donsutherland1

For one thing, the blocking wasn’t as strong as forecast 5-7 days ago.

From Larchmont, NY:

Light snow.

Nothing reported yet.

Morning thoughts… Today will be variably cloudy and cold. Some snow flurries and snow showers are possible, especially this morning. The areas with the highest chance of measurable snow are to the north and west of Newark, New York City, and Bridgeport. High temperatures will likely reach the lower and middle 40s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 43° Newark: 46° Philadelphia: 45° Normals: New York City: 30-Year: 49.7°; 15-Year: 50.0° Newark: 30-Year: 50.3°; 15-Year: 50.7° Philadelphia: 30-Year: 51.3°; 15-Year: 51.8° The cool weather will continue through the remainder of November.

Tomorrow will be another unseasonably cool day. There is a small chance that a weak system could bring a period of snow showers or light snow or flurries to parts of the region tomorrow. The areas with the highest probability of seeing measurable snow are those that are to the northwest of Newark, New York City, and Bridgeport. First measurable snowfall statistics for select cities: Allentown: Normal: December 6; 2020-21: December 9 Bridgeport: Normal: December 3; 2020-21: December 16 Islip: Normal: December 10; 2020-21: December 16 New York City: Normal: December 13; 2020-21: December 16 Newark: Normal: December 9; 2020-21: December 9 Philadelphia: Normal: December 19; 2020-21: December 16 As the ongoing blocking weakens over the next week, temperatures will likely turn milder for at least a time starting during the first week of December. The probability of a relatively mild EPO+/AO+ pattern through at least the first half of December has increased in recent days. Fall 2021 is well on course to being wetter to much wetter than normal in the northern Middle Atlantic region. Since 1869, there have been 9 August cases where New York City picked up 20.00" or more rainfall during the summer. Two thirds of those cases (and 4/5 of those with summer mean temperatures of 73.0° or above) had 17.00" or more fall precipitation in New York City. 2011 is probably the closest match in terms of precipitation and a nearly identical summer mean temperature. Mean fall precipitation for those 9 cases was 14.86". The median was 17.35". The 1991-2020 normal value is 12.27". Fall rainfall through November 26 4 pm is 16.41". Following very wet July-September periods, winter (December-February) precipitation has typically been near or below normal. The most recent exception was winter 2018-19. The ENSO Region 1+2 anomaly was -1.0°C and the Region 3.4 anomaly was -1.0°C for the week centered around November 17. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.67°C and the ENSO Region 3.4 anomaly has averaged -0.92°C. La Niña conditions will likely persist into at least late winter. The SOI was +20.87 today. The preliminary Arctic Oscillation (AO) figure was -1.336 today. On November 25 the MJO was in Phase 4 at an amplitude of 1.171 (RMM). The November 24-adjusted amplitude was 1.308 (RMM). 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 November (1991-2020 normal). November will likely finish with a mean temperature near 46.2° (1.8° below normal).

So far, no such event is showing up on the EPS forecast, which goes out two weeks. At present 1 mb, 10 mb, and 30 mb are all near normal or cooler than normal. Until there is consensus, my confidence in a stratospheric warming event remains low. That the MJO has been stuck in phases 3-5 (currently 4) for almost all of November isn’t helping things either. I agree with you that we need something to trigger a pattern change that would yield more sustained wintry weather.

Morning thoughts… Today will be partly sunny and unseasonably cold. High temperatures will likely reach the lower and middle 40s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 41° Newark: 44° Philadelphia: 44° Normals: New York City: 30-Year: 50.0°; 15-Year: 50.3° Newark: 30-Year: 50.7°; 15-Year: 51.1° Philadelphia: 30-Year: 51.7°; 15-Year: 52.1° There remains a possibility that parts of the region could see snow showers or even a light snowfall tomorrow. The areas with the highest chance of measurable snow are to the north and west of Newark, New York City, and Bridgeport.

A much colder air mass began moving into the region today. A few locations saw some snow flurries during the late afternoon. An unseasonably cold weekend lies ahead. There is a small chance that a weak system could bring a period of light snow or flurries to parts of the region late Sunday into Monday. The areas with the highest probability of seeing snowfall are those that are northwest of Newark, New York City, and Bridgeport. First measurable snowfall statistics for select cities: Allentown: Normal: December 6; 2020-21: December 9 Bridgeport: Normal: December 3; 2020-21: December 16 Islip: Normal: December 10; 2020-21: December 16 New York City: Normal: December 13; 2020-21: December 16 Newark: Normal: December 9; 2020-21: December 9 Philadelphia: Normal: December 19; 2020-21: December 16 As the ongoing blocking weakens over the next week, temperatures will likely turn milder for at least a time starting during the first week of December. The probability of a relatively mild EPO+/AO+ pattern through at least the first half of December has increased in recent days. Fall 2021 is well on course to being wetter to much wetter than normal in the northern Middle Atlantic region. Since 1869, there have been 9 August cases where New York City picked up 20.00" or more rainfall during the summer. Two thirds of those cases (and 4/5 of those with summer mean temperatures of 73.0° or above) had 17.00" or more fall precipitation in New York City. 2011 is probably the closest match in terms of precipitation and a nearly identical summer mean temperature. Mean fall precipitation for those 9 cases was 14.86". The median was 17.35". The 1991-2020 normal value is 12.27". Fall rainfall through November 26 4 pm is 16.41". Following very wet July-September periods, winter (December-February) precipitation has typically been near or below normal. The most recent exception was winter 2018-19. The ENSO Region 1+2 anomaly was -1.0°C and the Region 3.4 anomaly was -1.0°C for the week centered around November 17. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.67°C and the ENSO Region 3.4 anomaly has averaged -0.92°C. La Niña conditions will likely persist into at least late winter. The SOI was +30.98 today. The preliminary Arctic Oscillation (AO) figure was -0.906 today. On November 24 the MJO was in Phase 4 at an amplitude of 1.303 (RMM). The November 23-adjusted amplitude was 0.937 (RMM). 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 November (1991-2020 normal). November will likely finish with a mean temperature near 46.2° (1.8° below normal).

A snow flurry:

Morning thoughts… Light rain will move out of the region and the clouds could break late in the day. High temperatures will likely reach the middle and upper 40s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 46° Newark: 49° Philadelphia: 49° Normals: New York City: 30-Year: 50.4°; 15-Year: 50.6° Newark: 30-Year: 51.0°; 15-Year: 51.4° Philadelphia: 30-Year: 52.0°; 15-Year: 52.4° A cold weekend lies ahead. There remains a possibility that parts of the region could see a light snowfall Sunday night into Monday. The areas with the highest chance of measurable snow are to the north and west of Newark, New York City, and Bridgeport.

After today's brief shot of warmer air, much colder air is again poised to move into the region. Tomorrow will see temperatures hold steady or fall from the 40s during the afternoon and evening hours. An unseasonably cold weekend will follow. There is a small chance that a weak system could bring a period of light snow or flurries to parts of the region late Sunday into Monday. First measurable snowfall statistics for select cities: Allentown: Normal: December 6; 2020-21: December 9 Bridgeport: Normal: December 3; 2020-21: December 16 Islip: Normal: December 10; 2020-21: December 16 New York City: Normal: December 13; 2020-21: December 16 Newark: Normal: December 9; 2020-21: December 9 Philadelphia: Normal: December 19; 2020-21: December 16 The temperature anomaly for November 20-30 is on course to average below normal due to the development of AO blocking. The recent guidance has been correcting colder in response to this blocking. The Arctic Oscillation fell below -1.000 on November 23. Such strong blocking typically favors a period of colder than normal weather (November 20-30, 1991-2020 period): Boston: Normal: 42.2°; AO cases: 38.4° New York City: Normal: 45.5°; AO cases: 41.7° Philadelphia: Normal: 45.4°; AO cases: 41.7° The duration of the blocking remains uncertain. Should blocking dissipate, warmer conditions could develop near the start of December. Both the CFSv2 and EPS weeklies favor a return of warmer air at some point during the first week of December. Fall 2021 is well on course to being wetter to much wetter than normal in the northern Middle Atlantic region. Since 1869, there have been 9 August cases where New York City picked up 20.00" or more rainfall during the summer. Two thirds of those cases (and 4/5 of those with summer mean temperatures of 73.0° or above) had 17.00" or more fall precipitation in New York City. 2011 is probably the closest match in terms of precipitation and a nearly identical summer mean temperature. Mean fall precipitation for those 9 cases was 14.86". The median was 17.35". The 1991-2020 normal value is 12.27". Fall rainfall through November 25 4 pm is 16.28". Following very wet July-September periods, winter (December-February) precipitation has typically been near or below normal. The most recent exception was winter 2018-19. The ENSO Region 1+2 anomaly was -1.0°C and the Region 3.4 anomaly was -1.0°C for the week centered around November 17. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.67°C and the ENSO Region 3.4 anomaly has averaged -0.92°C. La Niña conditions will likely persist into at least late winter. The SOI was +24.68 today. The preliminary Arctic Oscillation (AO) figure was -1.222 today. On November 23 the MJO was in Phase 4 at an amplitude of 0.931 (RMM). The November 22-adjusted amplitude was 0.733 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 99% probability that New York City will have a cooler than normal November (1991-2020 normal). November will likely finish with a mean temperature near 46.2° (1.8° below normal).

Morning thoughts… Sunshine will give way to increasing clouds this afternoon. It will be noticeably milder. High temperatures will likely reach the lower and middle 50s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 53° Newark: 56° Philadelphia: 55° Normals: New York City: 30-Year: 50.7°; 15-Year: 50.9° Newark: 30-Year: 51.4°; 15-Year: 51.8° Philadelphia: 30-Year: 52.4°; 15-Year: 52.7° After some overnight showers, it will turn colder again. There remains a possibility that parts of the region could see a light snowfall Sunday night into Monday.

Tomorrow will witness the return of a milder air mass, but its stay will be short-lived. Another strong cold front will move across the region tomorrow night. In its wake, an unseasonably cold weekend will follow. There is a small chance that a weak system could bring a period of light snow or flurries to parts of the region late Sunday into Monday. First measurable snowfall statistics for select cities: Allentown: Normal: December 6; 2020-21: December 9 Bridgeport: Normal: December 3; 2020-21: December 16 Islip: Normal: December 10; 2020-21: December 16 New York City: Normal: December 13; 2020-21: December 16 Newark: Normal: December 9; 2020-21: December 9 Philadelphia: Normal: December 19; 2020-21: December 16 The temperature anomaly for November 20-30 is on course to average below normal due to the development of AO blocking. The recent guidance has been correcting colder in response to this blocking. The Arctic Oscillation fell below -1.000 on November 23. Such strong blocking typically favors a period of colder than normal weather (November 20-30, 1991-2020 period): Boston: Normal: 42.2°; AO cases: 38.4° New York City: Normal: 45.5°; AO cases: 41.7° Philadelphia: Normal: 45.4°; AO cases: 41.7° The duration of the blocking remains uncertain. Should blocking dissipate, warmer conditions could develop near the start of December. Both the CFSv2 and EPS weeklies favor a return of warmer air at some point during the first week of December. Fall 2021 is well on course to being wetter to much wetter than normal in the northern Middle Atlantic region. Since 1869, there have been 9 August cases where New York City picked up 20.00" or more rainfall during the summer. Two thirds of those cases (and 4/5 of those with summer mean temperatures of 73.0° or above) had 17.00" or more fall precipitation in New York City. 2011 is probably the closest match in terms of precipitation and a nearly identical summer mean temperature. Mean fall precipitation for those 9 cases was 14.86". The median was 17.35". The 1991-2020 normal value is 12.27". Fall rainfall through November 23 4 pm is 16.28". Following very wet July-September periods, winter (December-February) precipitation has typically been near or below normal. The most recent exception was winter 2018-19. The ENSO Region 1+2 anomaly was -1.0°C and the Region 3.4 anomaly was -1.0°C for the week centered around November 17. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.67°C and the ENSO Region 3.4 anomaly has averaged -0.92°C. La Niña conditions will likely persist into at least late winter. The SOI was +11.90 today. The preliminary Arctic Oscillation (AO) figure was -1.749 today. On November 22 the MJO was in Phase 4 at an amplitude of 0.733 (RMM). The November 21-adjusted amplitude was 1.027 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 98% probability that New York City will have a cooler than normal November (1991-2020 normal). November will likely finish with a mean temperature near 46.2° (1.8° below normal).

Morning thoughts… Today will partly to mostly sunny but still chilly. High temperatures will likely reach the middle and upper 40s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 45° Newark: 49° Philadelphia: 49° Normals: New York City: 30-Year: 51.1°; 15-Year: 51.3° Newark: 30-Year: 51.8°; 15-Year: 52.1° Philadelphia: 30-Year: 52.8°; 15-Year: 53.1° Tomorrow be milder as clouds increase ahead of the next cold front. There remains a possibility that parts of the region could see a light snowfall Sunday night into Monday.

I agree. It will probably fall to 30.

It reached 32 this morning.

Let’s see how things work out on tonight’s guidance. It would be nice to have at least a light snowfall to before the end of the month.

About 20% of EPS members have 1” or more. The potential exists for a light snowfall.

The coldest air of the season so far covers the region. Tomorrow will be another fair but cold day. Thanksgiving Day will witness the return of a milder air mass, but its duration will be short-lived. Another strong cold front will move across the region Thursday night. In its wake, an unseasonably cold weekend will follow. There is a small chance that a weak system could bring a period of light snow or flurries to parts of the region on Sunday. First measurable snowfall statistics for select cities: Allentown: Normal: December 6; 2020-21: December 9 Bridgeport: Normal: December 3; 2020-21: December 16 Islip: Normal: December 10; 2020-21: December 16 New York City: Normal: December 13; 2020-21: December 16 Newark: Normal: December 9; 2020-21: December 9 Philadelphia: Normal: December 19; 2020-21: December 16 The temperature anomaly for November 20-30 is on course to average below normal due to the development of AO blocking. The recent guidance has been correcting colder in response to this blocking. The Arctic Oscillation fell below -1.000 on November 23. Such strong blocking typically favors a period of colder than normal weather (November 20-30, 1991-2020 period): Boston: Normal: 42.2°; AO cases: 38.4° New York City: Normal: 45.5°; AO cases: 41.7° Philadelphia: Normal: 45.4°; AO cases: 41.7° The duration of the blocking remains uncertain. Should blocking dissipate, warmer conditions could develop near the start of December. Both the CFSv2 and EPS weeklies favor a return of warmer air at some point during the first week of December. Fall 2021 is well on course to being wetter to much wetter than normal in the northern Middle Atlantic region. Since 1869, there have been 9 August cases where New York City picked up 20.00" or more rainfall during the summer. Two thirds of those cases (and 4/5 of those with summer mean temperatures of 73.0° or above) had 17.00" or more fall precipitation in New York City. 2011 is probably the closest match in terms of precipitation and a nearly identical summer mean temperature. Mean fall precipitation for those 9 cases was 14.86". The median was 17.35". The 1991-2020 normal value is 12.27". Fall rainfall through November 23 4 pm is 16.28". Following very wet July-September periods, winter (December-February) precipitation has typically been near or below normal. The most recent exception was winter 2018-19. The ENSO Region 1+2 anomaly was -1.0°C and the Region 3.4 anomaly was -1.0°C for the week centered around November 17. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.67°C and the ENSO Region 3.4 anomaly has averaged -0.92°C. La Niña conditions will likely persist into at least late winter. The SOI was +8.40 today. The preliminary Arctic Oscillation (AO) figure was -1.410 today. On November 21 the MJO was in Phase 4 at an amplitude of 1.023 (RMM). The November 20-adjusted amplitude was 1.305 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 95% probability that New York City will have a cooler than normal November (1991-2020 normal). November will likely finish with a mean temperature near 46.4° (1.6° below normal).

A small accumulation also shows up on the National Blend of Models.

Morning thoughts… Today will partly to mostly sunny but brisk. High temperatures will likely reach the lower and middle 40s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 44° Newark: 47° Philadelphia: 46° Normals: New York City: 30-Year: 51.4°; 15-Year: 51.6° Newark: 30-Year: 52.1°; 15-Year: 52.4° Philadelphia: 30-Year: 53.1°; 15-Year: 53.4° Tomorrow will be another fair but cold day.

Early showers marked the passage of a strong cold front. At Central Park, 0.04" of rain was measured today. That raised the year-to-date precipitation total to 58.21", which ranks 2021 as New York City's 12th wettest year on record. Out West, Denver has now surpassed the record for its latest first measurable snowfall. The longstanding record was set on November 21, 1934. Phoenix tied 2017 for its 3rd warmest November 1-21 period on record. Each of the last three years has ranked among the 10 warmest November 1-21 periods on record. Today saw Phoenix reach 82° today, its 22nd consecutive 80° or warmer day this month. The previous November record was 17 consecutive days, which was set during November 1-17, 1999. Prior to that the records were 16 days (November 1-16, 1989) and 15 days (November 1-15, 1934 and 1967). The coldest air of the season so far is continuing to push into the region. New York City's Central Park could see its first freeze tomorrow or Wednesday. That would be slightly later than the mean 1991-2020 date of November 20. Last year's first freeze occurred on October 31, which was the earliest first freeze since 1988. No measurable snow appears likely in much of the region through this week. Much of the region typically sees its first measurable snowfall in December. First measurable snowfall statistics for select cities: Allentown: Normal: December 6; 2020-21: December 9 Bridgeport: Normal: December 3; 2020-21: December 16 Islip: Normal: December 10; 2020-21: December 16 New York City: Normal: December 13; 2020-21: December 16 Newark: Normal: December 9; 2020-21: December 9 Philadelphia: Normal: December 19; 2020-21: December 16 The temperature anomaly for November 20-30 will likely wind up below normal due to the development of AO blocking. The latest teleconnections forecasts continue to suggest that the AO will drop sharply to somewhere between -3.000 and -1.000 on or after November 20. Such strong blocking typically favors a period of colder than normal weather (November 20-30, 1991-2020 period): Boston: Normal: 42.2°; AO cases: 38.4° New York City: Normal: 45.5°; AO cases: 41.7° Philadelphia: Normal: 45.4°; AO cases: 41.7° The duration of the blocking is uncertain. Should blocking dissipate, warmer conditions could develop near the start of December. Fall 2021 is well on course to being wetter to much wetter than normal in the northern Middle Atlantic region. Since 1869, there have been 9 August cases where New York City picked up 20.00" or more rainfall during the summer. Two thirds of those cases (and 4/5 of those with summer mean temperatures of 73.0° or above) had 17.00" or more fall precipitation in New York City. 2011 is probably the closest match in terms of precipitation and a nearly identical summer mean temperature. Mean fall precipitation for those 9 cases was 14.86". The median was 17.35". The 1991-2020 normal value is 12.27". Fall rainfall through November 22 4 pm is 16.28". Following very wet July-September periods, winter (December-February) precipitation has typically been near or below normal. The most recent exception was winter 2018-19. The ENSO Region 1+2 anomaly was -1.0°C and the Region 3.4 anomaly was -1.0°C for the week centered around November 17. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.67°C and the ENSO Region 3.4 anomaly has averaged -0.92°C. La Niña conditions will likely persist into at least late winter. The SOI was +9.92 today. The preliminary Arctic Oscillation (AO) figure was -0.835 today. On November 20 the MJO was in Phase 4 at an amplitude of 1.303 (RMM). The November 19-adjusted amplitude was 1.242 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 91% probability that New York City will have a cooler than normal November (1991-2020 normal). November will likely finish with a mean temperature near 46.6° (1.4° below normal).

Morning thoughts… Today will see clouds break later in the day after some earlier showers. After a mild start, temperatures will begin to fall, especially during the afternoon hours. High temperatures will likely reach the lower and middle 50s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 51° Newark: 53° Philadelphia: 53° Normals: New York City: 30-Year: 51.8°; 15-Year: 51.9° Newark: 30-Year: 52.5°; 15-Year: 52.8° Philadelphia: 30-Year: 53.5°; 15-Year: 53.7° The coldest air mass of the season will bring about widespread freezes tonight and tomorrow night.

A cold front will cross the region tonight with some showers. Tomorrow will start mild but the temperature will hold steady or fall during the afternoon as the coldest air so far this season overspreads the region. New York City's Central Park could see its first freeze on either November 23 or November 24. That would be slightly later than the mean 1991-2020 date of November 20. Last year's first freeze occurred on October 31, which was the earliest first freeze since 1988. No measurable snow appears likely in much of the region through the coming week. However, any such snowfall would be unusually early. Much of the region typically sees its first measurable snowfall in December. First measurable snowfall statistics for select cities: Allentown: Normal: December 6; 2020-21: December 9 Bridgeport: Normal: December 3; 2020-21: December 16 Islip: Normal: December 10; 2020-21: December 16 New York City: Normal: December 13; 2020-21: December 16 Newark: Normal: December 9; 2020-21: December 9 Philadelphia: Normal: December 19; 2020-21: December 16 The temperature anomaly for November 20-30 will likely wind up below normal due to the development of AO blocking. The latest teleconnections forecasts continue to suggest that the AO will drop sharply to somewhere between -3.000 and -1.000 on or after November 20. Such strong blocking typically favors a period of colder than normal weather (November 20-30, 1991-2020 period): Boston: Normal: 42.2°; AO cases: 38.4° New York City: Normal: 45.5°; AO cases: 41.7° Philadelphia: Normal: 45.4°; AO cases: 41.7° The duration of the blocking is uncertain. Should blocking dissipate, warmer conditions could develop near the start of December. Fall 2021 is well on course to being wetter to much wetter than normal in the northern Middle Atlantic region. Since 1869, there have been 9 August cases where New York City picked up 20.00" or more rainfall during the summer. Two thirds of those cases (and 4/5 of those with summer mean temperatures of 73.0° or above) had 17.00" or more fall precipitation in New York City. 2011 is probably the closest match in terms of precipitation and a nearly identical summer mean temperature. Mean fall precipitation for those 9 cases was 14.86". The median was 17.35". The 1991-2020 normal value is 12.27". Fall rainfall through November 20 4 pm is 16.23". Following very wet July-September periods, winter (December-February) precipitation has typically been near or below normal. The most recent exception was winter 2018-19. The ENSO Region 1+2 anomaly was -0.7°C and the Region 3.4 anomaly was -0.8°C for the week centered around November 10. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.53°C and the ENSO Region 3.4 anomaly has averaged -0.85°C. La Niña conditions will likely persist into at least late winter. The SOI was +7.00 today. The preliminary Arctic Oscillation (AO) figure was -0.793 today. On November 19 the MJO was in Phase 4 at an amplitude of 1.244 (RMM). The November 18-adjusted amplitude was 1.141 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 87% probability that New York City will have a cooler than normal November (1991-2020 normal). November will likely finish with a mean temperature near 46.8° (1.2° below normal).