1. Weather Forecasting
Predicting the Future

2. Weather Forecasting Science is about predicting the future.
That could be telling what will happen when you drop a ball or split an atom.
We want to know what will happen before it happens.

3. Weather Forecasting
One thing people are always interested in predicting is the weather.
Should I bring an umbrella?
Do I need a jacket?
Is it time to evacuate?
Do I need to hide?

4. Persistence Forecasting
How can we predict the weather?
One way is to look at today’s weather, and predict that tomorrow’s weather will be the same.
This is called persistence forecasting because the weather persists from one day to the next.

5. Trend Forecasting
Imagine you’re making a weather forecast for Norfolk, VA.
24 hours ago, a cold front was 1600 miles (2500km) to the west.
Now the front is only 800 miles (1300km) away.
Where do you will think it will be in 24 hours?
What will that mean for the weather?
This is called trend forecasting because it relies on continuing trends.

6. Climatology
Climatology is the study of climate, the weather conditions that are normal for a place.
By averaging the many years of weather data, you can predict weather far in advance.
Climatology is most useful in areas like Thailand with stable climates.
It is less reliable in places with more variable weather.

7. Analog Forecasting
An analogy is a comparison of two things that are similar.
When trying to predict the weather, it can be useful to look at what happened in the past when conditions were the same.
Finding a day with exactly the same conditions can be very difficult, but if a match can be found, analog forecasting is very accurate.

8. Computer Modeling
Computers are a powerful tool for weather forecasting.
Statistical models use climatology data to make predictions.
Numerical models use computers to combine trend and analog forecasting.