This helps them to put their bulletins together using the latest information.

Making Up Forecast Charts

The weather forecasters are equipped with computer-based weather information displays linked directly to the super-computers at Met Office HQ in Exeter. These powerful computer forecast models take in data from around the world continuously and then simulate the world's atmosphere mathematically, from sea-level to the upper atmosphere, and predicts what is going to happen.

Forecasters therefore have access to up-to-date information arriving by computer, as well as by fax and email. They interpret this using their skills and experience in meteorology, and in consultation with the Met Office chief forecasters, they select the details they wish to use to support the weather story for that day. The BBC production team work with the forecasters to make sure that the editorial line 'fits' with the BBC's output for the day, and is consistent across all platforms. They also help the forecaster to concentrate on the meteorology by managing the operational, scheduling, data and graphics issues of the day.

Data also arrives continuously from the Met Office in the form of charts showing pressure, temperature, rainfall, cloud cover. In addition, satellite pictures for every continent, and hourly satellite images for the UK provide observational information. Half-hourly radar rainfall charts are also drawn up and forecasters can see where the rain is falling and compare this against what the computer forecast models are predicting will happen next. Over 6,000 graphics products are drawn up automatically every day and the forecasters can also make up their own symbol charts, or text charts using a range of background maps and images.

The state-of-the-art graphics system allows forecasters to put together a sequence of charts and other graphics, including stills, animations, video clips, live weather cameras and text charts. They can be in or out of vision, and can be customised for different channels or platforms. All the forecasts are ad-libbed and so can be shortened or lengthened as needed, but the bulletins themselves can't be altered at the very last minute. Because of this the forecasters will often put a summary chart at the end of their bulletin that they can jump to, using a foot switch, should the bulletin have to be cut short suddenly.

Broadcasting the Forecast Bulletin

The solo operation continues in the studio where the forecasters switch on the lights and put in their ear-piece so that they can listen to the programme before their broadcast and to any last-minute instructions from the director in the network control room.

The TV studios, designed for digital broadcasting and widescreen technology, incorporate a device which, at the touch of a button, adjusts the height of the camera, lighting configuration and microphone level to suit each of the presenters individually.

The forecaster stands in front of a translucent screen on which is projected a faint image of the graphics. This gives the weatherman or woman an idea of where to point. The back of the screen is flooded with blue light and an electronic system known as Colour Separation Overlay (CSO) causes any area where the camera detects blue to be replaced by a 'clean feed' of the charts from the computer, called up in sequence by the forecaster at the touch of a button. The forecasters can't dress in blue clothing as this would cause them to merge with the graphics.

Monitors next to the camera show the output of the graphics computer and the output of the studio. In front of the camera is an autocue screen on to which is projected the service - BBC ONE etc on which the forecaster is about to broadcast. Superimposed on to this image is a countdown clock. The forecaster starts their forecast when they see themselves appear and stops when the countdown clock reaches zero. The forecast is ad-libbed and so the forecasters can shorten or lengthen their bulletin if directed to by the network director or news gallery.

For radio broadcasts, the forecaster is again alone in the sound studio, ad-libbing from notes or hand-drawn charts and linked via headphones to the relevant continuity studio at Broadcasting House in central London which 'tops and tails' the forecast.

A dedicated, BBC designed weather graphics system has also been installed into each of the national and regional BBC Centres. This allows each local weather presenter around the UK to prepare and transmit their own weather bulletin using the same information and graphics systems as the forecasters based in the BBC Weather Centre.