Welcome Spring!

     Before I get to the forecast, I must note that the airport reached a milestone yesterday. It FINALLY reached +5°C yesterday with a high of 5.5°C. That makes April 24, 2013 the latest date on record to hit the first +5°C of the year. What's so impressive about this record is the fact we beat the old record by more than a week. The previous latest date to hit the first +5°C of the year was April 15, 1950.

     Now, yesterday was just a taste of what's to come. A long-awaited pattern change is beginning to take shape as we speak. The jet stream, which has been diving way to our south in the last several weeks will finally move northwards and become more zonal. This will allow clipper systems from Alberta to move to our north instead of to our south, putting us into the warmer side of these systems. This change begins today with increasing southerly winds this afternoon. They are expected to be sustained near 30 km/h with gusts up to 50 km/h at times possible. These winds will lighten a little tonight, but still remain breezy which will keep temperatures a little higher tonight. Lows between -2°C and 1°C are expected across southern Manitoba.

Model image courtesy of A Weather Moment's Model Viewer

     Much warmer air aloft will be moving in from the southwest over the next couple days, but it's hard to say just how much the record snow pack over the eastern Prairies and North Dakota will impact the temperature climb at the surface. As a result, daytime highs are a little more unpredictable than usual between today and Sunday. Cloud cover will also hinder the temperature rise on the weekend.

     Tomorrow, it will be a close call for Winnipeg to hit the first 10°C of the year. I'm expecting a high between 9 and 11°C for the city.

     Saturday is when things get interesting and even a little unknown. With such warm air aloft, it will difficult for the snow pack to put a severe dent on the temperature climb. However, cloud cover could slow the climb. Nonetheless, I'm expecting a high between 15 and 17°C in Winnipeg right now, but it could be warmer if we get more sunshine than anticipated. Dewpoint is the big question mark. NAM brings in fantasy-like surface moisture with dewpoints in the mid teens, unusually high for this time of year.

     With a trough of low pressure and an associated cold front Saturday night, showers are expected, and perhaps even some rumbles of thunder if we can get as much moisture as the NAM suggests. For now, I'm considering the thunderstorm threat as very small, but I will keep an eye out.

     In the longer-long range, another clipper system is expected Monday night. For now, it looks like precipitation will remain as rain for us here in Winnipeg. Some models give us 10-20 mm while others give just a couple mm,  therefore it will have to be watched. Any rain is unwelcomed right now. Behind that system, a cool down is expected, but not nearly as long-lived as what we've been seeing lately.


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Source of the image of flowers at the top of this page here.