What will the weather be like tomorrow? What about three or five days from now? Will we be able to enjoy our garden wedding? What about the camping trip next weekend? Will that be a “sit-in-a-leaky-tent-all-weekend-bonding experience” or will it be a fine weekend of hiking and bird watching?
Weather Forecast
Modern weather forecasting relies on a combination of many methods. In the past, fair weather usually followed a red evening sky. So using the past as our pattern, we figure that if we see a red evening sky tonight, we will have fair weather tomorrow. People still use the analog method today. But instead of looking at just sky color, for example, we take thousand of other factors into consideration. The method is good but suffers from the fact that no two days are just alike in all the thousands of other factors involved.
Other methods go by such terms as persistence, trends, climatology, and numerical weather prediction (NWP). Briefly, the persistence method states that the weather we are having today will most likely continue tomorrow. And barring strong winds or other changes, that works pretty well. The trends method looks at wind directions and speeds and suggests that what they are experiencing 50 miles west of here will arrive in a couple hours. The climatology method simply averages what has happened at this time and place for the past 100 years or so. The best method is NWP method. This method utilizes current data from thousands of weather stations all over the world; temperature, humidity, wind, barometric pressure, water temperature, current, cloud cover, and so much more. The data comes from the surface and from many different altitudes and ocean depths. All the numbers go into giant supercomputers that crunch them using mathematical formulas, and out comes the forecasts. But because of missing data and flaws in the mathematical assumptions and understandings, forecasts are still not completely reliable.