First Alert Weather Day: Flood Watch issued with showers and thunderstorms

Flood Watch in Effect Through Wednesday Evening

Overview:

Flooding caused by excessive rainfall is possible across portions of Idaho. Flash flooding is also a concern, especially over recent burn scars.

Affected Areas:

Central Idaho: Big Lost Highlands/Copper Basin, Challis/Pahsimeroi Valleys, Frank Church Wilderness, Lost River Range, Lost River Valley, Sun Valley Region, Wood River Foothills

Eastern Idaho: Beaverhead-Lemhi Highlands, Big Hole Mountains, Centennial Mountains–Island Park, Teton Valley

South Central Idaho: Eastern Magic Valley, Shoshone/Lava Beds

Southeast Idaho: Arco/Mud Lake Desert, Bear Lake Valley, Bear River Range, Blackfoot Mountains, Caribou Range, Franklin/Eastern Oneida Region, Lower Snake River Plain, Marsh and Arbon Highlands, Raft River Region, Southern Hills/Albion Mountains, Upper Snake River Plain

Timing: Now through Wednesday evening

Impacts: Excessive runoff may lead to flooding of rivers, creeks, streams, and low-lying areas Urban and poor drainage areas may also experience flooding Creeks and streams could rise out of their banks

Forecast Details:

More scattered showers and thunderstorms are expected to develop Wednesday afternoon, gradually becoming more widespread by evening. These storms will bring heavy rain but aren’t expected to produce strong winds or hail. By tonight, the rain will likely form a solid band with embedded thunderstorms. Expect overnight temperatures to drop to around 60°, with light southeast winds shifting to the north at about 5 mph.

A low-pressure system moving from northern Nevada into southwest Idaho will keep the region wet. Showers and thunderstorms are expected throughout the day, with steady temperatures near 60°. Winds will start from the east at around 5 mph and shift to the south-southwest later in the afternoon. The chance of rain is very high, and heavy rainfall remains the main concern.

Rain continues Thursday, with possible thunderstorms developing after noon. The high will be near 70°, with winds from the south at about 10 mph, gusting up to 20 mph by the afternoon. On Friday, conditions begin to improve, though there’s still a 40% chance of showers or a thunderstorm in the afternoon. Skies will be partly sunny with a high around 70°F.