E014042 FAST RADIO BURSTS (FRBS) ARE A NEW CLASS OF EXTRAGALACTIC TRANSIENTS WITH UNKNOWN ORIGINS. NEW OBSERVATIONAL RESULTS DEMONSTRATE THAT MAGNETAR-DRIVEN ERUPTIONS ARE A LIKELY FRB PROGENITOR SCENARIO. HOWEVER THE LACK OF DETECTED EMISSION OUTSIDE OF THE RADIO MAKES IT DIFFICULT TO MATCH THEIR BURSTS TO DETAILED EMISSION MODELS. MULTI-WAVELENGTH OBSERVATIONS OF FRBS ARE COMPLICATED BY THEIR RAPID TIMESCALES AND GENERALLY UNPREDICTABLE BURST TIMING. THE DETECTION OF THE NEARBY (150 MPC) PERIODIC FRB 180916 THEREFORE O?ERS A UNIQUE OPPORTUNITY TO TEST PREDICTIONS FROM THIS EMISSION MECHANISM BY TARGETING THE COUNTERPART DURING THE FRB S ACTIVE STATE WHEN ONE OR MORE HIGH FLUENCE RADIO BURSTS ARE PREDICTED. THIS PROPOSAL WILL A JOINT OBSERVATION OF 20 KS NUSTAR AND 20 KS XMM-NEWTON TIME DURING ONE OF THESE WINDOWS. WITH CONTINUOUS X-RAY COVERAGE OF FRB 180916 WHEN ONE OR MORE BURSTS ARE EXPECTED WE WILL CONSTRAIN THE X-RAY FLUENCE PREDICTED FOR FRB EMISSION MODELS.