Public Policy Polling predicts a blowout for Democrat Ron Barber in tomorrow's special election to complete Gabrielle Giffords' seat:

Democrats are headed for a victory in tomorrow's special election to replace Gabby Giffords in the House, but the relevance of the result in Arizona to much of anything else appears limited.

Democrat Ron Barber leads with 53% to 41% for Republican Jesse Kelly, with Green Party candidate Charlie Manolakis polling at 4%. Barber is well liked by voters in the district, sporting a 54/38 favorability rating. Kelly, meanwhile, has very high negatives with only 37% of voters rating him positively while 59% have a negative opinion.

We find that the likely electorate for tomorrow's election supported Barack Obama over John McCain 50-44. McCain actually won the district by a 52-46 margin in 2008. This, along with the special election in New York's 26th Congressional District last May, is one of only two races recently where we've found a likely electorate significantly more Democratic than the Presidential one in 2008, and it suggests Democrats are unusually motivated to come out and vote to keep Giffords' seat in their hands.

Despite the likely Democratic victory tomorrow Barack Obama's approval rating in this district is only 44%, with 50% of voters disapproving of him. And even though Barber leads by 12, likely voters only say they want Democrats to have control of Congress by a 48-44 margin. That's an unusually large gap between the horse race and who voters want to have control, and again speaks to the unusual circumstances surrounding this race.

Barber appears to have the race pretty much already locked up. 57% of voters say they've already cast their ballots, and with that group Barber enjoys a 21 point advantage at 58-37. People planning to vote tomorrow are much more evenly split with 46% for Barber and 45% for Kelly.

Barber's winning 90% of the Democratic vote, while Kelly's getting just 82% of Republicans. Barber also has a 51-34 advantage with independents. Barber's advantage is pretty thorough along demographic lines- he leads with men, women, whites, Hispanics, and voters in every age group.

One final note- 67% of voters in Giffords' district have a positive opinion of her to only 24% with a negative one. There aren't many special House elections where the departing incumbent has a 67% favorability rating, and that fact makes this a very difficult one for the GOP to win.

More details on the survey here.