UPDATE 1-PetSmart cuts forecast on weak sales

(Adds more revised estimates, analysts estimate)

ATLANTA, Jan 22 (Reuters) - Retailer PetSmart Inc (PETM.O: Quote, Profile, Research) cut its quarterly profit outlook on Tuesday, citing weak sales for part of November and much of December 2007, sending its shares down about 7 percent in extended trading.

The specialty pet retailer said it now expects profit in the range of 57 cents to 61 cents a diluted share for its fourth quarter, down from a previous forecast of 70 cents to 74 cents a share.

The lowered quarterly forecast includes a 7 cents a share benefit tied to an extra week, while the previous forecast included 8 cents a share for the 53rd week.

Analysts expected 71 cents a share for the fourth quarter, according to Reuters Estimates.

Same-store sales are now expected to be flat to up 1 percent for the quarter, compared with a previous forecast of of growth in the low single-digit percentage range.

In a statement, PetSmart cited "relatively weak sales during the later half of November and the majority of December in what we believe was a challenging consumer environment."

The pet groomer and trainer added that it saw "slight improvements" during the last week of December and first part of January, but said it was unlikely that strength would help it meet previous profit estimates.

The warning came after markets closed. PetSmart shares were down to $21.50 in extended trading on Tuesday from their $23.05 close on Nasdaq. (Reporting by Karen Jacobs; Editing by Andre Grenon)