Pacific water temperatures could foretell heat waves in the US

Associated Press : Weather forecasters in the US may soon be able to predict heat waves as much as 50 days in advance. Based on weather data from 1982 to 2015, Karen McKinnon of the National Center for Atmospheric Research and colleagues have found a strong correlation between periods of extremely dry, hot weather in the Eastern US and a system of sea-surface temperature anomalies, called the Pacific Extreme Pattern (PEP), in the Pacific Ocean. During a PEP event, a large area of the Pacific north of Hawaii experiences unusual temperature extremes: The southern part gets much hotter than normal, and the northern part gets much colder. The unusual temperature patterns appear to generate a train of atmospheric weather waves that travel across the US to the humid East Coast, where they get stopped and create a sustained high-pressure zone. Better understanding of the physical mechanisms underlying such weather anomalies could allow forecasters to improve predictions of extreme weather events. The ability to forecast a heat wave could allow time for farmers to plan irrigation efforts, city governments to set up cooling centers for the poor and elderly, and utilities to anticipate additional electrical power needs.