DENVER – The threat of severe weather will be considerably higher across northeast Colorado Thursday afternoon, with damaging winds and golf ball-sized hail possible along and east of the I-25 Corridor, according to forecasters with the National Weather Service (NWS).
A severe thunderstorm watch has already been issued by the NWS for parts of the Denver metro as well as the eastern plains until 9 p.m. Scattered golf ball-sized hail, frequent lighting storms and scattered gusts up to 75 mph are possible, officials said.
In Denver, a severe thunderstorm warning was issued until 4:15 p.m. Half-dollar sized-hail which could damage vehicle is expected, NWS forecasters said.
The greatest risk of severe storm with wind gusts potentially between 60 and 80 mph will be east of the I-25 Corridor, “but that could organize farther west toward Sterling, Akron,” weather service officials said in their latest forecast discussion.
Modeling also suggests that just before sunset, the threat of a supercell tornado forming “mainly east of a line from Sterling to Akron” is possible is weather conditions come together at the right moment.
⛈️Severe storm threat is considerably higher today.— NWS Boulder (@NWSBoulder) August 3, 2023
Storms will develop by early afternoon, and then organize and strengthen as they move east across the plains. Damaging winds (60-80 mph!) and large hail will be the highest threats. #COwx pic.twitter.com/JQJPtWkqHz
The best chance of storms – between 25% to 30% – will be east of Highway 71 between 4 and 7 p.m., with up to 1.3 inches of additional rain possible by the time the storm moves out of the area.
“While this is not an all-star team, they are still above average in terms of severe and flooding potential,” forecaster said, warning that recent down pours could make for localized flooding because of saturated soils.
The storms will form over the mountains in the early afternoon before organizing and strengthening as the move east across the eastern plains.
So, about that monsoon season in Colorado
The word monsoon refers to the seasonal shift in the wind direction.
In Colorado, that leads to stormy weather in the months of July and August. We get an area of low pressure over the Desert Southwest that draws up moisture from the Pacific Ocean. In addition to that, a ridge of high pressure to the east pulls in moisture from the Gulf of Mexico.
August in Denver: The heat eases up but monsoon moisture remains in full force
"Some hail, primarily heavy rain flash flood and definitely lots of cloud to ground lightning strikes occur when the monsoon season gets going," Greg Heavener, a warning coordination meteorologist at the National Weather Service in Boulder, said.
He also said our summer monsoon produces our most active lightning season. That is due to the amount of moisture, the amount of lift and how slowly storms tend to move.
Heavener said this year, we can expect a later start to the season, and just how much rain we'll see is hard to forecast. One thing is for sure: Heavener said monsoon season is on its way, and any additional rainfall we get could cause high water levels and issues with some of our streams and creeks which could lead to flash flooding.