donsutherland1

With milder air moving into the region overnight, temperatures rose into the upper 40s and lower 50s today. Tomorrow will be even milder. The remainder of the week will feature above normal to perhaps some much above normal temperatures. Colder air could return to the region after next weekend. The recent guidance has suggested a more impressive cold shot than had previously been modeled. The return of the colder air could coincide with some storminess. The potential exists for at least part of the region to experience one or two snow events. A sustained warmer pattern could develop toward the winter solstice. The closing 10 days of December could wind up generally warmer than normal. The EPS weeklies and new subseasonal guidance are in strong agreement that the last week of December will likely be warmer than normal. The latest CFSv2 weekly guidance favors much warmer than normal readings. Historic experience following exceptionally warm November cases suggests that a warmer than normal December remains the base case. Almost 90% of cases with a November mean temperature of 51.5° or above in Central Park (2020 saw the temperature average a record 52.9° in November) went on to record a warmer than normal December and just over three-quarters of such cases saw December register a monthly mean temperature of 40.0° or above. The ENSO Region 1+2 anomaly was -0.5°C and the Region 3.4 anomaly was -1.1°C for the week centered around December 2. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.77°C and the ENSO Region 3.4 anomaly has averaged -1.35°C. La Niña conditions will likely prevail at least through the winter. The SOI was +10.79. Today, the preliminary Arctic Oscillation (AO) figure was -1.126. On December 9 the MJO was in Phase 5 at an amplitude of 1.079 (RMM). The December 8-adjusted amplitude was 0.906. Based on the latest guidance, no significant stratospheric warming event is likely through the third week of December. Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 10/11 (91%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. A predominant EPO+/AO+ pattern is very likely for winter 2020-21. It is likely that the Middle Atlantic and southern New England areas will see a warmer than normal winter with below normal snowfall. Based on sensitivity analysis applied to the latest guidance, there is an implied 69% probability that New York City will have a warmer than normal December. December will likely finish with a mean temperature near 39.8°.

New analysis on Australia’s record-warm spring: http://nespclimate.com.au/record-2020-spring-event-attribution/

Morning thoughts... Overnight, warmer air began overspreading the region. Today will be partly sunny and noticeably warmer than yesterday. Temperatures will likely top out in the upper 40s and lower 50s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 50° Newark: 50° Philadelphia: 50° Milder air will prevail through the remainder of the week. Next week could see the return of colder air.

Milder air is now poised to move into the region. The remainder of the week will feature above normal to perhaps some much above normal temperatures. Somewhat cooler air could return to the region after next weekend. A sustained warmer pattern could develop toward the winter solstice. The closing 10 days of December could wind up generally warmer than normal. The EPS weeklies and new subseasonal guidance are in strong agreement that the last week of December will likely be warmer than normal. The latest CFSv2 weekly guidance favors much warmer than normal readings. Historic experience following exceptionally warm November cases suggests that a warmer than normal December remains the base case. Almost 90% of cases with a November mean temperature of 51.5° or above in Central Park (2020 saw the temperature average a record 52.9° in November) went on to record a warmer than normal December and just over three-quarters of such cases saw December register a monthly mean temperature of 40.0° or above. The ENSO Region 1+2 anomaly was -0.5°C and the Region 3.4 anomaly was -1.1°C for the week centered around December 2. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.77°C and the ENSO Region 3.4 anomaly has averaged -1.35°C. La Niña conditions will likely prevail at least through the winter. The SOI was +5.29. Today, the preliminary Arctic Oscillation (AO) figure was -0.913. On December 8 the MJO was in Phase 5 at an amplitude of 0.901 (RMM). The December 7-adjusted amplitude was 0.678. Based on the latest guidance, no significant stratospheric warming event is likely through the first half of December. Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 10/11 (91%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. A predominant EPO+/AO+ pattern is very likely for winter 2020-21. It is likely that the Middle Atlantic and southern New England areas will see a warmer than normal winter with below normal snowfall. Based on sensitivity analysis applied to the latest guidance, there is an implied 73% probability that New York City will have a warmer than normal December. December will likely finish with a mean temperature near 40.0°.

Flurries in White Plains.

34 degrees and snow in Central Park.

It was probably too light to qualify as a trace. Parts of the City received flurries yesterday. The trace initially reported at EWR was retained. JFK also reported a trace. LGA did not.

The trace was in the preliminary daily climate report, but removed from the one issued overnight.

The ground is covered by snow in Hawley, PA (northeast PA).

Arctic Report Card 2020 is now available at: https://www.arctic.noaa.gov/Portals/7/ArcticReportCard/Documents/ArcticReportCard_full_report2020.pdf

Morning thoughts... Today will be variably cloudy. Some snow flurries and snow showers are possible. A rain shower is also possible during the afternoon. Some parts of the region could pick up a coating of snow. Temperatures will likely top out in the upper 30s and lower 40s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 38° Newark: 41° Philadelphia: 42° Milder air will return tomorrow and prevail through the remainder of the week.

There were flurries in parts of the area, including Central Park.

New York City received its first snowfall of winter 2020-21 today. However, it was not measurable. Just a trace of snow was reported. Through today, the preliminary AO average for December is -0.949. On 75% of days, the AO has been negative, including 63% when the AO has been -1.000 or below. Nevertheless, a warm anomaly has prevailed during the first eight days of December. Moreover, December remains likely to finish with a warm anomaly. Such situations are not common. December 2001 was one such case. The AO was negative on all 31 days and at or below -1.000 on 53% of days. The AO averaged -1.276 with a minimum value of -3.293 on December 28. At New York City, the monthly mean temperature was 44.1° (then the warmest December on record, which was eclipsed in 2015) and only a trace of snow was recorded. Tomorrow will likely remain cooler than normal. Some snow flurries and snow showers are likely. Some parts of the region could pick up a coating of snow. Afterward, milder air will move into the region. Somewhat cooler air could return to the region after next weekend. A sustained warmer pattern could begin to develop toward the winter solstice. The closing 10 days of December could wind up generally warmer than normal. The EPS weeklies and new subseasonal guidance are in strong agreement that the last week of December will likely be warmer than normal. The latest CFSv2 weekly guidance favors much warmer than normal readings. Historic experience following exceptionally warm November cases suggests that a warmer than normal December remains the base case. Almost 90% of cases with a November mean temperature of 51.5° or above in Central Park (2020 saw the temperature average a record 52.9° in November) went on to record a warmer than normal December and just over three-quarters of such cases saw December register a monthly mean temperature of 40.0° or above. The ENSO Region 1+2 anomaly was -0.5°C and the Region 3.4 anomaly was -1.1°C for the week centered around December 2. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.77°C and the ENSO Region 3.4 anomaly has averaged -1.35°C. La Niña conditions will likely prevail at least through the winter. The SOI was +7.73. Today, the preliminary Arctic Oscillation (AO) figure was -1.261. On December 7 the MJO was in Phase 4 at an amplitude of 0.677 (RMM). The December 6-adjusted amplitude was 0.784. Based on the latest guidance, no significant stratospheric warming event is likely through the first two weeks of December. The warming above 3 mb in response to recent strong Wave 1 activity could abate toward or just after mid-month. Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 10/11 (91%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. A predominant EPO+/AO+ pattern is very likely for winter 2020-21. It is likely that the Middle Atlantic and southern New England areas will see a warmer than normal winter with below normal snowfall. Based on sensitivity analysis applied to the latest guidance, there is an implied 73% probability that New York City will have a warmer than normal December. December will likely finish with a mean temperature near 40.0°.

I expect that NYC will fall short of having its warmest year on record. LaGuardia has perhaps a better shot.

Morning thoughts... Clouds will yield to partly sunny skies. It will remain cool. Temperatures will likely top out in the upper 30s and lower 40s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 38° Newark: 40° Philadelphia: 40° Cool temperatures should persist through tomorrow. Some snow flurries and snow showers are likely tomorrow, as well.

That happened in winter 2001-02, as well.

Earlier today, a system brought snow to parts of Virginia. Richmond picked up 1.0" snow. Another weak system could bring some snow flurries and snow showers to the region late tomorrow night or early Wednesday morning. Parts of the area could pick up a coating. Before then, tomorrow will be partly sunny and cool. Through mid-week, temperatures will run somewhat below normal. Milder weather will return for a time afterward, before the next push of cooler air arrives. Through mid-December, no exceptional cold is likely. Meanwhile, another round of near record and record warmth is likely in parts of western Canada through mid-week. A warmer pattern could begin to develop toward the winter solstice. The closing 10 days of December could wind up generally warmer than normal. The EPS weeklies and new subseasonal guidance are in strong agreement that the last week of December will likely be warmer than normal. The duration of the current AO-/PNA+ pattern will be key to how long the developing colder pattern persists. Statistical guidance based on the ENSO state and teleconnections would typically favor a colder regime for the first half of December in the Middle Atlantic and southern New England regions. Both historic experience following exceptionally warm November cases suggest that a warmer than normal December remains the base case even if the first half of the month winds up colder than normal. Almost 90% of cases with a November mean temperature of 51.5° or above in Central Park (2020 saw the temperature average a record 52.9° in November) went on to record a warmer than normal December and just over three-quarters of such cases saw December register a monthly mean temperature of 40.0° or above. The ENSO Region 1+2 anomaly was -0.5°C and the Region 3.4 anomaly was -1.1°C for the week centered around December 2. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.77°C and the ENSO Region 3.4 anomaly has averaged -1.35°C. La Niña conditions will likely prevail at least through the winter. The SOI was +15.15. Today, the preliminary Arctic Oscillation (AO) figure was -1.528. On December 6 the MJO was in Phase 4 at an amplitude of 0.741 (RMM). The December 5-adjusted amplitude was 1.020. Based on the latest guidance, no significant stratospheric warming event is likely through the first two weeks of December. The warming above 3 mb in response to recent strong Wave 1 activity could abate toward or just after mid-month. Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 10/11 (91%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. A predominant EPO+/AO+ pattern is very likely for winter 2020-21. It is likely that the Middle Atlantic and southern New England areas will see a warmer than normal winter with below normal snowfall. Based on sensitivity analysis applied to the latest guidance, there is an implied 67% probability that New York City will have a warmer than normal December. December will likely finish with a mean temperature near 40.0°.

Bamwx focuses on Indiana and the Midwest. It will likely be warmer there relative to normal than it is in the New York City area.

Morning thoughts... At 7:45 AM, Richmond reported a temperature of 32 degrees with light snow. South and east of Richmond, moderate snow was falling. This system will pass too far offshore to affect the New York City and Philadelphia areas. Today will be partly sunny, breezy and cool. Temperatures will likely top out in the upper 30s and lower 40s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 39° Newark: 42° Philadelphia: 42° Cool temperatures should persist through the middle of the week.

The new weekly numbers will be in tomorrow. They will provide further insight into the evolution of the ongoing La Niña event.

Through today, New York City has received no snowfall. Winter 2020-21 is the 18th case on record during which New York City had seen no snowfall through December 6. For the prior 17 cases, mean winter snowfall was 19.9". The most snowfall occurred during winter 1870-71 when 33.1" was measured. The least snowfall occurred during winter 2001-02 when just 3.5" snow fell. Records go back to 1869. Through mid-week, temperatures will run somewhat below normal. Milder weather will return for a time afterward, before the next push of cooler air arrives. Through mid-December, no exceptional cold is likely. Meanwhile, another round of near record and record warmth is likely in parts of western Canada through mid-week. A warmer pattern could begin to develop toward the winter solstice. The closing 10 days of December could wind up generally warmer than normal. The EPS weeklies and new subseasonal guidance are in strong agreement that the last week of December will likely be warmer than normal. The duration of the current AO-/PNA+ pattern will be key to how long the developing colder pattern persists. Statistical guidance based on the ENSO state and teleconnections would typically favor a colder regime for the first half of December in the Middle Atlantic and southern New England regions. Both historic experience following exceptionally warm November cases suggest that a warmer than normal December remains the base case even if the first half of the month winds up colder than normal. Almost 90% of cases with a November mean temperature of 51.5° or above in Central Park (2020 saw the temperature average a record 52.9° in November) went on to record a warmer than normal December and just over three-quarters of such cases saw December register a monthly mean temperature of 40.0° or above. 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 18. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.87°C and the ENSO Region 3.4 anomaly has averaged -1.40°C. La Niña conditions will likely prevail at least through the winter. The SOI was +11.78. Today, the preliminary Arctic Oscillation (AO) figure was -1.324. On December 5 the MJO was in Phase 4 at an amplitude of 1.023 (RMM). The December 4-adjusted amplitude was 1.020. Based on the latest guidance, no significant stratospheric warming event is likely through the first two weeks of December. The warming above 3 mb in response to recent strong Wave 1 activity could abate toward or just after mid-month. Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 10/11 (91%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. A predominant EPO+/AO+ pattern is very likely for winter 2020-21. It is likely that the Middle Atlantic and southern New England areas will see a warmer than normal winter with below normal snowfall.

Morning thoughts... Today will be partly to mostly sunny, breezy and cool. Temperatures will likely top out in the upper 30s and lower 40s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 41° Newark: 43° Philadelphia: 43° Cool temperatures should persist through the middle of the week.

That was a really nice storm: http://wintercenter.homestead.com/photodec2003b.html

That appears to be the case. I didn’t see any snow on the ground until I was near Guilford in CT. Some areas were dusted around there. From the latest PNS: 000 NOUS41 KOKX 052253 PNSOKX CTZ005>012-NJZ002-004-006-103>108-NYZ067>075-078>081-176>179-061053- Public Information Statement Spotter Reports National Weather Service New York NY 553 PM EST Sat Dec 05 2020 The following are unofficial observations taken during the past 8 hours for the storm that has been affecting our region. Appreciation is extended to highway departments, cooperative observers, Skywarn spotters and media for these reports. This summary also is available on our home page at weather.gov/nyc ********************STORM TOTAL SNOWFALL******************** LOCATION STORM TOTAL TIME/DATE COMMENTS SNOWFALL OF /INCHES/ MEASUREMENT CONNECTICUT ...Middlesex County... East Hampton 2.0 215 PM 12/05 Broadcast Media ...New Haven County... Wolcott 3.5 130 PM 12/05 Broadcast Media 2 W Rockland 1.8 245 PM 12/05 Broadcast Media 1 ESE Platts Mills 0.8 200 PM 12/05 Trained Spotter

There could have been. I didn’t go back to MPING to see what was happening afterward.