J1.5 20th AMS Conference on Severe Local Storms
11-15 September, Orlando, Florida


Stephan B. Smith*

Techniques Development Laboratory
National Weather Service
Silver Spring, Maryland


Thunderstorms are high impact weather phenomena. The lightning, winds, hail, tornadoes, and heavy precipitation they produce pose significant threats to life and property and have large negative impacts on transportation and commerce in the United States. Not surprisingly, accurate forecasts of thunderstorms are a high priority for government agencies whose missions and operations are affected by them. These include the Federal Aviation Administration (FAA), the Federal Highway Administration, the Federal Emergency Management Agency, the National Aeronautical and Space Administration, the Department of Defense (DoD), the Department of Energy and of course, the National Oceanic and Atmospheric Administration (NOAA). NOAA, FAA, and DoD in particular have independently funded thunderstorm research and development activities to help meet their operational needs. Given the level of interest and size of the problem, it makes sense to coordinate and leverage these various efforts and the information technology (IT) infrastructure of various government agencies (FAA 1999; OFCM 1999 a,b, and c) in a comprehensive effort to improve operational services for the American public and provide the biggest bang for the U.S. tax dollar.

NOAA's National Weather Service (NWS) has invested a great deal into its modernization in an effort to improve its traditional thunderstorm products, i.e. severe thunderstorm and tornado watches and warnings for the general public (NWS 1999). The NWS also possesses a wealth of thunderstorm forecasting expertise embodied in the staff of its Weather Forecast Offices (WFO), Storm Prediction Center (SPC), Aviation Weather Center (AWC) and Central Weather Service Units (CWSU). This invaluable human resource could be further leveraged to support the missions of other high impact government users. The advent of the NWS Advanced Weather Interactive Processing System (AWIPS) and high speed, broadband communications, ushers in a new era of digital/graphical products which will convey more information and exploit common GIS formats and could be the cornerstone of other governmental IT weather-decision support systems. In order to make this vision a reality for thunderstorm forecasts, several questions must be answered:

- How do automated thunderstorm guidance forecasts compare with one another? In particular, how does a state-of-the-art numerical weather prediction model perform in forecasting thunderstorms compared with simpler, less sophisticated techniques?

- How can critical judgement skills of human forecasters be best utilized to improve thunderstorm forecasts?

- What types of thunderstorm forecasts and warnings best meet the needs of users?

- What skill do we have in detecting tornadoes?

To arrive at answers to these critical questions, I am proposing a multi-year, multi-agency effort named the THunderstorm Operational Research (THOR) Project.

The Goals of THOR would be to:


New thunderstorm forecast applications would be implemented on AWIPS in the System for Convection Analysis and Nowcasting (SCAN; Smith et. al 1999). The AWIPS Local Data Acquisition and Dissemination (LDAD) function would be used to import the output of experimental products running outside of the AWIPS firewall into AWIPS. In this manner, NWS forecasters would be able to use current and experimental guidance via the principle AWIPS graphical user interface, the Display 2 Dimensional (D2D), in order to prepare and issue digital thunderstorm forecasts. These value-added human forecasts would be verified along with those of the guidance products to establish baseline thunderstorm forecast accuracies at multi-hour projections. Storm-based tornado detection decisions would be made on relevant days and verified with ground chase teams. These would be used to establish baseline accuracies for tornado detection and compared with automated guidance. A version of the NOAA Forecast Systems Laboratory's (FSL) Real-time Verification System (RTVS, Mahoney et. al 2000) would be used to provide verification of both human and automated forecasts (Fig. 1). Evaluation of current operational and experimental products would be provided by the societal impacts team.


Implementation teams would be formed to cover the following areas: Coordination, nowcasting (0-1 h), tornado detection, short-range forecasting (1-6 h), synoptic-range forecasting (6-48 h), verification, societal Impacts, forecasting/training, and IT systems (AWIPS and other Federal government weather information systems).

The following would constitute deliverables from the 4-year project that would start in the summer of 2001:

a) Implementation plan

b) Baseline accuracy of both human and automated thunderstorm forecasts/detections

c) Prototype digital/graphical products for high impact users

d) Societal impacts evaluation

e) A paradigm for further Federal government technology transfer efforts for other high impact weather phenomena.

THOR sites will focus on areas of the U.S. which experience both a high frequency of thunderstorms and commercial air traffic. The mostly likely areas include, but are not limited to, central Florida, the Dallas/Fort Worth area of Texas, and northern Alabama.


The author would like to thank Jim Wilson, Rita Roberts, and Cindy Mueller for their feedback on this proposal.


FAA, 1999: Decision-based weather needs for the Air Route Traffic Control Center Traffic Management Unit, U.S. Department of Transportation, 21 pp.

Mahoney, J. L., B. G. Brown, and J. Hart, 2000: Statistical verification of results for the Collaborative Convective Forecast Product, NOAA Technical Report OAR 457-FSL 6, U.S. Department of Commerce, 29 pp.

NWS, 1999: Vision 2005 - National Weather Service Strategic Plan for Weather, Water, and Climate Services 2000-2005, National Oceanic and Atmospheric Administration, U.S. Department of Commerce, 24 pp.

OFCM, 1999a: National Aviation Weather Initiatives. Joint Action Group for Aviation Weather FCM-P34-1999, National Oceanic and Atmospheric Administration, U.S. Department of Commerce, 70 pp.

OFCM, 1999b: Proceedings for the Weather Information for Surface Transportation: Delivering Improved Safety and Efficiency for Tomorrow Symposium, National Oceanic and Atmospheric Administration U.S. Department of Commerce, 80 pp.

OFCM, 1999c: The Federal Plan for Meteorological Services and Supporting Research FY2000 FCM P1-1999, National Oceanic and Atmospheric Administration, U.S. Department of Commerce, 152 pp.

Smith, S. B., S. Goel, M. T. Filiaggi, M. E. Churma, and L. Xin, 1999: Overview and status of the AWIPS System for Convection Analysis and Nowcasting (SCAN). Preprints, 15th International Conf. on IIPS, Amer. Meteor. Soc, Dallas, 326-329.

Figure 1: Schematic showing operational concept for THOR. Stick figure represents NWS forecasters. RTVS is the Real-Time Verification System developed by the Forecast Systems Laboratory.


*Corresponding author address:

Dr. Stephan B. Smith, TDL/NWS, SSMC2, 1325 East-West Highway, Silver Spring, MD 20910.
e-mail: Stephan.Smith@noaa.gov