WATER VAPOR IN THE UPPER TROPOSPHERE/LOWER STRATOSPHERE (UTLS) REGION HAS A STRONG IMPACT ON THE EARTH S RADIATION BUDGET CLIMATE AND STRATOSPHERIC CHEMISTRY HOWEVER THE PROCESSES CONTROLLING UTLS HUMIDITY ARE NOT FULLY UNDERSTOOD AND NOT WELL REPRESENTED IN GLOBAL CLIMATE MODELS. IN PARTICULAR PROCESSES DRIVING THE VARIABILITY OF ENHANCED WATER VAPOR IN THE UTLS OVER THE BOREAL SUMMER NORTH AMERICAN MONSOON (NAM) REGION OBSERVED BY THE AURA MICROWAVE LIMB SOUNDER (MLS) ARE POORLY UNDERSTOOD.