September 2025 OBS-Discussion centered NYC subforum

[LibertyBell]

10 hours ago, lee59 said:

I was surprised Islip got that warm, only made it to 81 here.

85 here too

[LibertyBell]

10 hours ago, winterwarlock said:

Usually we have a high in the 60s with full sun by mid September so this year its way late and its only day so very weak with any cool down this year

ehhhh maybe you mean mid October? usually we're still up around 90 in mid September LOL

 

[LibertyBell]

10 hours ago, WestBabylonWeather said:

Sitting on the deck right now like it’s July 

did you get your new pc yet?

what are its specs and how much was it?

[LibertyBell]

12 hours ago, FPizz said:

First step down for me was adjusting the time the landscape lights popped on.  Second step down is the pool closing on Monday haha. After that is shutting off the irrigation system

you should have your landscape lights set to automatically turn on when the sun goes down.

[LibertyBell]

15 hours ago, donsutherland1 said:

The consistency has been remarkable.

Smallest Mean Temperature Standard Deviation for September (through September 25th for 2025) for Central Park:

1. 1968 3.43°
2. 2025 3.75° (10th smallest difference between the mean temperatures for the first and second halves of September)
3. 1870 3.81° (6th smallest difference between the mean temperatures for the first and second halves of September)
4. 2024 3.94°
5. 1908 4.08°

where is September 1983 on this list, Don?

It was continuously hot!

[LibertyBell]

10 hours ago, donsutherland1 said:

Rainfall amounts in the New York City area were generally less than the 0.50"-1.50" forecast amounts. There was a stripe of heavier rainfall in parts of Connecticut.

Storm total amounts included:

Hartford: 1.72"
Islip: 0.30"
New Haven: 1.34"
New York City-Central Park: 0.35"
New York City-JFK Airport: 1.38"
New York City-LaGuardia Airport: 0.33"
Newark: 0.17"
Storrs: 2.76"
White Plains: 0.47"

As a result, New York City is on track to finish with rainfall that is below the 4.31" monthly normal value for September. Almost as if to add insult to injury to the dry New York City area, in the past hour, Phoenix has picked up 1.09" of rain, along with winds gusting to 56 mph. The 1.11" so far today is its biggest rainstorm since October 13, 2018.

Above normal temperatures will continue through the remainder of September. Another round of showers is possible Saturday night into Sunday. A significant rainfall is unlikely.

The guidance and historical experience following a second half September mean temperature of 70° or above suggest that October will be warmer than normal in the New York City area. The two most recent Octobers with a cooler than normal first half like 2025 and a second half with a mean temperature of 70° or above were: 2017 (October mean temperature: 64.1° and October 2019: October mean temperature 59.9°).

The extent of ridging to the north and interaction between the Humberto and Invest. 94 could ultimately determine whether Invest. 94 poses an eventual threat to a portion of the Southeast or stays out to sea.

The potential Fujiwhara interaction would be unusual for the Atlantic basin. Typically, if the stronger system is to the right or east of the weaker one (possibly Invest. 94 as per most of the guidance at present), the stronger system will tend to deflect the weaker one northward and eastward sooner than might otherwise be the case. If both systems are of similar strength, they can rotate counterclockwise around a midpoint roughly between the centers of the two storms as they move along the steering flow. Two plausible scenarios are landfall along the South Carolina coast or a sharp turn out to sea after an approach toward the coastline. 

For now, tropics bear watching for the Southeast. 

The ENSO Region 1+2 anomaly was 0.0°C and the Region 3.4 anomaly was -0.4°C for the week centered around September 17. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.03°C and the ENSO Region 3.4 anomaly has averaged -0.38°C. La Niña conditions will likely develop during mid- or late-autumn.

The SOI was +9.81 today. 

The preliminary Arctic Oscillation (AO) was +1.341 today. 

Based on sensitivity analysis applied to the latest guidance, there is an implied near 86% probability that New York City will have a warmer than normal September (1991-2020 normal). September will likely finish with a mean temperature near 70.1° (0.9° above normal). 

Supplemental Information: The projected mean would be 2.1° above the 1981-2010 normal monthly value.

 

Hartford: 1.72"
Islip: 0.30"
New Haven: 1.34"
New York City-Central Park: 0.35"
New York City-JFK Airport: 1.38"
New York City-LaGuardia Airport: 0.33"
Newark: 0.17"
Storrs: 2.76"
White Plains: 0.47"

Don are you sure JFK got so much rain? I saw a report of around 0.58 from that area.