User manual OREGON SCIENTIFIC PRO WEATHER 08 05

[. . . ] It often feels like this before a large thunderstorm. A low humidity feels more pleasant even on the hottest days. If the air is too dry however, this can irritate asthma or other respiratory diseases. Accuracy of Oregon Scientific Weather Stations Temperature (resolution 0. 1oC): -200C ~ 00C: +/- 20C 00C ~ 400C: +/- 10C 400C ~ 500C: +/-20C Humidity (resolution 1% RH): 25% RH ~ 40% RH: +/- 7% RH 40% RH ~80% RH: +/- 5% RH 80% RH ~90% RH: : +/- 7% RH Pressure (resolution 1mb): 795mb ~ 1050mb: +/- 7mb (for products w/pressure reading) Rain rate (resolution 1 mm/hr): 0 ~ 15 mm/hr:+/- 1 mm/Hr 15mm/hr ~ 998 mm/hr: +/- 10% mm/hr Wind speed (resolution 0. 2 metre/sec): Min. [. . . ] The vein measures the direction the wind is coming from usually given as a compass direction or bearing and speed given in knots, kph. mph or m/s. Oregon Scientific Australia 1300 300 155 oregonscientific. com. au Level 10, 30 Clarence Street, Sydney NSW 2000 proweather DL 07. 05 12/8/05 12:35 PM Page 2 PC Link Professional Weather Station WMR928NX - PC Link Professional Weather Station · Anemometer · Rain Gauge · Thermo-hygrometer · Barometer · Graphical weather forecast for the next 12-24hrs · Long range sensors up to 100m from base · Solar powered data transmitters relay the weather data via 433Mhz from sensors to the base display unit · Touch screen base display unit · Max and Min memories for all weather readings · Interchangeable measurements for all readings; select either metric or imperial · Hi/Lo alarms for all weather measurements · Virtual Weather Station PC software and connecting cable supplied Understanding the Weather What is Barometric Pressure? Also known as Air Pressure: Air pressure is the force of the air pressing down on the Earth's surface. As air is all around us, there is air pressure all around us too. Near sea level there is more air above you than there would be on the top of Mount Everest, therefore the air pressure is higher near the sea than it is on the top of a mountain. WMR928NX touch screen monitor display panel Barometer, thermo/hygrometer Outside thermo/hygrometer Rain gauge Anemometer ­ wind speed/direction gauge Low Pressure: In an area of low pressure the air has a tendency to rise. This general upward motion means that there is less pressure from the air pushing down on the earth, in other words there is low pressure. As air rises, it cools and if there is enough water vapour it may condense to form clouds and rain. This is why a low pressure is generally associated with wet weather. Low pressures often form on the boundary of warm and cold air. A small disturbance may cause the pressure to fall along this boundary, causing a circulation of air to develop. This is the beginning of a low pressure where the winds circulate around the centre in clockwise `cyclonic' movement, and the boundaries of warm and cold air become weather fronts. Other common types of lows are `thermal lows'. One thermal low, a heat low, recurs over the mainland. During a summer day, the land gets much hotter than the surrounding sea. This in turn heats the air nearer the ground, which rises. [. . . ] The winds circulate around the centre in an anti-clockwise, `anticyclonic' movement. However, the winds are generally weaker than those around a low pressure, especially in the centre. In a high pressure, the air is generally slowly sinking, or `subsiding'. [. . . ]