Weather refers to the condition of the air on earth at a given place and time, and the basis of weather prediction depends on two major atmospheric phenomenon. They are:
ATMOSPHERIC PRESSURE, which is caused by the pressure of air dictates, low and high pressure systems, fronts and consequently wind sheer. Generally due to behaviour of pressure, air moves from high pressure into lower pressure areas, thus creating winds. Rain is indicated by low pressures, because clouds tend to move from high to low pressure areas. While high pressure systems indicate fair skies.
THE SOLAR EFFECT, where the sun heats up the surface, causing warm and less dense air parcels to rise together with moisture. As the parcels rise, they cool and the water vapour within them condenses into clouds. The air mass, which consists of many of these parcels, is indicative of future temperatures, moisture, wind and pressure. Eventually the moisture becomes too heavy and precipitates out as rain, hail and snow.
These principles are universal, when determination of weather effects are needed. however, the atmosphere is much more complex with outside feedbacks and influences that need to be considered. For that the following is done in two accepted ways:
USING OBSERVATIONS for forecasts by implementing physical evidence that can be seen or felt produces many results and is the basis of many lore. Seeing a red sun with fog or an equally red moon is an indicator of ash and dust in the atmosphere, which in turn indicates high winds and and dryness. The dust becomes dry and light, and is picked up by the winds and the rising warm air parcels. However. cloudless and bright days, as well as clear and starry nights indicate cold fronts or cold pressure systems developing. Strong winds are an indication of large pressure gradients, while storm systems move from West to East in the northern hemisphere and East to West in the southern hemisphere. This indicates that winds blowing towards the east or west, depending on the location may indicate approaching precipitation. Rainbows indicate passing rains, as the water droplets left behind refract sunlight, thus indicating clearing conditions.
Clouds have been a major indicator for meteorology for many centuries. Fluffy white clouds indicate slightly unstable, but generally fine conditions. Whereas large, low lying, and dark clouds indicate worsening conditions, cooling and potential rain. A major indicator most associated with worsening conditions are the Cumulonimbus clouds that signal severe weather changes. While stratus clouds generally indicate improving conditions, as well as some cooling.
Animals such as birds also play an important role in weather warning. Birds tend to fly away in large groups from oncoming storms. Other animals howl and growl as their ears are more sensitive to atmospheric pressure changes. Cows lie down in storms and seagulls rest on beaches when high winds, rain and storms are on the way.
USING INSTRUMENTATION, more detailed forecasts can be created. As science advanced, various instruments and devices were created to aid in the study of weather. This has allowed them to create forecasts of a much greater detail.
At first the invention of the telegraph was allowed to accumulate weather related data at much greater speeds across large geographical locations. This was further aided by developments of hygrometers, barometers, rain seasaw guages and thermometers all allowed to predict changes in the atmosphere. The barometer proved to be very valuable in measuring pressure changes and thus establish different tendencies. These exist in air, mercury, and aneroid forms. They became the basis for any models, as low pressure indicated worsening and wet conditions, while increasing pressures were a sign of improving and warmer atmosphere.
The baurfort scale that was invented in 1805 was allowed to determine the trajectory of moisture fused winds. Thus allowing them to predict the prosperity of agriculture, as well as making the accurate forecasts of wind speed and velocity. This allowed them to build structures to withstand certain natural elements like storms. This was the first time that man-made structures were planned to withstand the forces of nature. The dopplar radar had taken this step further and allowed them to look inside powerful wind systems such as tornadoes and thus made it a possibility to study the structure of weather phenomenon, thus improving their predictions and providing early warnings.
The weather balloon, that was invented in 1929, took meteorology to a new height, as it was able to collect frequent readings of atmospheric conditions over many layers of air and over large areas of geography. These Radiosondes have the following structure: They are very lightweight containers equipped with various weather related instrumentation and radio transmitters. Since the balloons are either filled with hydrogen or helium, they tend to rise high up in the atmosphere due to the fact that these two gases are much lighter than air.
In the 1950’s numerical weather predictions became available with the availability of computers. This made it possible to predict the dynamically changing weather conditions with high detail and accuracy. However, accuracy was also improved by far when satellites and supercomputers became abundant and were able to collect, analyse and calculate enormous amounts of weather data, that aids aircraft, agriculture, the military and household plants.