It looks like another very active weather week ahead. Another atmospheric river plume of moisture will move on shore Tuesday bringing increased precipitation throughout the day. Early Tuesday, there could be enough cold air trapped in the valley to start out as snow, although most of the precipitation is likely to hold off until the afternoon, which will allow the warmer airmass associated with the sub-tropical flow to move in, raising snow levels to as high as 7,000’ by the late afternoon hours. Rain, heavy at times will continue into Wednesday morning, with a brief break before another warm and wet storm hits the region on Thursday. By the weekend, temperatures will cool dramatically and stay at or below the freezing mark in Reno Saturday and Sunday.

So far this season we’ve already had some strong temperature inversions. That means that the temperature here in the valley isn’t any warmer… and in some cases will be cooler… than what we see up in the mountains. Some ask why the temperature up there is usually cooler. After all, if cold air sinks, shouldn’t it be colder down here? That only happens when the winds are very light and there’s no mixing of the atmosphere. But if you stir things up, adiabatic cooling begins. More on that tomorrow.