Weather: Warm then cool trend seems established

Forecast covering the period from August 18 to August 25

This map shows the 30-day per cent of average precipitation across the Prairies ending on August 11. Both Saskatchewan and Alberta have been very dry during this time, with large areas reporting less than 40 per cent of average rainfall. Thanks to some unsettled weather late in this period, Manitoba is actually reporting average to a little below average in most areas.

Interestingly, the last week’s forecast called for cool and unsettled weather from August 10 to 13, due to a couple of weak areas of low pressure.

Those lows formed as forecasted, but the first low turned into a large upper low that then captured the second low. The long and short of it is that we got more rainfall than originally expected as well as cooler temperatures and a lot more wind.

The forecast then correctly predicted the return of the upper-level ridge and hot temperatures last weekend and into the early part of this week, with high temperatures once again pushing into the low to mid-30s.

For this forecast period it looks as though the pattern of five days of hot weather followed by two or three days of cool, unsettled weather will continue. The models are showing an area of low pressure lifting northeastwards starting on Wednesday, bringing more sun than clouds, along with a good chance of measurable rainfall. The best chance for rain looks to be late on Wednesday and into Thursday.

Cool high pressure will build in behind this system with daytime highs over the weekend expected to be in the low 20s with overnight lows dropping to around the 10 C mark.

It looks like we will see at least one more shot of warm weather before summer comes to an end as the weather models are showing the upper ridge rebuilding across our region starting on Monday, August 16. We should expect plenty of sunshine and a return to hot temperatures. Forecasted daytime highs are expected to move back to around the 30 C mark with overnight lows falling to around 15 C. There is a slight chance of thunderstorms later in the week as a weak cold front is forecasted to move through, but that is a long way off, so confidence in this part of the forecast is low.

Usual temperature range for this period; highs: 20 to 28 C, lows: 8 to 13 C.

About the author

Co-operator contributor

Daniel Bezte

Daniel Bezte is a teacher by profession with a BA (Hon.) in geography, specializing in climatology, from the U of W. He operates a computerized weather station near Birds Hill Park.

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