According to the Herald, who is not exactly very sympathetic to Coakley's chances:
Turnout could hit as high as 70 percent (!) Tuesday in the high-stakes U.S. Senate battle between Democratic Attorney General Martha Coakley and GOP state Sen. Scott Brown, according to some local election officials.
Absentee ballot requests have increased - on par with levels ordinarily seen in a presidential election - some town clerks say. And town and city halls were buzzing last week with people voting and asking questions about registration in advance of the election to fill the late Sen. Edward M. Kennedy’s seat, said Theodora Eaton, president of the state’s city and town clerk’s association.
I worked for an elections division, and absentee and registration requests are very closely correlated with turnout. This really suggests that Dem turnout efforts are working.
Another excellent piece of news is the amount of interest in Boston, Coakley's key support center:
Gerry Cuddyer, chairwoman of the board of election commissioners in Boston, processed 4,800 absentee ballots and has been flooded with calls from voters checking their registration.
“That would indicate to me that turnout may be higher than expected,” she said.
Of course, as we have all been hearing,
“In a state where there’s a 3 to 1 Democrat advantage over Republicans, the higher the turnout, the better for the Democrats,” he said.
This is great news, but we need to keep fighting to make this really happen! Donate, call, doorknock...Keep pushing the turnout up and our chances will be great!
UPDATE 2: LordMike also has a great catch from the conservative blog Hot Air:
The fact is, Coakley still has every incentive to scare the hell out of her supporters by claiming the race is closer than it is. Ace says he’s fine with that, that winning a high turnout election in Massachusetts will only make victory sweeter, but ... Brown can’t win a high turnout election. He can win an election with average turnout among Democrats if indies and Republicans turn out hugely for him (which they probably will), but with all the big names, money, and earned media the Dems are pouring in there, it’s less and less likely that turnout will be average. At this point, the bigger this election gets — and a video statement from the president calling it big makes it officially Big, I’d say — the harder it is for Brown. Even if that moneybomb is still exploding.
UPDATE: I know that this isn't an ironclad guarantee of Dem turnout. Of course reports indicating big absentee turnout from the suburbs isn't probably great news. However, turnout levels similar to a presidential election and/or a 70% turnout of registered voters is likely to include a heck of a lot of Dems. So I changed it to "good" news.