Given the warmer oceans and constricting ice cap of recent decades, there is a tendency for warmer climate vs. the 30-year normal and September in the U.S. is an example. During the past 10 years, September has averaged 1-3F warmer than the 30-year normal, making summer feel longer.

The latest U.S. population weight CDD forecast was adjusted slightly warmer (321 to 329) for August which is a moderately hotter than normal signature (compared to the 30-year normal). August 2023 will average slightly less hot than the past 3 years.

Last week, Nino34 SSTA warmed to a robust +1.3C while waters off the northwest coast of South America (Nino12) are roasting at above 3C. Waters near the Dateline are warming although lagging the East Pacific. Upper ocean heat is plentiful across the entire equatorial Pacific.

A thunderous negative phase of the Antarctic oscillation (-AAO) also referred to as Southern Annular Mode (SAM) is present in the southern hemisphere. The result is uncharacteristic deep upper troughs in the southern hemisphere middle latitudes. One of these troughs impacts South America weather.