WEST NILE VIRUS (WNV) IS THE LEADING CAUSE OF MOSQUITO-BORNE DISEASE IN THE CONTINENTAL UNITED STATES AND HAS REMAINED A PERSISTENT PUBLIC HEALTH ISSUE. WNV TRANSMISSION IS HIGHLY SENSITIVE TO TEMPERATURE AND MOISTURE CONDITIONS THAT AFFECT HABITAT FOR THE MOSQUITO VECTORS AVIAN HOSTS AND THE WNV PATHOGEN AND THE CONTINUING OCCURRENCE OF RECORD HIGH TEMPERATURE THROUGHOUT THE UNITED STATES HAS RAISED CONCERNS THAT SUCH EVENTS ARE LIKELY TO BECOME MORE COMMON. THUS THERE IS NEED FOR BETTER KNOWLEDGE OF THE CLIMATIC CONDITIONS THAT INCREASED WNV TRANSMISSION AND FOR MODELS THAT CAN HELP TARGET PUBLIC HEALTH RESPONSES BY PREDICTING WHEN AND WHERE WNV OUTBREAKS WILL OCCUR. WE WILL ANALYZE DISEASE-ENVIRONMENT RELATIONSHIPS FOR WEST NILE VIRUS IN LOUISIANA WHICH A MAJOR WNV TRANSMISSION HOTSPOT WITH THE SEVENTH-HIGHEST INCIDENCE OF WEST NILE NEUROINVASIVE DISEASE IN THE U.S. TEMPERATURES HAVE BEEN HIGHER-THAN-NORMAL IN LOUISIANA AND OTHER PARTS OF THE SOUTH-CENTRAL U.S. DURING JANUARY-MARCH 2019 AND ARE PROJECTED TO REMAIN WARM THROUGH SPRING AND EARLY SUMMER 2019. THESE UNUSUALLY WARM WINTER TEMPERATURES ARE THE SAME CONDITIONS THAT WERE HISTORICALLY ASSOCIATED WITH LARGE WNV OUTBREAKS SUCH AS OCCURRED IN 2012. THUS THE CURRENT WNV SEASON PROVIDES A UNIQUE AND URGENT OPPORTUNITY TO EXTEND PRIOR NASA-SUPPORTED DISEASE FORECASTING RESEARCH BY (1) ANALYZING RELATIONSHIPS BETWEEN CLIMATE VARIATIONS AND WNV TRANSMISSION IN LOUISIANA (2) PRODUCING AND VALIDATING PROSPECTIVE FORECASTS OF WNV TRANSMISSION FOR THE 2019 AND 2020 WNV SEASONS AND (3) USING THE RESULTS TO UPDATE THE ARBOVIRUS FORECASTING AND PREDICTION (ARBOMAP) FORECASTING SYSTEM SO THAT IT CAN BE APPLIED FOR FUTURE DISEASE FORECASTING BY THE LOUISIANA DEPARTMENT OF HEALTH (LADOH) AND OTHER PUBLIC HEALTH AGENCIES IN THE UNITED STATES. THE PROPOSED RESEARCH IS URGENT BECAUSE IT OFFERS AN OPPORTUNITY TO TEST OUR CAPABILITIES TO FORECAST WNV TRANSMISSION IN A REGION WHERE RECENT TEMPERATURE ANOMALIES HAVE PROVIDED AN EARLY INDICATOR OF RISK. THE RESULTS WILL HAVE A SIGNIFICANT IMPACT BECAUSE THEY WILL ADVANCE OUR UNDERSTANDING OF THE ENVIRONMENTAL EPIDEMIOLOGY OF THE MOST IMPORTANT MOSQUITOBORNE DISEASE IN THE UNITED STATES AND BECAUSE THEY WILL BE TRANSLATED INTO AN IMPROVED APPLICATION FOR DISEASE EARLY WARNING. THERE ARE NO NASA HEALTH AND AIR SOLICITATIONS PLANNED FOR ROSES-2019 AND THEREFORE THIS RAPID RESPONSE AND NOVEL RESEARCH IN EARTH SCIENCE SOLICITATION THAT IS THE ONLY MECHANISM THAT IS TIMELY ENOUGH FOR IMMEDIATE ACTION.