Monday, 29 April 2013

A Little Bit of Everything in Manitoba Over the Next 36 hours

     A vigorous clipper system is already spreading an area of rain in southwestern and western Manitoba this morning and early this afternoon. These showers will spread eastward through the day today and likely reach the Red River Valley by late afternoon. Generally 2-5 mm is expected with this area of rain. However, due to the convective nature of the rain, locally heavy rains are expected giving locally higher amounts.

     A breezy south wind will also be felt today, and that mixed with the cloudy skies will make it feel chillier than it really is. However, enjoy the little warmth we have right now (hint hint)...

     By this evening, a few thundershowers will be possible in southwestern Manitoba, including in Brandon. However, keep in mind this threat is small, so I wouldn't get too excited about it just yet. I'll let you know in the comments if any lightning is reported.

     Meanwhile, scattered showers will continue across southern Manitoba until another more organised batch of rainfall and possibly embedded rumbles of thunder from North Dakota moves in overnight. Moderate to heavy rains are expected at times, especially in southeastern Manitoba. By noon on Tuesday, an additional 5-15 mm is expected to have fallen over southeastern Manitoba, lesser amounts out west.

     In the overnight, rainfall will changeover to snowfall over western Manitoba and the central/northern Interlake regions. This snowfall will continue all day on Tuesday, heavy at times. 10-20 cm is expected from Russell to Wasagaming, Dauphin, Swan River, the central and northern Interlake and east of Lake Winnipeg. Locally higher amounts are possible. Strong northwest winds will create drifting snow and poor visibility.

     The following table is my precipitation forecast for some of Manitoba's biggest cities for the entire system (up to Wednesday morning). Keep in mind that due to the convective nature of the precipitation in many areas, amounts will vary. This forecast is simply a generalisation and gives a good idea of where the heaviest amounts are expected.

5-10 mm
2-4 cm
Less than 5 mm
10-20 cm
5-10 mm
Less than 2 cm
5-10 mm
10-20 mm
Less than 2 cm
10-20 mm
Kenora, Ontario
15-25 mm

     Tuesday will be miserable! Strong northwest winds will dominate southern Manitoba and temperatures will fall throughout the day. Here in Winnipeg, temperatures will fall to the freezing mark by late afternoon which will turn any falling precipitation into snow. A slushy cm or two is possible, but it will be a close call as most of the precipitation late tomorrow is expected to stay to our north.

     Unfortunately, behind this system we end up under another northerly flow and very chilly temperatures aloft. Overnight lows will be below zero through until Friday with daytime highs in the single digits. Wednesday is expected to be the coldest with daytime highs struggling to exceed the freezing mark. This will be well-below the normal high of 15-16°C for this time of year.

    However, thankfully this cool down is not expected to last long. Temperatures are expected to rebound by the weekend. As for the longer long range, no major systems are expected for the next week after today's system. Temperatures look fairly seasonal to seasonably cool with no major prolonged warmups expected anytime soon.