Once again, large marine heatwaves are causal to a catastrophic climate event, this time extreme rainfall in Libya. A large marine heat wave formed off the Northwest Coast earlier this year and recently expanded into the Mediterranean Sea. The upper air pattern associated with the MHW featured an amplified summertime ridge over Europe compensated for by a downstream trough across the east-central Mediterranean Sea. The most recent version of this pattern featured an omega blocking high-pressure centered on Germany.

Meteorological summer 2023 was the 15th hottest on record and included the hottest summer in recorded in history for Louisiana. However, because the hot summer did not strike the Northeast Corridor, the U.S. population weight cooling degree days were greatly diminished. In fact, the last 3 summer seasons were hotter then summer 2023.

The meteorological summer 2023 season was the 15th hottest on record for the U.S. Louisiana observed their hottest summer on record. Texas and Florida observed their 2nd hottest summer on record. New Mexico and Mississippi observed a top-6 hottest summer season. The Ohio and Tennessee Valley(s) managed a slightly cooler than normal summer of 2023.