For all the time and resources both presidential campaigns are investing in sophisticated efforts to target and turn out voters, the outcome of Election Day often comes down to something more elemental.

In any election, polls reflecting a candidate's level of support tell only part of the story. Much also depends on how successful campaigns are in motivating voters to actually make it to the polls -- President Obama's commanding lead among Latinos, for example, will mean little if those voters stay home.

With turnout such a critical factor, the steady advance of the weather pattern dubbed Frankenstorm -- the confluence of Hurricane Sandy, churning northward, and another storm heading east -- could play an outsize role in this election.

Research has affirmed that the weather influences voting patterns, and a 2007 study suggested that inclement weather favors Republican candidates by causing potential Democratic voters -- who tend to rely on public transport more than Republicans, for example -- to avoid braving the rain or the snow. That seems to lend some truth to the adage "Republicans, pray for rain."

President Obama's resounding victory in 2008 was due in part to the formidable voter mobilization network the Obama campaign built. Part of that is bolstering early voting, which tends to skew toward more liberal voting blocs like minorities and low-income voters -- the Obama campaign successfully beat back Ohio's attempt to curtail early voting, for example, while Democrats challenged Florida's attempt to do the same. The Obama campaign has been touting its advantage in early voting tallies so far.

So with just over a week left before Election Day, a massive storm capable of cutting off power, shutting down public transportation and generally keeping voters indoors is an unwelcome sight for the Obama campaign. That's especially true in a handful of swing states that could feel some of the effects.

Pennsylvania, Virginia, North Carolina, New Hampshire and Ohio all look likely to be lashed by wind and rain. All of those states, to varying degrees, are considered in play. Obama has a clear advantage in Pennsylvania, while Romney seems to be en route to a victory in Virginia; the other three states are tighter, with Ohio standing out as the main prize.

The storm will likely play little role in Virginia, New Hampshire and Pennsylvania. Those states do not extend early voting and require an excuse for absentee ballots.

But in North Carolina and Ohio, it's a different story. While North Carolina may be out of reach for Obama, polls suggest that the president may be ahead in early voting in Ohio, although the picture remains murky.