Extratropical Highlights – March 2025

 

1. Northern Hemisphere

The 500-hPa circulation during March featured an elongated region of above average heights over the North Pole and into Eurasia, and below average heights over the Hudson Bay and Southern Europe (Fig. E9). The main land-surface temperature signals include above average temperatures for North America and Europe (Fig. E1). The main land-surface precipitation signals include drier than average conditions in parts of Europe and eastern North America, and wetter than average conditions in northern Russia and western North America (Fig. E3).

 

a. North America

The height pattern across North America was predominantly near normal. Below average heights were recorded over the Hudson Bay and over the Gulf of Alaska (Fig. E9). Temperatures were broadly above average across most of Alaska and the U.S. with many areas in the eastern half of the U.S. reaching the highest 90th percentile of occurrences (Fig. E1). Drier than average conditions were recorded along the Atlantic Seaboard, the Gulf Coast, and the Alaska Panhandle, and wetter than average conditions were recorded in the Pacific Northwest and Great Lakes region (Fig. E3).

 

b. Eurasia

The 500-hPa height pattern was near normal across eastern Eurasia and above average across western Eurasia (Fig. E9). Warmer than average conditions were observed across much of Eurasia with many areas reaching the highest 90th percentile of occurrences (Fig. E1). Wetter than average conditions were observed in Southern Europe while drier than average conditions were recorded in Northern Europe, where many areas reached the lowest 10th percentile of occurrences (Figs. E3, E4).

 

2. Southern Hemisphere

The 500-hPa height pattern featured a near concentric ring of above average height anomalies around the South Pole, enclosing a center of anomalous below average heights (Fig. E15). Parts of South America and Australia recorded above average temperatures with many areas in Australia reaching the highest 90th percentile of occurrences (Fig. E1). Drier than average conditions continue for much of South America with many areas, again, reaching the lowest 10th percentile of occurrences, and wetter than average conditions were recorded in eastern Australia where many areas reached the highest 90th percentile of occurrences (Figs. E3, E4). The South African monsoon season runs from October to April. Following a wetter than average January and February, March rainfall totals approached the 60th percentile of occurrences, indicating slightly above normal rainfall during the month (Fig. E4).