Question

Meteorologists have many sophisticated tools to help them forecast the weather. However, weather forecasts are still sometimes incorrect. Why do you think this is the case?

Answer 1

The various number of variables are simply too numerous, there is no way for any model to implicitly take in to account all of the things that influence weather. A big one is solar variability from greenhousing and from the sun itself--to my knowledge there is only one forecasting model that even tries to include these... and NOAA is the only ones with access and they only use it for super far range models (ie: to model all of the USA for 3-5 months) because of the cost of running the supercomputer for so long. (more regional models use this data as their starting points... aka: random number generation)

Answer 2

Conditions in the atmosphere are ALWAYS changing and in order to keep up with these changes to make accurate forecasts, we need to have experienced meteorologists on hand as well as very reliable technology such as satellites, Doppler radar and computer models.

For instance, if a forecast called for a brief rain storm two days from now, that means that according to computer models (which gather the data from a variety of sources) predicted specific conditions to be in place for that rain storm to arrive at your area at that time. These conditions may include wind speeds and directions high in the atmosphere, location and direction of pockets of moisture, location and direction of low or high pressure systems, etc...

You see, every one of these variables will change as they have the possibility to. If the wind speeds high in the atmosphere happened to increase, that rain storm would arrive tomorrow instead of two days from now. If a high or low pressure system formed in the area, it would steer that rain storm away from you.

This is why meteorologists can go wrong sometimes despite their best efforts.