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Wednesday, December 9, 2015

drama potential... (pm.09.dec.15)>

Wednesday's stats:

Low temp: 52.2F (11.2C)
High temp: 56.0F (13.3C)
Rainfall: none

Our air quality is quite good this evening, as this air mass starts to get mixed and churned up a bit in advance of an incoming storm system.  We can call it partly cloudy as the sky turns dark -- there's some scattered mid-level altocumulus out there.  You can see from the stats above that temperatures moved very little today, thanks to a predominance of cloud cover along with some cooler air in the middle layers of the atmosphere starting to filter in.

Interesting times are ahead for us during the next couple of days, as we await the impact of a complex upper-level storm system now easing in from the west-northwest.  A preliminary wave/disturbance is already affecting us with the increased cloudiness and slightly cooler temps today, but the main event, in the form of a broad low pressure trough now just east of the Caspian Sea, could deliver some drama by this time tomorrow (Thu) evening.

By far the coldest air of this new winter season is waiting in the wings across central Asia, while a moderate amount of moisture is being pulled up from the south, against the north Indian Himalayan ranges.  According to the latest data, ingredients should coalesce and converge by Thursday afternoon or evening, leading to an outbreak of precipitation which should last into Friday night.  The models are not in total agreement, but there are some impressive precip totals hinted at -- possibly in the 1-2" (2.5-5cm) range.  That translates into around a foot (or more) of snow across elevations above 8000ft/2400m or so.

For those of you who've tracked these winter systems with me over the years, you know there are a variety of ways the whole thing can tip significantly one way or another!  So -- let's watch it come together.  THE 7-DAY OUTLOOK (tab above) has the forecast details.