donsutherland1

New York City saw its first low temperature in the 30s this morning. That was tied with 1946 for the third latest first sub-40° temperature of the season. The average first such temperature occurs on October 24th (1991-2020 baseline). 2024 is the fourth consecutive year with the first such temperature occurring in November. The old record was three consecutive years during 1994-1996. The temperature will again top out in the middle and upper 40s tomorrow. A warm front will also slip across the region tomorrow. Afterward, it will again turn milder to end the week. A mild and dry weekend is likely with readings in the lower 60s. The dry weather will likely continue into at least early next week. The NAO fell to a preliminary -2.751 on September 24th (all-time September record: -2.371, September 12, 1971). That was the 9th lowest value on record. La Niña winters following September cases where the NAO fell to -1.900 or below featured a predominantly positive NAO. The most recent such winters were 2016-2017 and 2022-2023. The mean temperatures for those winters in New York City were 39.3° and 41.0° respectively. The 1991-2020 normal value is 36.2°. A warmer to much warmer than normal outcome is favored by the November run of the ECMWF for Winter 2024-2025. The ENSO Region 1+2 anomaly was -0.2°C and the Region 3.4 anomaly was -0.3°C for the week centered around November 6. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.32°C and the ENSO Region 3.4 anomaly has averaged -0.35°C. Neutral ENSO conditions may evolve into a La Niña event during the late fall. The SOI was +15.08 today. The preliminary Arctic Oscillation (AO) was +0.476 today. Based on sensitivity analysis applied to the latest guidance, there is an implied 91% probability that New York City will have a warmer than normal November (1991-2020 normal). November will likely finish with a mean temperature near 51.6° (3.6° above normal).

A just published paper revealed that a new climate oscillation is emerging in the Arctic Ocean due to climate change. This oscillation is characterized by multidecadal variations in annual surface temperature and is driven by intensified air-sea interaction due to sea-ice loss. This new mode of internal variability is projected to emerge when sea ice declines below a critical threshold, potentially impacting global weather and climate. Multiple lines of evidence from climate model simulations support the emergence of this new oscillation. The CMIP6 ensemble shows the oscillation emerging in the 21st century. Additionally, analysis of mid-Pliocene simulations from the PlioMIP2 suggests the potential existence of this oscillation in past warm climates. https://www.nature.com/articles/s41558-024-02171-3

A strong cold shot will deliver the coldest air mass, by far, this fall into the region. The temperature will fall into the 30s tomorrow morning in Central Park. This would rank as the third latest first sub-40° temperature of the season. The average first such temperature occurs on October 24th (1991-2020 baseline). 2024 will be the fourth consecutive year with the first such temperature occurring in November. The old record was three consecutive years during 1994-1996. The temperature will remain in the middle and upper 40s for highs tomorrow and Thursday. A warm front will also slip across the region Thursday. Afterward, it will again turn milder to end the week. A mild and dry weekend is likely. The dry weather will likely continue into at least early next week. The NAO fell to a preliminary -2.751 on September 24th (all-time September record: -2.371, September 12, 1971). That was the 9th lowest value on record. La Niña winters following September cases where the NAO fell to -1.900 or below featured a predominantly positive NAO. The most recent such winters were 2016-2017 and 2022-2023. The mean temperatures for those winters in New York City were 39.3° and 41.0° respectively. The 1991-2020 normal value is 36.2°. A warmer to much warmer than normal outcome is favored by the November run of the ECMWF for Winter 2024-2025. The ENSO Region 1+2 anomaly was -0.2°C and the Region 3.4 anomaly was -0.3°C for the week centered around November 6. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.32°C and the ENSO Region 3.4 anomaly has averaged -0.35°C. Neutral ENSO conditions may evolve into a La Niña event during the late fall. The SOI was +14.50 today. The preliminary Arctic Oscillation (AO) was +0.278 today. 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 November (1991-2020 normal). November will likely finish with a mean temperature near 51.6° (3.6° above normal).

Today will be the warmest day for some time to come. A strong cold shot is likely during the middle of the week. The temperature will very likely fall below 40° during Wednesday morning (November 13th) or perhaps late Tuesday night in Central Park. This would rank as the third or fourth latest first sub-40° temperature. The average first such temperature occurs on October 24th (1991-2020 baseline). 2024 will be the fourth consecutive year with the first such temperature occurring in November. The old record was three consecutive years during 1994-1996. A few scattered showers will be possible on Thursday as a warm front moves across the region. Afterward, it will again turn milder. A mild weekend is likely. The NAO fell to a preliminary -2.751 on September 24th (all-time September record: -2.371, September 12, 1971). That was the 9th lowest value on record. La Niña winters following September cases where the NAO fell to -1.900 or below featured a predominantly positive NAO. The most recent such winters were 2016-2017 and 2022-2023. The mean temperatures for those winters in New York City were 39.3° and 41.0° respectively. The 1991-2020 normal value is 36.2°. A warmer to much warmer than normal outcome is favored by the November run of the ECMWF for Winter 2024-2025. The ENSO Region 1+2 anomaly was -0.2°C and the Region 3.4 anomaly was -0.3°C for the week centered around November 6. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.32°C and the ENSO Region 3.4 anomaly has averaged -0.35°C. Neutral ENSO conditions may evolve into a La Niña event during the late fall. The SOI was +4.77 today. The preliminary Arctic Oscillation (AO) was -0.104 today. Based on sensitivity analysis applied to the latest guidance, there is an implied 85% probability that New York City will have a warmer than normal November (1991-2020 normal). November will likely finish with a mean temperature near 51.5° (3.5° above normal).

Showers and periods of rain are now overspreading the region. Light rain is falling in parts of the New York City area. Wilmington, DE has seen its first measurable rainfall since September 28th. Periods of rain are likely overnight into tomorrow. A general 0.25"-0.50" rainfall is likely. A few showers will be possible on Thursday as a warm front moves across the region. A strong cold shot is likely during the middle of the week. The temperature will very likely fall below 40° during Wednesday morning (November 13th) or perhaps late Tuesday night in Central Park. This would rank as the third or fourth latest first sub-40° temperature. The average first such temperature occurs on October 24th (1991-2020 baseline). 2024 will be the fourth consective year with the first such temperature occurring in November. The old record was three consecutive years during 1994-1996. It will again turn milder late in the week or during the following weekend. The NAO fell to a preliminary -2.751 on September 24th (all-time September record: -2.371, September 12, 1971). That was the 9th lowest value on record. La Niña winters following September cases where the NAO fell to -1.900 or below featured a predominantly positive NAO. The most recent such winters were 2016-2017 and 2022-2023. The mean temperatures for those winters in New York City were 39.3° and 41.0° respectively. The 1991-2020 normal value is 36.2°. A warmer to much warmer than normal outcome is favored by the November run of the ECMWF for Winter 2024-2025. The ENSO Region 1+2 anomaly was -0.5°C and the Region 3.4 anomaly was -0.2°C for the week centered around October 30. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.42°C and the ENSO Region 3.4 anomaly has averaged -0.33°C. Neutral ENSO conditions will likely evolve into a La Niña event during the late fall. The SOI was +4.83 today. The preliminary Arctic Oscillation (AO) was +0.691 today. Based on sensitivity analysis applied to the latest guidance, there is an implied 85% probability that New York City will have a warmer than normal November (1991-2020 normal). November will likely finish with a mean temperature near 51.6° (3.6° above normal).

Most products I have seen are fine.

It's absurd. The correct map, and I deliberately use "correct," as that's from the NCEP website: It's unfortunate that WB continues to post flawed maps. At the end of the winter, it would be a useful exercise to compare the actual outcomes to the official NCEP CFSv2 map and the WB version.

The final C3S winter 2024-2025 guidance is now in. Temperatures: Precipitation: October Comparisons: Temperatures: Precipitation: It should be noted that there is some variation on a month-to-month basis with December featuring the most widespread warmth (monthly average). There can still be shorter periods of cold that don't stand out on seasonal or monthly guidance. The upcoming cold shot for parts of the eastern half of the U.S. this week is one example.

A new paper, "Anthropogenic warming has ushered in an era of temperature-dominated droughts in the western United States", has revealed that the nature of droughts in the Western United States has changed due to climate change. Three key points: 1. The western United States has experienced a significant shift in the primary driver of drought, from precipitation deficits to high evaporative demand, primarily due to anthropogenic warming. This change occurred around the year 2000. Rising surface temperatures increase the atmosphere's capacity to hold water vapor, leading to higher evaporative demand and intensifying drought severity. 2. Historically, precipitation deficits were the main factor in WUS droughts, but since 2000, rising temperatures and resulting high evaporative demand have contributed more to drought severity (62%) and coverage (66%). 3. The paper revealed that natural climate variability is the dominant factor influencing precipitation, while anthropogenic warming is mainly responsible for the observed changes in evaporative demand.

Clouds will increase on tomorrow with periods of rain developing during the evening and continuing into Monday. A general 0.25"-0.50" rainfall is likely. An additional round of rain is possible late next week. Aside from unseasonable warmth, next week will generally see near normal to occasionally somewhat below normal readings. Today is Philadelphia's 42nd consecutive day with no measurable precipitation. The old record of 29 days was set during October 11 through November 8, 1874. Wilmington, DE has also gone 42 consecutive days without measurable precipitation. The old record of 34 days was set during January 7 through February 9, 1909. Those record streaks will end tomorrow. The NAO fell to a preliminary -2.751 on September 24th (all-time September record: -2.371, September 12, 1971). That was the 9th lowest value on record. La Niña winters following September cases where the NAO fell to -1.900 or below featured a predominantly positive NAO. The most recent such winters were 2016-2017 and 2022-2023. The mean temperatures for those winters in New York City were 39.3° and 41.0° respectively. The 1991-2020 normal value is 36.2°. A warmer to much warmer than normal outcome is favored by the November run of the ECMWF for Winter 2024-2025. The ENSO Region 1+2 anomaly was -0.5°C and the Region 3.4 anomaly was -0.2°C for the week centered around October 30. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.42°C and the ENSO Region 3.4 anomaly has averaged -0.33°C. Neutral ENSO conditions will likely evolve into a La Niña event during the late fall. The SOI was -2.29 today. The preliminary Arctic Oscillation (AO) was +0.691 today. 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 November (1991-2020 normal). November will likely finish with a mean temperature near 51.5° (3.5° above normal).

I smelled the smoke yesterday.

It’s also the second warmest January-October period on record.

Tomorrow will be a noticeably cooler day. Temperatures will climb into only the lower 50s after starting out in the lower 40s in New York City and 30s outside the City. Clouds will increase on Sunday with periods of rain developing during the night and continuing into Monday. A general 0.25"-0.50" rainfall is likely. An additional round of rain is possible late next week. Today is Philadelphia's 41st consecutive day with no measurable precipitation. The old record of 29 days was set during October 11 through November 8, 1874. Wilmington, DE has also gone 41 consecutive days without measurable precipitation. The old record of 34 days was set during January 7 through February 9, 1909. The NAO fell to a preliminary -2.751 on September 24th (all-time September record: -2.371, September 12, 1971). That was the 9th lowest value on record. La Niña winters following September cases where the NAO fell to -1.900 or below featured a predominantly positive NAO. The most recent such winters were 2016-2017 and 2022-2023. The mean temperatures for those winters in New York City were 39.3° and 41.0° respectively. The 1991-2020 normal value is 36.2°. A warmer to much warmer than normal outcome is favored by the November run of the ECMWF for Winter 2024-2025. The ENSO Region 1+2 anomaly was -0.5°C and the Region 3.4 anomaly was -0.2°C for the week centered around October 30. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.42°C and the ENSO Region 3.4 anomaly has averaged -0.33°C. Neutral ENSO conditions will likely evolve into a La Niña event during the late fall. The SOI was -14.64 today. The preliminary Arctic Oscillation (AO) was +0.986 today. 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 November (1991-2020 normal). November will likely finish with a mean temperature near 51.7° (3.7° above normal).

I suspect that the 1950 record at Ann Arbor will stand for quite some time to come. It's just so far beyond anything that has occurred in January that it's difficult to see its being matched or broken anytime soon. The Detroit record might be something that could be challenged over the next decade or so.

Today was another warm day, though quite a bit cooler than yesterday's record warmth. However, parts of the Mid-Atlantic region experienced additional near record and record heat. Daily records included: Atlantic City: 81° (old record: 81°, 2022) Norfolk: 80° (old record: 79°, 2022) Richmond: 85° (old record: 84°, 2022) Salisbury: 82° (tied record set in 2022) Sterling: 80° (old record: 79°, 2022 and 2023) Washington, DC: 84° (old record: 81°, 2022) In addition, Norfolk's 80° day was its fourth this month. That tied the November record set in 1950 and tied in 1974. It will turn somewhat cooler for tomorrow, but temperatures will remain well above seasonal norms. The gradual cooldown will continue into the weekend. Some rain to affect the region Sunday night into Monday. Parts of the region could be in line for 0.25"-0.50" of rain. An additional round of rain is possible late next week. Today is Philadelphia's 40th consecutive day with no measurable precipitation. The old record of 29 days was set during October 11 through November 8, 1874. Wilmington, DE has also gone 40 consecutive days without measurable precipitation. The old record of 34 days was set during January 7 through February 9, 1909. The NAO fell to a preliminary -2.751 on September 24th (all-time September record: -2.371, September 12, 1971). That was the 9th lowest value on record. La Niña winters following September cases where the NAO fell to -1.900 or below featured a predominantly positive NAO. The most recent such winters were 2016-2017 and 2022-2023. The mean temperatures for those winters in New York City were 39.3° and 41.0° respectively. The 1991-2020 normal value is 36.2°. A warmer to much warmer than normal outcome is favored by the November run of the ECMWF for Winter 2024-2025. The ENSO Region 1+2 anomaly was -0.5°C and the Region 3.4 anomaly was -0.2°C for the week centered around October 30. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.42°C and the ENSO Region 3.4 anomaly has averaged -0.33°C. Neutral ENSO conditions will likely evolve into a La Niña event during the late fall. The SOI was -11.46 today. The preliminary Arctic Oscillation (AO) was +1.443 today. 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 November (1991-2020 normal). November will likely finish with a mean temperature near 51.7° (3.7° above normal).