October 2025 Discussion and Obs

[donsutherland1]

A strong NAO blocking regime is in place and will persist into early November. As a result, an extended period of cooler than normal weather will prevail through the end of the month. 

Tomorrow will be a bit milder as temperatures rise into the upper 50s or lower 60s.

Rain will arrive late tonight or early tomorrow. A general 1"-3" rainfall is likely late Wednesday night through Friday. There remains some uncertainty about the area of heaviest rainfall. The storm will be followed by a continuation of cool weather.

In the long-range, the guidance suggests that an AO+/NAO+ regime could develop the first week in November. As has often happened with the loss of strong blocking, a milder regime could develop late in the first week of November or shortly afterward. 

The ENSO Region 1+2 anomaly was +0.3°C and the Region 3.4 anomaly was -0.6°C for the week centered around October 22. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.07°C and the ENSO Region 3.4 anomaly has averaged -0.48°C. La Niña conditions will likely continue through mid-winter.

The SOI was +18.18 today. 

The preliminary Arctic Oscillation (AO) was -0.392 today. The NAO was -1.634. 

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 October (1991-2020 normal). October will likely finish with a mean temperature near 58.3° (0.4° above normal). 

Supplemental Information: The projected mean would be 1.4° above the 1981-2010 normal monthly value.

 

[SI Mailman]

2 hours ago, the_other_guy said:

if you had kids, you would understand. 

 

what you’re really mad at is shorter days… it’s like yelling at a cloud. Move south

 

People don't realize there's really only 9 hours of daylight in December, and they don't know how to allocate it.