A five-day weather forecast today is generally as reliable as a three-day forecast two decades ago. Outlooks of up to a week, especially in temperate mid-latitude regions are becoming increasingly reliable. Information can be disseminated around the world from one location to another within three hours, while recently understood phenomena such as El Niño Southern Oscillation (ENSO) (El Niño, La Niña and neutral phases) can be forecast up to a year in advance. Seasonal climate predictions can be forecast up to a month, three months or six months ahead although these climate predictions are probabilistic in nature. Such forecasts, often from more advanced centres, are made available globally to all nations.
Air pressure, temperature, mountain ranges, ocean currents and many other factors combine to produce an enormous quantity of interacting variables all of which can alter the weather to a greater or lesser extent. However, greater understanding of the science, plus the use of powerful computer models, continue to improve our ability to make more accurate predictions with longer lead times.
The WMO 10-year THORPEX (The Observing System Research and Predictability Experiment (an activity of the World Weather Research Programme) is currently addressing this very concern. It focuses on identifying problems with forecasting and research. Enhanced observation and data analysis systems, increased understanding of atmosphere dynamics and predictability; and improved global and regional numerical weather prediction models are some areas where improvements can be made. Training more meteorologists in developing nations and providing them with more and sophisticated equipment are also necessary.
Concerted efforts are being made by some National Meteorological and Hydrological Services and leading international climate modelling groups under the coordination of the World Climate Research Programme to develop regional climate models so that they become capable of providing regional-scale (typically 25 x 25 km and higher resolution with appropriate computing facilities), climate information for impact studies, to facilitate their use within the modest computational infrastructure of developing countries, and to provide training in the use of this information as necessary.
Experiments on weather modification have been, and continue to be, carried out. The most prevalent method is cloud seeding, which dates back to 1946 and is the attempt to alter the amount or type of precipitation produced by clouds. This is done by targeting clouds from aircraft or from the ground with substances such as silver iodide, dry ice and even salt. In the 1950s and 1960s, US scientists experimented in modifying tropical cyclones (Project Stormfury) but the research was inconclusive.
Today, cloud seeding is employed in many countries in an effort to increase precipitation in drought-stricken areas, reduce the size of hailstones that form in thunderstorms, reduce fog around airports and even to provoke snow at major ski resorts. However, the impacts of operations in rainfall enhancement and hail suppression have still not been properly quantified and modification remains an area of active research.
Every year, natural disasters affect many communities around the world, leading to the loss of lives, the destruction of social and economic infrastructure and the degradation of already fragile ecosystems. Such hazards are inevitable and can threaten everyone, but they tend to hit communities in developing and least developed countries the hardest, increasing their vulnerability and setting back their economic and social goals, sometimes by decades.
While economic losses in dollars for developing countries are lower than those for developed countries, impact (as a percentage of GDP) is often much higher. Many developing nations lie in tropical zones where extreme weather events such as tropical cyclones, droughts and flooding are more frequent than in other regions. Developing nations possess limited facilities and qualified human resources to monitor and predict these phenomena and provide warnings to all sectors of the population. Addressing this challenge is a major concern for WMO.
Meteorology requires knowledge of higher mathematics, physics and chemistry as well as good computer proficiency. The basic requirement for becoming a Meteorologist is a BSc degree in Meteorology or Atmospheric Sciences. Another option is to first get a BSc in Mathematics, Physical Sciences or Engineering and then follow courses in Meteorology. Teaching, research or management positions usually require higher degrees. Meteorological technicians, who may not possess an academic degree, generally undertake the responsibility of collecting and reporting observational weather data. Their qualification is normally obtained through completion of technical-level courses of a varying duration (between a few months and 1-2 years) depending on the envisaged work.
Weather forecasts require observations of our environment around the clock and around the world. The bulk of those observations are carried out by National Meteorological Services as part of the WMO World Weather Watch, which networks the observing stations to national, regional and global weather and climate prediction centres 24 hours a day in real-time.