November 2025 OBS Discussion

[ForestHillWx]

I didn’t check the low, but the top layer of ground was frozen. 

[donsutherland1]

There was a heavier snow shower in the Harriman, NY area this afternoon.

[donsutherland1]

Tomorrow will be unseasonably cold. There is potential for New York City's Central Park to experience its first freeze of 2025 tomorrow morning. The 1991-2020 normal first date is November 21. The 1961-1990 baseline was November 11. Last winter's first freeze occurred on November 30.

Saturday and Sunday will see a snowstorm blanket parts of the Great Lakes Region. Chicago and Milwaukee could see 6"-12" of snow. Detroit could pick up 4"-8". Toronto could see 3"-6".

Sunday and Monday will be somewhat milder. Showers are possible on Monday as a cold front moves across the region. Generally colder than normal conditions could then continue into or through the second week of December. Severe cold appears unlikely through at least the first 10 days of December. Nevertheless, December 1-10 will be a solidly colder than normal period. 

Moreover, a storm could affect the region on Tuesday into Wednesday, bringing 0.50"-1.50" precipitation to the region. There is a distinct possibility that New York City could see its first measurable snowfall of the season. Interior sections have the highest probability of seeing accumulations of snow.

The ENSO Region 1+2 anomaly was -0.7°C and the Region 3.4 anomaly was -0.7°C for the week centered around November 12. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.16°C and the ENSO Region 3.4 anomaly has averaged -0.65°C. La Niña conditions will likely continue through at least mid-winter.

The SOI was -3.12 today. 

The preliminary Arctic Oscillation (AO) was +0.081 today. 

Based on sensitivity analysis applied to the latest guidance, there is an implied 99% probability that New York City will have a cooler than normal November (1991-2020 normal). November will likely finish with a mean temperature near 47.2° (0.8° below normal). 

Supplemental Information: The projected mean would be 0.5° below the 1981-2010 normal monthly value.