The Treasure Valley and central Idaho mountains will see continued warm temperatures and daily thunderstorm chances through Thursday before a significant pattern change arrives Friday, bringing a cold front, remnant tropical moisture from Tropical Storm Iselle, and the potential for severe thunderstorms with heavy rain.
Sizzling heat gives way to weekend cooling in Scott Dorval’s video forecast
Wednesday and Thursday: Heat Continues with Thunderstorm Chances
Temperatures will remain well above normal Wednesday and Thursday, with the Treasure Valley seeing highs near 97 degrees Wednesday and 95 degrees Thursday. For context, Boise’s average high for late August is around 89 degrees, meaning these temperatures will run about 6 to 8 degrees above normal.
Isolated afternoon thunderstorms will be possible near the Nevada border into the western Magic Valley both Wednesday and Thursday afternoons, with strong gusty winds being the primary threat. The central Idaho mountains will also see isolated thunderstorm chances each afternoon. Anyone planning outdoor activities in the mountains or Magic Valley area Wednesday and Thursday should be prepared for rapidly changing weather conditions in the afternoon hours.
By Thursday, increasing southwest flow aloft associated with a strengthening trough will bring gusty winds to southeast Oregon and far southwest Idaho. Combined with low relative humidity and warm temperatures, this will create an elevated wind-driven fire weather threat across these areas. Outdoor recreationists and travelers in these areas should be aware of the elevated fire danger Thursday afternoon.
Friday: Cold Front and Tropical Moisture Bring Severe Storm Potential
The most significant weather event of the week arrives Friday as a cold front drops temperatures back to near normal. What makes this system particularly noteworthy is the remnant moisture from Tropical Storm Iselle, which will be transported over the area in southwesterly flow aloft ahead of the cold front…