Taking a look forward to Super Tuesday, and the polling margins (newest polls used, where available):
Democrats:
Alabama (66): Clinton 59, Sanders 31
American Samoa (10): no poll results (Clinton will likely win -- territories tend to vote establishment)
Arkansas (37): Clinton 57, Sanders 32
Colorado (79): Sanders 49, Clinton 43
Expat vote (17): no poll results (Anecdotal evidence that Sanders has a strong following abroad)
Georgia (117): Clinton 60, Sanders 26
Massachusetts (116): Sanders 46, Clinton 46
Minnesota (93): Clinton 59, Sanders 25 (poll is a month old)
Oklahoma (42): Clinton 46, Sanders 44
South Carolina (59): Clinton 60, Sanders 32
Tennessee (76): Clinton 58, Sanders 32
Texas (252): Clinton 57, Sanders 34
Vermont (26): Sanders 86, Clinton 10
Virginia (109): Clinton 56, Sanders 34
So out of all those (and I lumped SC in, because it's in the same primary "week"), Sanders looks set to win 3 (VT, CO, expat vote) and maybe squeak out a win in MA. Clinton looks set to win 10, and could squeak out a win in MA. And her margins of victory are larger. To put it another way, Sanders needs to be winning Massachusetts by 35 points, to offset losing Georgia by 35 points, since they're almost identical in delegate share.
Put simply, the South is going to kill Sanders -- several large states that Clinton is set to win by hefty margins. He's going to destroy her in Vermont, but it doesn't matter because Vermont has about 0.5% of the total delegate pool.
But now you see why the hubbub over Sanders possibly winning the Latino vote is causing such a stir -- if they could swing Texas and Colorado his way and give him an edge in Massachusetts, that might give him the momentum to carry forward. If he developed the kind of advantage with Latinos that Clinton has with blacks (which I don't see happening unless she puts on a bullfighter mustache and makes Speedy Gonzalez impressions), then June 7 would be his chance at a comeback: several Latino-heavy states (California, New Jersey, New Mexico, Puerto Rico) are on the ballot, including mammoth California.