BBC Weather Watchers Guidance - Royal … Watchers guidance...1) Becoming a Weather Watcher • Sharing our interest in the weather • Fun, interesting and educational • Accessible

BBC Weather Watchers Guidance

1) Becoming a Weather Watcher

• Sharing our interest in the weather• Fun, interesting and educational• Accessible to anyone• Engage with others• Deepen our understanding about the weather• Introduction to digital skills• Share content and local information with BBC

audience

2) Current weather – choosing the right weather symbol

Sunny Sunny Intervals Light Cloud Heavy Cloud Drizzle

Sunshine & Showers Heavy Showers Light Rain Heavy Rain Thunderstorm

Thundery Showers Sleet Showers Sleet Light Snow Heavy Snow Showers Showers

2) Current weather – choosing the right weather symbol

Light Snow Heavy Snow Hail Showers Hail Fog

Hazy Mist Hail showers Heavy Snow Snow Showers at Night at Night at Night

2) Current weather – choosing the right weather symbol

Sleet Showers Thundery Showers Heavy Showers Light Showers Partly Cloudy at Night at Night at Night at Night at Night

Clear Night

2) Current weather – choosing the right weather symbol

3) Instrumentation and siting

• Temperature (including maximum and minimum)• Humidity• Rainfall• Snow depth• Wind speed and direction• Pressure• Automatic weather stations• Visual observations

Air TemperatureWhat instrument do we use?• Simple thermometer – can be read at any time of

the day• Max-min thermometer – usually read at same time

each day• Digital thermometer - can be read at any time of

the day.• Alternative options?

How do we use it?• All observations should be in degrees Celsius (ºC)• Measure away from large buildings, trees etc. • Thermometers must be kept out of direct sunlight• Hang on a north-facing wall or (preferably) in a

ventilated white box so that sun is reflected away, yet air can pass freely over the thermometer.

SimpleThermometer

(£1 – 3)

Digitalmax-min

Thermometer£10

Traditionalmax-min

Thermometer£10

UK Hottest:38.5°C

Faversham, Kent

UK Coldest:-27.2°C

Braemar, Eastern Grampians

Air Temperature• The Weather Watchers sliding scale

Humidity• The amount of water vapour present in the air

is known as the humidity. • Relative humidity (RH) - amount of water

vapour in the air as a percentage of that required to saturate it completely.

• RH will be 100% in fog, but might be as low as 30% on a dry summer’s day.

What instrument do we use?• There are several different types of instrument,

such as simple wet-dry bulb thermometers, but the simplest to read is the digital hygrometer.

How do we use it?• Hygrometers must be protected from direct

sunlight using some form of screen which still allows air to pass over the instrument freely.

Digitalhygrometer

£10

Rainfall amount• The total depth of rain which has fallen over the

past 24 hours.

What instrument do we use?• A rain gauge which has a funnel collector to prevent

the rain already in the gauge evaporating.• A straight cylinder with flat bottom, such as a tin

can. Rainfall depth can then be measured with a ruler.

How do we use it?• Put the rain gauge in as open an area as possible,

away from obstructions (houses, trees). • To prevent it blowing over, dig a shallow hole in a

lawn and push the rain gauge into it, or put into a large plant pot.

• Rainfall is manually measured at the same time each day and is reported in millimetres (mm) for the past 24 hours

• [mm/hr is reported for automatic weather stations]

Rain gauge with collecting funnel

£15

Open rain gauge £3 - 5

Snow depthCan be simply measured by sticking a ruler into the snow, away from drifts. Measure in centimetres (cm).

Make your own

Wind speed and direction• Wind speed is the speed of the air moving past us.• Wind direction is the direction which the wind is

coming FROM.

What instrument do we use?• Wind speed is measured with an anemometer.• Wind direction can be measured with a wind vane or

windsock• Blowing bubbles and using a compass can also be

helpful in assessing wind direction.

How do we use it?• Measure wind in open space and as high up off the

ground as possible. • The anemometer should be held up in front of you

at arms length, facing into the wind. We report the speed in mph.

• The windsock can be put on a pole (e.g. bamboo)• Report the direction the wind coming from one of

eight compass points, i.e. N, NW, W, SW, etc.

Propeller anemometer

£10

Windsock£1 - 3

Pressure• Pressure is due to the weight of the column of air above

us pressing down. • Pressure varies with the type of weather.

What instrument do we use?• Barometer• Digital sensor (used in AWSs)

How do we use it?• Pressure can be measured indoors with the barometer

hanging on a wall.• Tap the barometer gently before reading as the needle

sometimes sticks. • We use units called hectopascals (hPa) or millibars (mb)

Calibration• Wait for a calm day (i.e. high pressure system) then look

at the pressure at your location on the BBC weather website, then alter your barometer to read this value (turning a small screw at the back).

Barometer£15

Feeling under the weather

Headache and joints ache – drop in air pressure

Nausea – build up in static in the atmosphereHeat stress

Automatic wireless weather station

• You can buy an automatic weather station which transmits data to a console indoors and displays it.

• You can read these observations directly from the indoor display console and then report them manually on the BBC Weather Watchers website.

Wireless temperature and humidity station,

showing indoor console and (right) outdoor

sensors. £20

Full automatic wireless weather station and

indoor display console£60 - 90

temp andhumidity

rainfall

wind speed and direction

Visual observations

Visibility• This is how far you can see in daylight. If you can

see less than 1000m report as fog. If you can see more than this but less than 4km, report as mist.

Snow/sleet/hail falling• Type of precipitation• Report this as heavy, medium or light snow, or sleet

or hail.

Cloud amount• Estimate how much of the sky is covered in cloud.

Use eighths as a unit, so if the sky is half cloudy report 4/8 (four eighths), overcast is 8/8. Any small cloud in a clear sky is 1/8.

Cloud type• You can identify the type of cloud from the chart

supplied or using the online key to clouds.