JIM'S WEATHER GENERATOR

                                       by
                                   Jim Heath
                          <heath@anchor.as.utexas.edu>


Start with whatever precipitation and wind conditions you wish, then roll d% at the start of each day for the change in weather conditions:

     01-03   5 steps better      PRECIPITATION             WIND
     04-07   4 steps better
     08-15   3 steps better      Clear                     Calm
     16-24   2 steps better      Ptly Cloudy               Breeze
     25-39   1 step better       Mostly Cloudy             Lt. Wind
     40-60   same                Cloudy                    Windy
     61-75   1 step worse        Misty/Drizzle (*)         Heavy Wind (***)
     76-85   2 steps worse       Rain/Sleet (**)           Gale (+)
     86-93   3 steps worse       Thunderstorm/Snow (***)   Cyclone/Tornado (+++)
     94-97   4 steps worse       Deluge/Blizzard (+)
     98-00   5 steps worse       Hurricane/Monsoon (++)

       * Maximum Duration 14 days
      ** Maximum Duration 10 days
     *** Maximum Duration 6 days
       + Maximum Duration 3 days
      ++ Maximum Duration 1 day
     +++ Maximum Duration 6 hours; also fast-moving phenomena

Obviously contradictory results (Clear + Tornado, Misty + Gale) are always decided in favor of precipitation.  That is, the wind conditions are re-rolled or a suitable wind selected.

If a change would place a condition off the scale (say, 3 places better than Partly Cloudy) the change is re-rolled.  If the re-roll is still impossible, treat as "same".

Severe weather conditions can only persist for their maximum duration.  At the expiration of that duration, the weather immediately improves one place. For the next three days, subtract 20% from all change rolls.