When all polls close by 8 p.m. Eastern tonight in Florida, the winner of the state’s Republican primary may not initially be apparent. After all, the winner takes all, which means the candidate who gets the most votes gets all of the delegates. But the state, with 10 different media markets and a cultural mélange that ranges from Alabama South to Cuba North, is by no means homogeneous. Here are five crucial indicators to keep track of as the returns come in:

Absentee Voters

The first key factor is, about a third of Florida voters have already cast their ballots, and they have disproportionately favored Mitt Romney. According to polls in the past two days from PPP and Suffolk, both of which have the former Massachusetts governor ahead, Romney’s margin increased by more than 50 percent among those who have already cast their ballots, as opposed to those waiting to vote at their polling places. This is not a surprise, considering that Romney is the only candidate to have built up a strong campaign infrastructure in the state. His campaign emphasized both traditional absentee voting by mail and pushing voters out for early voting. The only other candidate making a major play to win Florida, Newt Gingrich, has deemphasized organization and instead is trying to run a “campaign of ideas.” The result, according to Sid Dinerstein, chairman of the Palm Beach County Republican Party, is that Gingrich has simply been “out-organized."

If Romney’s lead among absentee voters is about 10 percent, Gingrich still could surmount it with a strong finish. However, if Romney’s margin is larger than that and anywhere near the 30 points that the Suffolk poll gives him among ballots cast in advance, Gingrich may have lost the election before the polls opened. As Rick Wilson, an unaffiliated Florida Republican strategist, notes, Romney likely “won in Florida a month ago.”

Santorum Supporters

Rick Santorum is not competing in Florida. The campaign had expressed some earlier interest in competing in certain congressional districts, but once the Republican National Committee made clear that it wasn’t going to overturn the decision of the Florida Republican Party to make the state’s primary winner-take-all, Santorum pulled out. While his campaign has accepted that Santorum is unlikely to emerge in first place, top strategist John Brabender felt confident that he would finish in a clear first place in “cost per vote.” The campaign had not “spent one cent” in the state, was able to use its resources for states like Colorado, Minnesota, Missouri, and Nevada, and was relieved that it had “stayed away from the gunfight at the OK Corral” waged between Romney and Gingrich.

Santorum won’t win tonight; but he may be a spoiler. Significantly more of his voters will come from Gingrich than from Romney, according to Wilson. The result is that if the "anti-Romney vote” exists, it will split. Thus, the more votes Santorum receives, the better things look for Romney. If Santorum breaks 10 percent, Gingrich will be in trouble. If he breaks 15 percent, the Romney campaign will be able to break out the celebratory beverages.

North Florida Voters

In the South Carolina primary, Gingrich, who represented Georgia for 20 years in Congress, piled up his biggest margins in the counties along the South Carolina–Georgia border. He needs to pile up roughly the same margins in north Florida, near its border with Georgia. Gingrich may not win these counties with the same decisive margins he had in the Palmetto State (including winning Edgefield County, the home of Strom Thurmond, with 60 percent of the vote—the biggest win in any county so far in the GOP primary for any candidate). These counties are deeply Southern, rural, and removed from the rest of the state. In fact, from the far western panhandle of the state, the drive to Miami, Ohio, is only an hour longer than the drive to Miami, Fla. Gingrich needs to pull out large margins in these counties in order to have a shot. Further, because of his relative strength there, it will compound the effects of a significant defeat. Part of western Florida is in the central time zone, and if an early Romney victory is prognosticated, it could deter Gingrich voters from turning out. This could amplify a Romney win by adding an extra percentage point or two to the ex-governor’s margin. But regardless, Gingrich must pile up healthy margins in these counties to win statewide. In a winner-take-all primary, there is no prize for second place.

The Jewish Vote

Florida will be the first GOP primary state with a significant Jewish vote (not to impugn Newt Gingrich’s campaign stop at the only kosher deli in Des Moines). All the remaining Republican candidates, save Ron Paul, have been actively appealing to the Jewish vote nationally, not just in Florida. In Palm Beach County, where 25 percent of households are Jewish, Dinerstein, the Republican county chair there, said, “It’s the first year that the Republican Jewish vote has finally gotten attention from anybody, and it’s getting attention from everybody!” But he didn’t think many Jewish voters would make their decision based on Israel. After all, he said, Romney, Gingrich, and Santorum are all “good for Israel,” thus taking it off the table.

In any case, Tevi Troy, a Romney supporter who was the Jewish liaison in the George W. Bush White House, cautioned that Jews aren’t “narrow,” one-issue voters. Instead, he said, they are concerned about a variety of different issues, like health care and the debt, and look for candidates who are strong on a combination of issues. But a strong Jewish turnout could be a significant indication of growing Republican inroads in the Jewish community, especially on the heels of a special election in New York City last year for the congressional seat previously held by Anthony Weiner, won by a Republican who made a strong appeal to the Jewish vote. It also would serve as a key indicator of how the Jewish vote will break in upcoming February primary states like Nevada, Michigan, and Arizona.

The Tea Party Vote

One of the most promising trends for Romney is that polling in Florida has shown him leading among Tea Party supporters, despite attacks from Gingrich labeling him a “timid Massachusetts moderate.” In both Iowa and South Carolina, exit polls had Romney losing voters who “strongly supported” the Tea Party. (Although Romney did win among Tea Party supporters in his New Hampshire landslide, his margin lagged behind his overall performance with all primary voters.) In fact, Romney has faced attacks as a “RINO” throughout the primary. All the way back in June, then-candidate and now Romney supporter Tim Pawlenty coined the term “Obamneycare” to describe the similarities between President Obama’s and Romney’s health-care plans.

But Romney was not always seen as a 21st-century Rockefeller Republican by the conservative base. In the 2008 Republican primary, he ran to the right of field. However, recent polling shows him with a plurality among these voters. If he can win them tonight, it will guarantee victory, especially as he’s running closest to the center of all the GOP candidates. The ex-governor has done an excellent job shoring up his conservative bona fides in Florida. As Dinerstein put it:  “By U.S. standards, [Romney] is solid right of center. There’s very little that comes out of his mouth that makes you say 'Obama light.'” If Romney successfully reclaims these conservative Tea Party voters in Florida, it puts him in a strong position not just to win the Sunshine State decisively but to wrap up the Republican nomination.