Smoke from the Butte Fire will continue to send haze into the Reno area for the next couple of days, and a very strong ridge of high pressure will give us another shot at a record high temperature (upper 90s) on Saturday. The heat will generate some cloudiness Saturday afternoon and could allow a few showers or thunderstorms to develop Sunday afternoon. A cold front will move through the region after the weekend causing the temperatures to drop and the winds to pick up early in the week. High temperatures will fall from the mid-80s down to the mid-70s on Tuesday and Wednesday before recovering to the low 80s by the end of the week.
So why are our thunderstorms weaker than in the middle of the country? Let’s start with airmasses. Even though we can get what we call a monsoonal flow up from the subtropics, we are still the driest state in the union, and there is much less moisture in our air than you get from the central part of the country. Dew points here rarely get out of the 50s. But there’s more to it than that.
Geography, or more specifically topography, also plays an important role, especially when it comes to producing some of the more dramatic side effects of plains thunderstorms like tornados. Because we live in a mountainous area, we tend to get a lot more turbulent flow at lower altitudes, and that can disrupt the elements necessary for supercell thunderstorms. Even if we do get a very strong thunderstorm to form here, because it usually doesn’t have a strong and consistent frontal boundary and upper level shear to keep it developing, they tend to collapse on themselves before they can build up to the “supercell” level.
But out in the plains, the flat land and huge contrasts in airmass types allows a continuing “feeding” of thunderstorms, giving them a much longer lifespan, and a chance to become much more powerful than those in our neck of the woods. Not that that’s a bad thing… after all, it’s not like we could use more tornados cruising through town.