Wednesday, 15 August 2012

Gloomy, But There's a Light at the End of the Tunnel

     We will see some scattered showers behind the main system this evening over much of southern Manitoba. Accumulations will be lighter than this morning, with an additional 2 to 5 mm possible. Locally higher amounts will be possible downwind of the lakes where cold northwest winds blowing over the lakes will create lake-effect streamers; enhancing rainfall. Some of these may persist into the overnight. It appears at this point that areas between Portage and Winnipeg, and southeast of Lake Winnipeg (Pinawa, Whiteshell) have the best chance to see these streamers. They may dump an additional 10 to 20 mm of rain in these areas.

     Here are some rainfall amounts as of 3 PM this afternoon: (from MB Agriculture and Environment Canada)
Morris.................. 1.5 mm
Altona.................. 2.0 mm
Souris.................. 3.3 mm
Winnipeg..............    5 mm
Steinbach............. 5.6 mm
Portage.............. 10.9 mm
Minnedosa.......... 12.4 mm
Gladstone........... 14.5 mm
Russell................ 25.0 mm
Berens River....... 25.8 mm
Fisher Branch..... 28.5 mm
Mafeking............. 52.0 mm
George's Island... 56.5 mm

     Highest amounts have been in the Interlake and eastern Manitoba where rainfall warnings were posted and are still in effect. Lower amounts elsewhere.

     As mentioned, cold northwest winds will be blowing behind this system. These winds will be sustained at 40 to 50 km/h, and gusts will be between 60 and 70 km/h. These winds, along with cloud cover and possible showers, will keep our temperatures tonight in southern Manitoba a few degrees warmer than they would have been otherwise. Generally, lows between 8 and 12°C can be expected. Tomorrow will be quite cool with highs around 17 to 20°C. We will see some sun tomorrow, however just how much is uncertain. Continued northwest winds over the lakes may keep us in low cloud much of the day. We will have to wait and see.
Things will be brightening up
     Conditions will really improve beyond Friday. Friday and Saturday will still be a little unstable with a mix of sun and cloud. A slight chance of showers exists Friday in the Interlake, and for most of southern Manitoba Saturday. It is a very small chance therefore most of us wont see anything. Highs in Winnipeg will be in the low twenties.

     Next week remains uncertain. Some models bring back summer-like temperatures in the high twenties and low thirties while other models keep us in a cool weather pattern. Stay tuned for updates.

1 comment:

  1. Lake effect streamers are now evident on radar. A streamer off Lake Manitoba will bring some steady rains to the Elie and Starbuck regions for part of the night. An additional 10 to 20 mm is possible there. Remember that these streamers are very localized. Areas just outside the streamer, such as Winnipeg and Portage, may not see much at all from the lakes.

    Same story southeast of Lake Winnipeg with a streamer evident near Pinawa.

    You know it's unseasonably cold for August when we're talking about lake effect precipitation! Let's just be happy it's not snow!