Even a week plus into the future…
In: Earth Science
A weather system checks the current and recent weather situation. Based on what recently happened it calculated what might happen, by comparing it to all similar systems that have been recorded in the past. Based on that calculation, the weather systems gives a model. There are dozens of different models all with a different calculation.
A meteorologist basically compares those models to see what the most likely outcome is, because most models are pretty similar. The meteorologist I used to work with, used about 50 different models to make a prognosis.
Also worth noting, the more weather stations are connected to the model, the more accurate it will be. Cause a low pressure area a thousand kilometers away can have an effect on the development of the weather on your current location.
Source: I used to work with a meteorologist a lot.
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