The North Atlantic Warm Hole (NAWH) is an area of persistent cooler-than-normal sea surface temperature anomalies (SSTA) becoming more prominent in 2013 related to increased melting of the Greenland Ice Sheet and persistent each warm season since that time including 2021. The NAWH has been displaced eastward to just-off Western Europe (Fig. 1). Aloft, the air cools over the NAWH and becomes a home for a persistent upper trough. During July, the upper trough has shifted slightly east from the 2021 source region causing excessive rain storms extending from France to Germany to Poland (Fig. 2). Most recently, the rains have caused devastating widespread flooding in Germany.

Dryness propels intensifying drought and historic heat across the Canadian Prairies and North-central U.S. in the medium-range forecast. The dryness and anomalous heat expands into the west and northwest U.S. Corn Belt.

NOAA/CPC identifies many June historic weather and climate events occurring during June 2021. The June 2021 upper air pattern provided by the International Research Institute for Climate and Society helps to explain the super warmth.

The deep tropics of the North Atlantic basin are becoming somewhat warmer than normal. SSTA of >1C is considered a moderate warm anomaly and much of the deep tropics have recently reached that threshold. Robust warm anomalies of >2C rest on the equator. Anomalous warm SSTA in this region are generally well-correlated with increased convection (and tropical cyclone/hurricane risk) especially if the proper atmospheric conditions are present.