Mo Cowan gets a farewell hug from Sen. Heidi Heitkamp. (Sarah L. Voisin/THE WASHINGTON POST)

The bow tie is baaack!

Just a week ago, Washington said its fond farewell to Mo Cowan, the temporary senator appointed to fill the seat left vacant when Massachusetts Democrat John Kerry was plucked from the Senate ranks to be secretary of state.

There were goodbye hugs and handshakes, photos and a touching final address on the Senate floor. Democratic Rep. Ed Markey had won the special election to permanently replace Kerry, and Cowan’s five-month stint as a seat-warmer looked to be over.

But not so fast — with Senate votes beginning on Monday evening, and Markey not slated to be sworn in until Wednesday at the earliest (Massachusetts law calls for a lengthy post-election certification process), Cowan will have to put in a two-day encore performance.

Call it ‘mo Mo. A Mo-dux.