Signals Summary: Record-breaking triple digit heat has taken hold in the southwestern US. Recent years have shown an uptick in the number of extreme, record-breaking heat events in the region. The increase in extreme heat events is a clear signal of climate change. At least half of all record breaking heat waves in the West would not have been record-breaking without climate change, according to a 2012 study.
Article Excerpt: Temperatures in Las Vegas have never hit the century mark in April before, but that’s the forecast for Wednesday, as a record-setting and potentially historic spring heat wave peaks in the Desert Southwest.
Phoenix is predicted to hit 106 degrees Thursday, which would likewise be its hottest weather ever observed during the month.
The heat wave is due to a zone of intense heat pressure sprawled over the Southwest.
Excessive heat warnings stretch from southwest California into southern Nevada and through much of southern Arizona. The warnings, in effect through Thursday, caution “dangerously hot conditions” are expected.
“These extreme temperatures this early in the season will likely bring significant heat impacts and precautions should be taken to limit exposure to the heat,” wrote the National Weather Service forecast office in Phoenix.
While the current weather pattern has set the stage for this heat wave in the Southwest, it is probably more intense because of climate warming from the long-term buildup of greenhouse gases in the atmosphere.
“Every part of the Southwest experienced higher average temperatures between 2000 and 2015 than the long-term average (1895-2015). Some areas were nearly 2°F warmer than average,” stated a report on climate change indicators from the U.S. Environmental Protection Agency.