Thunderstorms bringing rain, hail and winds up to 60 mph may be headed to Boise

Yahoo

a day ago

Grab your umbrellas, Boise! Weather experts are forecasting wind, rain and hail this week.
Les Colin, a Boise-based National Weather Service meteorologist, said there is a 20 to 30% chance of a thunderstorm hitting the Boise area Tuesday evening, with a nearly 60% chance of a larger storm hitting Wednesday.
'It looks like there are going to be thunderstorms that are going to form first in southeast Oregon, and the outflow from those storms could go all the way over to here,' Colin told the Idaho Statesman by phone on Tuesday morning.
Colin expects the first storm to hit sometime after 5 p.m. Tuesday evening and last through 11 p.m. The Tuesday storm would most likely be dry, bringing high winds and blowing dust up to 60 mph, but no rain, according to the meteorologist.
The National Weather Service predicts the Wednesday storm to be more significant, with rain, gusty winds and hail. Colin predicted that second storm would begin after 2 p.m. and last through sunset.
Colin said if the thunderstorm's path moves in such a way as to directly hit Boise, it could bring up to half an inch of rain. However, Colin said a direct hit is unlikely, and Boise is expected to see measurements closer to 0.1 to 0.2 inches of rain.
Experts at the National Weather Service are weighing whether to issue a flash flood warning for Wednesday. The biggest areas of concern are places where recent wildfires left a burn scar. National Weather
Service meteorologist Spencer Tangen said the burn scars left by the Wapiti Fire near Grandjean and Stanley are of particular concern. He warned people planning to camp or drive near those areas to be aware of the risks from debris flow.
Hot wildfires can cause soil to become hydrophobic, meaning the soil can't absorb water anymore, Tangen explained.
'Basically, water just kind of runs off the soil and will wash out a thin layer of dirt that's developed on top of that burned hydrophobic layer,' Tangen said by phone. 'That makes it so that you can get debris flows and flash flooding much easier, because the ground can't absorb the water.'
The National Weather Service said a trough — an elongated area of relatively low atmospheric pressure — coming in off the Pacific Ocean is causing this stormy weather to begin forming in Oregon.
After Wednesday, it's sunny skies and above-average temperatures ahead for the Treasure Valley.
'The rest of the week, it should be dry and pretty hot, actually,' Colin said. 'It will continue to be about 5 to 10 degrees hotter than normal, which would put it close to 90 degrees for highs, similar to what you would expect in the first week or so of July.'