The FAA Operational Evolution Plan (OEP) has identified en route severe weather as one of the four problems that must be addressed if the U.S. air transportation system is to alleviate the growing gap between the demand for air transportation and the capacity to meet that demand. In this paper, we describe a major new FAA initiative, the Corridor Integrated Weather System (CIWS), to improve convective weather decision support for congested en route airspace.

Convective weather in highly congested airspace is of particular concern because many of the delays arise from these corridors. For example, re-routing aircraft around areas of actual or predicted weather can be very difficult when one must be concerned about controller overload in the weather free sectors. When major terminals also underlie the en route airspace, convective weather has even greater adverse impacts.

The objective of the CIWS initiative is to provide en route traffic flow managers with accurate, automated high update information on storm locations and 0-2 hour forecasts of storms so that they can achieve more efficient tactical use of the airspace. These "tactical" traffic flow management products will complement the longer-term (2-6 hr) national CCFP forecasts that are also needed for flight planning and traffic flow management.

The CIWS is in the concept exploration phase. A real time operational demonstration started in July 2001 in the "Great Lakes Corridor". Both terminal and en route weather sensors are utilized to create the CIWS products: the ASR9 and ARSR4 update once per minute to detect rapidly growing cells while the NEXRAD provides 3D storm information. Data from lightning sensors is also integrated with the radar data. Forecasts for 20-60 minutes were provided by an adapted version of the Terminal Convective Weather Forecast (TCWF) that has been very successfully used since 1998 in the transitional en route airspace around major terminals.

Very high spatial resolution of the CIWS precipitation products (1 km) enables users to manage traffic in a highly congested corridor that includes five major airports. Displays are provided at key ARTCCs (ZOB, ZIN, ZAU, ZNY, ZID), the ATCSCC, and the New York, Chicago, Detroit, Pittsburgh, Cincinnati, and Cleveland TRACONs. Airline systems operations centers have access to the CIWS products via servers on the Internet and CDMnet.

Initial operational experience from 2001-02 will be described as well as new thrusts for 2002. These new thrusts include:

1. Fully automated 2 hour forecasts that have explicit estimates of storm growth and decay through joint use of radar and satellite data,

2. Extending the CIWS coverage to the east coast by taking advantage of the existing coverage provided by the New York Integrated Terminal Weather System (ITWS) demonstration system, and

3. Integration of the CIWS weather products with contemporary air traffic automation systems (e.g., URET and "Direct To") that can facilitate flight plan amendment coordination and, with traffic flow management systems (e.g., CRCT) to permit "what if" assessment of the traffic loading from re routes

The talk will conclude with a discussion of possible system architectures for the implementation of the CIWS technology into the National Air System.

* This work was sponsored by the Federal Aviation Administration under Air Force Contract No. F19628-00-C-0002. The views expressed are those of the authors and do not reflect the official policy or position of the U.S. Government. Opinions, interpretations, conclusions, and recommendations are those of the authors and are not necessarily endorsed by the US Government.