A region of non-terrestrial sodium emission seen in the sky on the nights of November 18--20, 1998, has been interpreted as the Moon's distant sodium tail, possibly enhanced by micrometeor impact vaporization of the lunar regolith by the Leonid meteor shower. We show that the location and morphology of the spot can be explained by standard steady-state models of the Moon's sodium atmosphere. Moreover, using a new time-dependent simulation of the lunar atmosphere, we find that the Na escape rate from the Moon increased to 2 or 3 times its normal level during the most intense period of the 1998 Leonid meteor shower on November 16th and 17th. ¿ 1999 American Geophysical Union