Snow and caucus realignment could make things more unpredictable, as final polls have race shifting

The final South Carolina polls released today by Zogby and by ARG are I believe the only surveys to have been in the field on Friday, so that might account for the wide swings we are seeing today:

• Zogby's tracking poll has McCain falling from 29% to 27%, with Huckabee surging ahead from 22% to 26%. Romney comes in at 16%, ahead of Thompson at 12%. Paul at 4% and Giuliani at 3% are left far behind.
• Now the strange ARG poll that is completely off from everything we've seen: The poll was taken Thursday-Friday, replacing a previous survey in the field on Tuesday-Wednesday. ARG finds Huckabee at 33% (+10!), McCain at 26% (-7!), Thompson at 21% (+8!) and Romney at 9% (-11!!).

Needless to say that the ARG survey should be taken with extreme caution. ARG also showed widely differing results in Iowa from everyone else and ended being gravely mistaken there. And while the Zogby and ARG polls both find Huckabee surging, they do not agree at all on the direction of Romney's and Thompson's movement.

For all it's worth, ARG also has a poll of the Democratic primary in South Carolina, with Obama holding a 6% lead yet again, 45% to 39%. But the important vote today for Democrats, of course, is Nevada and Zogby's tracking poll shows no real movement besides Edwards's collapse:

• Clinton gets 45% to 39%, with Edwards at 6% (yesterday it was 42-37-12).

The polls generally agree that Clinton is ahead but consider something that no one is really talking about: Nevada is a caucus and, just like Iowa, there will be a realignment phase for voters who are backing an unviable candidate! And considering the percentage that Edwards has been getting in the past few days, it is very possible that he stays unviable in many precincts. That could push him to low totals and it could also make Edwards voters the king-maker in the Obama-Clinton showdown. And the CW is, of course, that that should help Obama, at least in a state like Nevada that does not appear to be voting along strict racial lines like South Carolina.

The X factor among the Republicans in South Carolina, meanwhile, is the weather, with a snow advisory being put out in many parts of the states, with directives to be cautious while driving. This could have a significant effect on turnout -- the same way snow probably helped Romney increase his margin on Tuesday by making Democrats and some indies stay home. Here, the same dynamic could play a role if Democrats or uncommitted indies decide that it's not worth to go vote -- and that could hurt McCain. But it could also hurt Huckabee as the regions of the state that are likely to be the most affected or the most dangerous to travel in should be the areas in which Huckabee is the strongest because of the evangelical vote (this report for example has the Huck camp worried about severe weather upstate, which is a crucial area for Huck's chances). We shall wait a few more hours to know the answers.