Let's talk about Arizona weather: Thundersnow
Despite what some may think, Arizona does get snow -- lots of it. In fact, Flagstaff, Arizona, gets around 100 inches of snow every year. Though many Arizona snow storms are run-of-the-mill, some can produce rare thundersnow.
What is thundersnow?
Thundersnow can also be known as a thunder snow storm. It's an unusual kind of thunderstorm with snow falling as the primary precipitation instead of rain. Pretty cool, huh?
Check out this example of thundersnow in Flagstaff, Arizona
Question: Why don't we get as many thunderstorms in the winter as we do in the summer? We seem to get more rain, but it usually doesn’t come with lightning and thunder.
We actually do get winter thunderstorms in Arizona. The cold front that brought rain to the Phoenix area and snow to the high country contained thunderstorms. The National Weather Service issued a severe thunderstorm warning late on Jan. 31 and there were also reports of rare thundersnow storms up north that night.
However, there are more instances in the winter months where we get rain without the atmospheric violence that occurs during the monsoon season. The reason for that is there is often less atmospheric instability during the cooler months.
James Sawtelle, a meteorologist with the National Weather Service in Phoenix, explains that warm, moist air near the surface mixing with colder, dry air aloft makes for instability, which can spawn storms.
This instability allows for taller clouds to form (the massive cauliflower-like clouds we often seen in summer) which develop the necessary charges to form lightning. The clouds we most often see in the winter don’t usually have that kind of height.
“The instability is greatest in the summer time when the low levels of the atmosphere and the surface of the earth are quite warm or hot,” Sawtelle said. “That produces a stronger lapse rate, or in other words, as you go from lower elevations to higher elevations, the temperature drops much quicker in the summer time.”
There are times when the conditions necessary for storm development are more favorable in the winter as the Jan. 31 storms illustrate. In the winter the polar jet stream is more likely to be further south and other dynamics are also in place.
“Those factors do support thunderstorms in the winter,” Sawtelle said. “It’s just that in general you’ll see more thunderstorm activity with summer monsoon-type weather patterns.”