donsutherland1

There's a growing body of literature linking climate change to a slowing of the jet stream. The end result is "stuck patterns." Alaska's record warm summer last year, Siberia's record warmth earlier this year, and Phoenix's record-setting summer this year are some recent examples resulting from a greater persistence in prevailing patterns.

BDL had yet another 90 degree day.

This PBS Newshour interview was conducted in 2018 but is as timely now as it was then. Since then, Australia recorded its worst fire season on record. More big wildfires are currently burning in California. https://www.pbs.org/newshour/show/climate-change-is-making-wildfires-more-extreme-heres-how And an animated satellite photo from the August 2020 fires in California:

Under mainly sunny skies, temperatures rose to the middle and upper 80s today. A few parts of the region reached 90° or slightly above. 90° Days for Select Cities (through August 22): Albany: 13 (2019: 12 days) Allentown: 23 (2019: 24 days) Baltimore: 40 (2019: 59 days) Boston: 14 (2019: 15 days) Burlington: 20 (2019: 8 days) Harrisburg: 30 (2019: 33 days) Hartford: 37 (2019: 27 days) Islip: 6 (2019: 8 days) New York City-JFK: 10 (2019: 7 days) New York City-LGA: 31 (2019: 26 days) New York City-NYC: 18 (2019: 15 days) Newark: 28 (2019: 28 days) Philadelphia: 32 (2019: 35 days) Scranton: 24 (2019: 12 days) Washington, DC: 41 (2019: 62 days) New York City-Newark Average: 22 (2019: 19 days) ...Expected: 22 (based on regression equation tied to JFK-LGA-EWR data) Tomorrow will be another warm day. At the height of the warmth early next week, readings could approach or reach 90° in much of the region. However, the month could end on a cool note before temperatures return to above normal levels during the first week of September. In addition, the remnants of Laura could exit off the Middle Atlantic coast late next week. The current predominantly warmer than normal pattern will likely persist through much of September, paving the way for a solidly warmer than normal summer and a warm start to fall throughout the region. Occasional short-lived cool shots remain possible. Parts of the West continued to experience near record to record warmth. Select high temperatures included: Death Valley, CA: 121° Denver: 97° Flagstaff: 90° (old record: 88°, 1938) Las Vegas: 105° Needles, CA: 111° Phoenix: 106° Pueblo, CO: 103° (old record: 100°, 2003 and 2013) ***hottest so late in the season*** At Death Valley, the temperature topped out at 120°. That was also the 9th consecutive day on which the temperature reached 120° or above. That is the longest August stretch since August 6-17, 2012 when the mercury reached 120° or above on 12 consecutive days. Phoenix has an implied near 100% probability of having its warmest summer on record. Phoenix will likely finish with a summer mean temperature of 96.6° - 97.0°. The existing record is 95.1°, which was set in summer 2013 and tied in summer 2015. July 2020 was Phoenix's warmest month on record with a mean temperature of 98.9°. August 2020 could approach or exceed that figure. There is currently an implied 56% probability that August will exceed July's monthly record. As recently, as 2000, the 30-year average summer minimum temperature in Phoenix was 79.8°. The last time Phoenix had an average summer minimum temperature below 80.0° was 1998 when the average minimum temperature was 79.7°. The first time Phoenix recorded an average summer mean temperature of 80° or above was in 1977 when the average low temperature was 81.5°. Records go back to August 1895. The ENSO Region 1+2 anomaly was -0.9°C and the Region 3.4 anomaly was -0.5°C for the week centered around August 12. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.17°C and the ENSO Region 3.4 anomaly has averaged -0.45°C. Neutral-cool conditions will likely into the start of autumn. During the autumn, La Niña conditions will likely develop. The SOI was +9.53. Today, the preliminary Arctic Oscillation (AO) figure was -0.397. On August 21, the MJO was in Phase 1 at an amplitude of 1.533 (RMM). The August 20-adjusted amplitude was 1.572. The MJO's recent passage through Phase 8 at an amplitude of 1.500 or above has been fairly uncommon during the August 10-25 timeframe. During the 1981-2019 period only 2002 and 2004 saw the MJO move through Phase 8 with an amplitude of 1.500 or above during this period. Both cases were followed by a warmer than normal September. Last year, the MJO went through a very strong passage through Phase 1 during the closing days of May. About four weeks later, a warmer than normal pattern locked in and predominated through early autumn. This year, the MJO was in Phase 1 for 3 consecutive days with an amplitude of 1.500 or above during the June 1-3 period. Last year, the SOI fell to -42.04 on June 22 when the MJO was in Phase 6. This year, the SOI plunged below -46.68 on June 5, its lowest level in more than three years. The dramatic plunge in the SOI could be the proverbial spark that kicks off a sequence of events leading to the development of a sustained warmer than normal period. The cases that saw both the MJO and SOI thresholds satisfied generally saw 10-20 days where the temperature reached or exceeded 90° in New York City during the July 1-August 31 period. Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September. 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. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. Based on sensitivity analysis applied to the latest guidance, there is an implied 88% probability that New York City will have a warmer than normal August. August will likely finish with a mean temperature near 76.9°. Finally, on August 21, Arctic sea ice extent was 4.386 million square kilometers (JAXA). There is an implied 86% probability that Arctic sea ice extent will reach a minimum figure below 4.000 million square kilometers for the second consecutive year and third time on record. The highest 25% bound is 3.870 million square kilometers. The lowest 25% bound is 3.460 million square kilometers.

Unfortunately, based on 2010-19 melt rates, it is very likely that 2020 will finish solidly with the second lowest minimum extent on record. It will also be the second consecutive year with a minimum extent below 4 million square kilometers and third such year on record.

Temperatures topped out mainly in the lower 80s across the region today. Tomorrow will see noticeably warmer weather begin to overspread the region. At the height of the warmth, readings could approach or reach 90° in much of the region early next week. However, the month could end on a cool note before temperatures recover to above normal levels. The current predominantly warmer than normal pattern will likely persist through much of September, paving the way for a solidly warmer than normal summer and a warm start to fall throughout the region. Occasional short-lived cool shots remain possible. Although cooler readings prevailed in the Southwest today, Las Vegas reached 111°. That surpassed the daily record of 110°, which was set in 2009. At Death Valley, the temperature topped out at 124°. That surpassed the prior daily record of 122°, which was set in 1992. Today was also the 8th consecutive day on which the temperature reached 120° or above. That is the longest August stretch since August 6-17, 2012 when the mercury reached 120° or above on 12 consecutive days. Phoenix has an implied near 100% probability of having its warmest summer on record. Phoenix will likely finish with a summer mean temperature of 96.5° - 96.9°. The existing record is 95.1°, which was set in summer 2013 and tied in summer 2015. July 2020 was Phoenix's warmest month on record with a mean temperature of 98.9°. August 2020 could approach or exceed that figure. Since recordkeeping began in August 1895, two years saw both July and August rank among Phoenix's 20 warmest months on record: 2007 and 2019. It is all but certain that 2020 will become the third such case. The ENSO Region 1+2 anomaly was -0.9°C and the Region 3.4 anomaly was -0.5°C for the week centered around August 12. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.17°C and the ENSO Region 3.4 anomaly has averaged -0.45°C. Neutral-cool conditions will likely into the start of autumn. During the autumn, La Niña conditions will likely develop. The SOI was +23.79. Today, the preliminary Arctic Oscillation (AO) figure was -1.058. On August 20, the MJO was in Phase 8 at an amplitude of 1.567 (RMM). The August 19-adjusted amplitude was 1.470. The MJO's recent passage through Phase 8 at an amplitude of 1.500 or above has been fairly uncommon during the August 10-25 timeframe. During the 1981-2019 period only 2002 and 2004 saw the MJO move through Phase 8 with an amplitude of 1.500 or above during this period. Both cases were followed by a warmer than normal September. Last year, the MJO went through a very strong passage through Phase 1 during the closing days of May. About four weeks later, a warmer than normal pattern locked in and predominated through early autumn. This year, the MJO was in Phase 1 for 3 consecutive days with an amplitude of 1.500 or above during the June 1-3 period. Last year, the SOI fell to -42.04 on June 22 when the MJO was in Phase 6. This year, the SOI plunged below -46.68 on June 5, its lowest level in more than three years. The dramatic plunge in the SOI could be the proverbial spark that kicks off a sequence of events leading to the development of a sustained warmer than normal period. The cases that saw both the MJO and SOI thresholds satisfied generally saw 10-20 days where the temperature reached or exceeded 90° in New York City during the July 1-August 31 period. Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September. 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. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. Based on sensitivity analysis applied to the latest guidance, there is an implied 79% probability that New York City will have a warmer than normal August. August will likely finish with a mean temperature near 76.9°. Finally, on August 20, Arctic sea ice extent was 4.485 million square kilometers (JAXA). Recent days have seen an increase in the melt rate. There is an implied 81% probability that Arctic sea ice extent will reach a minimum figure below 4.000 million square kilometers for the second consecutive year and third time on record. The highest 25% bound is 3.938 million square kilometers. The lowest 25% bound is 3.503 million square kilometers.

Yes. It was 46 at MPO. It has been dry in the Southwest. However, Phoenix was hit by heavy thunderstorms last night with 0.90” rain.

The coolest temperatures since mid-June covered many parts of the area. Low temperatures included: Albany: 48° (coolest since June 14: 43°) Allentown: 54° (coolest since June 17: 53°) Boston: 61° (coolest since July 17: 59°) Bridgeport: 61° (coolest since June 17: 58°) Islip: 60° (coolest since June 17: 56°) New York City: 62° (coolest since June 17: 60°) Newark: 61° (coolest since June 17: 60°) Philadelphia: 64° (coolest since August 17: 63°) Poughkeepsie: 50° (coolest since June 16: 49°) Noticeably warmer weather will likely arrive this weekend. Readings could approach or reach 90° in much of the region early next week. Temperatures remained warmer than normal in many parts of the Southwest, even as temperatures backed off their recent extreme levels. Select high temperatures included: Death Valley, CA: 122° Flagstaff: 89° Kingman, AZ: 107° (tied record set in 1915) Lake Havasu City, AZ: 115° Las Vegas: 112° (old record: 110°, 1950) Mesa, AZ: 109° Needles, CA: 118° Palm Springs, CA: 109° Phoenix: 112° Stockton, CA: 97° Tucson: 107° Yuma, AZ: 107° Phoenix has an implied 99% probability of having its warmest summer on record. Phoenix will likely finish with a summer mean temperature of 96.5° - 96.9°. The existing record is 95.1°, which was set in summer 2013 and tied in summer 2015. July 2020 was Phoenix's warmest month on record with a mean temperature of 98.9°. Since recordkeeping began in August 1895, two years saw both July and August rank among Phoenix's 20 warmest months on record: 2007 and 2019. It is all but certain that 2020 will become the third such case. Consistent with the forecasts related to climate change, Phoenix has been witnessing an increased number of annual days on which the temperature reaches 100° or above and on which the low temperature remains at or above 90°. For the 30-year period ending in 1999, Phoenix averaged 100.1 days per year with maximum temperatures of 100° or above and 1.1 days per year on which the minimum temperature was 90° or above. For the 30-year period ending in 2019, those increased to 109.6 days per year and 6.6 days per year respectively. The current predominantly warmer than normal pattern will likely persist through much of September, paving the way for a solidly warmer than normal summer and a warm start to fall throughout the region. Occasional short-lived cool shots remain possible. The ENSO Region 1+2 anomaly was -0.9°C and the Region 3.4 anomaly was -0.5°C for the week centered around August 12. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.17°C and the ENSO Region 3.4 anomaly has averaged -0.45°C. Neutral-cool conditions will likely into the start of autumn. During the autumn, La Niña conditions will likely develop. The SOI was +26.40. Today, the preliminary Arctic Oscillation (AO) figure was -1.330. On August 19, the MJO was in Phase 8 at an amplitude of 1.470 (RMM). The August 18-adjusted amplitude was 1.700. The MJO's recent passage through Phase 8 at an amplitude of 1.500 or above has been fairly uncommon during the August 10-25 timeframe. During the 1981-2019 period only 2002 and 2004 saw the MJO move through Phase 8 with an amplitude of 1.500 or above during this period. Both cases were followed by a warmer than normal September. Last year, the MJO went through a very strong passage through Phase 1 during the closing days of May. About four weeks later, a warmer than normal pattern locked in and predominated through early autumn. This year, the MJO was in Phase 1 for 3 consecutive days with an amplitude of 1.500 or above during the June 1-3 period. Last year, the SOI fell to -42.04 on June 22 when the MJO was in Phase 6. This year, the SOI plunged below -46.68 on June 5, its lowest level in more than three years. The dramatic plunge in the SOI could be the proverbial spark that kicks off a sequence of events leading to the development of a sustained warmer than normal period. The cases that saw both the MJO and SOI thresholds satisfied generally saw 10-20 days where the temperature reached or exceeded 90° in New York City during the July 1-August 31 period. Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September. 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. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. Based on sensitivity analysis applied to the latest guidance, there is an implied 80% probability that New York City will have a warmer than normal August. August will likely finish with a mean temperature near 77.0°.

Another short-lived cool shot is overspreading the region in the wake of the showers and thundershowers and moved across the area earlier today. Overnight, parts of the region could see their coolest readings so far this month. Noticeably warmer weather will likely arrive this weekend. Readings could approach or reach 90° in much of the region early next week. Out west, extreme heat again prevailed in the Southwest. Select high temperatures included: Blythe, CA: 116° (old record: 114°, 1973) Death Valley, CA: 125° (tied record set in 2001) Flagstaff: 89° (old record: 88°, 1928 and 1973) Kingman, AZ: 107° Lake Havasu City, AZ: 117° (old record: 116°, 2011) Las Vegas: 113° (old record: 111°, 1937 and 1992) Mesa, AZ: 112° (old record: 108°, 2019) Needles, CA: 118° (old record: 117°, 2018) Palm Springs, CA: 114° Phoenix: 115° (old record: 113°, 1986) Sacramento: 101° Stockton, CA: 105° Tucson, AZ: 111° (old record: 110°, 1915) Yuma, AZ: 112° Death Valley reached 125° or above for the fifth consecutive day. That further extended its August record streak. The previous August record of three days was set during August 11-13, 1933 and tied during August 6-8, 1998. In addition, Phoenix has now registered a record-tying four consecutive days with temperatures of 115° or above for the second time this summer. No previous year had more than one such stretch. Phoenix has an implied 98% probability of having its warmest summer on record. Phoenix will likely finish with a summer mean temperature of 96.5° - 96.9°. The existing record is 95.1°, which was set in summer 2013 and tied in summer 2015. July 2020 was Phoenix's warmest month on record with a mean temperature of 98.9°. Since recordkeeping began in August 1895, two years saw both July and August rank among Phoenix's 20 warmest months on record: 2007 and 2019. It is all but certain that 2020 will become the third such case. The current predominantly warmer than normal pattern will likely persist through much of September, paving the way for a solidly warmer than normal summer and a warm start to fall throughout the region. Occasional short-lived cool shots remain possible. The ENSO Region 1+2 anomaly was -0.9°C and the Region 3.4 anomaly was -0.5°C for the week centered around August 12. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.17°C and the ENSO Region 3.4 anomaly has averaged -0.45°C. Neutral-cool conditions will likely into the start of autumn. During the autumn, La Niña conditions will likely develop. The SOI was +28.46. That was the highest SOI figure since April 2, 2018 when the SOI was +31.29. Today, the preliminary Arctic Oscillation (AO) figure was -1.394. On August 18, the MJO was in Phase 8 at an amplitude of 1.698 (RMM). The August 17-adjusted amplitude was 1.835. The MJO's recent passage through Phase 8 at an amplitude of 1.500 or above has been fairly uncommon during the August 10-25 timeframe. During the 1981-2019 period only 2002 and 2004 saw the MJO move through Phase 8 with an amplitude of 1.500 or above during this period. Both cases were followed by a warmer than normal September. Last year, the MJO went through a very strong passage through Phase 1 during the closing days of May. About four weeks later, a warmer than normal pattern locked in and predominated through early autumn. This year, the MJO was in Phase 1 for 3 consecutive days with an amplitude of 1.500 or above during the June 1-3 period. Last year, the SOI fell to -42.04 on June 22 when the MJO was in Phase 6. This year, the SOI plunged below -46.68 on June 5, its lowest level in more than three years. The dramatic plunge in the SOI could be the proverbial spark that kicks off a sequence of events leading to the development of a sustained warmer than normal period. The cases that saw both the MJO and SOI thresholds satisfied generally saw 10-20 days where the temperature reached or exceeded 90° in New York City during the July 1-August 31 period. Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September. 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. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. Based on sensitivity analysis applied to the latest guidance, there is an implied 83% probability that New York City will have a warmer than normal August. August will likely finish with a mean temperature near 77.0°.

That is Newark’s latest 100 degree reading.

Morning thoughts... At 7:50 am, a shower was crossing the Hudson River just north of Yonkers and a thundershower was approaching Englewood. A larger area of showers and thundershowers covered an area running from northern Virginia to eastern Pennsylvania. That area as headed northeastward and will likely affect the Philadelphia, Newark and New York City areas later this morning. Sunshine should return to those areas during the afternoon. In the wake of the frontal passage, tonight will see temperatures fall into the lower 60s in New York City and 50s in many places outside the City. Out west, intense heat will again topple records in parts of California, Arizona and Nevada. Out in the eastern Atlantic, a new tropical depression could develop in over the next 24-48 hours.

July 2020 was also Phoenix’s hottest month on record by 0.6 degrees.

The region saw its coolest readings since just after mid-June this morning. During the afternoon, the temperature rebounded into the lower and middle 80s. Another brief cool shot is possible near mid-week. Noticeably warmer weather could arrive for the weekend. Out west, extreme heat again prevailed in the Southwest. Select high temperatures included: Death Valley, CA: 126° (old record: 124°, 2001) Flagstaff: 88° (old record: 87°, 1992 and 2002) Kingman, AZ: 110° (old record: 109°, 1915) Lake Havasu City, AZ: 115° Las Vegas: 114° (old record: 111°, 1992) Mesa, AZ: 111° (old record: 102°, 2019) Needles, CA: 118° (old record: 115°, 1992 and 2011) Palm Springs, CA: 114° Phoenix: 115° (old record: 112°, 2011) Sacramento: 106° Stockton, CA: 107° (tied record set in 1967) Tucson, AZ: 107° (old record: 107°, 2013) Yuma, AZ: 111° Death Valley reached 125° or above for the fourth consecutive day. That surpassed the previous August record, which was set during August 11-13, 1933 and tied during August 6-8, 1998. Intense heat will likely continue in that region into the coming weekend although the most severe heat will fade after midweek. Phoenix has an implied 97% probability of having its warmest summer on record. Phoenix will likely finish with a summer mean temperature of 96.4° - 96.8°. The existing record is 95.1°, which was set in summer 2013 and tied in summer 2015. July 2020 was Phoenix's warmest month on record with a mean temperature of 98.9°. Since recordkeeping began in August 1895, two years saw both July and August rank among Phoenix's 20 warmest months on record: 2007 and 2019. It is all but certain that 2020 will become the third such case. The current predominantly warmer than normal pattern will likely persist through much of September, paving the way for a solidly warmer than normal summer and a warm start to fall throughout the region. Occasional short-lived cool shots remain possible. The ENSO Region 1+2 anomaly was -0.9°C and the Region 3.4 anomaly was -0.5°C for the week centered around August 12. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.17°C and the ENSO Region 3.4 anomaly has averaged -0.45°C. Neutral-cool conditions will likely into the start of autumn. During the autumn, La Niña conditions will likely develop. The SOI was +10.56. Today, the preliminary Arctic Oscillation (AO) figure was -1.377. On August 17, the MJO was in Phase 8 at an amplitude of 1.837 (RMM). The August 16-adjusted amplitude was 1.632. The MJO's recent passage through Phase 4 at an amplitude of 1.500 or above has been uncommon during the first half of August. During the 1981-2019 period only 1983 and 2019 saw the MJO move through Phase 4 with an amplitude of 1.500 or above during the first half of August. August 1983 had the longest such stretch. Both cases saw the second half of August average generally warmer than normal in the Middle Atlantic region. Both cases also featured a warmer than normal September. Last year, the MJO went through a very strong passage through Phase 1 during the closing days of May. About four weeks later, a warmer than normal pattern locked in and predominated through early autumn. This year, the MJO was in Phase 1 for 3 consecutive days with an amplitude of 1.500 or above during the June 1-3 period. Last year, the SOI fell to -42.04 on June 22 when the MJO was in Phase 6. This year, the SOI plunged below -46.68 on June 5, its lowest level in more than three years. The dramatic plunge in the SOI could be the proverbial spark that kicks off a sequence of events leading to the development of a sustained warmer than normal period. The cases that saw both the MJO and SOI thresholds satisfied generally saw 10-20 days where the temperature reached or exceeded 90° in New York City during the July 1-August 31 period. Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September. 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. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. Based on sensitivity analysis applied to the latest guidance, there is an implied 79% probability that New York City will have a warmer than normal August. August will likely finish with a mean temperature near 77.0°. Finally, on August 17, Arctic sea ice extent was 4.782 million square kilometers (JAXA). There is an implied 63% probability that Arctic sea ice extent will reach a minimum figure below 4.000 million square kilometers for the second consecutive year and third time on record. The highest 25% bound is 4.129 million square kilometers. The lowest 25% bound is 3.609 million square kilometers.

I tried to take it, but received the following message: This survey is now closed, but the Haz Simp team will still be accepting comments on the proposal via email ([email protected]) through August 21, 2020. Thank you for your interest!

Morning thoughts... It was another cool morning in parts of the region. At New York City, the temperature fell to 63 degrees, its coolest figure since June 17 when the temperature fell to 60 degrees. At Newark, the temperature fell to 63 degrees. The last time it was at least as cool there was on June 17 when the temperature dropped to 60 degrees. Under bright sunshine, temperatures will rebound to the lower and even middle 80s. After another short mid-week cool shot, noticeably warmer conditions will likely develop for the coming weekend. Out west, intense heat will again topple records in parts of California, Arizona and Nevada. Out in the eastern Atlantic, a new tropical depression could develop in coming days.

From this evening as a thunderstorm passed to the north of Larchmont. The Village received a downpour, but only a few drops fell right at the Long Island Sound.

The region saw its coolest readings since just after mid-June this morning. However, under sunshine, the temperature rebounded into the upper 70s and lower 80s. The day ended with scattered thunderstorms. Another brief cool shot is possible near mid-week before a more prolonged warming trend takes hold. Out west, extreme heat again prevailed in the Southwest. Select high temperatures included: Bishop, CA: 105° Blythe, CA: 117° (old record: 116°, 1950 and 1992) Death Valley, CA: 127° (old record: 125°, 1994) Flagstaff: 91° (old record: 88°, 2002) Kingman, AZ: 108° (old record: 106°, 2001) Lake Havasu City, AZ: 115° Las Vegas: 112° (old record: 111°, 1939) Mesa, AZ: 113° (old record: 106°, 2019) Needles, CA: 117° (tied record set in 1892) Palm Springs, CA: 114° Phoenix: 115° (old record: 114°, 2013) Sacramento: 105° Stockton, CA: 109° (old record: 106°, 1967) Tucson, AZ: 109° (old record: 108°, 2013) Yuma, AZ: 114° (tied record set in 1892 and tied in 1953 and 1992) Death Valley reached 125° or above for the third consecutive day. That ties the August record, which was set during August 11-13, 1933 and tied during August 6-8, 1998. Intense heat will likely continue in that region into the coming weekend although the most severe heat will fade after midweek. Phoenix has an implied 96% probability of having its warmest summer on record. Phoenix will likely finish with a summer mean temperature of 96.3° - 96.7°. The existing record is 95.1°, which was set in summer 2013 and tied in summer 2015. July 2020 was Phoenix's warmest month on record with a mean temperature of 98.9°. The current predominantly warmer than normal pattern will likely persist through much of September, paving the way for a solidly warmer than normal summer and a warm start to fall throughout the region. Occasional short-lived cool shots remain possible. The ENSO Region 1+2 anomaly was -0.9°C and the Region 3.4 anomaly was -0.5°C for the week centered around August 12. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.17°C and the ENSO Region 3.4 anomaly has averaged -0.45°C. Neutral-cool conditions will likely into the start of autumn. During the autumn, La Niña conditions will likely develop. The SOI was -3.52. Today, the preliminary Arctic Oscillation (AO) figure was -0.917. On August 16, the MJO was in Phase 8 at an amplitude of 1.635 (RMM). The August 15-adjusted amplitude was 1.367. The MJO's recent passage through Phase 4 at an amplitude of 1.500 or above has been uncommon during the first half of August. During the 1981-2019 period only 1983 and 2019 saw the MJO move through Phase 4 with an amplitude of 1.500 or above during the first half of August. August 1983 had the longest such stretch. Both cases saw the second half of August average generally warmer than normal in the Middle Atlantic region. Both cases also featured a warmer than normal September. Last year, the MJO went through a very strong passage through Phase 1 during the closing days of May. About four weeks later, a warmer than normal pattern locked in and predominated through early autumn. This year, the MJO was in Phase 1 for 3 consecutive days with an amplitude of 1.500 or above during the June 1-3 period. Last year, the SOI fell to -42.04 on June 22 when the MJO was in Phase 6. This year, the SOI plunged below -46.68 on June 5, its lowest level in more than three years. The dramatic plunge in the SOI could be the proverbial spark that kicks off a sequence of events leading to the development of a sustained warmer than normal period. The cases that saw both the MJO and SOI thresholds satisfied generally saw 10-20 days where the temperature reached or exceeded 90° in New York City during the July 1-August 31 period. Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September. 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. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. Based on sensitivity analysis applied to the latest guidance, there is an implied 74% probability that New York City will have a warmer than normal August. August will likely finish with a mean temperature near 77.0°.

Yes, LaGuardia's record-breaking 44-day streak (July 3 through August 15) during which the temperature remained at or above 70 degrees or above ended. The previous record was 34 days, which was set July 8 through August 10, 2006. Islip had a high temperature of 69 degrees yesterday and White Plains only reached 68. Rainfall totals were not impressive around the area.

At White Plains, the temperature fell to 59 degrees this morning. That ended the 58-day stretch (June 20 through August 16) during which the minimum temperature was 60 degrees or above. The old record of 53 days was set during June 27 through August 18 in 2012.

Morning thoughts... In the wake of yesterday’s rainfall, the temperature fell to the coolest levels since near mid-June in parts of the region. At New York City, the temperature fell to 64 degrees, its coolest figure since June 17 when the temperature fell to 60 degrees. At Newark, the temperature fell to 64 degrees. The last time it was at least as cool there was on June 18 when the temperature dropped to 64 degrees. After a cool start, temperatures will reach the upper 70s and lower 80s across the region today. Parts of the region could see some thunderstorms during the afternoon or evening hours. Out west, intense heat will again topple records in parts of California, Arizona and Nevada. Death Valley reached 130 degrees yesterday. That smashed the August monthly record of 127 degrees, which was set on August 12, 1933 and tied on August 3, 1993 and August 1, 2017. That was also Death Valley’s hottest temperature since July 13, 1913 when the mercury reached 131 degrees. However, there are questions about the accuracy of the July 1913 temperatures, which were far above what would have been expected from temperatures reported on the same dates elsewhere in the region. https://www.wunderground.com/blog/weatherhistorian/an-investigation-of-death-valleys-134f-world-temperature-record.html Unlike in July 1913, many areas in the Southwest recorded daily and even monthly record high temperatures. One location recorded an all-time high temperature. In short, yesterday’s 130-degree temperature could have become the world’s highest reliably recorded temperature on record. In addition, Phoenix reached 115 degrees. That was the 8th time this year that Phoenix reached 115 degrees or above. The prior record was 7 times in 1974.

Parts of the region experienced a soaking rainfall today with temperatures topping out mainly in the lower 70s. At New York City, the high temperature was 72°. The last time August had a maximum temperature of 72° or below was August 19, 2018 when the temperature also reached 72°. Rainfall amounts included: Baltimore: 1.06" Islip: 0.58" New York City: 0.21" Newark: 0.14" Philadelphia: 0.63" Poughkeepsie: 0.12" Washington, DC: 1.03" Wilmington, DE: 1.04" Out west, extreme heat again prevailed in the Southwest. Select high temperatures included: Bishop, CA: 108° (old record: 106°, 1994) Death Valley, CA: 128° (old record: 124°, 1994 and 2002) ***New August Record*** Everett, WA: 99° (old record: 87°, 2010 and 2012) ***New August Record*** Flagstaff: 93° (old record: 89°, 1939) ***Tied August Record*** Kingman, AZ: 109° Lake Havasu City, AZ: 117° Las Vegas: 113° (tied record set in 1939) Lemoore, CA: 120° (old record: 109°, 1967) ***New All-Time Record*** Mesa, AZ: 113° (old record: 108°, 2019) Modesto, CA: 111° (old record: 104, 1992, 2015 and 2019) ***New August Record*** Needles, CA: 117° Palm Springs, CA: 114° Phoenix: 115° (old record: 113°, 1992 and 2013) Sacramento: 112° (old record: 106°, 1992 and 2015) ***New August Record*** Seattle: 97° Stockton, CA: 113° (old record: 106°, 1983) ***New August Record*** Tucson: 110° (old record: 108° 1992 and 2013) Yuma, AZ: 113° Death Valley reached 125° or above for the second consecutive day. The last time that happened in August was August 9-10, 2012. Final figures should be available for Death Valley and Lake Havasu City tomorrow. More intense heat is likely in that region through midweek. Phoenix has an implied 93% probability of having its warmest summer on record. Phoenix will likely finish with a summer mean temperature of 96.2° - 96.6°. The existing record is 95.1°, which was set in summer 2013 and tied in summer 2015. July 2020 was Phoenix's warmest month on record with a mean temperature of 98.9°. Today was also Phoenix's 40th day on which the temperature reached 110° or above. The old record was 33 days, which was set in 2011. Following the storm, readings will warm up tomorrow and Tuesday. The current predominantly warmer than normal pattern will likely persist through much of September, paving the way for a solidly warmer than normal summer and a warm start to fall throughout the region. Occasional short-lived cool shots remain possible. The ENSO Region 1+2 anomaly was -1.2°C and the Region 3.4 anomaly was -0.6°C for the week centered around August 5. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.15°C and the ENSO Region 3.4 anomaly has averaged -0.37°C. Neutral-cool conditions will likely into the start of autumn. During the autumn, La Niña conditions will likely develop. The SOI was +5.46. Today, the preliminary Arctic Oscillation (AO) figure was -0.449. On August 15, the MJO was in Phase 8 at an amplitude of 1.363 (RMM). The August 14-adjusted amplitude was 0.836. The MJO's recent passage through Phase 4 at an amplitude of 1.500 or above has been uncommon during the first half of August. During the 1981-2019 period only 1983 and 2019 saw the MJO move through Phase 4 with an amplitude of 1.500 or above during the first half of August. August 1983 had the longest such stretch. Both cases saw the second half of August average generally warmer than normal in the Middle Atlantic region. Both cases also featured a warmer than normal September. Last year, the MJO went through a very strong passage through Phase 1 during the closing days of May. About four weeks later, a warmer than normal pattern locked in and predominated through early autumn. This year, the MJO was in Phase 1 for 3 consecutive days with an amplitude of 1.500 or above during the June 1-3 period. Last year, the SOI fell to -42.04 on June 22 when the MJO was in Phase 6. This year, the SOI plunged below -46.68 on June 5, its lowest level in more than three years. The dramatic plunge in the SOI could be the proverbial spark that kicks off a sequence of events leading to the development of a sustained warmer than normal period. The cases that saw both the MJO and SOI thresholds satisfied generally saw 10-20 days where the temperature reached or exceeded 90° in New York City during the July 1-August 31 period. Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September. 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. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. 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 August. August will likely finish with a mean temperature near 77.0°.

Yes. Central Park had an 80.0 mean temperature.

Four photos of the leaf burn following Tropical Storm Isiais (Larchmont, NY):

I agree.

At 12 pm, the temperature at LaGuardia Airport was 69°. That ended LaGuardia's record-breaking 44-day streak (July 3 through August 15) during which the temperature remained at or above 70°. The previous record was 34 days, which was set July 8 through August 10, 2006.