Quickly and accurately display and analyze tornado data with SATT. Obtain an analysis of all tornadoes passing within a specified radius of a given location. Tabular and graphical output provided.



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Contact John Tatom for purchase information at or 256.327.3373.

The Site Assessment of Tornado Threat, Third Edition, (SATT 3.0 for Windows) software developed by VorTek LLC (VORTEK), provides the user with a means of quickly and accurately displaying and analyzing tornado data for any portion of the United States, excluding Alaska. This Windows-based program contains all National Weather Service (NWS) data since 1950 and is updated annually.

Two versions of the SATT 3.0 software are currently available:

  • National Version – the 48 contiguous states plus Hawaii
  • Regional Version – Primary State plus all neighboring states

With each version the user can obtain an analysis of all tornadoes passing within a specified radius of any given location, within the states included. The analysis provides both tabular and graphical output and includes a tabulation of tornadoes by year, month, time of day, and intensity. The annual coverage fraction (ACF), which is the average annual fraction of land area covered by tornadoes within the reference area, is included. (The ACF is the same as the annual probability of being struck by a tornado within the reference area.) A plot of tornadoes tracks, color-coded by intensity, with state boundaries indicated, is presented along with the most frequent direction from which tornadoes have approached the region of interest. Of special significance, both versions of SATT 3.0 have the capability to generate color-coded plots of the tornado threat for each of the states included.

The user can limit the analysis geographically to a specific Region of Interest and can also limit the analysis, in terms of time, to specific hours, months, or years. Given such inputs, the software generates a series of Output Displays, both graphical and tabular. These outputs include the following:

Graphical Output

  • Annual Distribution by Intensity
  • Annual Distribution by Time of Day
  • Annual Distribution by Month
  • Annual Distribution by Year
  • Tornado Track Display
    • Color-Coded by Intensity
    • Identified by Month and Year (optional)
    • State Boundaries Displayed
  • Threat Sector Plots (frequency color-coded)
  • Annual Coverage Fraction (ACF)
  • Tornado Threat Contour Plot
    • Generated for Primary State
    • Color-Coded by Probability (ACF) Level
  • Population Density Map
    • Generated for Primary State
    • Color-Coded by Population Density

Tabular Output

  • The average annual number of tornadoes distributed by
    • Intensity
    • Hour
    • Month
  • Summary of tornadoes distributed by year
  • Listing of the NWS data within the Region of Interest
  • Annual Coverage Fraction (ACF)
  • Analysis of direction of approach of tornadoes

In some cases the path of a tornado may extend across several counties and/or states. For such a case the path may be divided into segments. Because the characteristics of a tornado may vary from segment to segment, each segment is counted as a separate tornadic event.

SATT 3.0 software has a number of applications. For purposes of weather reviewing it provides a clear, accurate display of pertinent characteristics of tornadoes for a specific region. For purposes of weather analysis it provides a basic, flexible tool which allows the user to quickly evaluate the behavior of previous tornadoes in a given region, and compare one region with another, especially with regard to tornado probability. Because SATT 3.0 software is based entirely on historical data, it is not suited for predicting the occurrence of a tornado at a specific point at a specific time in the future. For purposes of weather education SATT 3.0 provides a means of explaining to the general public all available weather data pertaining to tornadoes, and thereby raising the general awareness of the threat posed by tornadoes within a given region.