National Integrated Drought Information System Reauthorization Act of 2018 This bill reauthorizes through FY2023 and modifies the National Integrated Drought Information System (NIDIS) Program. (Sec. 2) The bill amends the National Integrated Drought Information System Act of 2006 to require, under NIDIS, that the collection and integration of information on the key indicators of drought and drought impacts includes indicators of precipitation, soil moisture, and evaporative demand. NIDIS shall also provide timely data, information, and products that reflect watershed differences in drought conditions; through interagency agreements, coordinate and integrate future federal research and monitoring in support of a drought early warning information system; utilize existing forecasting and assessment programs and partnerships, including forecast communication coordinators and cooperative institutes, and improvements in seasonal and subseasonal precipitation and temperature and low flow water prediction; and continue ongoing research and monitoring activities related to drought, including research activities relating to the prediction of drought. NIDIS may engage with the private sector to improve drought monitoring, forecast, and communication if the National Oceanic and Atmospheric Administration (NOAA) determines such partnership is appropriate, cost-effective, and beneficial to the public and certain decision-makers; facilitate the development of academic cooperative partnerships to assist with NIDIS functions; and utilize and support monitoring by citizen scientists, including by developing best practices to facilitate maximum integration of data. NIDIS shall develop a strategy for a national coordinated soil moisture monitoring network. (Sec. 3) The bill amends the Food Security Act of 1985 to extend through FY2023 certain activities related to the provision of agricultural and silvicultural weather and climate information. The bill amends the Weather Research and Forecasting Innovation Act of 2017 to reauthorize through FY2023 the Office of Oceanic and Atmospheric Research of NOAA to carry out (1) weather laboratories and cooperative institutes, (2) weather and air chemistry research programs, and (3) a certain joint technology transfer initiative to ensure the continuous development and transition of the latest scientific and technological advances into the operations of the National Weather Service (NWS). (Sec. 4) The bill requires the office to advance weather modeling skill, reclaim and maintain international leadership in the area of numerical weather prediction, and improve the transition of research into operations, including by creating a community global weather research modeling system that is accessible by the public. The bill also requires the Committee on Earth and Environmental Sciences, under the U.S. Weather Research Program, to carry out the activities of the Earth Prediction Innovation Center for improving and understanding how the public receives, interprets, and responds to warnings and forecasts of high impact weather events that endanger life and property. (Sec. 5) The bill amends the Weather Research and Forecasting Innovation Act of 2017 to repeal annual reporting on the efficiency of prioritizing computing resources. NOAA shall, when appropriate and cost-effective, assess and prioritize options to enter into multiyear lease agreements for computing capabilities over options to purchase computer hardware outright. The bill requires NOAA to create pilot programs to assess new or innovative information and technology capabilities and services. The bill requires NOAA to submit triennial reports on specified activities related to weather prediction, including how NOAA intends to continually support upgrades to pursue the fastest, most powerful, and cost-effective high performance computing technologies in support of its weather prediction; and facilitate cloud computing. (Sec. 6) NOAA shall analyze, test, and plan the procurement of future data sources and satellite architectures, including specified respective ground system elements, identified in NOAA's Satellite Observing System Architecture Study. In meeting such requirement, NOAA must evaluate relative value and benefits of future data sources and satellite architectures. NOAA may enter into and perform transaction agreements to carry out basic, applied, and advanced research projects in order to enhance the effectiveness of data and satellite systems used by NOAA in meeting its missions. After a transaction agreement is arranged, NOAA shall make publicly available on its website all uses of its authority under such agreement, including an estimate of committed NOAA resources and the expected benefits to NOAA objectives. (Sec. 7) The bill requires the NWS, in weather service regions where ocean and coastal data would improve forecasts, to support increasing the use of autonomous, mobile-surface, subsurface, and submarine vehicle ocean and freshwater sensor systems and the infrastructure necessary to share and analyze those data in real time and feed them into predictive early warning systems. The bill reauthorizes through FY2023 procurement, acquisition, and construction at the National Environmental Satellite, Data, and Information Service. (Sec. 8) The NWS shall improve the Cooperative Observer Program by providing support to related state-coordinated programs and states and regions where observations provided through the program are scarce; working with state weather service headquarters to increase participation in the program and adding stations to such states and regions; ensuring that data streams from stations that have been contributing data to the program for more than 50 years are maintained and continually staffed by volunteers; and ensuring that program volunteers may quickly and easily report qualitative observations, such as drought conditions, snow observations, and hazardous weather events. The NWS must coordinate with state and regional offices regarding the status of program stations no less frequently than every 180 days. The NWS shall also coordinate with other federal agencies to leverage opportunities to grow the program's network and to more effectively use its existing infrastructure, weather stations, and staff. Harmful Algal Bloom and Hypoxia Research and Control Amendments Act of 2017 (Sec. 9) This bill amends the Harmful Algal Bloom and Hypoxia Research and Control Act of 1998 to reauthorize for FY2019-FY2023 the national harmful algal bloom and hypoxia program and the action strategy of the Inter-Agency Task Force on Harmful Algal Blooms and Hypoxia. An algal bloom is a rapid growth of algae that may create toxic or hypoxic (severely low-oxygen) conditions that are harmful to humans, animals, aquatic ecosystems, and the economy. The task force must include a representative from the U.S. Army Corps of Engineers. NOAA, in administering the program, shall promote the program to local and regional stakeholders through a public website that provides information on program activities; administer grants for the acceleration of the utilization of effective methods of intervention and mitigation to reduce the frequency, severity, and impacts of harmful algal bloom and hypoxia events; work cooperatively to provide technical assistance to regional, state, tribal, and local government agencies and programs that address marine and freshwater harmful algal blooms and hypoxia; and integrate, coordinate, and augment existing extension programs to improve public understanding and awareness of the causes, impacts, intervention, and mitigation efforts for marine and freshwater harmful algal blooms and hypoxia. NOAA must develop and enhance, with respect to unmanned systems, critical observations, monitoring, modeling, data management, information dissemination, and operational forecasts that are relevant to harmful algal blooms and hypoxia events; use cost effective methods in carrying out the Act; and develop contingency plans for the long-term monitoring of hypoxia. Federal officials may determine that a harmful algal bloom or hypoxia event is an event of national significance and give funding to the affected state or local government for assessing and mitigating the event's detrimental environmental, economic, subsistence use, and public health effects.