After a rather dull December and start to the new year it is starting to actually feel like winter around here. It was nice to get some snow in the Sierra this past week, and we have a couple more chances this coming week too. The first storm to move through here will bring only a few inches to the High Sierra, and possibly a dusting to the valley, but overall the storm appears to be rather weak. The second storm will move through midweek and will pack more of a punch.
Half way up in the atmosphere is 500mb, and this is where meteorologists look for ridges and troughs and areas that can create uplift. In a scientific sense, we’re looking for positive vorticity advection, which is pretty mush spin in the atmosphere that is moving into another area. Sometimes you can just have a small dip in the flow to get air to rise. This is called a short wave. Sunday night's system is just that, a small wiggle in the upper levels that will give us enough lift for some light snow showers in the Sierra, and possibly a dusting in the valley Monday morning. There is also warm air moving into and over cooler air, which can cause uplift as well.
Most of the latest model runs shows the rain and snow breaking up as it hits the Sierra and moves southeast, which makes me think totals will be light, and it will be hard to get anything in the valley. Regardless this will be a quick hitting system and will be out of here by the afternoon.
There is a slight chance of a stray shower or two Tuesday, but overall looks to be a dry forecast. Have a great week.
