The Site Assessment of Tornado Threat, Third Edition, SATT 3.0, is the most current version of the software. SATT 3.0 provides the user with a means of quickly and accurately displaying and analyzing tornado data for any portion of the United States, excluding Alaska. The program contains all National Weather Service (NWS) data from 1950 to 2011. By means of this software we have calculated and tabulated the probability of tornadoes for the twenty most tornado prone states (excluding Alaska) on both an annual and a month-by-month basis and also for the twenty most tornado prone cities on both an annual and a month-by-month basis. We also have developed color-coded contour maps of tornado probability for various states including Alabama and Georgia, as well as a color-coded map of tornado probability for the United States. A number of technical papers have been published dealing with our work in this area.  For a listing of customers we have a table available.

Two versions of the SATT 3.0 software are available:

Regional Version - primary state plus all neighboring states

National Version - the 48 contiguous states plus Hawaii

In either version of SATT 3.0 the user could obtain an analysis of all tornadoes passing within a specified radius of any given location, within the state(s) included in that particular version. 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 employed as a measure of tornado probability. This technique is consistent with the FEMA approved model for tornado probability. A plot of tornado 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.

The user can restrict the analysis to any combination of times of day, months, years, and intensities. For example, the user can set up the program to satisfy the question: "How many tornadoes of intensity four or five passed within 20 miles of Little Rock, Arkansas, between 6:00 and 8:00 p.m., for the months of June and July, during the years 1980 to 1989?" By means of the user-friendly SATT 3.0 software, the user can quickly obtain both an accurate tabulation and a clear display of the characteristics of all tornadoes which have passed through a specified region.


To ensure the widest possible utilization of the software, the hardware requirements have been kept to a minimum, as follows:

IBM PC or compatible

Hard disk drive

Color monitor and graphics card

DOS 3.2 or later

322K RAM

SATT 3.0 supports both printer and plotter output, and is compatible with Windows XP.


The user specifies the case by entering the following about the location in question:

Radius in statute miles about that point

Reference area for ACF

State(s) of interest

Time convention

The user then has the option to restrict the program's analysis to any combination of:

Specific period of years

Specific sequence of months

Specific time of day interval

Specific range of intensities


Both versions of SATT 3.0 are capable of providing both tabular and graphical outputs as follows:

Tabular output

o    Listing of the NWS data within the region of interest

o    Annual coverage fraction (ACF)

o    Analysis of direction of approach of tornadoes in terms of threat sectors

o    Summary of the annual number of tornadoes by:






o    Tornado track display

  Color-coded by intensity

  Identified by month and year

  State boundaries displayed

o    Threat sector plots (color-coded by frequency)

o    Annual tornado distribution by hour

o    Annual tornado distribution by month

o    Annual tornado distribution by intensity

o    Tornado distribution by year


o    Weather reviewing/reporting

  Clear tornado representation

  Accurate display of pertinent characteristics

o    Risk Analysis

  Quick evaluation of regional tornado behavior

  Flexible investigation of previous tornadoes

o    Public education

  Simple explanation of NWS tornado data

  Raised awareness of tornado threat

o    NWS data check

  Review of tornado data

  Correction of discrepancies

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