Nov 12, 2015 8:58 pm
Cry me an atmospheric river
Rain, rain go away
A classic atmospheric river (AR) pattern is producing heavy rain in the mountains for the next 36 hours. Well get spanked pretty good with the rain and wind. This wild weather will really beat up the fragile existing snow pack. Lower elevations will get cleaned out and the upper elevations will be partially reduced. But, what is leftover, will be consolidated into a shallow base. Then new snow will fall.
Expect 5-10 of rain with a snow level of 7000ft for about 36 hours that is painful to write. This AR is a westerly zonal type, which is slightly cooler than the well-known Pineapple Express type from Hawaii. In the end it really does matter, both produce snow levels higher than any NW chairlift its all rain on snow or rain on dirt.
The very top of some peaks (Whistler, maybe Crystal and Mt Baker too) will get some snow during this AR, as those upper lifts are above 6000ft range. Also, the SL will be a tad lower at Whistler. They plan to open next week.
There is good news. On Saturday the AR moves south and cooler air flows behind it and that means snow levels will drop to 4000ft, so in the end, some of the lost snow will get replenished on Saturday.
There are mixed messages from the models re the timing of snow level with the storminess next week. The position of the storm track is different and changing in some models. A slight movement north or south will make a difference with the cold or warm air dominating at a certain time. So expect unsettled weather Monday-Thursday, with initially some rain on snow, then the snow level lowering, with new snow.
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Larry Schick meteorologist
Whats an atmospheric river? Go to powderpoobah.com blog