Bezte: Frost Watch for Aug. 20

NEW FEATURE: In many areas of the Prairies, the story is the same. It could be a great crop — if it doesn’t freeze, which it’s already done in some parts of Alberta.

No one can prevent frost, but a heads-up might be useful.

Daniel Bezte is a climatologist and regular columnist for the Manitoba Co-operator and Alberta Farmer Express. Many readers have been impressed by the consistent accuracy of his Manitoba forecasts for the week ahead, so we’ve asked him to keep a similar watch for potential weather systems that might mean frost in parts of the Prairies over the next few days. Here’s Daniel’s first report:

Currently we put out a weekly forecast that can be found in the weekly edition of the Co-operator. This forecast relies on data from different weather models which are currently available to the general public. Unfortunately, this forecast is only a snapshot of what the weather might be at the time it is created, and as well all know, the weather in this part of the world can change very rapidly.

So while we might see cold weather coming in one of our forecasts, we are usually trying to predict it a little too far off to be really reliable. Enter the Internet.

Being able to update information via a web page can allow us to offer a more up-to-date forecast. No, we are not going to attempt to create daily forecasts — that’s way beyond what we can do and we will leave that up to the good folks over at Environment Canada. What we are going to attempt to do is watch the medium- to long-range weather models looking for signs of cold weather, or simply, try to predict when and where there might be frost four to seven days in advance.

This type of forecast will be a general one, simply stating which regions can expect temperatures to be near the freezing mark. We will leave it up to you, the reader, to decide if you will need to worry. After all, who knows your area better than you? For example, my property is in a bit of a frost hollow. When the forecast calls for lows around 3° to 5°C, I have to worry about frost.

So keeping this in mind, we will be watching not only for conditions that will likely bring widespread frost, but also for cool weather that may bring local or patchy frost.

We are not sure just how well this is going to work, but we’ll be trying our best and I always feel some early warning is better than no warning at all!

The average date of the first fall frost varies not only with latitude but also with the local geology.  Here is a list of average dates for the first fall frost for a few sites across the Prairies. Remember, the average date can vary by as much as 15 days, meaning we can see frost as early as late August or as late as the end of September.

Prince Albert Sept. 4
Regina Sept. 10
Weyburn Sept. 12
Saskatoon Sept. 15
Moose Jaw Sept. 18
Grande Prairie Sept. 11
Edmonton Sept. 13
Calgary Sept. 14
Lloydminster Sept. 15
Lethbridge Sept. 18
Medicine Hat Sept. 23
Brandon Sept. 11
Dauphin Sept. 15
The Pas Sept. 16
Winnipeg Sept. 21
Morden Sept. 25

Current outlook

As of Thursday, Aug. 20, all the weather models are pointing to relatively warm weather right to the end of the month of August. There is a very slight chance for frost around Aug. 26 for extreme northern agricultural parts of Manitoba but other than that there do not appear to be any chances of frost until September.


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