Met Éireann - The Irish Meteorological Service Online. India Meteorological Department. Tropical Cyclone Information. Weather. Explanations | Weather. MSLP patterns Isobars join points of equal atmospheric pressure. On one side of the isobar pressure is smaller than the isobar value, on the other side greater. A common metaphor is a topographic map with it's lines denoting height: mountains are equal to areas of high pressure, dales equal to lows.
Similarly, we can talk about ridges and troughs (or valleys). Furthermore, there are several local effects (e.g. the sea breeze) which affect wind and make this general rule not valid in such cases. The closer the isobars are to each other, the higher the wind speed. Between tropical and arctic areas, at so called mid-latitudes, the isobars tend to form closed circles round the lowest pressure. (* this was first defined & explained by a Dutch meteorologist, Buys Ballot in 1857, and the 'Law' is named in his honour.) 500 hPa patterns Level of 500 hPa is roughly dividing the mass of the atmosphere in two. Spaghetti plots So named because of their resemblance to a certain Italian food. Thickness ** Italy - Servizio Meteorologico Aeronautica Militare. WeatherSpark | Beautiful Weather Graphs and Maps.
RAP Real-Time Weather. Associazione MeteoNetwork ONLUS. Europe SAT24.com, Satellite Weather Europe, Weather Forecast, Rainfall, Clouds, Sun in Europe. Argentina - Servicio Meteorológico Nacional.