Thermal extremes are present and more are ahead! The Central U.S. heat wave marches on and fades later this week into early next week. Another heat wave re-emerges in the West and expands to the North-central U.S. later next week. A North Africa to Western Russia heat wave emerges next week. Meanwhile a freeze strikes Southeast Brazil.

La Nina development appears to be developing rapidly! The Nino34 SSTA region is already at the La Nina threshold. Last week, the subsurface equatorial East Pacific cooled rapidly and if that trend continues a La Nina onset will be here quickly, possibly by September

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.