About the Author
Cindy Day grew up on a dairy farm in Bainsville, Ontario, surrounded by nature and influenced by wise parents and a grandmother with a keen sense for forecasting the weather. She has been a meteorologist for over twenty-five years, most recently on television with CTV Atlantic.
She lives in Dartmouth, Nova Scotia.
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RAIN BEFORE SEVEN, FINE BY ELEVEN
Grandma was an early riser. In fact I don't think I ever heard an alarm clock go off in her bedroom. She was up with the roosters!
When the day got off to a rainy start, she would tell us that before long, the rain would stop: "Rain before 7, fine by 11".
This is one of those weather sayings that is not always correct but it is often right and it can be explained with a quick look at a weather map.
Some systems are more active at certain times of the day. A cold front is often made more powerful with the benefit of daytime heating, especially if the sun is out. Cold fronts trigger those dramatic late day thunderstorms that we sometimes experience at the end of a hot summer day. A few hours after sunset, a lot of that energy subsides.
A warm front on the other hand has a much more gentle approach. It's a slower moving wide band of moisture that comes in to replace cooler air. Because the warm air is less dense, it slides up and over the colder air; condensation occurs and rain falls behind the front. That process is helped along by the cooling of the air after sunset. The slow moving system can take as long as 12 hours to move through, so if the rain began at sunset, it should be on its way out shortly after sunrise. Once the front passes, the sky clears and the air pressure rises. Temperatures also rise as warm air replaces cold air. So if you wake up to the sound of light rain dancing on the roof, don't despair,the day might not be right off after all. Grandma would tell you that there's a good a chance that rain could end before noon with some sun to brighten the rest of your day.