CONSISTENT WITH THE OVERARCHING OBJECTIVE TO DETERMINE THE ROLE OF INTERNAL PROCESSES IN TROPICAL CYCLONE (TC) INTENSITY CHANGE THE GOAL OF WORK PROPOSED HERE IS TO IDENTIFY THE PROCESSES THAT GOVERN AN INCREASE IN THE AZIMUTHAL PRECIPITATION SYMMETRY AS A TC INTENSIFIES. THIS REQUIRES AN EXAMINATION OF THE RELATIONSHIP BETWEEN PRECIPITATION AND THE THERMODYNAMIC AND KINEMATIC STRUCTURES OF THE INNER CORE IN THE CONTEXT OF THE ENVIRONMENTAL CONDITIONS (E.G. VERTICAL WIND SHEAR AND SEA SURFACE TEMPERATURE). AN INCREASED SYMMETRY OF MODERATE PRECIPITATION HAS BEEN IDENTIFIED IN A RECENT COMPOSITE STUDY CO-AUTHORED BY ZAWISLAK AND ZIPSER AS ONE OF THE PREDOMINANT SYMPTOMS OF INTENSIFYING TCS IN PARTICULAR ONE THAT IS EXPERIENCING RAPID INTENSIFICATION. THIS RESULT DEVIATES FROM THE TRADITIONAL VIEWPOINT THAT DEEP CONVECTION IS THE PREDOMINANT STRUCTURE OF IMPORTANCE. PARTICIPANTS ON THIS PROPOSAL HAVE VERIFIED THIS COMPOSITE RESULT IN AN OBSERVATIONAL STUDY OF HURRICANE EDOUARD (2014) A TC SAMPLED THROUGHOUT ITS LIFECYCLE DURING THE NASA HURRICANE AND SEVERE STORM SENTINEL (HS3) EXPERIMENT. THAT STUDY ALSO SHOWS EVIDENCE FOR A RELATIONSHIP BETWEEN INCREASING PRECIPITATION SYMMETRY AND MOISTENING OF THE INITIALLY RELATIVELY DRIER MIDDLE TO UPPER TROPOSPHERE UPSHEAR. BOTH THE COMPOSITE AND CASE STUDY APPROACHES REVEAL THE IMPORTANCE OF EXAMINING TCS IN A VERTICAL WIND SHEAR RELATIVE FRAMEWORK. BUILDING ON THE APPROACH DEMONSTRATED FOR EDOUARD THE GOAL OF THIS PROJECT IS TO REVISIT WELL-OBSERVED CASES FROM PREVIOUS NASA HURRICANE FIELD PROGRAMS BY SYNTHESIZING AN ANALYSIS OF OBSERVATIONAL DATASETS (SUCH AS AIRBORNE REMOTE SENSORS AND DROPSONDES AND PASSIVE MICROWAVE SATELLITE SENSORS) WITH NUMERICAL MODELING EXPERIMENTS TO UNDERSTAND THE THERMODYNAMIC AND KINEMATIC PROCESSES THAT GOVERN AN INCREASE IN PRECIPITATION SYMMETRY. SOME KEY TASKS TOWARDS MEETING THIS GOAL INCLUDE: QUANTIFYING THE RELATIONSHIP OF MID- TO UPPER-TROPOSPHERIC RELATIVE HUMIDITY UPSHEAR WITH INTENSITY AND INTENSITY CHANGE EXAMINING THE STRUCTURE ORIGIN AND EVOLUTION OF PRECIPITATION IN THE UPSHEAR QUADRANTS AND EXAMINING WHETHER THE UPSHEAR QUADRANTS ARE LOCALLY MOISTENED BY PRECIPITATION AND IF SO WHAT PRECIPITATION MODE (SHALLOW OR MODERATELY-DEEP CONGESTUS OR STRATIFORM RAIN) IS RESPONSIBLE. AIRBORNE PRECIPITATION RADAR DATA WILL BE CRITICAL TOWARDS CHARACTERIZING PRECIPITATION IN THE UPSHEAR QUADRANTS WHILE HIGH-ALTITUDE DROPSONDE PROFILES WILL CONTRIBUTE TOWARDS UNDERSTANDING THE VORTEX-SCALE THERMODYNAMIC PROPERTIES. HIGH-RESOLUTION ENSEMBLE MODEL SIMULATIONS OF SELECT CASES WILL ALSO BE EXAMINED FOR HOW WELL THE MODEL REPRESENTS THE OBSERVED PRECIPITATION DISTRIBUTION AND THERMODYNAMIC AND KINEMATIC STRUCTURES. OTHER EXPERIMENTS WILL PROVIDE A MEANS TO TEST THE SENSITIVITY OF THE AZIMUTHAL AND RADIAL DISTRIBUTION OF PRECIPITATION TO SPECIFIC THERMODYNAMIC PROFILES (E.G. VARYING RELATIVE HUMIDITY UPSHEAR) WHILE DATA DENIAL EXPERIMENTS WILL IDENTIFY HOW THE ASSIMILATION OF DATA IN TARGETED REGIONS (E.G. UPSHEAR) NOT ONLY IMPACTS THE REPRESENTATION OF THE TC EVOLUTION BUT ALSO THE ACCURACY OF THE FORECAST. THE RELEVANCE OF THESE RESULTS DIRECTLY ADDRESS THE OBJECTIVES OF THE WEATHER FOCUS AREA OF THE EARTH SCIENCE RESEARCH PROGRAM TO IMPROVE THE PREDICTION OF EXTREME EVENTS AS WELL AS MORE SPECIFICALLY THE GOALS OF NASA HURRICANE SCIENCE RESEARCH TO USE FIELD OBSERVATIONS COMPLEMENTED BY NUMERICAL WEATHER PREDICTION MODELS TO UNDERSTAND AND IMPROVE THE PREDICTABILITY OF THE PHYSICAL PROCESSES THAT DICTATE TC INTENSITY CHANGE.