Colour state other than clouds or low visibility (e.g. ice or other obstructions) then the word BLACK is written in full and placed immediately before the actual colour state (e.g. BLACKWHT). The colour state may be appended to a METAR report. A short period forecast called a "TREND" which covers the following two hours from the observation may also be added, often with reference to the colour state. The following criteria are used to determine the colour state: Colour state Colour states is a system used for quickly showing meteorological conditions. Meteorological colour states are determined by the relevant worst condition from
Expert witnesses in English law of forensic evidence, such instances are now commonplace, and the need for experts has been described as 'ever-expanding'. Common areas that expert witnesses offer opinion on are ballistics, blood-alcohol calculations and levels, DNA or genetic fingerprinting, and fingerprint identification. Such areas are the least controversial, as the expert is testifying on science which is generally accepted, and their opinion will, in the absence of fraudulent process, be reproducible by other experts. It is where the opinions of experts are not firmly grounded in fact that they have faced controversy, but it is arguable that to deny any experts where their