Another hotter than normal summer and early autumn in California thanks in large part to the emergence of Marine Heat Wave NEP24A which started last April offshore and spread into the U.S. West Coast and intensified during the summer season. As usual, the presence of the MHW helped amplify an upper-level high-pressure ridge to cause the hot summer. One fascinating aspect of MHW24A is the persistent and strengthening cool phase of the Pacific decadal oscillation (PDO), normally present when the Northeast Pacific Ocean surface is cooler than normal.

Stronger jet stream flow in the middle latitudes is expected to generate peaking in the 6-10-period and possibly lasting longer due to the Madden Julian oscillation (MJO) influence on the global wind oscillation (GWO) and consequently global atmospheric angular momentum (GLAAM).