donsutherland1

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.

Morning thoughts... A cold front is moving through the area right now. Clouds will break and the sun will return later this morning or during the early afternoon on Long Island. The temperature will gradually fall from the middle 50s at 8 am into the 40s during the afternoon. Tomorrow will be sunny but cool.

Tonight into tomorrow, a cold front associated with a storm that brought snow from Detroit to Toronto will move across the region with showers and periods of rain. Tomorrow will be mild, but cooler weather is likely Tuesday and Wednesday before readings warm again. From late tomorrow into Thursday, a storm will move from the Plains States toward the Great Lakes Region and into Canada. The 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. In the East, a mild Thanksgiving Day holiday looks likely. December could see above to perhaps much above normal temperatures redevelop during the first week of the month after starting off on a cool note. The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -1.0°C for the week centered around November 11. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.98°C and the ENSO Region 3.4 anomaly has averaged -1.44°C. La Niña conditions will likely prevail at least through the winter. The SOI was -7.51. Today, the preliminary Arctic Oscillation (AO) figure was +2.797. On November 21 the MJO was in Phase 3 at an amplitude of 1.351 (RMM). The November 20-adjusted amplitude was 1.393. Based on the latest guidance, no significant stratospheric warming event is likely through the end of November. The lack of such warming could favor the gradual strengthening of the stratospheric polar vortex. A strong polar vortex, which is favored on the long-range guidance, could have implications for the opening of meteorological winter. 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. The November run of the seasonal European guidance suggests that winter 2020-21 will likely be warmer to much warmer than normal in the region. The potential also exists for below to much below normal seasonal snowfall in the Middle Atlantic and southern New England areas. 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 51.5°. The implied probability for a November mean temperature of 50.0° in Central Park is now approximately 90%. 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.

One photo and a short video clip from this afternoon:

FYI, Phoenix tied its record high minimum temperature with a low of 61 degrees yesterday. The record was set in 2006.

No. Every place that I saw fell just short of 70.

Morning thoughts... At 8:35, rain and snow was falling in northern Pennsylvania along a warm front associated with a storm that will be tracking north and west of the region. Rain was falling in part of the Ohio Valley and light snow was falling in Detroit. Today will be another mostly cloudy. Showers will become increasingly likely during the afternoon and evening. Steadier rain will likely arrive tonight. High temperatures in the region 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: 58° A brief shot of cooler air is likely Tuesday into Wednesday.

Phoenix Experiences Latest 90° Days on Record Often a great earthquake is followed by strong aftershocks that reverberate in the days and weeks that follow it. 2020 has witnessed a similar phenomenon in Phoenix following what was, by far its hottest summer on record. In this case, waves of unseasonable heat have recurred periodically deep into the autumn. Summer 2020 had a mean temperature of 96.7°, which obliterated the previous mark of 95.1° set in 2013 and tied in 2015. Summer 2020 also saw July become Phoenix's hottest month on record and then August eclipse that record. The extreme heat of summer carried over into early September when the temperature topped out at 115°on September 5 and September 4-6 saw readings of 113° or above on each day. Cooler weather returned, but Phoenix has witnessed five distinct heat episodes since then, the most recent of which produced that city's latest 90° temperatures on record: 1. Mid-September: Peak temperature: 109°, September 16-17 2. Early October: Peak temperature: 107°, October 1 (tied monthly record). October 1-5: 105° or above on each day. October 1-7: Hottest week on record in October. 3. Mid-October: Peak temperature: 102°, October 16. That brought Phoenix's total 100° days to 145, surpassing the record of 143 such days set in 1989. 4. Early November: Peak temperature 99°, November 5. That smashed the November record of 96°, which was most recently tied on November 1, 2020. November 1-5 was the warmest 5-day period on record in November. 5. Mid-November: Peak temperature: 92°, November 16-17. The previous latest 90° temperature on record occurred on November 15, 1999 when the temperature reached 90°. In addition to surpassing the record for the latest 90° temperatures on record, November 2020 tied the monthly record of 7 such days. That record was set in 1999. Table 1: 90° Days during November 2020: Table 2: November Temperature Thresholds: Table 3: Daily Record High Maximum Temperatures: Table 4: Daily Record High Minimum Temperatures:

With sunshine that persisted into the afternoon, temperatures rose well into the 60s in much of the region. Tomorrow will be cooler under mainly cloudy skies. Showers are likely. A steadier rain could develop later in the day or at night. Most of the remaining days this month could see readings near or above normal with some short-lived cool shots possible. One such cool shot is likely early next week. December could see above to perhaps much above normal temperatures redevelop during the first week of the month. The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -1.0°C for the week centered around November 11. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.98°C and the ENSO Region 3.4 anomaly has averaged -1.44°C. La Niña conditions will likely prevail at least through the winter. The SOI was +2.86. Today, the preliminary Arctic Oscillation (AO) figure was +3.262. On November 20 the MJO was in Phase 2 at an amplitude of 1.401 (RMM). The November 19-adjusted amplitude was 1.581. Based on the latest guidance, no significant stratospheric warming event is likely through at least November 25. The lack of such warming could favor the gradual strengthening of the stratospheric polar vortex. A strong polar vortex, which is favored on the long-range guidance, could have implications for the opening of meteorological winter. 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. The November run of the seasonal European guidance suggests that winter 2020-21 will likely be warmer to much warmer than normal in the region. The potential also exists for below to much below normal seasonal snowfall in the Middle Atlantic and southern New England areas. 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 99% probability that New York City will have a warmer than normal November. November will likely finish with a mean temperature near 51.2°. The implied probability for a November mean temperature of 50.0° in Central Park is now approximately 81%. 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.

I share Bluewave’s sentiments. Much would need to change to produce a cold, especially snowy outcome.

Under sunshine that last into the early afternoon, the temperature soared to 64° at Central Park. At the New York Botanical Garden, most of the leaves are now down. Three photos from this afternoon:

Temperatures are running well above the guidance. Central Park will likely reach the middle 60s and Newark will be in the upper 60s to near 70.

Morning thoughts... Today will be another mostly sunny and mild day. High temperatures in the region will likely reach the lower 60s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 61° Newark: 63° Philadelphia: 64° Tomorrow will be somewhat cooler and there could showers.

In a day filled with sunshine, the temperature soared into the 60s across much of the region today. Most of the remaining days this month could see readings near or above normal with some short-lived cool shots possible. One such cool shot is likely early next week. December could see above to perhaps much above normal temperatures redevelop during the first week of the month. The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -1.0°C for the week centered around November 11. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.98°C and the ENSO Region 3.4 anomaly has averaged -1.44°C. La Niña conditions will likely prevail at least through the winter. The SOI was +16.86. Today, the preliminary Arctic Oscillation (AO) figure was +3.144. On November 19 the MJO was in Phase 2 at an amplitude of 1.579 (RMM). The November 18-adjusted amplitude was 1.551. Based on the latest guidance, no significant stratospheric warming event is likely through at least November 25. The lack of such warming could favor the gradual strengthening of the stratospheric polar vortex. A strong polar vortex, which is favored on the long-range guidance, could have implications for the opening of meteorological winter. 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. The November run of the seasonal European guidance suggests that winter 2020-21 will likely be warmer to much warmer than normal in the region. The potential also exists for below to much below normal seasonal snowfall in the Middle Atlantic and southern New England areas. 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 98% probability that New York City will have a warmer than normal November. November will likely finish with a mean temperature near 51.2°. The implied probability for a November mean temperature of 50.0° in Central Park is now near 80%. 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.

Morning thoughts... Yesterday, temperatures rose into the lower and middle 60s in the Great Lakes Region. Some of this warmer air will move into the region for today and tomorrow . As a result, today will be mostly sunny and much warmer than yesterday. High temperatures in the region will likely reach the upper 50s and lower 60s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 59° Newark: 62° Philadelphia: 62° The weekend will start on a mild note, but somewhat cooler air should arrive for Sunday.

Temperatures rebounded into the upper 40s after a cold start with most locations seeing low temperatures in the 20s and even teens. Most of the remaining days this month could see readings near or above normal with some short-lived cool shots possible. One such cool shot is likely early next week. December could see above to perhaps much above normal temperatures redevelop during the first week of the month. The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -1.0°C for the week centered around November 11. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.98°C and the ENSO Region 3.4 anomaly has averaged -1.44°C. La Niña conditions will likely prevail at least through the winter. The SOI was +20.17. Today, the preliminary Arctic Oscillation (AO) figure was +2.882. On November 18 the MJO was in Phase 2 at an amplitude of 1.555 (RMM). The November 17-adjusted amplitude was 1.682. Based on the latest guidance, no significant stratospheric warming event is likely through at least November 25. The lack of such warming could favor the gradual strengthening of the stratospheric polar vortex. A strong polar vortex, which is favored on the long-range guidance, could have implications for the opening of meteorological winter. 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. The November run of the seasonal European guidance suggests that winter 2020-21 will likely be warmer to much warmer than normal in the region. The potential also exists for below to much below normal seasonal snowfall in the Middle Atlantic and southern New England areas. 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 95% probability that New York City will have a warmer than normal November. November will likely finish with a mean temperature near 51.0°.

The cold was impressive. The high wasn’t far off the daily record low minimum temperature, but now the cold air is departing rapidly.