Howdy. One way to do this:
Define a named formula. Select a cell (not in row 1, say B3) (Go to Insert > Name > Define)
Use CellAbove as the name and as the reference type in:
=!B2
(no dollars signs)
Click OK.
Then Select your data (A1:A3000), and go to
Edit > Go To > Special and choose Blanks. Click OK. Then in the formula bar, type in
=CellAbove and hit CTRL + ENTER (not just ENTER)
If you don't want to keep the formulas, then copy, paste special values.