12AM Day 1 Convective Outlook for Saturday, August 23. THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE CENTRAL HIGH PLAINS .
SUMMARY
Strong to isolated severe storms are possible in the central High Plains today.
Synopsis
A mid-level trough will amplify across the Great Lakes today with strengthening mid-level flow across the Northern Plains. Surface high pressure building into the northern Plains this morning will advance into the central Plains by this afternoon and push a cold front south across the Plains and Upper Midwest. Farther east, a cold front, associated with the mid-level trough across the northern Great Lakes, will move across the Great Lakes and Ohio Valley.
Central High Plains
Upslope flow in the wake of the cold front across the central High Plains may provide an environment favorable for a few isolated strong to severe storms this afternoon/evening. Terrain driven storms are anticipated across much of the central Rockies. A few storms are expected to move off of the higher terrain, and with support from low-level upslope flow, maintain themselves along the Front Range as they move south. Steep mid-level lapse rates and around 35 to 40 knots of mid-level flow will support the potential for isolated supercell structures capable of isolated large hail and severe wind gusts. Storm motions around 350 degrees and storm formation expected along the mountains and immediate foothills will result in a very narrow area of risk along the Front Range from southeast Wyoming to central Colorado. Slightly stronger instability across southeast Colorado and the potential for some clustering of storms supports a slightly wider marginal extending into this region.
Great Lakes
A few showers and thunderstorms will likely develop along a cold front as it moves across the Great Lakes this afternoon. Warm 700mb temperatures in the presence of only low 60s dewpoints will limit overall buoyancy and updraft strength. Therefore, no severe thunderstorms are expected.