WDTB Project 10 – Warning Decision-Making Research and Training: Storm-Based Warnings
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:
- Tornado warning for an isolated, single supercell
- Tornado warning for supercells in close proximity
- Tornado warning for squall line storms (single tornado warning with multiple adjacent severe thunderstorm warnings)
- Tornado warnings for merging storms
- Tornado warnings for training supercells
- Severe thunderstorm warnings for bowing segments of squall lines
- Severe thunderstorm warnings for pulse storms
- Flash flood warning for isolated, single storm
- Flash warning for an area of storms
- Extreme wind warning for area of tropical-storm induced winds
- Tornado and/or severe thunderstorm warnings for storms that cross NWS County Warning Area borders (hand-off from one WFO to another)
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: http://www.wdtb.noaa.gov/modules/SBW/
Specific Modules produced by CIMMS staff:
Lesson 1 (Introduction): http://www.wdtb.noaa.gov/modules/SBW/lessons/Lessson1/player.html
Lesson 2-T4 (Merging Storms): http://www.wdtb.noaa.gov/modules/SBW/lessons/T4-stormMerger/player.html
Lesson 2-T5 (Training Storms) : http://www.wdtb.noaa.gov/modules/SBW/lessons/T5-stormTraining/player.html