Weather systems will play an important role in the FAA modernization, as weather information services are critical to the safety and capacity of the NAS. The 1997 Aviation Capacity Enhancement Plan reveals that from 1991 to 1996 adverse weather was a major factor affecting NAS capacity, accounting for 70 percent of system delays greater than 15 minutes.
The deployment of the Integrated Terminal Weather System (ITWS) vastly improves the FAA's ability to monitor and predict aviation-impacting weather. Its accurate forecasts of wind shifts associated with frontal passage across runways will mitigate weather-related capacity reductions. Furthermore, the wind shear and microburst predictive capability of ITWS will improve NAS safety. ITWS implementation will provide enhanced terminal weather forecasts to tower and Terminal Radar Approach Control (TRACON) personnel, and terminal automation systems. ITWS situation displays located in the Air Traffic Control System Command Center and Air Route Traffic Control Centers will enhance traffic flow management across the NAS.
ITWS will ingest NWS Rapid Update Cycle (RUC II) forecast data, Meteorological Data Collection and Reporting System (MDCRS) aircraft observations, and lightning data. It will also acquire and process data from sensors such as the WSR-88D (or NEXRAD), Terminal Doppler Weather Radar (TDWR), Low Level Wind Shear Alert System (LLWAS), and Airport Surveillance Radar (ASR-9). ITWS then generates products for NAS non-meteorologist users and the Center TRACON Automation System (CTAS).
ITWS will function as a "weather server" at 45 TDWR airports. Terminal controllers and traffic managers can more efficiently sequence aircraft in and out of terminal airspace through the use of wind shift or gust front predictions. ITWS provides significant information associated with severe storms and facilitates routing aircraft around hazardous weather. It will also process ASR-9 data to remove anomalous propagation and ground clutter. The Terminal Weather Information for Pilots (TWIP) functionally will be enhanced through the addition of ITWS products. TWIP is a prototype system that currently provides airline pilots with a coarse graphical depiction of hazardous weather at TDWR sites.
Later in the NAS modernization, ITWS will incorporate satellite data and implement algorithms for vertical wind shear, storm growth and decay, icing aloft in the terminal, in-flight icing, and RVR/visibility & ceiling predictions. The goal is to expand the ITWS predictive capability from 30 minutes out to six hours, which will significantly enhance cross-country traffic flow. Also ITWS will provide enhanced products for transmission to the cockpit via the Flight Information Services (FIS) processor.
With the advent of new NAS automation systems, the FAA requires NWS higher-resolution computer model data. However, with the increased volume of RUC II data, existing NAS communications are insufficient to move this data quickly. The FAA developed a Bulk Weather Telecommunications Gateway (FBWTG) to facilitate this exchange. ITWS will also receive MDCRS observations over the FBWTG. To reduce communications bandwidth and associated costs, the ITWS NWS Filter Unit (NFU) will send each ITWS only the RUC data and MDCRS observations which geographically correspond to the associated TRACON
The 8th Conference on Aviation, Range, and Aerospace Meteorology