Cooperative Institute for Mesoscale Meteorological Studies


NOAA Strategic Goal 3: Serve Society’s Need for Weather and Water Information

Forecast Improvements

WDTB Project 10 – Warning Decision-Making Research and Training: Storm-Based Warnings

Morris, Wood, NWS/WDTB collaborators

Funding Type: CIMMS Task II

Improve understanding of warning-related issues; help NWS implement service changes.

On 1 October 2007, the NWS changes warning methodology for short-fused convective warnings from the legacy county-based system to a polygon, “storm-based” system. In the new system, more specificity and reduction of false alarm area are anticipated. However, verification methodologies also change because credit will no longer be given for a storm report outside a warning polygon but inside a warned county. Although forecasters have been drawing warning polygons for several years, the service change requires all forecasters to be refreshed on polygon design for a number of convective warning situations including:

In addition, all warning forecasters require updated information on requisite customer service issues, such as highlighting affected areas in warning products and recognizing that warned populations are still organized by county areas. Additional storm-based concepts include handling adjacent warnings, multiple threats for a single storm and anticipation of storm evolution and uncertainty. To support this change, CIMMS and WDTB staff along with other NWS collaborators designed stormbased warning lessons, activities that include two training modules and a number of practice exercises involving the Weather Event Simulator.

This project has been completed.

Main Storm-Based Warnings Web Page:

Specific Modules produced by CIMMS staff:
Lesson 1 (Introduction):
Lesson 2-T4 (Merging Storms):
Lesson 2-T5 (Training Storms) :

radar images showing comparison of county based to storm based warnings

Service change presented by storm-based warnings.