Team records over the last ten, thirty, and fifty games.
The long term trends still say we lose the division, but we're looking mediocre of late, and mediocre looks like it might be enough to win the NL West this year. Arizona has been so bad lately that I don't know if the Rockies will need to worry about them or the Dodgers more at the end of the season. Paritcularly since the Dodgers seem to be in the best position to add help by the trade deadline.
Run differentials in each of those spans are showing similar signs, the Rockies have an advantage over LA and Arizona in that both their pitching and offense are improving over the last three months. My big worry with Arizona is that they were very good against other NL West teams in April, and until the Rockies or the other teams prove otherwise, it's probably safe to assume that this is still true.