Before we get to the predicting part, let’s revel in the weather of the recent weekends in the region. First, the first weekend of August, a long weekend for some in Ontario . . . sunshine, seasonal temperatures (actually a hint above average), and . . . no rain in many areas! Although some brief light showers did occur in Armstrong . Weekend # two featured the warmest days so far in August but a cold front late Sunday evening triggered substantial showers. These persisted through the early hours of Monday. Perhaps these showers caused some grief for the tenting population, but hopefully they were prepared for the weather. Speaking of weekends, August has an abundance of weekends this year; five in total and it finishes with the final long weekend of the summer. Okay, it is not really a long weekend without including Labour Day on September 1.
A common complaint this summer has been all those rainy weekends. Your weather sleuth checked on the 13 weekends we have had this summer so far. The count for Thunder Bay began on the May long weekend which, if you need a reminder, had light rain on two of three days. Any day on a weekend with 1 mm or more resulted in a rain weekend. It does not matter if it happened overnight. For example, last weekend did not have any rain for 45 hours, but did for the last hours on Sunday. Hence this equals a rainy weekend. So far, 10 rainy and 3 dry weekends have occurred.
This result is not so remarkable because the odds of measurable rain on summer days is about 40 per cent. Three-day weekends are fighting the odds to emerge rain free. There is another consideration – air pollution. A so-called Sunday effect has been noted in and downwind of large cities and industrial areas. Pollution and related aerosols build up in such areas and can seed cloud formation. This cause/effect is not a factor in this region. Air quality is generally very good, especially when compared to areas such as the Ohio Valley.
Have you noticed that weekend forecasts often tend to be gloomier as we approach the actual weekend? There may be some psychology prompting this pessimism. If weather turns out better than expected, many people think “great”! If the skies unleash something worse than advertised . . . people do not like unpleasant surprises.
Weekend Weather Outlook: A ridge of high pressure is likely to dominate the region from today to Friday. Mainly clear or scattered clouds should prevail with a cool Thursday morning. A warming trend begins later Thursday as the ridge moves east and warmer air from the south pushes northward. This eastern movement is likely to be followed by a frontal system on Saturday or Sunday. As for exact timing and rain amounts – check your favourite forecast on Friday.