Nebraska weather is anything but stable and predictable. February reiterated that point to us as we saw record numbers of days with highs in the 70s, our first thunder of 2017 followed by up to two feet of snow in some parts of the state. Severe thunderstorms and tornadoes are most common during May, June and July but they can occur at any time and are increasingly common as warm air patterns begin to dominate during the spring months.