Extending the Integrated Terminal Weather System (ITWS) to Address Urgent Terminal Area Weather Needs

The Integrated Terminal Weather System (ITWS) will provide a major improvement in safety and, significantly reduce delays when the Initial Operational Capability (IOC) ITWS production systems commence operational use in 2001. The IOC ITWS features represent a tradeoff between the urgent terminal weather information needs and the available technology circa 1994. Subsequent to 1994, major new needs have been identified, for example:

· A new era in FAA/airline partnership in traffic flow planning as exemplified by the Collaborative Decision Making (CDM) program

· Air carrier accidents that have highlighted the need for enhancements in ITWS convective weather forecast lead time and product distribution

· Needs developed from operational experience with ITWS demonstration systems in different meteorological and operational environments, and

· Dramatic increases in US air system delays during the spring/summer convective weather.

Fortunately, there have also been major advances in aviation weather information technology as exemplified by the Terminal Convective Weather Forecast (TCWF) and the use of Internet technology for the transfer and perusal of graphical weather products.

Since the terminal areas and en route sectors covered by the ITWS are critical to the overall U.S. air system operations, the aviation weather community urgently needs to consider which improvements need to be made to the IOC ITWS in the very near future.

In this paper, we review the evolution of critical terminal weather information needs that have become clearer since 1994-95 (including needs identified in the operational experience with demonstration systems at New York, Memphis, Orlando and Dallas since 1995) and, recommend some very near term ITWS improvements that would yield major benefits to the NAS users.

The highest priority items (e.g., those that warrant commencing ITWS production system development in the 2001-02 time frame) include:

· addressing sensor data quality problems,

· improving wind shear detection capability,

· increasing the current ITWS 20 minute convective forecast lead time to 60 minutes and,

· providing airline operations centers (AOCs) with real time access to the ITWS products.

Following this initial set of system improvements, we suggest a second system improvement phase focussing on winter weather information needs, improving the ITWS 3D gridded wind products, explicit estimation of cell growth and decay, and extending the ITWS terminal areas to include several major west coast airports.