donsutherland1

Under brilliant sunshine, the temperature soared into the lower and middle 50s this afternoon across the New York City area. Three photos from the New York Botanical Garden from this afternoon:

Morning thoughts... Today will be mostly sunny and mild. 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): 55° Newark: 57° Philadelphia: 57° A storm will bring strong southeasterly winds, mild temperatures, and rain on Monday. Some areas could see a thunderstorm.

Under variably cloudy skies, temperatures rose into the lower and middle 50s across the region. Tomorrow will be partly to mostly sunny, but clouds will increase late in the day or during the evening. Readings will remain warmer than normal. Tomorrow into Monday, a storm could bring moderate to perhaps heavy rainfall to the Southeast and then up the East Coast. Following the storm, the Southeast could see unseasonably cool temperatures. The core of this colder air will likely stay south of the region, but somewhat below normal to near normal readings are likely in the Middle Atlantic and southern New England areas for a period. Meanwhile, there are now early hints that an extended duration much warmer than normal regime will begin to develop in parts of western Canada starting during the first half of next week. Overall, December could start off mild before that period of cooler than normal to near normal temperatures commences. This cooler period could still give way to warmer readings at some point during the second week of December, but there is is still uncertainty. The development of a AO-/PNA+ pattern has shifted the outlook toward colder temperatures during the first half of December (consistent with statistical guidance). Exceptional cold is unlikely. The duration of the AO-/PNA+ pattern could delay any warmup until near mid-month. Statistical guidance based on the ENSO state and teleconnections would typically favor a colder regime for the first half of December. Both historic experience following exceptionally warm November cases and the latest weekly and monthly guidance 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 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 -0.7°C and the Region 3.4 anomaly was -1.5°C for the week centered around November 18. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.90°C and the ENSO Region 3.4 anomaly has averaged -1.42°C. La Niña conditions will likely prevail at least through the winter. The SOI was +1.21. Today, the preliminary Arctic Oscillation (AO) figure was +0.528. On November 27 the MJO was in Phase 4 at an amplitude of 1.032 (RMM). The November 26-adjusted amplitude was 1.172. Based on the latest guidance, no significant stratospheric warming event is likely through the first week of December. Some warming above 2 mb is likely toward the end of that timeframe on account of Wave 1 activity. 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. Since 1950, there have been four La Niña winters that started with a warm December in the Northeast and warmth across much of Canada, as is the current forecast on the monthly EPS, latest weekly EPS and latest CFSv2 monthly guidance: 1974-75, 1998-99, 1999-00, and 2011-12. All featured a warmer than normal winter and among the winter months that followed December, only January 2000 was colder than normal in the East. Median seasonal snowfall figures were as follows: New York City: 12.9" and Philadelphia: 13.1". Since 1970, there were 9 winters that saw the AO and EPO average +0.25 or above. Mean snowfall for Boston, Harrisburg, New York City, Philadelphia, and Washington, DC averaged 50% of the most recent 30-season mean. The largest snowfall deficits relative to the most recent 30-season mean figure were located in the Philadelphia to New York City corridor. In addition, 33% of cases saw less than 10" seasonal snowfall in New York City and 44% saw less than 10" seasonal snowfall in Philadelphia. Based on sensitivity analysis applied to the latest guidance, there is an implied near 100% probability that New York City will have a warmer than normal November. November will likely finish with a mean temperature near 52.7° (tied for the 2nd warmest November on record). Considering modeling errors, there is a possibility that 2020 could compete with 2016 for the warmest November on record. November 2015 had a monthly mean temperature of 52.8°.

I hope it ends soon. Another “non-winter” would be anything but satisfying.

While the pattern change after mid-December is not assured, there are enough hints on the guidance to suggest that it is plausible. We’ll see how things evolve. There can always be surprises along the way.

Boll expresses my own concern about the pattern evolution, namely the possible shift back to sustained warmer conditions in the extended range.

It’s tough to be certain at that timeframe. Should blocking be more persistent, more time would be available. If it breaks down more quickly than the opportunities could disappear fairly quickly, whether or not they are realized.

Hopefully, we can get something before the pattern changes after mid-December.

Both December 2000 and 2010 had a lot of blocking.

Morning thoughts... Today will be partly sunny and still mild for the season. High temperatures in the region will likely reach the middle and upper 50s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 57° Newark: 59° Philadelphia: 58° A storm will bring strong southeasterly winds, mild temperatures, and rain on Monday.

Under partly sunny skies that yielded to mainly overcast skies during the afternoon, temperatures in the region rose into the upper 50s and lower 60s. Tomorrow will be partly sunny and somewhat cooler with readings mainly in the lower and middle 50s. Sunday into Monday, a storm could bring moderate to perhaps heavy rainfall to the Southeast and then up the East Coast. Following the storm, the Southeast could see unseasonably cool temperatures. The core of this colder air will likely stay south of the region, but somewhat below normal to near normal readings are likely in the Middle Atlantic and southern New England areas for a period. Meanwhile, there are now early hints that an extended duration much warmer than normal regime will begin to develop in parts of western Canada starting during the first half of next week. Overall, December could start off mild before that period of cooler than normal to near normal temperatures commences. This cooler period could still give way to warmer readings at some point during the second week of December, but there is is still uncertainty. The development of a AO-/PNA+ pattern has shifted the outlook toward colder temperatures during the first half of December (consistent with statistical guidance). Exceptional cold is unlikely. The duration of the AO-/PNA+ pattern could delay any warmup until near mid-month. Statistical guidance based on the ENSO state and teleconnections would typically favor a colder regime for the first half of December. The dynamical guidance has moved closer toward this idea for the Middle Atlantic region. Both historic experience following exceptionally warm November cases and the latest weekly and monthly guidance 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 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 -0.7°C and the Region 3.4 anomaly was -1.5°C for the week centered around November 18. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.90°C and the ENSO Region 3.4 anomaly has averaged -1.42°C. La Niña conditions will likely prevail at least through the winter. The SOI was +3.18. Today, the preliminary Arctic Oscillation (AO) figure was +1.847. On November 26 the MJO was in Phase 4 at an amplitude of 1.171 (RMM). The November 25-adjusted amplitude was 0.944. Based on the latest guidance, no significant stratospheric warming event is likely through the middle of the first 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. Since 1950, there have been four La Niña winters that started with a warm December in the Northeast and warmth across much of Canada, as is the current forecast on the monthly EPS, latest weekly EPS and latest CFSv2 monthly guidance: 1974-75, 1998-99, 1999-00, and 2011-12. All featured a warmer than normal winter and among the winter months that followed December, only January 2000 was colder than normal in the East. Median seasonal snowfall figures were as follows: New York City: 12.9" and Philadelphia: 13.1". Since 1970, there were 9 winters that saw the AO and EPO average +0.25 or above. Mean snowfall for Boston, Harrisburg, New York City, Philadelphia, and Washington, DC averaged 50% of the most recent 30-season mean. The largest snowfall deficits relative to the most recent 30-season mean figure were located in the Philadelphia to New York City corridor. In addition, 33% of cases saw less than 10" seasonal snowfall in New York City and 44% saw less than 10" seasonal snowfall in Philadelphia. Based on sensitivity analysis applied to the latest guidance, there is an implied near 100% probability that New York City will have a warmer than normal November. November will likely finish with a mean temperature near 52.6° (3rd warmest on record). Considering modeling errors, there is a possibility that 2020 could compete with 2015 for the warmest November on record. November 2015 had a monthly mean temperature of 52.8°.

Into the early afternoon, parts of the region enjoyed partly sunny skies and temperatures in the 60s. It was another early autumn-like late November day.

Morning thoughts... Today will be partly cloudy and quite mild for the season. Temperatures will likely top out in the upper 50s and lower 60s across the area. Likely high temperatures around the region include: New York City (Central Park): 59° Newark: 61° Philadelphia: 61° The remainder of November will be generally warmer than normal.

Temperatures soared well into the 60s across the region this Thanksgiving Day. Tomorrow will be partly cloudy and still unseasonably mild. Late this weekend into early next week, a storm could bring moderate to heavy rainfall to the Southeast and then up the East Coast. Following the storm, the Southeast could see unseasonably cool temperatures. The core of this colder air will likely stay south of the region, but somewhat below normal to near normal readings are likely in the Middle Atlantic and southern New England areas. Overall, December could start off mild before that period of cooler than normal to near normal temperatures commences. This cooler period could still give way to warmer readings at some point during the second week of December, but there is considerable uncertainty. The now likely development of a AO-/PNA+ pattern has shifted the outlook toward colder temperatures during the first half of December (consistent with statistical guidance). The duration of the AO-/PNA+ pattern could delay any warmup until near mid-month. Statistical guidance based on the ENSO state and teleconnections would typically favor a colder regime for the first half of December. The dynamical guidance has moved closer to this idea for the Middle Atlantic region. Both historic experience following exceptionally warm November cases and the latest weekly and monthly guidance 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 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 -0.7°C and the Region 3.4 anomaly was -1.5°C for the week centered around November 18. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.90°C and the ENSO Region 3.4 anomaly has averaged -1.42°C. La Niña conditions will likely prevail at least through the winter. The SOI was +5.21. Today, the preliminary Arctic Oscillation (AO) figure was +2.227. On November 25 the MJO was in Phase 4 at an amplitude of 0.937 (RMM). The November 24-adjusted amplitude was 0.705. Based on the latest guidance, no significant stratospheric warming event is likely through the start 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. Since 1950, there have been four La Niña winters that started with a warm December in the Northeast and warmth across much of Canada, as is the current forecast on the monthly EPS, latest weekly EPS and latest CFSv2 monthly guidance: 1974-75, 1998-99, 1999-00, and 2011-12. All featured a warmer than normal winter and among the winter months that followed December, only January 2000 was colder than normal in the East. Median seasonal snowfall figures were as follows: New York City: 12.9" and Philadelphia: 13.1". Since 1970, there were 9 winters that saw the AO and EPO average +0.25 or above. Mean snowfall for Boston, Harrisburg, New York City, Philadelphia, and Washington, DC averaged 50% of the most recent 30-season mean. The largest snowfall deficits relative to the most recent 30-season mean figure were located in the Philadelphia to New York City corridor. In addition, 33% of cases saw less than 10" seasonal snowfall in New York City and 44% saw less than 10" seasonal snowfall in Philadelphia. Based on sensitivity analysis applied to the latest guidance, there is an implied near 100% probability that New York City will have a warmer than normal November. November will likely finish with a mean temperature near 52.2°.

A moderate La Niña event has developed. Since 1950, 80% of La Niña events that developed in the June-July-August or later saw predominant EPO+/AO+ winter tendencies. All cases that saw the MJO in Phases 4-6 for 20 or more days experienced such tendencies. As November progressed, the stratosphere over the Arctic region was abnormally cool. At the same time, the stratospheric polar vortex was strengthening. These developments are consistent with an atmospheric state that favors a positive AO. As a result, even as an AO-/PNA+ pattern is likely to begin December, that pattern should eventually give way to a predominant AO+ pattern. December will likely be the coldest month relative to normal during meteorological winter in the eastern United States. Since winter 1979-80, there have been 7 cases where December-February saw both the EPO and AO average +0.25 or above for the winter: 1998-99, 1999-00, 2001-02, 2006-07, 2007-08, 2011-12, and 2019-20. Winter 2020-21 will very likely become the 8th such case. Key Assumptions: 1. Cold ENSO 2. Generally positive NAO 3. Negative PDO 4. Predominantly positive AO 5. Predominantly positive EPO Given the differences in details that can occur winter-to-winter and the differing ENSO states from the EPO+/AO+ cases, a look at mean anomalies and, if possible, clustered outcomes can provide insight. December-February Temperature Anomalies (EPO and AO +0.25 or Above): Clustered 500 mb Scenarios: C3S Multi-System Seasonal Forecast: Additional factors to be considered include the observed ongoing Arctic warming. This variable can promote an increased persistence of events. Based on all of the above factors, my estimated December-February temperature thinking is: Colder than normal (1.0° to 2.0° below normal): Alaska, Northwestern Canada Near Normal (0.5° below normal to 0.5° above normal): Pacific Northwest, British Columbia Somewhat above normal (0.5° to 1.5° above normal): Canada (except for southern Ontario, southern Quebec, and western Canada), West Coast (except for Pacific Northwest) Warmer than Normal (1.0° to 3.0° above normal): Middle Atlantic Region, New England, Plains States (Southern, Central, and Northern Plains), Southeast, Southern Ontario, Southern Quebec, Southwest Much Warmer than Normal (More than 3.0° above normal): Great Lakes Region Select seasonal snowfall estimates are below: Albany: 45"-55" Atlanta: 0.5" or less Baltimore: 6"-12" Binghamton: 65"-75" Boston: 25"-35" Buffalo: 80"-90" Burlington: 65"-75" Chicago: 33"-43" Detroit: 35"-45" Harrisburg: 10"-20" New York City: 8"-16" Newark: 8"-16" Philadelphia: 7"-14" Providence: 20"-30" Richmond: 4" or less Scranton: 30"-40" Sterling: 6"-12" Washington, DC: 5"-10" What could lead to higher amounts: 1. Periods of deep blocking (AO of -1.000 or below) 2. The MJO's persistently being in Phases 7, 8, 1, and 2 at a high amplitude 3. A mainly positive PNA What could lead to lesser amounts: 1. The development of a persistently strongly positive AO, especially if coupled with a strongly positive EPO 2. The MJO's persistently being in Phases 4, 5, and 6 at a high amplitude 3. A sharply negative PDO driving a frequently strongly negative PNA

This morning, temperatures were in the lower 60s along the Long Island Sound where low clouds periodically broke to allow for some sunshine.

Unfortunately, the U.S. is quite polarized right now. Crises have become the major driver for breaking policy impasses. Otherwise, there is unusual inertia. The Millennial generation is not polarized, so as that generation gains influence, the polarization that currently hobbles American policy making should begin to recede.

Morning thoughts... A storm is currently moving up the St. Lawrence River Valley. Rain and showers associated with that storm will end and the sun could return during the afternoon. It will be very mild for the season. Temperatures will likely top out in the lower and middle 60s across the area. Likely high temperatures around the region include: New York City (Central Park): 64° Newark: 65° Philadelphia: 66° The remainder of November will be generally warmer than normal.

Readings will rebound into the upper 50s and lower 60s for Thanksgiving Day as a storm passes to the north and west of the region. There will also be some rain and showers, especially during the first half of the day. December could start off mild before a period of cooler than normal to near normal temperatures commences. This cooler period could still give way to warmer readings at some point during the second week of December, but there is considerable uncertainty. The now likely development of a AO-/PNA+ pattern has shifted the outlook toward colder temperatures during the first half of December (consistent with statistical guidance). The duration of the AO-/PNA+ pattern could delay any warmup until near mid-month. Statistical guidance based on the ENSO state and teleconnections would typically favor a colder regime for the first half of December. Both historic experience following exceptionally warm November cases and the latest weekly and monthly guidance 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 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 -0.7°C and the Region 3.4 anomaly was -1.5°C for the week centered around November 18. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.90°C and the ENSO Region 3.4 anomaly has averaged -1.42°C. La Niña conditions will likely prevail at least through the winter. The SOI was +5.66. Today, the preliminary Arctic Oscillation (AO) figure was +0.705. On November 24 the MJO was in Phase 4 at an amplitude of 0.702 (RMM). The November 23-adjusted amplitude was 0.764. Based on the latest guidance, no significant stratospheric warming event is likely through the start 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. Since 1950, there have been four La Niña winters that started with a warm December in the Northeast and warmth across much of Canada, as is the current forecast on the monthly EPS, latest weekly EPS and latest CFSv2 monthly guidance: 1974-75, 1998-99, 1999-00, and 2011-12. All featured a warmer than normal winter and among the winter months that followed December, only January 2000 was colder than normal in the East. Median seasonal snowfall figures were as follows: New York City: 12.9" and Philadelphia: 13.1". Since 1970, there were 9 winters that saw the AO and EPO average +0.25 or above. Mean snowfall for Boston, Harrisburg, New York City, Philadelphia, and Washington, DC averaged 50% of the most recent 30-season mean. The largest snowfall deficits relative to the most recent 30-season mean figure were located in the Philadelphia to New York City corridor. In addition, 33% of cases saw less than 10" seasonal snowfall in New York City and 44% saw less than 10" seasonal snowfall in Philadelphia. Based on sensitivity analysis applied to the latest guidance, there is an implied near 100% probability that New York City will have a warmer than normal November. November will likely finish with a mean temperature near 52.1°.

The appointment of former Secretary of State John Kerry as a cabinet-level climate envoy is encouraging. He has international clout, relationships and credibility. Nevertheless, the dying climate change denial movement and the status quo interests that back it likely won't yield without putting up a big fight. Translating goals into policy will be a significant challenge, even as the issue is urgent.

Morning thoughts... Today will be mostly cloudy and mild as a storm tracking to the toward the Great Lakes region brings warmer air to the East. High temperatures in the region will likely reach the middle and upper 50s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 55° Newark: 57° Philadelphia: 58° An unseasonably mild Thanksgiving Day holiday lies ahead.

Yes. Raleigh picked up 20” snow, Baltimore had almost 15”, but NYC had less than 6”.

Tomorrow should be somewhat milder. Readings will rebound into the upper 50s and lower 60s for Thanksgiving Day as a storm passes to the north and west of the region. December could see above normal temperatures redevelop during or after the first week of the month after starting off on a cool note. The possible development of a period where the AO is negative and PNA is positive could delay the warmup. Statistical guidance based on the ENSO state and teleconnections would typically favor a colder regime for the first half of December, but this is no typical La Niña pattern. Both historic experience following exceptionally warm November cases and the latest weekly and monthly guidance still suggest a warmer than normal December is the base case even if the first half of the month winds up near normal or even somewhat cooler than normal. Almost 90% of cases with a November mean temperature of 51.5° or above in Central Park 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 -0.7°C and the Region 3.4 anomaly was -1.5°C for the week centered around November 18. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.90°C and the ENSO Region 3.4 anomaly has averaged -1.42°C. La Niña conditions will likely prevail at least through the winter. The SOI was +2.92. Today, the preliminary Arctic Oscillation (AO) figure was +1.345. On November 23 the MJO was in Phase 3 at an amplitude of 0.765 (RMM). The November 22-adjusted amplitude was 0.962. Based on the latest guidance, no significant stratospheric warming event is likely through the end of November. 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. Since 1950, there have been four La Niña winters that started with a warm December in the Northeast and warmth across much of Canada, as is the current forecast on the monthly EPS, latest weekly EPS and latest CFSv2 monthly guidance: 1974-75, 1998-99, 1999-00, and 2011-12. All featured a warmer than normal winter and among the winter months that followed December, only January 2000 was colder than normal in the East. Median seasonal snowfall figures were as follows: New York City: 12.9" and Philadelphia: 13.1". Since 1970, there were 9 winters that saw the AO and EPO average +0.25 or above. Mean snowfall for Boston, Harrisburg, New York City, Philadelphia, and Washington, DC averaged 50% of the most recent 30-season mean. The largest snowfall deficits relative to the most recent 30-season mean figure were located in the Philadelphia to New York City corridor. In addition, 33% of cases saw less than 10" seasonal snowfall in New York City and 44% saw less than 10" seasonal snowfall in Philadelphia. Based on sensitivity analysis applied to the latest guidance, there is an implied near 100% probability that New York City will have a warmer than normal November. November will likely finish with a mean temperature near 51.9°.

Morning thoughts... Today will be variably cloudy and cool. High temperatures in the region will likely reach the upper 40s to around 50° in most of the region. Likely high temperatures around the region include: New York City (Central Park): 47° Newark: 50° Philadelphia: 50° An unseasonably mild Thanksgiving Day holiday lies ahead.

Tomorrow will be fair but cool. Most of the region will see high temperatures top out in the middle and upper 40s. Wednesday should be somewhat milder. Readings will rebound into the upper 50s and lower 60s for Thanksgiving Day as a storm passes to the north and west of the region. Tomorrow through Thursday, a storm will move out of the Plains States toward the Great Lakes Region and into Canada. This storm could bring a significant rainfall to the Central Plains States into the eastern Great Lakes Region. North and west of the storm track, including southern Minnesota, southern Wisconsin, Michigan's Upper Peninsula, and parts of Ontario (excluding the greater Toronto area), a moderate to significant snowfall is possible. December could see above normal temperatures redevelop during the first week of the month after starting off on a cool note. However, the possible development of a period where the AO is negative and PNA is positive could delay the warmup. However, both historic experience following exceptionally warm November cases and the latest weekly and monthly guidance still suggest a warmer than normal December is the base case. The ENSO Region 1+2 anomaly was -0.7°C and the Region 3.4 anomaly was -1.5°C for the week centered around November 18. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.90°C and the ENSO Region 3.4 anomaly has averaged -1.42°C. La Niña conditions will likely prevail at least through the winter. The SOI was -7.83. Today, the preliminary Arctic Oscillation (AO) figure was +2.264. On November 22 the MJO was in Phase 3 at an amplitude of 0.962 (RMM). The November 21-adjusted amplitude was 1.344. Based on the latest guidance, no significant stratospheric warming event is likely through the end of November. 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. Since 1950, there have been four La Niña winters that started with a warm December in the Northeast and warmth across much of Canada, as is the current forecast on the monthly EPS, latest weekly EPS and latest CFSv2 monthly guidance: 1974-75, 1998-99, 1999-00, and 2011-12. All featured a warmer than normal winter and among the winter months that followed December, only January 2000 was colder than normal in the East. Median seasonal snowfall figures were as follows: New York City: 12.9" and Philadelphia: 13.1". Since 1970, there were 9 winters that saw the AO and EPO average +0.25 or above. Mean snowfall for Boston, Harrisburg, New York City, Philadelphia, and Washington, DC averaged 50% of the most recent 30-season mean. The largest snowfall deficits relative to the most recent 30-season mean figure were located in the Philadelphia to New York City corridor. In addition, 33% of cases saw less than 10" seasonal snowfall in New York City and 44% saw less than 10" seasonal snowfall in Philadelphia. Based on sensitivity analysis applied to the latest guidance, there is an implied near 100% probability that New York City will have a warmer than normal November. November will likely finish with a mean temperature near 51.6°. The implied probability for a November mean temperature of 50.0° in Central Park is now approximately 95%. Since 1869, there have been 19 cases where November had a mean temperature of 50.0° or above. 14/19 (74%) went on to have a warmer than normal December, including 9/19 (47%) with a December mean temperature of 40.0° or above (2.5° or more above normal). The winter mean temperature for those 14 cases was 37.5° (2.2° above normal). The winter mean temperature for the subset of December cases with a mean temperature of 40.0° or above was 38.9° (3.6° above normal) and four of those cases wound up having an average winter temperature of 40.0° or above.