According to statistics compiled by the Federal Aviation Administration (FAA), inclement weather is the primary cause of delays within the National Airspace System (NAS). The FAA is currently procuring aviation weather systems, which are designed to enhance safety/capacity and reduce delays at U.S. airports. The two most widely publicized systems being installed are the Integrated Terminal Weather System (ITWS) at airports equipped with a Terminal Doppler Weather Radar (TDWR) and the Weather System Processor (WSP) at those terminal areas that are only covered by an Airport Surveillance Radar, Model 9 (ASR-9). At airports not slated to receive either an ITWS or WSP, an emerging system coined the Medium-Intensity Airport Weather System (MIAWS) will be installed. Currently, terminal aircraft surveillance at these airports is provided by either an ASR-7 or an ASR-8. Unfortunately, these platforms do not provide calibrated precipitation intensity products or storm motion information. This will be rectified once the digitally enhanced ASR-11 radar system is operational at MIAWS supported sites. The Low Level Wind Shear Alert System - Relocation/Sustainment (LLWAS-RS) anemometer network, will provide MIAWS with surface-based wind data and wind shear alerts.

The primary MIAWS products are six-level composite reflectivity, storm motion, storm extrapolated position and precipitation impacts. The system was designed under the premise that the calibrated reflectivity and velocity data from start-of-the-art radar's can be utilized to produce a suite of current and forecasted storm positions to aid air traffic control decision-making. The forecasted location becomes a critical issue if the storms are moving rapidly. This can lead to a situation where the weather evolves from non-significant to significant in terms of safe flight operations within a matter of minutes. Thus, it is essential that both air traffic control specialists and aircrews be cognizant of the location and severity of convection within the terminal area. MIAWS will address this by providing the estimated arrival time of any significant weather cells (level 3+) within 20 minutes of impacting an active runway corridor.

The FAA has contracted the Massachusetts Institute of Technology Lincoln Laboratory (MIT/LL) to conduct a proof-of-concept evaluation of MIAWS. To this end, MIT/LL has installed two prototype systems at the Jackson, MS (JAN) and Memphis, TN (MEM) International Airports. The system at MEM is used solely for product evaluation and refinement, while the FAA is operationally evaluating the utility of the JAN MIAWS. The scope of this paper is to evaluate the product suite based solely on NEXRAD product data. Of particular interest is the impact that radar data quality degradation, such as anomalous propagation, has on the utility of the products. The researchers will also delve into possible enhancements to improve the NEXRAD radar data quality in order to offset some of the deficiencies reported herein.