San Juan Mountain Weather Forecast–Friday March 16, 2012–09:00
Another very warm, sunny day (Friday) with variable high clouds and light backing SW winds. We’ll see a warm night with increasing SSW winds (110 knot jet) Saturday in advance of a large low pressure trough moving down the coast from the Pacific NW. The deepening trough is in response to a strong Jet pushing in from the Gulf of Alaska combining with a strong surface cold front. The winds first move into Utah/Arizona then western Colorado bringing more red dust (ooohh) ahead of the storm.
The trough has plenty of Pacific moisture and instability so spring thunderstorms should be present on Sunday when the front collides with the unstable air mass by mid-day. The southern San Juans will receive the brunt of the storm with snow levels dropping into the valleys by Sunday evening. Models in fair agreement producing 15 to 20 inches of snow above 11,000′ on favored SSW slopes by Sunday evening. Looks like a nice March storm.
Unsettled weather through Monday evening then a warm-up beginning Tuesday with a high pressure ridge building overhead.