECMWF for Winter 2024-2025. The ENSO Region 1+2 anomaly was -0.2°C and the Region 3.4 anomaly was -0.3°C for the week centered around November 6. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.32°C and the ENSO Region 3.4 anomaly has averaged -0.35°C. Neutral ENSO conditions may evolve into a La Niña event during the late fall. The SOI was +6.87 today. The preliminary Arctic Oscillation (AO) was -0.131 today. Based on sensitivity analysis applied to the latest guidance, there is an implied 93% probability that New York City will have a warmer than normal November (1991-2020 normal). November will likely finish with a mean temperature near 51.5° (3.5° above normal).

I suspect that BC will see a stormy winter. Vancouver could see a lot of rain. Interior sections will probably see much above normal snowfall. Temperatures could also break on the cold side of normal.

When I referenced 2001-02 and 2016-17, I was referring to snowfall across large areas, not for any specific city. There was a lot of variability on a city-by-city bases for all the of the scenarios tested.