Monday, 26 March 2012

Stormy Forecast

     Uncertainty still exists with the upcoming system which will give us precipitation tonight through to Tuesday night. We really wont know for sure until the thunderstorms begin developping south of the border later this afternoon and evening. Today is definitely a windy day, with winds from the south east at 30 or 40 km/h, and gusts over 50 km/h. Hold on to your hats!

     Here's my current best forecast for tonight and tomorrow:

     I'll be updating my forecast throughout the event, but here's how it looks so far. Some scattered showers are moving through southern Manitoba this afternoon, though it really isn't much. Most of us will likely see nothing until tonight.
     More organised showers and thunderstorms are expected to form south of the border in the Dakotas, Wyoming and Montana this evening. These storms will move northeastward into southeast Saskatchewan, Manitoba and northern Ontario later in the evening and overnight. Rain looks to be heaviest and more widespread in northwest Ontario, over the Interlake, and over southwest Manitoba and southeast Saskatchewan. That being said, the highest risk for thunderstorms will be in south/southeast Manitoba and northwest Ontario. At this point it does not appear storms will be severe on our side of the border, though some bigger storms may give some small hail, gusty winds and torrential downpours. Areas that get storms will see higher rainfall amounts.
Map shows thunderstorm risk overnight tonight.
Light blue = small risk. Dark blue = medium risk
Details on storm potential by following tab at top.
     Generally, 5-10 mm can be expected around Winnipeg tonight with the showers, though higher amounts are possible if we get thunderstorms. At this point, it appears we will see a break in the precipitation in the dry slot tomorrow morning before wrap-around precipation takes over in the afternoon with an additional 5-10 mm possible by Tuesday night. This wrap-around precip. will dump heavy rain in southwest Manitoba and the Interlake where upwards of 30 mm of rain will be possible.     Rain will likely also make a switch over to snow in west and southwest Manitoba tomorrow afternoon and evening, and here in southeast Manitoba by Tuesday evening and overnight. 5-10 cm will be possible in areas north of Brandon, with 10-20 cm possible over higher elevations such as in the Riding and Duck Mountains. Areas around and south of Brandon, and over south-central and southeast Manitoba will likely only see meager snowfall amounts of less than 2 cm.
     All the precip. looks to be all set and done by early Wednesday morning, with a few lingering flurries possible in the morning before beginning to clear in the afternoon.

     Here's a map of predicted precipitation amounts by the GEM model for the whole system (tonight through to Wednesday morning). Please note that these amounts include both rain AND snow. Use the legend on the right for the colour-codes, and click on the image to enlarge:
     Thank you for taking the time to read my forecasts =)


  1. Environment Canada has issued snowfall warnings. You can view the warning with this link:

    The warning includes the areas of Dauphin, McCreary, Swan River, Berens River, Poplar River and Grand Rapids, all in western Manitoba and northern Interlake.

    10-20 cm can be expected in these areas tomorrow, with higher amounts possible in higher terrain.

    Here in the city, it is looking less likely we'll see accumulating snow tomorrow night.

  2. A cluster of thunderstorms has popped up just west of Dauphin now, between Dauphin and the Saskatchewan border. Main threat with these storms are locally torrential downpours and frequent lightning. Small hail would be possible, although I don't have access to the hail-detecting part of the radar. The storms are moving NNE.

  3. Storm just popped up to the west of Brandon and will affect the city, so watch for that cell if you're around Brandon. If you encounter any storms tonight, feel free to report what you saw. Nothing beats actual ground reports! =)


    Here's a cool webcam from Dauphin. If you press play, you can see the thunderstorm progress northwards, cool ;) That's about all the imagery I have of that storm for now

  5. Those storms that were near Dauphin earlier this evening are now really organising themselves over the northern Interlake this evening. Looks like a good MCS heading northeast aided by lift from the warm front, can't believe I'm talking about an MCS in that part of MB in late March!! Storms aren't severe right now though, but lots of rain and frequent lightning are occuring with those storms. Remember there's snowfall warnings in those areas at the moment!

    Storms are also finally firing up in South Dakota and southern North Dakota. That will be what to watch over the next few hours as it all moves north. I don't see why we wouldn't get some thunderstorms in southern Manitoba overnight tonight, considering dynamics are great for nocturnal storms, and the llj is very strong at over 40 knots in the eastern half of Manitoba and over 50 knots in North Dakota.

    Be prepared to be woken up by heavy rain or thunder overnight!

  6. Starting to see some lightning to the west and southwest. Storms will be rolling through WPG soon

  7. some decent hail coming down in south Wpg, batten down the hatches|

  8. intense lightning. Power went off in much of southern Winnipeg just a little while ago, my internet finally just started working again.

  9. Quite the storms last night over the Winnipeg area! Hail was coming down hard in many parts of the city, enough that it was actually accumulating! I didn't get that much hail hereat my place, though it was still the most hail I've seen since September 2005. Hail was the size of peas, and even dime sized.

    Lightning was awesome as well, some parts of the city lost power due to the lightning. I lost power here, and it appears most of River Park South, if not all, lost power as well. That is the first time ever that I've lost power because of a thunderstorm!

    Rain was impressive in some parts of the city as well. Here at my place it wasn't too significant, with just 4 mm. Other parts of the city received up to 10 mm.

    Overall, quite the event for late March.. Amazing that now we have to talk about some snow possible in the city tonight. Stay tuned

  10. Rain is gradually switching over to snow as we speak in the city. It shouldn't accumulated too much, but be prepared for some slippery roads at times.