JAN-26 Northern Hemisphere Snow Cover

Climate Impact Company U.S. Daily Report

Issued: Tuesday February 4, 2026

Highlight: Northern hemisphere JAN-26 snow cover, stratosphere update, and latest U.S. HDD projections.

Fig. 1-3: Rutgers University Snow Laboratory indicates snow cover anomalies observed during JAN-26 in the northern hemisphere, Eurasia, and North America.

Discussion: The northern hemisphere snow cover observed during JAN-26 was almost exactly normal (Fig. 1). 8 of the past 9 mid-winter’s have observed near normal snow cover. Eurasia snow cover was slightly above normal during JAN-26 and the most since 2017 (Fig. 2) while North America snow cover was moderately below normal and the least amount since 2012 (Fig. 3).

The stratosphere is in transition through mid-February. However, just-after mid-February organized warming in the polar region develops according to CMC ENS (Fig. 4). Beneath the warming stratosphere at that time, the polar vortex is located on the North Coast of Russia with a broad cold upper trough extending southwestward into Europe while North America observes an amplified upper ridge downstream a -PNA inspired trough across the Northwest U.S. (Fig. 5). Arctic air generation produced by stratospheric warming occurs later in February (if the warming stays organized).

Overnight, U.S. gas population weight HDD forecasts through February 19^th edged slightly milder (Fig. 6) while week 4-5 projections vary widely with 2 of 3 AI models shifting colder while CFS remains very warm (Fig. 7).

Fig. 4-5: CMC ENS 10 MB temperature anomaly forecast for the 11-15-day period and attendant 500 MB anomalies.

Fig. 6-7: U.S. gas population weight HDD forecast through February 19^th and estimated week 4-5 ahead HDD according to ECM, CFS, and 3 AI models.