32nd Conference on Broadcast Meteorology/31st Conference on Radar Meteorology/Fifth Conference on Coastal Atmospheric and Oceanic Prediction and Processes

Friday, 8 August 2003: 11:45 AM
A forecaster-computer interactive capability of the NCAR Auto-Nowcaster System for improved storm initiation nowcasts
Rita Roberts, NCAR, Boulder, CO; and T. Saxen, C. Mueller, and D. Albo
Poster PDF (239.4 kB)
The NCAR Auto-Nowcaster System (ANC) is an automated, convective storm nowcasting system that produces time and location-specific, 0-1 hr nowcasts of storms. It makes use of all operationally available datasets including WSR-88D, GOES, surface mesonet, and rawinsonde data. It has been run operationally at specific weather forecast offices and also has been run as part of the Federal Aviation Administration's Regional Convective Weather Forecast (RCWF) demonstration conducted from May-September 2002. The RCWF domain covered the northeast portion of the United States. Initially designed to run over a single radar domain, the ANC was modified last summer to run over a subset of the RCWF domain and pull in data from 4 different radars.

A key component and unique attribute of the ANC system is its ability to produce storm initiation nowcasts based on automated radar detections of surface convergence boundaries and characterization of the boundaries (e.g., estimation of shear profiles along the boundary). Running the ANC on a larger domain resulted in a deficiency in the ability to detect all boundaries on all scales, ranging from the local to the synoptic scale. For example, a cold front evident on synoptic maps was not always well-resolved as a distinct feature on one or more radars.

A new capability has been added to the ANC that allows a forecaster to insert, in real-time, the locations of convergence features that are not detected or are only partially detected on radar(s). These locations are immediately included in all of the boundary-related algorithms running in the ANC. In addition to radar mosaics, information available to the forecaster when delineating important, missed boundary features include numerical model output, frontal likelihood fields, satellite imagery and surface mesonet data. With the use of this new interactive tool it will now be possible to address the importance of different scale interactions on convection initiation and incorporate these scales in the nowcasts of storm initiation. This paper will provide details on the interactive tool plus show examples of the change in storm initiation nowcasts that result when larger scale boundary triggers are included in the nowcast process.

Supplementary URL: