After closed passes, heavy snow and high winds, the weather conditions will calm down as we head into the work week. Warmer air will move into the region and scattered rain and snow showers will decrease Monday morning after heavy snow causes a very difficult time getting across the Sierra. Temperatures will be mild through the rest of the work week (near the 50 degree mark in Reno) with the next storm moving through on Wednesday, with mountain snow above 6,500’ and valley rain.

Many have asked me what the difference between freezing rain and sleet is. Sleet is basically snow that starts to melt on the way down, and falls as a mix of rain and snow. Freezing rain is precipitation that has completely melted into rain on the way down, and then falls into cold air at the surface that is below freezing. This rain usually freezes rapidly as it hits the ground, and is perhaps the most dangerous winter weather pattern. How do you get it?

In general (and perhaps obviously) you need to have warm air aloft on top of cold air at the surface… along with (again obviously) some rain. This can occur a couple of different ways. A warm front will always shove warm air up over colder surface air, and is a relatively common way to get freezing rain in the central plains states. Here in Nevada, these cold air inversions that we have been having can also trap enough cold air in the valleys to create freezing rain, although it is fairly rare.

After a dry and warm Friday, the weather pattern will change as we go into the weekend, with a series of storms lined up to come through. None of the storms are particularly strong in and of themselves, but cumulatively they could add a nice boost to the mountain snowpack. The strongest of the storms gets going Saturday, with snow levels that will approach the valley floors, but it isn’t likely we will get any valley accumulations, and we will see significant shadowing out due to strong southwesterly flow over the mountains. A Winter Storm Watch is posted for the mountains starting early Saturday morning and going through Sunday morning. Snowfall amounts will range from a few inches at Lake Tahoe to a foot or more on the passes.

The weather remains unstable through the middle of next week with scattered valley rain and mountain snow.

We will have a very cold introduction to 2019, as clearing skies and a cold airmass will combine to ring in downtown Reno temperatures down into the 20s with wind chills that could drop into the teens. And the first day of the New Year will start out at sunrise in the tees (without wind chills, topping out in the mid-30s under mostly sunny skies. The first week of the New Year will be mostly dry, with a warming trend into the weekend with the low 50s reachable by the weekend. A weak storm system gives us our first chance of 2019 rain or snow by Sunday.

For those of you keeping score, winter officially began at 2:22 pm local time today (Friday.) And as is not always the case, this time the weather will play along.

A few light mountain showers should dry up for Saturday, before a moderate winter storm makes its way into the region late Sunday into early Christmas morning. Saturday’s high temperature will peak in the upper 40s with light winds, climbing to the low 50s on Sunday. By Sunday afternoon some light to moderate precipitation should start in the mountains, with winds picking up, especially along the ridgetops. A Winter Storm Watch has been posted for the mountains starting Monday morning and going into Christmas morning, with a few inches likely at Lake level, and a foot or more possible in the upper elevations.

As for the valleys, rain showers with gusty winds are likely Monday. As the cold front moves through the snow levels will drop to the valley floors, giving us a chance of a white Christmas, although the airmass should dry up with the passage of the front and accumulations should be limited in the lower valleys.

Three things will occur in our weather picture, all involving increases. First, the clouds will increase overnight tonight, ahead of a storm system that is likely to miss us here in western Nevada. Along with that frontal band, the winds will also increase overnight tonight, which should be enough to keep the temperature inversions from forming, and will keep our overnight low temperatures on the mild side. Finally, with the ejection of the inversions and the rebuilding of a ridge of high pressure, temperatures will also increase to the upper 40s on Wednesday and peaking in the low 50s by Friday. A couple of weak systems bring only a slight chance of rain showers late Friday night, and then a better chance of rain Sunday afternoon into Monday morning.

A Winter Storm Warning is in effect in the mountains from late Wednesday night through early Friday morning, with total accumulation ranging from a few inches at the Lake level to two feet or more up on the crests of the Sierra. After a break on Friday, a colder and slightly drier storm moves through the region bringing more snow, but this time to all elevations. Accumulations in the valley are likely to be light, but the foothills could accumulate enough to cause some travel issues. A Winter Storm Watch is now up for the upper elevations for Late Friday night through Saturday night, with a foot or more possible in the prime locations. Temperatures will drop to the 30s to end the week, with overnight lows likely to fall to the teens.