Forecast: Much cooler weather pattern developing

Issued July 23, 2018: Covering the period from July 25 to August 1

This map shows the total amount of precipitation that has fallen across the Prairies so far this agricultural year (Sept. 1 to Aug. 31) compared to historical amounts. Most regions have seen near-average amounts of precipitation, with only a few small pockets in south-central Alberta and Manitoba receiving below average. Wet areas were found along the northern edges and in southeastern Saskatchewan.

After a pretty hot first half of July it looks like we are going to see a slight cool-down during this forecast period. The big question is whether this is going to be a short-term or long-term change in our overall weather pattern.

This forecast period will begin with a slow-moving upper low tracking from northern Manitoba into Ontario. To our west an area of high pressure will be strengthening. Together, these two features will put us into a northwesterly flow that looks to stay in place right through this entire forecast period. On Wednesday, most regions will see a mix of sun and clouds along with a chance of showers as a piece of energy rotates down and around the upper low. Temperatures will be on the cool side, with highs only expected to be around 20 C and overnight lows around 10 C.

The western high will drift to the southeast, ending up south of the Great Lakes by the weekend. This track of the high should result in mainly sunny skies, with maybe a few afternoon clouds each day, along with daytime highs in the 22-25 C range. The weekend looks to be fairly nice, with sunny to partly cloudy skies and daytime highs in the mid-20s with overnight lows in the low teens, making for pleasant sleeping weather.

The weather models show an area of low pressure moving across north-central Manitoba late on Sunday. This will bring clouds and showers to northern regions. The low will also drag a cold front across southern and central regions late Sunday or early Monday. The front will likely trigger a few thunderstorms as it pushes through.

Cool high pressure is then forecast to slide in from the northwest to start next week. We should expect mainly sunny skies with some afternoon clouds once again, and daytime highs dropping back into the low 20s.

Usual temperature range for this period: Highs, 21 to 30 C; lows, 10 to 17 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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