Autumn storms provide longer advance warning of their arrival than summer storms. The reason is the change in what causes storms during each season. Summer storms are smaller in horizontal extent than winter storms. They are also have much shorter life-spans. Winter storms are not as tall as summer storms. Summer storms develop quickly, winter storms take many hours or days to develop after they are identified.
NOTE: There is rarely a situation where storms are completely a “summer” or a “winter” storm. I am using that comparison to help readers understand that there are usually major differences in what causes storms to form and develop and how long they live during summer and winter.
Summer storms form and live off large amounts of warm air and moisture and flow patterns. Winter storms form and live off changes in temperature wind velocity with height.
The heat and moisture available in summer are the main driver of summer thunderstorms. Flow patterns determine the type of thunderstorm and severity. Winter storms depend on air flow vertically through the atmosphere. Differences in temperature, moisture, and flow patterns shape the intensity and type of storms. Those differences cause summer storms to be relatively small in size when compared to winter storms but summer storms are usually taller than winter storms. Winter storms sprawl over several states at once, sometimes influencing weather in one-third to one-half of the nation. Commercial airliners go around thunderstorms but can usually fly over winter storms.
Today was a good example of how the sky looks in winter compared to summer. On the prairie we can see storms coming for many miles so it is easy to change in cloud types when looking from horizon to horizon. The flat clouds of winter were on display. Below are several pictures of the sky this afternoon. From the top picture to the bottom the evolution of clouds indicated more of a winter than summer type storm was approaching. It is too bad the Sun went down because there would have been more to see.