Clima

FORECASTING
Use some or all of the Instruments described on the previous pages together with your observational skills to keep weather records and prepare forecasts.
You don't need a speclalInstrument to determine visiblllty. Select promlnent objects at the following approximate distances from your locatlon: 0.5,1.0,1.5, 5,10,15. and 20 km. Try to choose objects which have good silhouettes.such as trees, flagpoles, spires, and large bulldings. Determine the visibllity at a given time by noting the object tvhlch Is farthest aivay and still visible. For example, ifyou can see the 5 km mark.but not the 10 km mark. then record the vislblllty as 5 km. Make vislbíllty observatlons in the momlng and afternoon. Always Include a note about why vlsibility is reduced (e.g. fog, snow).MATERIALS: Some or all of the Instruments on the previous pages; copies of following pages. Optional -- wood, nails, palnt and other building materials; plástic sheet protectors.
DOINGI7V

1. You don'tneed an instrument box for forecasting, but it can be a handy place to store instruments. A general design for the box is shown. The box should be painted white to reflect sunlight, and should nave holeswhich will let air circuíate.
You can keep instruments and papers inside the box, with the exception of the rain/snow collector and wind detection instruments. The rain/snow collector can sit on theground a few metres away from the box. The wind detection instru­ments may be mounted on top of the box; make the instruments out of wood or plástic so that they are durable. Several of the pages inthis One Leads to Another series contain graphs or listings of weather signs; photocopy these pages and mount them in plástic ¡n or on the instrument box.
3.Enter daily weather information on photo-copies of the Weather Conditions Record sheet.
4.Use the information on the following pages to
help you make weather forecasts. Weather
predictions are generally valid for 12 hours. At...