Presumably the heavily Democratic areas had already reported and few if any of the heavily Republican ones had. It might seem illogical at a glance but it happens, and I've seen Dems declared winners who are behind in the votes that have been reported so far as well (if say the heavily urban areas haven't reported yet).
I've never ever ever seen this happen with a Democrat ever. However, in the 1988 presidential election, Illinois was called for Dukakis, only to be taken back later when DuPage County "found" a whole bunch of votes for Pa Bush.
Maryland was called for O'Malley while Ehrlich was leading in the polls.
