Northern Hemisphere Snow Cover for NOV-25 Near Normal But Lowest Amount Since 2009

A graph showing the average temperature AI-generated content may be incorrect.
Dynamic/AI Models Verification Report: AIFS skill scores are best for medium range North America/Europe temperature forecasts; Ongoing wet bias in Brazil.
12/04/2025, 4:51 am EST
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NOV-25 Solar Cycle/Sunspot Number: Deceleration to Solar Minimum Underway
12/08/2025, 2:59 pm EST
A graph showing the average temperature AI-generated content may be incorrect.
Dynamic/AI Models Verification Report: AIFS skill scores are best for medium range North America/Europe temperature forecasts; Ongoing wet bias in Brazil.
12/04/2025, 4:51 am EST
A graph with blue lines and text AI-generated content may be incorrect.
NOV-25 Solar Cycle/Sunspot Number: Deceleration to Solar Minimum Underway
12/08/2025, 2:59 pm EST
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A graph of snow cover anomalies AI-generated content may be incorrect.

Climate Impact Company Week 2-4 Outlook

North America

Issued: Friday, December 5, 2025

Highlight: Cold North, warm South persistence maintained.

Charts of the day: NOV-25 snow cover was least snowy since NOV-09 (which was followed by a frigid winter season).

A graph of snow cover anomalies AI-generated content may be incorrect.A map of the united states AI-generated content may be incorrect.

Discussion: The North America and Eurasia snow cover during November were near normal and consequently northern hemisphere snow cover was near normal and the least snowy since November 2009. Note one of the coldest winter seasons on record followed as DEC/JAN/FEB 2009-10 was frigid! Early season snow cover dictating the following winter weather pattern was a reasonably reliable climate diagnostic late last century but less so in this century.

Week-2 Ahead Forecast valid December 14-21, 2025: Colder adjustments, likely colder than indicated Northwest.

A map of the united states AI-generated content may be incorrect.A map of the united states AI-generated content may be incorrect.

Discussion: Colder trend across Canada, the North-central and Northeast U.S. compared to outlook issued earlier this week. Additionally, the West is adjusted warmer. However, precipitation across the Northwest States and Great Basin is likely mostly snow implying warm forecasts for Interior West are overstated.

Week-3 Ahead Forecast valid December 21-28, 2025: Northern chill, southern warmth.

A map of the united states AI-generated content may be incorrect.A map of the united states AI-generated content may be incorrect.

Discussion: ECM maintains a forecast trend of colder North/warmer South. Driving a temperature regime with this character is usually driven by snow cover. There are no stratospheric warming of significant MJO events indicated for late December. The sensible forecast is snowy Interior West and possibly colder than indicated with rain, sleet, and snow Midwest States.

Week-4 Ahead Forecast valid December 28, 2025-January 4, 2026: Low confidence persistence forecast.

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Discussion: Persistence wins…Cold North, warm South. Other ideas? Of 3 AI models, 2 are much colder East and 1 much warmer East. Low confidence on the early January forecast.