Utah has a had a hot, dry summer. In fact, the hottest summer on record. So, everyone starts to panic and think that it means a low snow winter, we're in a drought.... Well, I've lived here long enough and have been a Meteorologist in Salt Lake City to know it is all about patterns, upper air patterns and of course everything is seasonal. With a dominant high pressure sitting over the western US all summer, it has meant a hot, dry summer. I personally have loved it. In summer, it is supposed to be hot, in winter it is supposed to be cold. In between, the change.
So here we are several days into Fall. A high pressure is hard to break down. It is all about studying the upper air patterns in the jet stream and looking out through the Pacific for some "big" storm that will come and finally push the high down. Like a boulder in a stream, it only takes one "bigger" boulder to knock the big guy out and all flow in the stream changes going forward. Our "bigger boulder" has arrived and the ridge is no longer. The pattern is breaking down and it allows for moisture+cold air=mountain snow.
In looking at the latest Pacific satellite, there is a stream of moisture west of Hawaii and it joins with a low pressure over Alaska. It combines the moisture with the cold and converges over Utah on Thursday. Looking at Thursday night, there is a lot of "green" on the map with a dip-or drop south-of the jet stream. Shows moisture over Utah and also the cold air dipping south. And in getting a little on the technical side, looking at all this computer model data, there is a couple of x's on the map...these indicate lift in the upper atmosphere. So, a cold front slides all the way through Utah.
So, with all this technical info I've just given you...all these "ingredients" come together:
1. Moisture coming in from the Pacific.
2. Upper low pressure swinging over bringing the colder air.
3. High pressure broken down.
4. Plenty of "lift" to lift the moisture over the mountains-remember, cold air doesn't hold as much moisture as warm air, so when it pushes up...moisture falls.
Conclusion: Late Wednesday evening through Friday, snow levels come down. For the highest elevations, wouldn't be surpised to see 6"+ and that will be a modest amount!
Looking ahead, next week goes into a zonal flow-west to east. That spells fronts sliding by and keeping moisture glazing northern Utah. Not as cold, but gets the flow going for a pattern change.
Join me this winter as I talk weather and kids!