1PM Day 3 Convective Outlook for Monday, July 14. THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE NORTHERN PLAINS
SUMMARY
Isolated strong to severe thunderstorms are possible across portions of the northern Plains Monday evening.
Synopsis and Discussion
A belt of moderate flow aloft will generally extend eastward along U.S./Canadian border on Monday, with weaker flow and higher heights across the remainder of the CONUS. Models do depict a positive-tilt trough dropping south across the Pacific Northwest and into MT, with increasing large-scale ascent favoring increasing rain and thunderstorm chances late.
A surface trough will deepen from eastern WA into southern MT and into western SD late Monday, ahead of the elongated west-east oriented cold front. Dewpoints in the 50s F will exist both near and behind the front from central MT into the Dakotas, contributing to MUCAPE over 1000 J/kg. Weak to moderate deep-layer effective shear near the front may yield a few storms capable of severe gusts as activity pushes south into the heated air mass south of the boundary. Otherwise, elevated/marginal hail may occur as well. A nocturnal low-level jet may support strong to locally severe storms into parts of northern MN overnight.
Elsewhere, an expansive area of low-level moisture will remain from the Plains to the East coast, beneath generally weak flow aloft. This will support scattered storms, though any severe wind potential should be quite localized.