It’s our fault.
Just last week, The Denver Post ran a story showing explaining that Colorado’s severe weather season had gotten off to a slow start.
This week, Mother Nature unleashed a vicious temper tantrum of severe thunderstorms on the Centennial State. While this week’s weather mostly affected the state’s rural eastern plains, it was filled with plenty of eye-catching and even history-making moments.
It started in earnest on Sunday, when massive hail near Otis was (allegedly) measured as large as 4.5 inches in diameter – that’s the size of a grapefruit – tying the state’s largest hailstone on record. A tornado was spotted nearby in Yuma, lasting for approximately 20 minutes, according to reports from local storm spotters.
But that was arguably just the beginning.
On Monday, storms mostly fizzled as they pushed through Colorado, but a dying thunderstorm at sunset on Monday left behind quite the view in Denver and parts of the Front Range. A dazzling display of orange “bubble clouds” – scientifically known as mammatus – brightened the skies of Denver, lighting up social media and the internet for a solid half hour before nightfall.
Tuesday, however, may have been the busiest overall day in terms of both storms and impacts. A five-inch diameter hailstone was measured near Bethune, making it the largest hailstone ever recorded in Colorado. Nearby, a tornado was spotted near Joes. At one point, twin tornadoes touched down near Kirk, creating, as you might imagine, quite the visual.
Up and down they go. @CReppWx @DaveFraserWX About 10 miles North of Kirk CO pic.twitter.com/R7tus1APtC
— Cory Drullinger (@CDrullinger) August 13, 2019
Miraculously, the record-setting five-inch hail in Bethune didn’t lead to any significant damage, according to meteorologist Becky Bolinger. Bolinger was part of the Colorado Climate Center team tasked with verifying the new state record.
In addition to the severe storms on the plains, a second round of dazzling colors moved back over the Denver area for Tuesday night’s sunset. It was almost an identical setup to Monday’s light show.
In all, 67 reports of severe weather were reported statewide from Sunday through Wednesday, according to the Storm Prediction Center’s official tally. So what caused such an active and wild week of weather, even in a place that’s so well known for it?
We’ve recently mentioned the strong correlation between 60 degree dew points and severe weather – it’s an indication of ample moisture in the atmosphere. But while that was the case at the surface, dry air at the mid and upper levels of the atmosphere increased instability. That clash helped fuel strong to severe thunderstorms.
The final factor at play was strong wind shear, the change in wind speed and direction with height that helps sustain and grow severe thunderstorms. Shear typically is strongest during the spring and early summer, typically when the jet stream is involved. But, ample shear this week kept storms rotating and growing this week.
“The mix of high surface dew points, very dry air aloft, unseasonably strong shear and abundant sunshine made for an active week of severe storms,” said Ben Castellani, a meteorologist with BoulderCast who specializes in severe weather.
We may, however, at least be able to hit pause on the wacky weather come Sunday and Monday. A big ridge of high pressure will likely mostly stifle thunderstorm development over the next few days, starting on Sunday. That ridge, however, could bring temperatures near 100 degrees on Sunday or Monday. If temperatures did indeed reach 100 degrees or above, it would mark the latest 100-degree reading on record in Denver.
*If* #Denver gets to 100°+ Sunday or Monday – not currently in the forecast, but close – it’d the latest 100°+ on record.
Current latest: August 16th (2002)#COwx pic.twitter.com/S4LGGsw4WL
— Chris Bianchi (@BianchiWeather) August 16, 2019
