Expanding Western Heat Dome Sets Up Dangerous New Wildfire Threats

A new heat dome in the Western U.S. is shifting extreme heat risk westward, following a record-setting July 4^th holiday week in the Eastern U.S.

A strengthening area of high pressure is forecast to bring building heat across the Southwest, Rockies and Plains through mid-July. These dry conditions will heighten wildfire danger in an already vulnerable region, as the North American monsoon begins to take shape—initially expanding fire risk before its rains eventually bring relief.

Heat Expands Across the West

AccuWeather forecasts temperatures will climb well above historical averages as the heat dome expands across the western United States, with highs forecast to average at least 5 degrees above normal across portions of the Rockies and High Plains.

Key impacts:

• 100-degree heat continues across the desert Southwest, including around Las Vegas and Phoenix
• Temperatures could approach or break daily records in the Rockies and High Plains, including in Salt Lake City, Denver and Rapid City
• Increasing energy demand and dangerous conditions for outdoor workers, hikes, recreation and tourism

Monsoon May Increase Fire Risk Before Bringing Relief

Hot, dry weather will continue to fuel existing wildfires while creating conditions that support wildfire ignition and spread. Lightning is frequent cause of wildfires, and the North American monsoon is expected to become more active during the second half of July. In its early stages, it may increase wildfire danger before widespread rainfall arrives and offers relief.

“Early monsoon thunderstorms can create a dangerous combination of lightning and strong wind gusts with little rainfall,” said AccuWeather long range forecaster Paul Pastelok. “Those storms can spark new fires while also generating blowing dust, or haboobs, that quickly reduce visibility and create hazardous travel conditions.”

AccuWeather expert meteorologists warn:

• Existing wildfires to grow, particularly across the Four Corners region
• New wildfires may develop across Montana, Idaho, Wyoming and parts of the northern High Plains as heat, low humidity and wind combine to create favorable fire conditions

The post by AccuWeather.com appears on South Florida Reporter.