Extratropical Highlights – January 2026

 

1. Northern Hemisphere

The 500-hPa circulation during January featured a strong anomalous ridge over Greenland, a moderate anomalous ridge over the North Pacific Ocean, and a strong anomalous trough centered near the Bay of Biscay in the North Atlantic Ocean (Fig. E9). The main land surface temperature signals include above average temperatures across western North America and below average temperatures across Eurasia (Fig. E1). The main precipitation signals include below average rainfall along the eastern and western coasts of North America, and above average rainfall in southern Europe (Fig. E3).

 

a. North America

 

The January 500-hPa circulation over North America featured above average height anomalies across the North Pacific Ocean, Alaska, western Canada, and the western United States, with below average heights centered over the Great Lakes region (Fig. E9). This anomalous height pattern contributed to largely above average temperatures across most of the western U.S., with most of the area reaching the highest 70th percentile of occurrences (Fig. E1). Drier than average conditions were recorded along both the west and east coasts of North America, and the Southeast, with many areas reaching the lowest 30th percentile of occurrences (Figs. E3, E5 E6).

 

b. Europe and Asia

 

The 500-hPa height anomalies in January featured an anomalously strong dipole with an enhanced ridge over Greenland and trough centered near the Bay of Biscay in the North Atlantic Ocean (Fig. E9). Below average temperatures were recorded for Scandinavia and Russia, where many areas recorded temperatures in the lowest 30th percentile of occurrences (Fig. E1). Precipitation totals were below average across Scandinavia and Russia and above normal across Southern Europe (Fig. E3).

 

2. Southern Hemisphere

 

The 500-hPa height pattern during January featured a pattern of slightly below average height anomalies over the South Pole, surrounded by slightly above average height anomalies (Fig. E15). Above average temperatures were widely recorded across South America, Africa, and Australia (Fig. E1). Drier than average conditions were recorded across southern Africa, southern Australia, and the majority of South America, continuing an extended drought in Brazil (Figs. E3, E4). Across the equatorial tropics in Africa, precipitation totals were largely above average, with some areas reaching the highest 90th percentile of occurrences (Figs. E3, E4). The South African monsoon season runs from October to April. This area received above average rainfall during January, with many areas reaching the highest 70th percentile of occurrences (Figs. E3, E4).