THIS PROPOSAL IS REQUESTING FUNDS TO BRING TOGETHER MEMBERS OF THE SCIENTIFIC COMMUNITY FOR THE 12TH INTERNATIONAL PRECIPITATION CONFERENCE (IPC12). IPC12 WILL TAKE PLACE IN IRVINE CALIFORNIA AT THE BECKMAN CENTER OF THE NATIONAL ACADEMIES ON JUNE 19-21 2019. THIS INTERNATIONAL CONFERENCE HAS A LONG HISTORY OF PRODUCING EXCELLENT RESULTS IN TERMS OF BRINGING TOGETHER THE INTERNATIONAL COMMUNITY TO DISCUSS THE NEWEST RESEARCH FINDINGS INTEGRATE RESEARCH AND ADVANCE THE USE OF DATA AND TECHNOLOGY TRANSFER DISCUSS CHALLENGES AND OPPORTUNITIES AND CRAFT NEW DIRECTIONS. IT HAS SERVED AS THE NUCLEATION POINT FOR THE ATMOSPHERIC SCIENCES HYDROLOGIC SCIENCES AND APPLIED PRECIPITATION RESEARCH COMMUNITIES TO ADVANCE A WIDE RANGE OF TOPICS INCLUDING IMPROVED CLOUD PARAMETERIZATIONS FOR NUMERICAL WEATHER PREDICTION MODELS STOCHASTIC AND DYNAMIC DOWNSCALING FROM CLIMATE MODELS IMPROVING THE RETRIEVAL OF GLOBAL PRECIPITATION FROM REMOTE SENSORS DERIVING FUSED PRECIPITATION PRODUCTS FOR HYDROLOGIC APPLICATIONS UNCERTAINTY QUANTIFICATION AND EXTREME VALUE ANALYSIS AND APPLICATIONS TO FLOODING AND WATER RESOURCES MANAGEMENT. THE FIRST IPC WAS ORGANIZED IN CARACAS VENEZUELA IN 1986 AS A CHAPMAN CONFERENCE AND IT HAS SINCE BEEN HOSTED AROUND THE WORLD WITH THE LAST IPC11 HOSTED IN THE NETHERLANDS IN 2013. IPC12 BRINGS THE COMMUNITY BACK TO THE US (17 YEARS LATER; IPC7 IN 2001 WAS HOSTED IN MAINE) IN THE BEAUTIFUL SETTING OF IRVINE AND WITHIN THE INSPIRING ENVIRONMENT OF THE BECKMAN CENTER TO PROMOTE FUTURE COLLABORATIONS AND SYNERGISTIC ACTIVITIES AND HENCE ADVANCE PROGRESS IN THE INCREASING CHALLENGES OF GLOBAL PRECIPITATION RESEARCH AND APPLICATIONS. INTELLECTUAL MERIT: THE OBJECTIVE OF THIS INTERNATIONAL CONFERENCE IS: 1) TO PROVIDE AN OPEN TECHNICAL FORUM THAT BRINGS TOGETHER RESEARCHERS FROM SEVERAL DISCIPLINES AND FROM ALL OVER THE WORLD TO DISCUSS CUTTING-EDGE RESEARCH ON PRECIPITATION ESTIMATION AND PREDICTION 2) TO CATALYZE IMPORTANT COLLABORATIONS THAT CAN LEAD TO BI-LATERAL RESEARCH EXCHANGE AT ALL LEVELS 3) TO DISCUSS SYNERGISTIC MECHANISMS FOR SHARING UNIQUE DATA SETS AND MODELS AND 4) TO INTRODUCE JUNIOR RESEARCHERS TO THE FIELD OF PRECIPITATION RESEARCH AT THE INTERNATIONAL LEVEL FOR FUTURE EXCHANGE AND COLLABORATION PROGRESS. IPC12 WILL FOCUS ON THREE MAIN THEMES: (1) ESTIMATION OF PRECIPITATION FROM MULTIPLE SENSORS; (2) WATER CYCLE DYNAMICS AND PREDICTIVE MODELING AT LOCAL TO GLOBAL SCALES; AND (3) HYDROLOGIC IMPACTS OF PRECIPITATION EXTREMES AND ANTICIPATED CHANGE. GIVEN THE CHALLENGES OF CLIMATE VARIABILITY AND CHANGE ESPECIALLY CHANGES IN PRECIPITATION EXTREMES AND SEASONALITY INCLUDING SNOWFALL TIMING EFFORTS WILL BE CONCENTRATED IN IMPROVED PHYSICAL AND STATISTICAL METHODOLOGIES FOR SUB-SEASONAL TO SEASONAL (S2S) PREDICTIONS USING MODELS AND OBSERVATIONS GLOBAL ESTIMATION OF PRECIPITATION AT HIGH SPATIAL AND TEMPORAL RESOLUTION FROM MULTIPLE SENSORS AND ASSESSMENT OF UNCERTAINTY PROPAGATION TO IMPACT STUDIES SUCH AS FLOODS DROUGHTS AND ECOLOGICAL CHANGES. BROADER IMPACTS: IMPROVING PRECIPITATION ESTIMATION AND PREDICTION HAS GREAT SOCIETAL IMPACT FOR DECISION SUPPORT IN WATER MANAGEMENT INFRASTRUCTURE PROTECTION AND DESIGN UNDER ACCELERATING EXTREMES QUANTIFYING WATER AND ENERGY BALANCES AT THE REGIONAL TO GLOBAL SCALES AND PREDICTING HURRICANES TORNADOES FLOODS AND DROUGHTS THAT AFFECT THE ECONOMY AND SECURITY OF THE US AND MANY NATIONS AROUND THE WORLD. IPC12 WILL ENGAGE JUNIOR SCIENTISTS GRADUATE STUDENTS AND POST-DOCS IN AN INTERNATIONAL COLLABORATIVE ENVIRONMENT AND WILL FOSTER OPPORTUNITIES FOR FUTURE VISITS AND RESEARCH COLLABORATION. THE IPC12 PROGRAM WILL ALSO INCLUDE SEVERAL TRAINING WORKSHOPS (RADAR ESTIMATION CLIMATE MODEL DOWNSCALING MULTI-SATELLITE GLOBAL PRECIPITATION RETRIEVAL) AND WILL SUBSIDIZE THE TRAVEL EXPENSES OF SELECTED YOUNG COLLEAGUES TO ALLOW THEM TO PARTICIPATE AND PRESENT THEIR WORK.