donsutherland1

Heat will begin to rebuild across the region starting tomorrow. The potential exists for parts of the region to experience their warmest readings this summer early next week. 90° Days for Select Cities (through July 24): Albany: 12 (2019: 12 days) Allentown: 13 (2019: 24 days) Baltimore: 29 (2019: 59 days) Boston: 5 (2019: 15 days) Burlington: 15 (2019: 8 days) Harrisburg: 19 (2019: 33 days) Islip: 3 (2019: 8 days) New York City-JFK: 7 (2019: 7 days) New York City-LGA: 18 (2019: 26 days) New York City-NYC: 11 (2019: 15 days) Newark: 16 (2019: 28 days) Philadelphia: 21 (2019: 35 days) Washington, DC: 31 (2019: 62 days) New York City-Newark Average: 13 (2019: 19 days) ...Expected: 13 (based on regression equation tied to JFK-LGA-EWR data) The current predominantly warmer than normal pattern will likely persist through at least August, paving the way for a solidly warmer than normal summer throughout the region. Occasional short-lived cool shots remain possible. One or more heatwaves are likely in July across the region, including New York City. The ENSO Region 1+2 anomaly was -1.5°C and the Region 3.4 anomaly was -0.2°C for the week centered around July 15. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.92°C and the ENSO Region 3.4 anomaly has averaged -0.22°C. Neutral-cool conditions will likely into the start of autumn. During the autumn, La Niña conditions could develop. The SOI was +20.74. Today, the preliminary Arctic Oscillation (AO) figure was -0.237. On July 23, the MJO was in Phase 2 at an amplitude of 1.913 (RMM). The July 22-adjusted amplitude was 1.820. The MJO has been in either Phase 1 or Phase 2 for 54 consecutive days. 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. 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 July. July will likely finish with a mean temperature near 79.8°. The probability of an 80° mean temperature in July remains near 50%.

Aside from a possible 100 degree reading at LGA, I don’t think either JFK or NYC will reach 100. Middle and upper 90s seems more likely there.

LGA will likely have an 80 degree average. Central Park has been at a near 50% probability. A lot will depend on the intensity of the coming heat for the Sunday-Tuesday period. I suspect that there will be an 80 degree minimum temperature during that period, possibly Monday.

Showers moved through the Bronx this morning. They blew up into strong thunderstorms as they pressed southward. The afternoon was mainly cloudy with temperatures in the 70s. The New York Botanical Garden reopened on July 21. The Conservatory is closed. Dining is limited to outdoor dining. Paths are marked with arrows to promote social distancing. Nevertheless, a number of people took off their masks to sniff the sunflowers. Below are some of the flowers at the Garden:

Absolutely. Such costs will likely continue to rise, as sea-level rise flooding from melting ice in Greenland and Antarctica is continuing to increase. The NOAA’s most recent report: https://tidesandcurrents.noaa.gov/publications/Techrpt_092_2019_State_of_US_High_Tide_Flooding_with_a_2020_Outlook_30June2020.pdf

Overnight, parts of the region will see some showers and thundershowers. Tomorrow will be similar to today with clouds, some sunshine, and additional showers and thundershowers. This weekend, heat will rebuild across the area. The potential exists for early next week to see the warmest readings this summer in parts of the region. The current predominantly warmer than normal pattern will likely persist through at least August, paving the way for a solidly warmer than normal summer throughout the region. Occasional short-lived cool shots remain possible. One or more heatwaves are likely in July across the region, including New York City. The ENSO Region 1+2 anomaly was -1.5°C and the Region 3.4 anomaly was -0.2°C for the week centered around July 15. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.92°C and the ENSO Region 3.4 anomaly has averaged -0.22°C. Neutral-cool conditions will likely into the start of autumn. During the autumn, La Niña conditions could develop. The SOI was +16.00. Today, the preliminary Arctic Oscillation (AO) figure was -0.829. On July 22, the MJO was in Phase 2 at an amplitude of 1.820 (RMM). The July 21-adjusted amplitude was 1.608. The MJO has been in either Phase 1 or Phase 2 for 53 consecutive days. 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. 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 July. July will likely finish with a mean temperature near 79.8°. The probability of an 80° mean temperature in July remains near 50%.

This afternoon, the temperature reached 92° in Central Park. That was the fifth consecutive 90° or warmer day in Central Park, which is the longest heat wave there since August 11-15, 2016 when the mercury also reached 90° or above on five consecutive days. Strong thunderstorms moved through parts of area this evening. The current predominantly warmer than normal pattern will likely persist through at least August, paving the way for a solidly warmer than normal summer throughout the region. Occasional short-lived cool shots remain possible. One or more heatwaves are likely in July across the region, including New York City. The ENSO Region 1+2 anomaly was -1.5°C and the Region 3.4 anomaly was -0.2°C for the week centered around July 15. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.92°C and the ENSO Region 3.4 anomaly has averaged -0.22°C. Neutral-cool conditions will likely prevail through mid-summer. The probability of the development of a La Niña event during late summer or early autumn has increased in recent weeks. The last time the six-week moving average for ENSO Region 1+2 was as cold as the current figure during July or August occurred in 2013. Winter 2013-14 had neutral-cool ENSO conditions. January and February featured ENSO Region 3.4 anomalies that were -0.50°C or below. The SOI was +13.54. Today, the preliminary Arctic Oscillation (AO) figure was -0.506. On July 21, the MJO was in Phase 1 at an amplitude of 1.615 (RMM). The July 20-adjusted amplitude was 1.469. The MJO has been in either Phase 1 or Phase 2 for 52 consecutive days. 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. Based on sensitivity analysis applied to the latest guidance, there is an implied 97% probability that New York City will have a warmer than normal July. July will likely finish with a mean temperature near 79.8°. The probability of an 80° mean temperature in July has increased in recent days to near 50%.

For about a week, that site also had not updated. So far, at least as far as NYC is concerned, the NBE has been running about 3 degrees warmer than the MEX for high temperatures and about a degree warmer than the MEX for low temperatures. For today, the MEX showed a maximum temperature of 88 at NYC while the NBE had 91.

Today was another very warm day with highs again reaching the 90s in many parts of the region. However, readings in the northern Middle Atlantic region and southern New England area were somewhat cooler than those of yesterday. Tomorrow will likely be a similar day. Some locations could pick up a shower or even thundershower. The current predominantly warmer than normal pattern will likely persist through at least August, paving the way for a solidly warmer than normal summer throughout the region. Occasional short-lived cool shots remain possible. One or more heatwaves are likely in July across the region, including New York City. The ENSO Region 1+2 anomaly was -1.5°C and the Region 3.4 anomaly was -0.2°C for the week centered around July 15. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.92°C and the ENSO Region 3.4 anomaly has averaged -0.22°C. Neutral-cool conditions will likely prevail through mid-summer. The probability of the development of a La Niña event during late summer or early autumn has increased in recent weeks. The last time the six-week moving average for ENSO Region 1+2 was as cold as the current figure during July or August occurred in 2013. Winter 2013-14 had neutral-cool ENSO conditions. January and February featured ENSO Region 3.4 anomalies that were -0.50°C or below. The SOI was +14.71. Today, the preliminary Arctic Oscillation (AO) figure was -0.370. On July 20, the MJO was in Phase 1 at an amplitude of 1.469 (RMM). The July 19-adjusted amplitude was 1.327. The MJO has been in either Phase 1 or Phase 2 for 51 consecutive days. 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. Based on sensitivity analysis applied to the latest guidance, there is an implied 96% probability that New York City will have a warmer than normal July. July will likely finish with a mean temperature near 79.8°. The probability of an 80° mean temperature in July has increased in recent days to near 50%.

Today was another scorcher in many parts of the region. High temperatures included: Allentown: 93° Baltimore: 100° Boston: 93° Burlington: 91° Harrisburg: 98° Hartford: 96° Islip: 93 New York City-JFK: 96° New York City-LGA: 97° (morning low temperature: 84°) New York City-NYC: 93° Newark: 96° Philadelphia: 96° Washington, DC: 99° With its third consecutive 90° day, New York City's Central Park recorded its first heat wave of summer 2020. 90° Days for Select Cities (through July 20): Albany: 12 (2019: 12 days) Allentown: 11 (2019: 24 days) Baltimore: 26 (2019: 59 days) Boston: 4 (2019: 15 days) Burlington: 15 (2019: 8 days) Harrisburg: 16 (2019: 33 days) Islip: 2 (2019: 8 days) New York City-JFK: 5 (2019: 7 days) New York City-LGA: 15 (2019: 26 days) New York City-NYC: 9 (2019: 15 days) Newark: 13 (2019: 27 days) Philadelphia: 18 (2019: 35 days) Washington, DC: 28 (2019: 62 days) New York City-Newark Average: 11 (2019: 19 days) ...Expected: 10 (based on regression equation tied to JFK-LGA-EWR data) Starting tomorrow, the excessive heat will begin to ease. Nevertheless, warmer than normal conditions will persist. The current predominantly warmer than normal pattern will likely persist through at least August, paving the way for a solidly warmer than normal summer throughout the region. Occasional short-lived cool shots remain possible. One or more heatwaves are likely in July across the region, including New York City. The ENSO Region 1+2 anomaly was -1.5°C and the Region 3.4 anomaly was -0.2°C for the week centered around July 15. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.92°C and the ENSO Region 3.4 anomaly has averaged -0.22°C. Neutral-cool conditions will likely prevail through mid-summer. The probability of the development of a La Niña event during late summer or early autumn has increased in recent weeks. The last time the six-week moving average for ENSO Region 1+2 was as cold as the current figure during July or August occurred in 2013. Winter 2013-14 had neutral-cool ENSO conditions. January and February featured ENSO Region 3.4 anomalies that were -0.50°C or below. The SOI was +4.12. Today, the preliminary Arctic Oscillation (AO) figure was -0.962. On July 19, the MJO was in Phase 1 at an amplitude of 1.327 (RMM). The July 18-adjusted amplitude was 1.224. The MJO has been in either Phase 1 or Phase 2 for 50 consecutive days. 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. Based on sensitivity analysis applied to the latest guidance, there is an implied 93% probability that New York City will have a warmer than normal July. July will likely finish with a mean temperature near 79.7°. The probability of an 80° mean temperature in July has increased in recent days to just under 50%.

In parts of the region, today was the hottest day so far this season. High temperatures included: Albany: 93° Baltimore: 100° Boston: 95° Burlington: 95° Harrisburg: 100° Hartford: 99° New York City: 94° Newark: 96° Philadelphia: 95° Washington, DC: 99° 90° Days for Select Cities (through July 19): Albany: 11 (2019: 12 days) Allentown: 10 (2019: 24 days) Baltimore: 25 (2019: 59 days) Boston: 3 (2019: 15 days) Burlington: 14 (2019: 8 days) Harrisburg: 15 (2019: 33 days) Islip: 1 (2019: 8 days) New York City-JFK: 4 (2019: 7 days) New York City-LGA: 14 (2019: 26 days) New York City-NYC: 8 (2019: 15 days) Newark: 12 (2019: 27 days) Philadelphia: 17 (2019: 35 days) Washington, DC: 27 (2019: 62 days) New York City-Newark Average: 10 (2019: 19 days) ...Expected: 9 (based on regression equation tied to JFK-LGA-EWR data) Tomorrow will again see temperatures reach the middle and upper 90s in parts of the region. Areas running from central Pennsylvania to Washington, DC could again see the temperature reach or even exceed 100° in some locations. Afterward, the excessive heat will ease, but warmer than normal conditions will persist. The current predominantly warmer than normal pattern will likely persist through at least August, paving the way for a solidly warmer than normal summer throughout the region. Occasional short-lived cool shots remain possible. One or more heatwaves are likely in July across the region, including New York City. The ENSO Region 1+2 anomaly was -0.8°C and the Region 3.4 anomaly was -0.1°C for the week centered around July 8. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.72°C and the ENSO Region 3.4 anomaly has averaged -0.25°C. Neutral-cool conditions will likely prevail through mid-summer. The probability of the development of a La Niña event during late summer or early autumn has increased in recent weeks. The last time the six-week moving average for ENSO Region 1+2 was as cold as the current figure during July or August occurred in 2013. Winter 2013-14 had neutral-cool ENSO conditions. January and February featured ENSO Region 3.4 anomalies that were -0.50°C or below. The SOI was -1.79. Today, the preliminary Arctic Oscillation (AO) figure was -1.103. On July 18, the MJO was in Phase 1at an amplitude of 1.231 (RMM). The July 17-adjusted amplitude was 1.073. The MJO has been in either Phase 1 or Phase 2 for 49 consecutive days. 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. Based on sensitivity analysis applied to the latest guidance, there is an implied 89% probability that New York City will have a warmer than normal July. July will likely finish with a mean temperature near 79.5°. Finally, on July 18, Arctic sea ice extent was 6.551 million square kilometers (JAXA). That was the lowest figure on record for July 18. The previous record was 7.059 million square kilometers, which was set in 2011.

Through 2 pm, Baltimore’s high temperature today is 100 degrees. The daily record is 103 degrees, which was set in 1930.

The temperature soared into the 90s across much of the region today. The South Shore of Long Island and Connecticut were exceptions. Tomorrow will be even hotter. Temperatures will likely approach or exceed 100° in the Baltimore-Washington region. 90° Days for Select Cities (through July 18): Albany: 10 (2019: 12 days) Allentown: 9 (2019: 24 days) Baltimore: 24 (2019: 59 days) Boston: 2 (2019: 15 days) Burlington: 13 (2019: 8 days) Harrisburg: 14 (2019: 33 days) Islip: 1 (2019: 8 days) New York City-JFK: 4 (2019: 7 days) New York City-LGA: 13 (2019: 26 days) New York City-NYC: 7 (2019: 15 days) Newark: 11 (2019: 27 days) Philadelphia: 16 (2019: 35 days) Washington, DC: 26 (2019: 62 days) New York City-Newark Average: 9 (2019: 19 days) ...Expected: 9 (based on regression equation tied to JFK-LGA-EWR data) The current predominantly warmer than normal pattern will likely persist through at least August, paving the way for a solidly warmer than normal summer throughout the region. Occasional short-lived cool shots remain possible. One or more heatwaves are likely in July across the region, including New York City. The ENSO Region 1+2 anomaly was -0.8°C and the Region 3.4 anomaly was -0.1°C for the week centered around July 8. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.72°C and the ENSO Region 3.4 anomaly has averaged -0.25°C. Neutral-cool conditions will likely prevail through mid-summer. The probability of the development of a La Niña event during late summer or early autumn has increased in recent weeks. The last time the six-week moving average for ENSO Region 1+2 was as cold as the current figure during July or August occurred in 2013. Winter 2013-14 had neutral-cool ENSO conditions. January and February featured ENSO Region 3.4 anomalies that were -0.50°C or below. The SOI was -2.65. Today, the preliminary Arctic Oscillation (AO) figure was -0.835. On July 17, the MJO was in Phase 2 at an amplitude of 1.078 (RMM). The July 16-adjusted amplitude was 1.181. The MJO has been in either Phase 1 or Phase 2 for 48 consecutive days. 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. Based on sensitivity analysis applied to the latest guidance, there is an implied 84% probability that New York City will have a warmer than normal July. July will likely finish with a mean temperature near 79.4°.

A widespread heat wave will be overspreading the region starting this weekend. Parts of the Baltimore-Washington, which saw readings top out at 98° in Baltimore today, could see temperatures approach or exceed 100° at the peak of the heat wave. The current predominantly warmer than normal pattern will likely persist through at least August, paving the way for a solidly warmer than normal summer throughout the region. Occasional short-lived cool shots remain possible. One or more heatwaves are likely in July across the region, including New York City. The ENSO Region 1+2 anomaly was -0.8°C and the Region 3.4 anomaly was -0.1°C for the week centered around July 8. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.72°C and the ENSO Region 3.4 anomaly has averaged -0.25°C. Neutral-cool conditions will likely prevail through mid-summer. The probability of the development of a La Niña event during late summer or early autumn has increased in recent weeks. The last time the six-week moving average for ENSO Region 1+2 was as cold as the current figure during July or August occurred in 2013. Winter 2013-14 had neutral-cool ENSO conditions. January and February featured ENSO Region 3.4 anomalies that were -0.50°C or below. The SOI was +5.91. Today, the preliminary Arctic Oscillation (AO) figure was -0.505. On July 16, the MJO was in Phase 2 at an amplitude of 1.178 (RMM). The July 15-adjusted amplitude was 1.250. The MJO has been in either Phase 1 or Phase 2 for 47 consecutive days. 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. 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 July. July will likely finish with a mean temperature near 79.4°.

Three warmest 4-Site Averages (JFK-LGA-NYC-EWR) for June-August: 1. 78.3, 2010 2. 77.4, 2016 3. 77.0, 2005

Yes. The data has been more stable. I will check out the summer data on Friday.

Cooler weather prevailed for another day in the Mid-Atlantic region. Temperatures will begin to rise tomorrow. A widespread heat wave could overspread the region starting this weekend. Parts of the Baltimore-Washington could see temperatures approach or reach 100° at the peak of the heat wave. With a high temperature of 87°, Washington, DC's 20-day heat wave came to an end. That was the second longest heat wave on record. Only July 25-August 14, 1980 and July 29-August 18, 1988 saw longer heat waves of 21-day durations. The current predominantly warmer than normal pattern will likely persist through at least August, paving the way for a solidly warmer than normal summer throughout the region. Occasional short-lived cool shots remain possible. One or more heatwaves are likely in July across the region, including New York City. The ENSO Region 1+2 anomaly was -0.8°C and the Region 3.4 anomaly was -0.1°C for the week centered around July 8. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.72°C and the ENSO Region 3.4 anomaly has averaged -0.25°C. Neutral-cool conditions will likely prevail through mid-summer. The probability of the development of a La Niña event during late summer or early autumn has increased in recent weeks. The last time the six-week moving average for ENSO Region 1+2 was as cold as the current figure during July or August occurred in 2013. Winter 2013-14 had neutral-cool ENSO conditions. January and February featured ENSO Region 3.4 anomalies that were -0.50°C or below. The SOI was -8.56. Today, the preliminary Arctic Oscillation (AO) figure was -0.489. On July 15, the MJO was in Phase 2 at an amplitude of 1.248 (RMM). The July 14-adjusted amplitude was 1.574. The MJO has been in either Phase 1 or Phase 2 for 46 consecutive days. 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. Based on sensitivity analysis applied to the latest guidance, there is an implied 82% probability that New York City will have a warmer than normal July. July will likely finish with a mean temperature near 79.3°. Finally, on July 15, Arctic sea ice extent fell to 6.996 million square kilometers (JAXA). That is the earliest date on record on which Arctic sea ice extent was less than 7.000 million square kilometers. The previous mark was July 19, 2011.

For all its issues, I believe a four-city composite makes the most sense. JFK's susceptibility to sea breezes is much greater than that for the other three cities.

Washington missed today.

Arctic sea ice extent fell to 6.996 million square kilometers (JAXA) today. The previous earliest figure below 7 million square kilometers was July 19, 2011 when extent was 6.995 million square kilometers.

From the World Weather Attribution Project: The current Siberian heat has contributed to raising the world’s average temperature to the 2nd hottest on record for the period January to May. Using published scientific methods we looked at a large region spanning most of Siberia, inclusive of the area affected by the prolonged six-month heat and the town of Verkhoyansk that recorded the record daily temperature for the Arctic region. We analysed the average temperatures between January and June 2020 for the large region, as well as the hottest maximum daily temperature in June 2020 for Verkhoyansk. We found in both cases that this event would have effectively been impossible without human-induced climate change. https://www.worldweatherattribution.org/siberian-heatwave-of-2020-almost-impossible-without-climate-change/

Cooler weather prevailed in the northern Mid-Atlantic region and another similar day lies ahead for tomorrow. Afterward, tempertures will rise. A widespread heat wave could overspread the region starting this weekend. With a high temperature of 91°, Washington, DC registered its 20th consecutive day on which the temperature reached 90° or above. That is Washington's longest heat wave since July 29-August 18, 1988 when the temperature reached 90° or above on 21 consecutive days. The current predominantly warmer than normal pattern will likely persist through at least August, paving the way for a solidly warmer than normal summer throughout the region. Occasional short-lived cool shots remain possible. One or more heatwaves are likely in July across the region, including New York City. The ENSO Region 1+2 anomaly was -0.8°C and the Region 3.4 anomaly was -0.1°C for the week centered around July 8. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.72°C and the ENSO Region 3.4 anomaly has averaged -0.25°C. Neutral-cool conditions will likely prevail through mid-summer. The probability of the development of a La Niña event during late summer or early autumn has increased in recent weeks. The last time the six-week moving average for ENSO Region 1+2 was as cold as the current figure during July or August occurred in 2013. Winter 2013-14 had neutral-cool ENSO conditions. January and February featured ENSO Region 3.4 anomalies that were -0.50°C or below. The SOI was -12.62. Today, the preliminary Arctic Oscillation (AO) figure was -0.803. On July 14, the MJO was in Phase 2 at an amplitude of 1.571 (RMM). The July 13-adjusted amplitude was 1.708. The MJO has been in either Phase 1 or Phase 2 for 45 consecutive days. 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. Based on sensitivity analysis applied to the latest guidance, there is an implied 78% probability that New York City will have a warmer than normal July. July will likely finish with a mean temperature near 79.3°.

You make an important point. I have been using NYC due to its long climate record, which dates back to 1869. However, there has been a pronounced tendency for Central Park to show fewer 90 degree days than would be implied by regional data, individually and as an average (EWR-JFK-LGA-NYC). Perspective 1: During the 1959-2019 period, the regression equation in which the cases from JFK, LGA, and EWR were treated as independent variables and the Central Park number was the dependent variable, the Central Park number was less than predicted on 56% cases. However, since 2000, that number was less than predicted in 80% cases. The coefficient of determination was 0.728. Perspective 2: During the 1959-2019 period, the regression equation in which the 4-city average (which included Central Park) was the independent variable and the Central Park number was the dependent variable, the Central Park number was less than predicted on 56% cases. However, since 2000, that number was less than predicted in 95% cases. The coefficient of determination was 0.834. That Central Park had a tendency to have fewer 90 degree days than expected even when it was included in the mix highlights a microclimate that has been diverging from overall recent trends. Central Park is warming overall, but the relationship of its 90 degree days relative to the rest of the region has been changing. I will add a four-site average comprised of JFK-LGA-NYC-EWR that better reflects the overall regional impact. The coefficient of determination for that average against the independent variables of JFK, LGA, and EWR is 0.977 and the standard error is < 1.3. Here is the data for 90° days for Select Cities (through July 14): Albany: 10 (2019: 12 days) Allentown: 8 (2019: 24 days) Baltimore: 21 (2019: 59 days) Boston: 1 (2019: 15 days) Burlington: 12 (2019: 8 days) Harrisburg: 11 (2019: 33 days) Islip: 1 (2019: 8 days) New York City-JFK: 4 (2019: 7 days) New York City-LGA: 12 (2019: 26 days) New York City-NYC: 6 (2019: 15 days) Newark: 10 (2019: 27 days) Philadelphia: 14 (2019: 35 days) Washington, DC: 23 (2019: 62 days) New York City-Newark Average: 8 (2019: 19 days) ...Expected: 8 (based on JFK-LGA-EWR data)

To date, New York City has yet to experience a heat wave this summer. That will remain the case through the remainder of this week. However, a widespread heat wave could overspread the region starting this weekend. 90° Days for Select Cities (through July 13): Albany: 10 (2019: 12) Allentown: 8 (2019: 24) Baltimore: 21 (2019: 59) Boston: 1 (2019: 15) Burlington: 12 (2019: 8) Harrisburg: 11 (2019: 33) Islip: 1 (2019: 8) New York City: 6 (2019: 15) Newark: 10 (2019: 27) Philadelphia: 14 (2019: 35) Washington, DC: 23 (2019: 62) With a high temperature of 90°, Washington, DC registered its 19th consecutive day on which the temperature reached 90° or above. That is Washington's longest heat wave since July 29-August 18, 1988 when the temperature reached 90° or above on 21 consecutive days. The current predominantly warmer than normal pattern will likely persist through at least August, paving the way for a solidly warmer than normal summer throughout the region. Occasional short-lived cool shots remain possible. One or more heatwaves are likely in July across the region, including New York City. The ENSO Region 1+2 anomaly was -0.8°C and the Region 3.4 anomaly was -0.1°C for the week centered around July 8. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.72°C and the ENSO Region 3.4 anomaly has averaged -0.25°C. Neutral-cool conditions will likely prevail through mid-summer. The probability of the development of a La Niña event during late summer or early autumn has increased in recent weeks. The last time the six-week moving average for ENSO Region 1+2 was as cold as the current figure during July or August occurred in 2013. Winter 2013-14 had neutral-cool ENSO conditions. January and February featured ENSO Region 3.4 anomalies that were -0.50°C or below. The SOI was -11.39. Today, the preliminary Arctic Oscillation (AO) figure was -0.885. On July 13, the MJO was in Phase 2 at an amplitude of 1.715 (RMM). The July 12-adjusted amplitude was 1.877. The MJO has been in either Phase 1 or Phase 2 for 44 consecutive days. 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. Based on sensitivity analysis applied to the latest guidance, there is an implied 78% probability that New York City will have a warmer than normal July. July will likely finish with a mean temperature near 79.3°.

That was the highest I have seen anywhere.