Severe storms expected again Tuesday


All of the ingredients are in place over southern Colorado for another day of widespread thunderstorms, some of which will be severe during the afternoon or early evening.

The Storm Prediction Center in Norman, Okla. extended a higher likelihood of severe thunderstorms westward into the I-25 corridor in an early morning update.

Severe thunderstorms need four ingredients in the right combination to happen. Moisture, lift, instability and wind shear all combine to produce organized, rotating thunderstorms, called supercells, that produce the bulk of severe weather. Severe weather can also occur from organized lines or clusters of storms. All of these storm types are possible in southern Colorado today.

Convective Available Potential Energy (CAPE) forecast by the FOX21 Storm Team Storm-Cast model for 12:00 pm, Tuesday.

Thunderstorms tend to develop on the edges of energy gradients. In the image above, you see that an axis of available storm energy will stretch from Springfield into the Denver metro area. Watch for the first strong storms of the day to

1) Develop in the foothills on the edge of this gradient
2) Intensify rapidly as they move east and hit the edge of this gradient

Storms will move off the hills into an environment favorable for large hail production.

As thunderstorms move into an environment with more storm energy, the updrafts will get stronger. The stronger the updraft, the larger the hail stone that can be held up inside the storm. Several reports of hail around Pueblo yesterday ranged from 1.5″ to 2.5″ in diameter. I don’t see any reason why the strongest storm or two early in the afternoon wouldn’t be capable of doing the same today.

The image below indicates what the atmosphere may look like around 3:00 pm Tuesday. Note that individual cells can be identified from the Pikes Peak region southward. While the cells remain isolated large hail and flash flooding will be the main threats.

FOX21 Storm Team Storm-Cast model depiction of clouds, precipitation, and temperatures for 3:00 pm Tuesday.

As the storms move east late in the afternoon and advance toward Kansas, they’ll tend to organize into a line or cluster. As this occurs, the threat of large hail will drop a little bit and the likelihood of damaging straight-line wind gusts will go up. As the storms go “upscale” the threat for flash flooding will continue.

Storm-Cast depiction of temperature, clouds, and radar at 6:45 pm Tuesday. Individual storm cells from earlier in the afternoon should be congealing into a line over the far eastern plains.

While the overall threat for tornadoes looks relatively low today, so did yesterday! Several tornadoes, including this one photographed in Kiowa County by veteran storm chaser Jeff Piotrowski, occurred with a few of the storms over the plains. That said, while the likely looks low, they can’t be ruled out.

Jeff Piotrowski photographed this tornado, one of several he reported, about 7 miles northeast of Arlington, Colo. Tuesday, June 18.

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