Forecast: Lots of uncertainty in the week ahead

Issued May 13, 2019: Covering the period from May 15 to May 22

This map shows the global temperature anomalies for April for the lower eight kilometres of the atmosphere as determined by satellite measurement and reported by the University of Alabama at Huntsville. The coldest readings across the planet, compared to average, were centred over northern Manitoba, with most of the Prairies feeling the effects of slightly colder-than-average temperatures in April.

The two main weather models I look at when trying to come up with the forecast each week are interpreting the overall big picture similarly for the next week or two — but as I’ve pointed out several times over the years, a difference of only a few hundred kilometres can have a major impact on our weather.

Both models show Wednesday starting off nice and sunny with warm temperatures. A low is then forecast to quickly track from British Columbia and through southern Manitoba late on Wednesday; it should be out of our region by early Thursday. Expect increasing clouds on Wednesday along with a good chance of showers by evening. Thursday looks to be nice, with sunny skies and daytime highs in the upper teens to around 20 C.

Now, this is where the forecast gets tough, just in time for the long weekend. Both weather models show a very large area of low pressure developing to our southwest on Friday. This low is then forecast by both weather models to kind of meander around to our south over the holiday weekend before finally weakening and moving off to the east early next week. The southerly flow ahead of this low should pump plenty of warm air into our region, with daytime highs expected to be in the low 20s if we can get some sunshine — and that’s a big “if.” One of the models shows clouds and showers moving in on Saturday and then keeps the clouds and showers around all weekend. The second model keeps most of the showers to our south, with only the extreme southern portion of the province seeing clouds. A third weather model agrees with this model and keeps any precipitation to our south until Monday. This weather model is also a little cooler, with high pressure to our north keeping temperatures in the mid-teens. It’s anybody’s guess!

Looking ahead to next week, the different weather models tend to agree on high pressure moving in, bringing sunny skies with near- to slightly below-average temperatures.

Usual temperature range for this period: Highs, 13 to 25 C; lows, 1 to 10 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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