2AM Day 3 Convective Outlook for Thursday, August 28. NO SEVERE THUNDERSTORM AREAS FORECAST
SUMMARY
A few strong thunderstorms are possible across parts of the southern Plains Thursday afternoon and evening.
Synopsis
Upper troughing will persist over the eastern CONUS while an upper ridge remains in place across the Southwest on Thursday. Multiple mid-level perturbations will rotate around the broader upper trough, promoting enough lift to support thunderstorms across portions of the Great Lakes. Multiple rounds of south-southeastward progressing thunderstorms are also likely across the southern Plains into the Southeast along a frontal boundary through the day. Rich low-level moisture and associated ample buoyancy will precede the southern Plains storms during the afternoon, which may promote strong storm potential given modest wind shear.
Southern Plains
An MCS may be ongoing across portions of the Southern Plains at the start of the period, leaving an outflow boundary in its wake. South of the outflow boundary, robust surface heating will take place, supporting surface temperatures reaching 90 F amid low 70s F dewpoints. Despite poor (i.e. 6-6.5 C/km) mid-level lapse rates, the rich low-level moisture may support 2000-3000 J/kg MLCAPE. Modest veering and strengthening of the flow with height will result in 35 kts of effective bulk shear. The development of multicells and/or the southwestward back-building of an older MCS is anticipated by mid to late afternoon, with strong thunderstorms possible. The main uncertainty at this point is the placement and movement of the outflow boundary, which will directly influence where any isolated severe thunderstorms may occur. As such, Category 1/Marginal risk probabilities have been withheld given placement uncertainties, though severe probabilities may be needed in future outlooks.