September 2025 OBS-Discussion centered NYC subforum

[donsutherland1]

18 minutes ago, LibertyBell said:

1983 was one amazing summer (and September was part of that summer.)

What did JFK hit, Don? I made it to 85 here.

86 (record was 90 in 1983).

[lee59]

83 the high here today

[uofmiami]

83.0 in Muttontown & 82.3 in Syosset for the high.

[donsutherland1]

Today was an unseasonably warm late September day. Preliminary highs included:

Bridgeport: 84°
Islip: 85° (tied record from 1983)
New Haven: 84°
New York Cty-Central Park: 84°
New York City-JFK Airport: 86°
New York City-LaGuardia Airport: 83°
Newark: 86°
Philadelphia: 84°
Westhampton: 83° (tied record set in 1967 and tied in 2024)
White Plains: 83°

Cooler air will return overnight for the weekend. Temperatures will top out mainly in the lower 70s tomorrow through Monday. It will then turn warmer on Tuesday before another cool front crosses the region on Wednesday. The advancing front could trigger some showers or thundershowers.

The ENSO Region 1+2 anomaly was -0.2°C and the Region 3.4 anomaly was -0.5°C for the week centered around September 10. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.10°C and the ENSO Region 3.4 anomaly has averaged -0.37°C. La Niña conditions will likely develop during mid- or late-autumn.

The SOI was -4.34 today. 

The preliminary Arctic Oscillation (AO) was -0.972 today. 

Based on sensitivity analysis applied to the latest guidance, there is an implied near 57% probability that New York City will have a cooler than normal September (1991-2020 normal). September will likely finish with a mean temperature near 69.0° (0.2° below normal). 

Supplemental Information: The projected mean would be 1.0° above the 1981-2010 normal monthly value.

 

[psv88]

85 today, same as Islip

[LibertyBell]

28 minutes ago, donsutherland1 said:

86 (record was 90 in 1983).

30C !!! The highest temperature for the rest of the year, Don ???

[LibertyBell]

20 minutes ago, donsutherland1 said:

Today was an unseasonably warm late September day. Preliminary highs included:

Bridgeport: 84°
Islip: 85° (tied record from 1983)
New Haven: 84°
New York Cty-Central Park: 84°
New York City-JFK Airport: 86°
New York City-LaGuardia Airport: 83°
Newark: 86°
Philadelphia: 84°
Westhampton: 83° (tied record set in 1967 and tied in 2024)
White Plains: 82°

Cooler air will return overnight for the weekend. Temperatures will top out mainly in the lower 70s tomorrow through Monday. It will then turn warmer on Tuesday before another cool front crosses the region on Wednesday. The advancing front could trigger some showers or thundershowers.

The ENSO Region 1+2 anomaly was -0.2°C and the Region 3.4 anomaly was -0.5°C for the week centered around September 10. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.10°C and the ENSO Region 3.4 anomaly has averaged -0.37°C. La Niña conditions will likely develop during mid- or late-autumn.

The SOI was -4.34 today. 

The preliminary Arctic Oscillation (AO) was -0.972 today. 

Based on sensitivity analysis applied to the latest guidance, there is an implied near 57% probability that New York City will have a cooler than normal September (1991-2020 normal). September will likely finish with a mean temperature near 69.0° (0.2° below normal). 

Supplemental Information: The projected mean would be 1.0° above the 1981-2010 normal monthly value.

 

Nice to see JFK equal EWR, this is what I call true heat.

 

[Sundog]

10 minutes ago, LibertyBell said:

30C !!! The highest temperature for the rest of the year, Don ???

I don't want to see anything above 20C until next April

 

[LibertyBell]

16 minutes ago, Sundog said:

I don't want to see anything above 20C until next April

 

thats too cold, 25C is okay

I dont want to start my heating until November

 

[donsutherland1]

27 minutes ago, LibertyBell said:

30C !!! The highest temperature for the rest of the year, Don ???

Probably. However, one can't completely rule out a later such temperature, even as it doesn't show up on any of the guidance right now. Just over 1-in-6 years in JFK's period of record saw 86° or above temperatures on September 20th or later. The most recent was 2019 with the epic 95° high on October 2. The last week of the month has some potential with the forecast drop in the PNA, though an even sharper drop would increase prospects.

[steve392]

1 hour ago, LibertyBell said:

Made it to 85 today, it's probably not going to be this warm again until next year so savor it!!

Fine with me.  I'm missing the 40s and a cool drive to work already at 6am

[LibertyBell]

37 minutes ago, donsutherland1 said:

Probably. However, one can't completely rule out a later such temperature, even as it doesn't show up on any of the guidance right now. Just over 1-in-6 years in JFK's period of record saw 86° or above temperatures on September 20th or later. The most recent was 2019 with the epic 95° high on October 2. The last week of the month has some potential with the forecast drop in the PNA, though an even sharper drop would increase prospects.

Last year had widespread 80s in November, but I don't think it ever reached 85 did it Don?

[TheClimateChanger]

10 hours ago, Sundog said:

The snow season was also longer, the first few decades of snow records from NYC show about half of Novembers having accumulating snowfall, some of them with major numbers. 

To be fair though we were on the tail end of ther Little Ice Age and so the background state was just overall naturally cooler even without global warming. 

I don't think the Little Ice Age would be much of a factor. Perhaps @donsutherland1 could weigh in? But looking at proxy-based global temperature reconstructions, it would appear globally temperatures varied no more than about .5C over the preceding 2,000 years until the mid 19th century. And that temperatures by about the 1930s were decidedly warmer than at any time in the preceding 2,000 years.

People often bandy around terms they don't understand. Even during the Holocene Thermal Optimum, mid-latitude winters were likely harsher than during the 19th century, as the earth would have been tilted at a greater angle away from the sun during wintertime. The summer warming is just a considerably larger impact, because that's when almost all of the solar radiation falls in the high latitude.

[donsutherland1]

12 hours ago, LibertyBell said:

Last year had widespread 80s in November, but I don't think it ever reached 85 did it Don?

Newark had the warmest temperature last November (83°).

[Sundog]

10 minutes ago, TheClimateChanger said:

I don't think the Little Ice Age would be much of a factor. Perhaps @donsutherland1 could weigh in? But looking at proxy-based global temperature reconstructions, it would appear globally temperatures varied no more than about .5C over the preceding 2,000 years until the mid 19th century. And that temperatures by about the 1930s were decidedly warmer than at any time in the preceding 2,000 years.

People often bandy around terms they don't understand. Even during the Holocene Thermal Optimum, mid-latitude winters were likely harsher than during the 19th century, as the earth would have been tilted at a greater angle away from the sun during wintertime. The summer warming is just a considerably larger impact, because that's when almost all of the solar radiation falls in the high latitude.

I understand the Little Ice Age quite fine. 

The northern hemisphere was affected more than the southern, so you can't just go by global averages. 

In addition to that, regionally the 1800s were quite cold in North America.

And with a name like the Climate Changer you should know even a couple of C deviation is massive for a long term average, which was what was occuring during that time period. 

All I was saying is that since snow records begin in 1869 in New York, those first few decades were weening off the cooler overall regime. 

[LibertyBell]

12 minutes ago, TheClimateChanger said:

I don't think the Little Ice Age would be much of a factor. Perhaps @donsutherland1 could weigh in? But looking at proxy-based global temperature reconstructions, it would appear globally temperatures varied no more than about .5C over the preceding 2,000 years until the mid 19th century. And that temperatures by about the 1930s were decidedly warmer than at any time in the preceding 2,000 years.

People often bandy around terms they don't understand. Even during the Holocene Thermal Optimum, mid-latitude winters were likely harsher than during the 19th century, as the earth would have been tilted at a greater angle away from the sun during wintertime. The summer warming is just a considerably larger impact, because that's when almost all of the solar radiation falls in the high latitude.

Volcanic eruptions might been a factor in some of those winters, but it doesn't explain the entire dataset of the 1800s being colder than what started happening during the 1930s either.

The most notable volcanic episode was Laki in 1782-83, the winter that followed its eruption was likely the coldest and snowiest winter either North America or Europe has ever had.  Washington kept quite the diary of that winter from Morristown NJ.  I wonder what the temperature had to be to make the ink in his pen freeze? The lowest documented temperature from that winter that we have is -16 F from NYC just a degree colder than the -15 F that was recorded in February 1934.  The 30s were a period of extremes....

Even more notable than the extreme cold was the over one dozen blizzards reported by Washington in our area in that historic winter.

 

 

[LibertyBell]

6 minutes ago, Sundog said:

I understand the Little Ice Age quite fine. 

The northern hemisphere was affected more than the southern, so you can't just go by global averages. 

In addition to that, regionally the 1800s were quite cold in North America.

And with a name like the Climate Changer you should know even a couple of C deviation is massive for a long term average, which was what was occuring during that time period. 

All I was saying is that since snow records begin in 1869 in New York, those first few decades were weening off the cooler overall regime. 

Laki (1782), Tambora (1815) and Krakatoa (1886) also had something to do with it.

[LibertyBell]

18 minutes ago, TheClimateChanger said:

I don't think the Little Ice Age would be much of a factor. Perhaps @donsutherland1 could weigh in? But looking at proxy-based global temperature reconstructions, it would appear globally temperatures varied no more than about .5C over the preceding 2,000 years until the mid 19th century. And that temperatures by about the 1930s were decidedly warmer than at any time in the preceding 2,000 years.

People often bandy around terms they don't understand. Even during the Holocene Thermal Optimum, mid-latitude winters were likely harsher than during the 19th century, as the earth would have been tilted at a greater angle away from the sun during wintertime. The summer warming is just a considerably larger impact, because that's when almost all of the solar radiation falls in the high latitude.

what causes changes in the tilt? is this a cyclic change?

 

[Sundog]

1 minute ago, LibertyBell said:

what causes changes in the tilt? is this a cyclic change?

 

Milankovitch Cycles, small cyclical changes in precession, obliquity and eccentricity. 

[donsutherland1]

22 minutes ago, TheClimateChanger said:

I don't think the Little Ice Age would be much of a factor. Perhaps @donsutherland1 could weigh in? But looking at proxy-based global temperature reconstructions, it would appear globally temperatures varied no more than about .5C over the preceding 2,000 years until the mid 19th century. And that temperatures by about the 1930s were decidedly warmer than at any time in the preceding 2,000 years.

People often bandy around terms they don't understand. Even during the Holocene Thermal Optimum, mid-latitude winters were likely harsher than during the 19th century, as the earth would have been tilted at a greater angle away from the sun during wintertime. The summer warming is just a considerably larger impact, because that's when almost all of the solar radiation falls in the high latitude.

Snow seasons were longer in the past in the colder climate. The numbers were not wildly different, though. 

Below are the numbers for Central Park:

[LibertyBell]

2 minutes ago, Sundog said:

Milankovitch Cycles, small cyclical changes in precession, obliquity and eccentricity. 

I wonder if this is caused by gravitational changes, the sun has an elliptical path around the center of the galaxy so when we pass through areas with a higher stellar density it could influence the tilt..... it could also lead to more ELE (period mass extinctions seem to happen every 20-25 million years or so.)

 

 

[LibertyBell]

3 minutes ago, donsutherland1 said:

Snow seasons were longer in the past in the colder climate. The numbers were not wildly different, though. 

Below are the numbers for Central Park:

Know why the 2 day snowfalls are not any different from the daily snowfall in the more recent period, Don? It's because we very rarely have 2 day snowfalls anymore =\ And especially not in November and April.

 

[Sundog]

14 minutes ago, donsutherland1 said:

Snow seasons were longer in the past in the colder climate. The numbers were not wildly different, though. 

Below are the numbers for Central Park:

There were very few dud years up until about 1920. 

Only 6 years recorded under 20 inches of snow in 52 years worth of records, 1869-1920. 

Couple that with cooler temps and longer snow seasons and the wintertime feel would have been much more epic than today. 

And it's true that we didn't have wildly more snow, although those decades are closer to our highest overall average on record of 30-ish inches. 

 

[donsutherland1]

If it holds, both JFK Airport and Newark will have had identical high and low temperatures today (86°-66°). The last time that happened was July 31. Fun fact: The record is 3 consecutive days (February 7-9, 2004).

[SACRUS]

 

Highs:

PHL: 89
ACY: 87
EWR: 86
BLM: 86
New Brnswck: 86
JFK: 86
TEB: 85
TTN: 85
ISP: 85
NYC: 84
LGA: 83
 

[dmillz25]

85 for the high felt hot today lol

[nycwinter]

3 hours ago, dmillz25 said:

85 for the high felt hot today lol

not really the air was dry and there was a northerly breeze..

[bluewave]

19 hours ago, LibertyBell said:

The real endangered species is the near normal snowfall seasons.  Maybe the same thing is happening with our rainfall patterns too.  Everything is becoming more extreme and much more variable.

 

Yeah, from the 60s to early 90s within a few inches of 25” was very common. There were a few seasons of near 30”+ and a few 20” and below. So a very balanced snowfall pattern during that stable colder era. 

The  snowfall became all or nothing since 93-94. Most seasons have been over 30” or under 20” since then as the winters have continued to warm. The storm tracks remained cold enough to our south for many 30”+ seasons from 09-10 to 17-18. 

The warmer storm tracks since 18-19 have resulted in most seasons ending up with under 20” of snow. So it has been challenging to get a 30”+ season. Plus NYC hasn’t had a season near 25” since 12-13. 

So losing the higher end 30”+ seasons and continuing the decline in the near 25” seasons has resulted in the under 20” season becoming most common. 

NYC snowfall seasons near 25”

12-13….26.1”

08-09…27.6”

92-93…24.5”

90-91….24.9”

86-87….23.1”

84-85….24.1”

83-84….25.4”

82-83…..27.2”

81-82……24.6”

78-79…..29.4”

76-77…..24.5”

73-74…..23.5”

71-72…..22.9”

69-70….25.6”

64-65….24.4”

 

 

[LoboLeader1]

43 here in the Berkshires this AM, no complaints here. Currently 60F back in HPN.

[SACRUS]

 

65 / 44 clear .  Sunny today cooler low - upper 70s in the warmest areas.  A bit cooler tomorrow.  Overall warmer and perhaps a period of rain as another low cuts off under the ridge between Tue - Sat next week.  Will see where it does and which areas get some rains.