Record high temperatures are occurring across the region this afternoon, with low-lying areas seeing highs in the 90s, before a powerful cold front sweeps through Wednesday bringing dangerous wind gusts, a slight chance of thunderstorms, and elevated fire weather conditions.
Record Heat to howling winds and much cooler in Scott Dorval's video forecast
Record Heat and Exceptional Dryness Today
High pressure and mostly clear skies are allowing temperatures to climb through late this afternoon. Low-lying areas including the Snake River Plain and valleys in the Boise Mountains, Weiser Basin, and Malheur County will see highs in the 90s, threatening daily high temperature records for many locations in southwest Idaho and southeast Oregon.
Alongside the record heat is exceptional dryness. The atmosphere is nearly dry all the way up to 500 millibars, creating dangerous fire weather conditions. Afternoon minimum relative humidity values will remain in the teens for southern areas.
Wind Advisory in Effect Wednesday
The primary hazard Wednesday will be the winds as a strong cold front sweeps through the Intermountain West. Wind gusts will increase to 40 to 55 mph across open areas and ridges from late morning through the early evening. A Wind Advisory has been issued for the areas expected to see the strongest winds. Outside of the advisory, winds will still gust 30 to 40 mph throughout the day, except in a few very sheltered mountain valleys.
Winds will kick up dust, especially along the front, leading to reduced visibilities. In the morning and early afternoon as the front passes, thunderstorms will be possible. Gusts out of thunderstorms could locally enhance the already gusty conditions in parts of the upper Snake River Plain, briefly taking winds up to 60 mph. Moderate rain and small hail will also be possible in storms. Forecasters continue to favor thunderstorm development over the west-central and central Idaho mountains.
The coincidence of dry air and gusty winds highlights elevated fire weather conditions, especially Wednesday. Winds will finally begin to weaken after sunset but will remain elevated overnight.
Near-Normal Temperatures Thursday and Friday
Behind the front, temperatures on Thursday will return to near-seasonal levels. Winds will stay elevated through the day, especially in central and south-central Idaho and central Oregon. Friday will bring dry westerly flow with temperatures around normal.
Cooler Weekend Before Warming Returns
A substantial cooldown is expected for the weekend as a shortwave trough moves across the area, dropping temperatures 10 degrees below normal. Not a lot of moisture is expected with this system, so there is only a 20 to 30 percent chance of precipitation for northern Baker County and portions of the west-central and Boise Mountains. Breezy northwest winds are expected Saturday and Sunday afternoon, especially across Baker County and the Snake River Plain. Temperatures will trend back up with dry conditions on Monday.
Tonight
Increasing clouds, with a low around 64. SE wind 5 to 7 mph becoming light and variable after midnight.
Wednesday
Isolated showers between 7am and noon. Cloudy through mid morning, then gradual clearing & not as hot, with a high near 80. Breezy, with wind becoming NW 15-20 mph in the morning. Winds could gust as high as 40 mph. Chance of precipitation is 20%.
Wednesday Night
Mostly clear, with a low around 46. NWwind 10 to 20 mph becoming light after midnight. Winds could gust as high as 35 mph.
Thursday
Sunny & cooler, with a high near 74. Calm wind becoming west NW 5 to 10 mph in the morning.
Thursday Night
Clear, with a low around 46. NW wind around 6 mph becoming calm in the evening.
Friday
Sunny & pleasant, with a high near 76.
Friday Night
Mostly clear, with a low around 45.
Saturday
Mostly sunny, with a high near 64.
Saturday Night
Partly cloudy, with a low around 40.
Sunday
Sunny, with a high near 65.
Sunday Night
Mostly clear, with a low around 41.
Monday
Sunny, with a high near 72.
Monday Night
Mostly clear, with a low around 44.
Tuesday
Sunny, with a high near 78.
