6PM Day 1 Convective Outlook for Thursday, February 19. NO SEVERE THUNDERSTORM AREAS FORECAST
SUMMARY
Severe storms are not expected today or tonight.
Synopsis
A negative-tilt shortwave trough responsible for isolated thunderstorms over eastern Lower MI this evening will continue to lift north across the Great Lakes, while westerly winds at 850 mb maintain a degree of instability over southwest Ontario and perhaps into parts of western NY. Thunderstorm chances here will be relatively low.
To the south, height falls will occur overnight across the Mid MS and OH Valleys as a low-amplitude shortwave trough moves across KS and OK. Isolated activity may occur into Thursday morning from parts of MO into TN and IL/IN as elevated instability develops within a subtle warm advection regime ahead of the upper trough.
Elsewhere, lift will increase across northern CA as a shortwave trough dives southeastward just offshore. Cold temperatures aloft and relatively warmer air near the coast may yield a few lightning flashes overnight.