A persistent marine heatwave in the mid-latitude West Pacific has elevated high pressure aloft risk for much of the past several years. A strong marine heatwave in the Northeast Pacific in 2014-16 having tendency to re-emerge in that area last decade shifted westward toward the China Coast and eastward to the Dateline in this decade. The marine heat wave is vividly evident east of China and Japan now and aloft is well-correlated to strong high-pressure ridging extending across the mid-latitude West Pacific to Mongolia during the past 45 days.

The latest forecast remains steady with 21 tropical storms, 11 hurricanes, and 5 major hurricanes expected. The Climate Impact Company hurricane tracks forecast indicates 7 of the 11 hurricanes will strike the U.S. Several of these coastal strikes could be major hurricanes.

During the past 30 days, a semi-permanent marine heat wave located northeast of Hawaii has strengthened sharply and is edging eastward. An eastward shift to the North America West Coast would promote widespread anomalous heat and dryness causing drought. This type of eastern surge is not likely during La Nina. However, close monitoring warranted into early summer 2024!