Monday, August 26, 2013

Hot weather to continue this week..

It was another hot day in Winnipeg and southern MB with temperatures again reaching the low 30s. In Winnipeg, today's high of 32.8C was the third straight day of 30C+ temperatures, and it looks like we'll be near or above the 30C mark much of the week. A massive dome of hot air over the central US is bulging north into southern MB, and the pattern will be persistent all week. The net result will be more summerlike weather for Winnipeg and southern MB through the end of August.. a welcome extension of summer that was interrupted by a 4 week stretch of cooler weather from mid July to mid August. The weather this week should be generally dry, although scattered thunderstorms are possible from time to time as weak impulses tap the hot and humid air to generate locally strong thunderstorms at times. High temperatures will be in the upper 20s to low 30s, with humidex values in the upper 30s to near 40 at times. Long range guidance is indicating a change to cooler weather possible over the Labour day holiday weekend. 


  1. Hey Rob,

    Here's a dumb question. Any chance that EC (or you preferably) can provide a daily dew point forecast? The humidex forcast provided by TWN is useful but since dew point factors into comfort level, why has nobody provided a forecast for this value during muggy condition? Especially in places like Ontario. Is it easier to predict a temperature than a dew point? Speaking for myself, I'd like to know when the dew point drops below 12° so that I can open the windows at night. I know you're busy, thanks in advance.

  2. I see mostly sunny skies and practically no breeze (the trees in the backyard are standing practically still). The temperature's already up to 28 degrees. I don't think it'll be too difficult to hit 32 today, which would make this "officially" a heat wave according to Environment Canada (three days or more running where the temperature hits 32 C or higher).

    Of course, regardless, I've always said that you don't really need Environment Canada to tell you that it's hot.

  3. Anonymous..

    One word for you.. SpotWx.

    SpotWx is a website that displays model data in graphical format, including temperature, dewpoint and humidex, every 3 hours (or every hour for some guidance) It's a very handy site run by a MB forestry worker who contributes to this blog (Garth), and has data from all the major models, specific to any grid point you ask for from a handy Google map. The data is mainly straight from the models, but it gives you a pretty good idea of forecast values and trends that you just can't get from the daily public forecast.

    I have SpotWx examples for Winnipeg on my main website under the forecast graphic. Use it all the time.

  4. >> Evan said.. Of course, regardless, I've always said that you don't really need Environment Canada to tell you that it's hot.

    You also don't have to be a weatherman to tell you which way the wind blows.. :) (Dylan reference)

    Interesting point about the offical definition of "heat wave".. 3 days of 32C or higher. That's a holdover from when we measured temperatures in Fahrenheit, and a heat wave was defined as 3 days of 90F or more.

    Now that we're metric, I've always thought that for much of Canada, 3 days of 30C or more would be sufficient to call it a heat wave. Most people in Canada consider 30C a "hot" day.. so why not define a heat wave based on that nice round number (rather than 32?)

  5. Rob, what does the severe thunderstorm threat look like for the Winnipeg/RRV aresa today? Or does the threat of severe weather exist mainly in the Interlake today?

  6. Thunderstorm threat is low for Winnipeg. There's a chance something may blow up on some lake breeze boundaries just north of the city, but we seem to be capped here in Winnipeg and the southern RRV. Other than that, looks like main activity will be further north through the Interlake.

  7. Thanks for the SpotWX reference Rob. Looks like a bit of a learning curve for an old fart like myself but it looks useful.

  8. Our 30C streak continues today for Winnipeg and the RRV with lots of sun and light winds.. temperatures in the 32-34C range again this afternoon with humidex values in the upper 30s. For tonight, models are showing an area of thunderstorms blowing up over North Dakota, possibly spreading over the southern RRV overnight into Thursday morning. Tough to say how far north this activity will spread, but at this time it looks like best potential is for main action to stay south of the border. We'll likely have convective debris cloud over us tomorrow morning through midday, before things become partly sunny in the afternoon. The extent and timing of that cloud cover will dictate whether our 30C streak continues tomorrow or not.

  9. Thanks for the mention Rob. I'm so pleased that real forecasters are finding SpotWx useful. It seems every major weather office in Canada, public and private, is now using it. I've even had some people jokingly tell me they've forgotten how to forecast the 'old-fashioned' way, which I never intended or expected.

    With that in mind, I've put some feature improvements on hold and am now focusing on building a parallel site on the Amazon Cloud, to be running this fall. The risk of hydro outages or hardware failures with my home server is starting to wear on my mind (especially when I'm on vacation and supposed to be relaxing).

    Thanks also for keeping this blog running. I certainly don't have your patience to moderate the comments, which unfortunately is required.

  10. No problem Garth. It's a great site and you deserve kudos for it. Good to hear that you'll be hosting a back up for it in case of hard drive failure or power outage… which is happening right now in much of northwest Winnipeg as we speak!

  11. I've noticed that Brett Anderson from Accuweather has indicated a frost potential for middle to late next week for Southern Manitoba as large high pressure from the north settles in.

    Rob, what's your opinion on this?

  12. Frost is the last thing we need right now. We had such a late spring and thus the harvest season will be much later this year. A frost 2 weeks early would be disaster for agriculture.

  13. Large convective complex pushing across ND and southern MB this morning.. with heaviest storms mainly south of the intl border. However there are some embedded tstorms over southern MB especially west of Winnipeg between Brandon and Portage where rainfall amounts of 20-40 mm have been recorded in the Carberry and Austin areas according to Weatherfarm mesonet. Further south, amounts have been generally in the 5-10 mm range towards the US border.

    Radar shows the southern precip shield is weakening as it heads towards Winnipeg, but we may get some action from the Portage area of convection as it moves through this morning.

    Looks like our 30C streak will be coming to an end today thanks to this convective complex. We've had 5 straight 30C days, with the year's hottest day yesterday at 34.1C. If this area of cloud and convection manages to clear out by afternoon, we still have a chance of hitting the 30C mark later today.. but doesn't look likely. Another shot at 30C Friday, then cooling off for Labour Day weekend.

  14. >> Anonymous said...I've noticed that Brett Anderson from Accuweather has indicated a frost potential for middle to late next week for Southern Manitoba as large high pressure from the north settles in. Rob, what's your opinion on this?

    I've heard some rumblings about a major cooldown coming later next week through central Canada.. based on some ECMWF and GFS long range guidance. All I can say is, it's possible.. but at this point, I'd wait and see if models continue that trend, or if they back off. Normally, our first frost in Winnipeg area is around Sep 21st. Last year, first fall freeze at the airport was Sep 14th at -1C.

  15. Hey rob,

    What are your thoughts for the weekend? In a ball tournament and really hoping doesn't rain.


  16. >> Jeff said... Hey rob, What are your thoughts for the weekend? In a ball tournament and really hoping doesn't rain.

    Jeff.. Looks like Saturday will see the best chance for some rain.. especially by afternoon with showers and thunderstorms possible as a cold front sweeps through. Still not certain how extensive or long lasting the rain will be as it depends on when the cold front goes through.. it could end up just being a band of showers lasting an hour or two.

    Things should clear out Sunday with cooler and drier conditions and highs near 20C. Nice day shaping up for Labour day Monday with lots of sun and afternoon temperatures near 25C.