The main goal of weather forecasting is to provide information to the public so informed life or business decisions can be made. This could range from using sunscreen when going out or getting prepared for severe weather entering the area. To provide this support, forecasters have to look through a myriad of different maps and charts all providing different information to create an effective forecast. Maps can range from satellite imagery, surface pressure maps, or numerical modeling. Forecasters must choose which information is best applicable to the situation involved. For example, an area under a high-pressure system could expect calmer conditions, so looking at an Energy Helicity Index map wouldn't be applicable. To do this, forecasters can use a concept called a forecast tunnel to create a forecast. This process describes how meteorologists can start from the top of the atmosphere to the surface to develop a succinct forecast.
Planetary and Hemispheric scales start this process and this could involve parameters like Rossby Waves. They are on the scale of tens of thousands of kilometers, in respect of size of the system. Afterward, you move to the synoptic-scale which is on the scale of several hundred to several thousand kilometers. This would typically involve features like high and low-pressure systems. Lastly, the smallest scale for the forecast tunnel is mesoscale. These are smaller-scale features on the order of a few to several hundred kilometers. An example of these features would be sea breeze and squall lines. These scales are interconnected and using the forecast tunnel helps forecasters see these features and how they relate dynamically.
Furthermore, it is imperative that meteorologists make forecasts promptly so that the forecast remains relevant to the public. Traditionally, the larger the scale, the fewer time forecasters will spend working on the specific features within that time scale. Planetary scale features are on such a large magnitude that they shouldn’t experience significant changes during a traditional forecast period, so monitoring it should take the least amount of time. Conversely, mesoscale features require more time because the nature of the size scale is smaller. These features are harder to examine if they are going to impact the forecast area and how they will evolve with time.
Photo Creds: The Comet Program
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©2020 Weather Forecaster Dakari Anderson