Weather Talk: Distinct weather patterns influence timing of thunderstorms
There are two times of day when thunderstorms are most likely to happen over eastern North Dakota and western Minnesota, and they are related to two distinctly different weather patterns. During spring, early summer and early fall, the most likely time for thunderstorms is in the late afternoon and early evening. Near the hottest time of the day, thermals rising off the warm grounds are at their strongest, and this may be just enough to kick off a few thunderstorms. During July and August, we tend to get more thunderstorms after midnight. When our weather is at its hottest, the upper levels of the atmosphere are often warm as well, making it harder for just the thermals to initiate storms. But at night here in the Northern Plains, storms can get a little boost from something called the nocturnal jet stream – a river of air a few hundred feet above the ground that blows from south to north causing a convergence of air that enhances rising motions in the atmosphere.