Discrete Supercells Set to Intensify over Northern CO into Southern WY with 3.5-Inch Hail — SevereWX

Thunderstorms are firing off the high terrain in northern Colorado and southern Wyoming this afternoon, primed to strengthen as they push east into the High Plains.

SPC's Mesoscale Discussion 1278 highlights gradual deepening of cumulus clouds in GOES imagery, fueled by orographic lift and steep mid-level lapse rates around 7.5-8°C/km. Daytime heating will spark lightning soon, with storms advecting into an environment boasting mid/upper 50s dewpoints and 1000-2000 J/kg MLCAPE.

Zonal flow aloft provides 45-50 knots of effective shear, favoring discrete supercells. While residual capping and weak large-scale forcing introduce uncertainty on coverage, sustained storms over the plains could deliver very large hail (2-3.5 inches), severe gusts (65-80 mph), and isolated tornadoes up to EF-2 intensity (90 mph).

Watch issuance odds stand at 60% within the next few hours for this zone from roughly Fort Collins northward into Cheyenne and Laramie areas. Storms spreading into lower elevations look most dangerous.

Stay prepared: Monitor radar and local NWS updates, have a severe weather plan, seek sturdy shelter if warnings issue, and avoid travel under storms.