Why Are Weather Forecasts Sometimes Wrong?
We've all heard the joke, "what job can you do wrong 50 percent of the time and still be employed... a meteorologist."
This joke is getting old... and isn't an accurate representation of the industry. Some forecasts are indeed a bust, but now it is rare for a short term forecast to not be accurate.
So what goes into a forecast?
Every weather forecast begins with the collection of information. There are several different types of information collected and then combined to create a forecast.
First is the current state of the atmosphere. The current conditions provide an accurate representation of the weather in a particular location. Then by using analysis charts, we can see fronts, areas of high and low pressure, areas of strong wind and some other parameters.
Radar and satellite help us determine areas of clouds and precipitation and while both are short term tools, Satellite can assist in determining where a system is headed.
Then there are weather models. Weather models use mathematical calculations based on current conditions to predict the state of the atmosphere in the future. Twice daily at multiple locations around the world, a radiosonde is launched. A radiosonde is an instrument carried by a balloon into the atmosphere that records and transmits several kinds of information back to the ground. That data is then inputted into supercomputers that run calculations.
A forecaster can then use a variety of different models which can all show a similar outcome or vastly different outcomes. Typically for short term forecasts, there are similar outcomes. Then using all of this plus knowledge past events, a forecaster can create a forecast.
Why are forecasts sometimes wrong?
Have you ever ordered food at a restaurant that was made wrong? There's a good chance you can remember such an experience. But what about a time you had a pleasant dining experience where nothing eventful happened? Maybe you cannot remember that quite as clearly. People tend to talk about and remember when things go wrong.
Weather forecasts are no different... when the forecast is wrong people flock to social media to talk about it, when was the last time you saw a post about how accurate the forecast was?
The truth is, forecasts may never be 100 percent accurate. The atmosphere is too chaotic.
Think of the atmosphere as your backyard in the autumn with leaves blowing everywhere. Your job is to know where every leaf will go and when it will get there. Sounds difficult right? Meteorology is the same way. It is our job to know where every molecule in the atmosphere will go when it will get there, what type and how much precipitation will fall. How strong the winds will be, when the fog will lift, will there be thunderstorms today?
There are endless parameters. At the end of the day were are attempting to provide exact numbers to an inexact science.