Wednesday, December 12, 2012

ready and waiting... (pm.12.dec.12)>

Wednesday's stats:

Early morning low temp: 39.7F (4.3C)
Afternoon high temp: 50.4F (10.2C) -- at 12:30pm
Rainfall: none

Our Wednesday shaped up pretty much according to expectations, with morning sun giving way to increasing/thickening clouds as the day progressed.  Temperatures were slightly milder than yesterday's, but not by much -- we're still solidly below normal for mid-December.

The updated weather data flowing in tonight indicates that our current forecast of a significant early winter storm remains on target.  It really is early in the season to be dealing with something of this magnitude, but so far, the various computer models haven't backed off on the intensity of this system as its center moves from Iran into Afghanistan this evening.  That circulation center should be squarely on top of us by mid-morning on Friday, with surface low pressure winding up across the plains of northwest India.  What this means is that we should see an increasing chance of rain during the coming 18 hours or so -- and atmospheric temperature profiles indicate that a change-over to snow could occur at elevations as low as McLeod Ganj during periods of sustained/heavy precipitation.  I am really hesitant to forecast accumulating snow here in McLeod nearly 3 weeks earlier than it normally occurs, but honestly, the situation looks precarious for us.  Please be on top of weather developments if you have travel plans on Thursday and Friday.

There are a couple of computer model guidance sources that are placing 4-7cm (1.5-2.8") of liquid equivalent precip right on top of us.  Assuming a 1:10 rain:snow ratio (which is an average figure), that translates into very heavy snowfall accumulations... if not right here, then certainly just above us at the 7,000-8,000ft/2100-2400m level.

An unsettled atmosphere may linger over the weekend as well, but then it does look like we could have at least a brief dry and milder spell by Monday.

WEDNESDAY NIGHT:
partly to mostly cloudy with a slight chance of a little light rain developing toward morning.
low: 4C (40F)

THURSDAY:
mostly cloudy with rain becoming more likely.  rain could mix with or change to snow.
high: 8C (46F)

THURSDAY NIGHT:
rain likely... possibly mixed with or changing to all snow.
low: 1C (34F)

FRIDAY:
more periods of rain and/or snow likely.  very cold.
high: 7C (44F)

SATURDAY:
a mix of clouds and some sun.  a bit milder, with a chance of a couple of rain showers in the area.
morning low: 2C (36F)
daytime high: 8C (47F)

SUNDAY:
both clouds and some periods of sun.  a few rain showers still possible.
morning low: 4C (39F)
daytime high: 9C (49F)

MONDAY:
partly cloudy and milder.
morning low: 5C (41F)
daytime high: 11C (52F)