; captain, commander, lieutenant commander, lieutenant (a) In general An officer in the grade of first lieutenant, captain, major, or lieutenant colonel in the Army, Air Force, or Marine Corps, or lieutenant (junior grade), lieutenant, lieutenant commander, or commander in the Navy, who is described in subsection (b) may be temporarily promoted to the grade of captain, major, lieutenant colonel, or colonel in the Army, Air Force, or Marine Corps, or lieutenant, lieutenant commander, commander, or captain in the Navy, as applicable, under regulations prescribed by the Secretary of the military department concerned. Appointments under this section shall be made by the President, by and with the advice and consent of the Senate. (b) Covered officers An officer described in this subsection is any officer in a grade specified in subsection (a) who— (1) has a skill in which the armed force concerned has a critical shortage of personnel (as determined by the Secretary of the military department concerned); and (2) is serving in a position (as determined by the Secretary of the military department concerned) that— (A) is designated to be held by a captain, major, lieutenant colonel, or colonel in the Army, Air Force, or Marine Corps, or lieutenant, lieutenant commander, commander, or captain in the Navy, as applicable