- -3 - 



C) Rain - Precipitation of comparatively long duration as distinguished from 

 showers. Precipitation expected over major portion of area, 



lo Occasional rain - Precipitation at infrequent intervals and not prolonged, 

 but rather v/idespread , 



2, Intermittent rain - Precipitation of more or less general and prolonged 

 character but frequently interrupted for short periods. 



Modifying Terms for Shovver and Rain Forecasts 



In Terms of Amount Expected In Terms of Bate of Accumulation 



Very light - less than ,03" 



Light - less than ,10" Tvr to ,10" per hour 



Moderate - ,10" to ,50" .11" to ,30" per hour 



Heavy - more than ,^0" over ,30" per hour 



Very heavy - more than 1,0" 



•M-T indicates a trace of rain, i,e,, an amovmt too small to measure, 



D) Drizzle - Precipitation consisting of numerous tiny droplets which appear to 

 float in the air. Usually accompanied by loi/, stratus type clouds and fog, 



E) Thunderstorm - liVhen thunder is heard a thixnderstorm is considered to be 

 occurring. It may or may not be accompanied by precipitation. If a shoiver 

 does accompany the thunder it is termed a "thundershower", (Treated similar 

 to showers in forecasts,) 



F) Fog - Minute water droplets suspended in the atmosphere (results in reduced 

 visibility) , 



G) Dew or Frost - Widespread liquid or frozen condensation on surface objects. 

 May be modified by the terms "light" or "heavy", or by "killing" in the case 

 of severe frost, 



III. TEMPERATURE 



In general, temperature forecasts, actual readings (usually maximum and minimum) 

 v/ill be given. However, in trenci forecasts for longer periodsthe following 

 terms apply; 



A) Ylarmerr or not quite so cool - The high or low teirperatures during the period 

 will be at least four degrees higher than the comparable extremes occurring 

 during the same period 2k hours before, 



B) Colder, cooler , or not quite so warm - The high or lovx temperatxires during 

 period will be at least four degrees lower ttian the cwnparable extremes 

 occurring during the same period 2k hours before, 



C) Little change - High or low temperatures during the period will not differ 

 by more than seven degrees from the comparable extreme occurring during the 

 same period 2k hours before. 



