Much of the northern hemisphere observed historic heat including most of Europe and the U.S. West Coast during July 2018. The hot temperatures are attributed in-part by anomalous warm ocean surface temperatures in the middle latitudes causing the atmosphere to warm extending downwind across land masses. The upper ridge areas are persistent, cause dryness and following heat. The phenomena is somewhat unrelated to El Nino southern oscillation.

The West/Southwest U.S. drought zone received some marginally beneficial rainfall last week particularly in Texas. However, concern increases regarding down trees/power outage potential in the Mid-Atlantic region where soil moisture is excessive.

The subsurface (and surface) ocean environment of the equatorial East Pacific can warm but the atmosphere must react to that warmth to initiate El Nino. A measure of the atmospheric environment to the ocean temperatures of the equatorial Pacific Ocean is the multivariate ENSO index. The mid-2018 trend of MEI is away from El Nino onset.

The U.S. climate observations for July 2018 continue to produce an extreme signature due to the tendency of recent climate (past 5-10 years) to produce increasing number of weather patterns featuring stagnant high pressure ridge areas that cause a dry climate which dries soils and enhances attendant anomalous heat or stationary upper troughs causing excessive rainfall to produce historic flooding.