Friday snow potential forecast, second call.

Examining the latest computer model data this evening, our general ideas about Friday’s snow have not changed. The best bet is around 1 inch of sweepable light snow, coinciding with the afternoon rush hour.

Here are some key points:

* Start time is most likely mid-to-late afternoon, between 2 and 5 p.m.

* Snow intensity should mainly be light, but some moderate bursts are possible, reducing visibilities.

* Given temperatures in the 20s, snow falling will stick to untreated roads and will aggravate the PM commute. Leave early if possible.

* This is not Commutageddon. Snow will not be crippling and heavy snow is not likely.

* The mountains will rob this storm system of some of its moisture and snow may be spotty and/or slow to get started particularly in the D.C. metro area and Virginia piedmont (D.C. snow hole).

* There are scenarios for more or less snow. 1) As little as a dusting if less moisture makes it across the mountains than forecast. 2) If the storm is a bit juicier, given the fluffy nature of the snow, it wouldn’t take much to get 2 inches or a little more.

* This is a fast moving storm. Snow should fairly quickly wind down between 7 and 10 p.m.

We will have more details and updates tomorrow.