Tornado Detection Algorithm (TDA) Rapid Update Requirements ORPG Build 5 – AWIPS OB4 Mike Istok NWS/OS&T/SEC NPI Development Manager 30 July 2003

Slide 2 July 30, 2003 – TDA Rapid Update ORPG Build 5 WSR-88D TRU Product Functional Requirements The Tornado Vortex Signature (TVS) Rapid Update product is generated once per elevation scan TDA Algorithm information from an elevation scan is based on elevations that have been completed thus far in the current volume scan This information is combined with the previous volume scan TDA, MDA, and Storm Track Algorithm information Average motion of all tracked MDA features from the previous volume is used to derive forecast positions of previous TVS features at the current volume scan time - If average MDA motion is unavailable, average SCIT motion is used. In priority rank order(TVS types before ETVSs, and within each type ranked by Low-level Delta Velocity (from the greatest to least)), the forecast position of each previous feature is matched to the closest current feature within a search radius defined by SCIT algorithm - Current unmatched 3D features are New - If previous volume is unavailable, all features are New

Slide 3 July 30, 2003 – TDA Rapid Update ORPG Build 5 WSR-88D TRU Product Functional Requirements(cont.) Current features inherit attributes (associated storm ID, feature type, low-level delta velocity, maximum delta velocity and its height, average delta velocity, maximum shear and its height, base and top heights, depth, and base azimuth and range) of the matched previous feature –Position attributes (base azimuth, range, and height) of matched previous features are always updated to the “current” detection Persistent. Maximum delta velocity, average delta velocity, and maximum shear are update to the “current” if increasing in magnitude. - If the maximum delta velocity or shear is updated, the height of that attribute is also updated. Increasing. Strength attributes (feature type, low-level delta velocity, depth) are updated to the “current” value, if increasing in magnitude. - Top height and depth is updated if the top of the current detection is taller –New. All attributes of unmatched current (new) features are provided. –Extrapolated. Position attributes (base azimuth and range only) of unmatched previous features are extrapolated to the forecast position. Feature status categories are persistent, increasing, new, and extrapolated At the end of the volume scan extrapolated features are removed

Slide 4 July 30, 2003 – TDA Rapid Update ORPG Build 5 WSR-88D TRU Product Functional Requirements(concluded) Product is used to generate a graphic display, graphic overlay to other products, and alphanumeric displays Product includes annotations for the product name, date and time of volume scan, and elevation angle Product format requirements –Graphic 3D feature symbols – 3D features that are new, persistent, increasing, or extrapolated – Packet #20 to report current (new, persistent, & increasing) and extrapolated TVS and ETVS features – Identify storm ID associated with each TVS feature –Position the storm ID relative to the storm cell centroid –Graphic alphanumeric table – Features that are new, persistent, increasing, or extrapolated – Display character ^ (8-bit hexadecimal 5E) next to current data –Tabular alphanumeric table – Features that are new, persistent, increasing, or extrapolated – Increasing, persistent, and extrapolated features – Display character ^ (8-bit hexadecimal 5E) next to current data –TDA features are listed in priority rank order Note: The TDA requires 3 elevation scans to identify a feature.

Slide 5 July 30, 2003 – TDA Rapid Update Standard TVS Product Examples

Slide 6 July 30, 2003 – TDA Rapid Update TRU Graphic Alphanumeric Block (GAB)

Slide 7 July 30, 2003 – TDA Rapid Update TRU Tabular Alphanumeric Block (TAB)

Slide 8 July 30, 2003 – TDA Rapid Update TRU Product Sample

Slide 9 July 30, 2003 – TDA Rapid Update TRU Overview and Terminology

Slide 10 July 30, 2003 – TDA Rapid Update AWIPS OB4 Functional Requirements TDA Rapid Update (ORPG Build 5 generates new elevation based product, based on user request) –User requests the TRU product three different ways – All elevations, lowest x elevations, specific elevation angles –Can archive and read-back all TRU products –Display as overlay to other products from same volume scan –User option to choose between displaying the latest elevation (i.e., highest elevation) and displaying a specific elevation –When the latest elevation is selected, the display will automatically update when higher elevation products are received –Highest elevation TRU is used as overlay in time loops –Negative condition (no TVS features) must be displayed –Annotate displays with elevation angle of the TRU product

Slide 11 July 30, 2003 – TDA Rapid Update AWIPS OB4 Functional Requirements TDA Rapid Update D2D display requirements –Graphic display of TVS and ETVS feature icons – Display traditional AWIPS TVS and ETVS symbols for current and use slightly different symbols (e.g., right triangle centered on the right angle) for extrapolated features – Toggle to turn off display of extrapolated features –Graphic alphanumeric table (grid/text D2D display) – Display like other graphic alphanumeric products –Tabular alphanumeric table (AWIPS text viewer) – Store/display like other tabular alphanumeric products