An upper-level ridge will build into the region over the next several days, bringing a steady warming trend and dry conditions for the holiday weekend, though isolated thunderstorms will continue over the Idaho highlands through Friday.
Lingering moisture over southwest Idaho will keep the threat of isolated thunderstorms over the mountains this afternoon and evening. Westerly flow will push the moisture east on Thursday, keeping a threat of isolated thunderstorms mainly over the southwest Idaho highlands near the Owyhees and south of the Snake River Plain to the Nevada border. Similar conditions are expected on Friday with slightly warmer temperatures.
The Fourth of July weekend will be dry area-wide as a Four Corners ridge continues to build. Guidance has continued to trend upward for maximum temperatures, with valley temperatures now forecast to reach the mid-90s on the Fourth, around 5 degrees above normal. Saturday will be dry across the entire area.
The heat will continue to build into early next week, with the hottest day coming Monday when near-triple-digit temperatures are expected in the Snake River Plain. This will bring moderate HeatRisk impacts to the Snake River Plain and lower valleys starting Sunday, with localized areas of major HeatRisk impacts on Monday. Those sensitive to heat should consider taking precautions if planning to be outdoors. Moisture advection in the southwesterly flow will bring a risk of terrain-driven showers and thunderstorms each afternoon starting early next week, while temperatures in the 90s will persist through at least the middle of next week.
Tonight
Mostly clear, with a low around 53. Light wind.
Thursday
Sunny & warm, with a high near 86. Light wind.
Thursday Night
Mostly clear, with a low around 57. Light wind.
Friday
Sunny and hotter, with a high near 90. Light wind.
Friday Night
Clear, with a low around 58. Light wind.
Saturday
Sunny and hotter, with a high near 95.
Saturday Night
Clear, with a low around 61.
Sunday
Sunny and quite hot, with a high near 98.
Sunday Night
Mostly clear, with a low around 65.
Monday
Mostly sunny and very hot, with a high near 100.
Monday Night
Partly cloudy, with a low around 65.
Tuesday
Sunny and hot, with a high near 97.
Tuesday Night
Mostly clear, with a low around 64.
Wednesday
Sunny and hot, with a high near 95.
