science of meteorology has not developed to the point where the precise location of individual showers can be reliably predicted. During this period in the years from 1950 through 1954, inclusive, ceilings have never been observed at less than 500 feet, Vi- sibilities have been observed below three miles on an average of one day in twenty with precipitation, including rain showers and thunder. storms, being the exclusive cause of the low visibilities. The du- ration of showers and low visibilities is generally thirty minutes _or less. B. Fronts. The terms "Intertropical Front" and "Equatorial Front" are in actuality misnomers, A density discontinuity and proper wind shear must exist to define a front. Rather conclusive evidence ex- ists that significant horizontal density discontinuities do not ex- ist in the Marshalls, The areas formerly designated "Intertropical or Equatorial Fronts" are in reality the paths of low-level eddies and vortices, The pattern of circulation about these disturbances produces areas and lines conducive to vertical motion. It is along these lines and in the areas where vertical motions are predominantly upward that middle and high cloudiness becomes extensive, precipitation grows to be general, and thunderstorms develop. The weath- er associated with these lines appears similar to the weather accom panying the true fronts of higher latitudes, However, these lines do not form or move as do true fronts nor are they subject to the same forecasting techniques which are applicable to the mid-latitude 162