This chapter examines optical phenomena that occur in the atmosphere. The displays of light explored are rainbows, inferior mirage, superior mirage, green flash, corona, glory, halos, sundogs, Sun pillars, and a couple of other “surprises”.

Additionally, weather forecasting is included in this chapter. Four weather forecast methodologies are available. One of the methodologies is numerical weather prediction, also known as computer models. Numerical weather prediction is the most widely used and generally the most accurate. This chapter discusses the details of each methodology, although  numerical weather prediction is examined the most.

Weather forecasts become less accurate the further they go out in time. After about 10 days, weather forecasts will be incorrect as often as they are correct. To get a seasonal outlook a different approach is needed. The details for how seasonal outlooks are created and interpreted is the last topic in this module.

Chapter Objectives:

1. Explain the reflection, refraction, and diffraction of light and the resulting optical effects.

2. Describe the four methods of weather forecasting.

3. Describe the phases of numerical weather prediction.

4. Interpret a seasonal outlook.