Friday, August 30, 2013

Labour Day weekend outlook.. unsettled start, nice finish.

After a blast of late summer heat, the summer of 2013 will be winding down this weekend as we roll into September. The last weekend of the traditional summer will start off warm and humid Saturday, but things will become more unsettled as a cold front pushes across southern MB bringing a few showers and thunderstorms by the afternoon. This activity is expected to push across Winnipeg and the RRV Saturday afternoon into the evening, with brisk northwest winds ushering in cooler air Saturday night into Sunday. Sunday will see a return to sunshine, but temperatures will be noticeably cooler than the past 2 weeks with highs only around 20C, which is actually fairly close to normal for early September. This will set the stage for a beautiful end to the Labour Day weekend with sunny skies and highs in the low to mid 20s for holiday Monday.  Generally above normal temperatures are expected to continue for the first week of September.

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. 

Thursday, August 22, 2013

Thunderstorms possible Friday night/early Saturday as heat and humidity rise for the weekend..

Hot and humid weather will be
returning to southern MB
this weekend 
After a couple of beautiful pleasant days with low humidity and mid 20 temperatures, things will be getting hotter and more humid over the weekend as a warm front pushes across southern MB. This front will usher in temperatures back in the thirties, along with noticeably more uncomfortable conditions as humidex values climb near the 40 mark over the weekend with increasing humidity levels.  As the front pushes through Friday night, scattered thunderstorms will move across southern MB Friday night into early Saturday, with locally heavy rain, hail and intense lightning possible. Skies will clear out Saturday as the storms move out, leaving hot and humid conditions for the weekend with temperatures climbing into the 30-34C range across southern MB.  Hot weather is expected to continue through much of the upcoming week, with temperature near or above the the 30C mark all week, along with the threat of scattered thunderstorms from time to time as weak impulses pass through southern MB. All in all, it looks like Mother Nature will be making up for some of our lost summer earlier this month. Stay cool!            

Wednesday, August 14, 2013

Pattern change signals return of summer warmth to southern MB

After 4 weeks of below normal temperatures, a major shift in the upper atmospheric weather pattern will finally signal a return to more typical summerlike weather over southern MB.  The weather pattern over the past month has been dominated by a persistent upper trough over Hudson Bay into the Great Lakes that has resulted in  a prolonged period of below normal temperatures over the eastern prairies into Ontario. Including today (August 14th), Winnipeg will have gone 27 consecutive days below normal, at a time when the hottest weather of the season often occurs. During this stretch, Winnipeg has hit the 25C mark only twice, with a maximum of only 25.2C.  The normal high during this period is 26C.

The below normal streak however will be coming to end starting tomorrow. The persistent upper trough over central Canada will finally be shifting east and replaced by an upper ridge over the Prairies, allowing warmer air from western Canada to finally spread eastward. High temperatures in southern MB will climb from the mid 20s today to the 30C mark by Friday, with 30c+ weather expected over the weekend into next week. Things may start getting a little more unsettled as well Sunday into Monday as a weak impulse passes though southern MB, tapping warm and more humid air and triggering scattered thunderstorms. Above normal temperatures however are expected to persist much of next week, great news for those who weren't quite ready to say goodbye to the summer of 2013 just yet.      

Tuesday, August 06, 2013

Below normal pattern continues this week.. moderating trend expected over weekend into next week

500 mb pattern for Wednesday Aug 7
Note deep Hudson Bay vortex over
northern Manitoba 
Those waiting for summer heat to return to southern Manitoba will be disappointed this week as another surge of cooler than normal temperatures spreads across the eastern Prairies. A deep Hudson Bay vortex (image left) will drift across northern MB into NW Ontario, bringing a surge of cool air over Manitoba for the next few days. Temperatures will struggle in the mid to upper teens over Winnipeg and the Red River valley, some 5-10C below normal for early August.

Temperature graph for
Winnipeg past 30 days  
This will continue a trend of cooler than normal weather that began around July 19th over southern MB. Since then, Winnipeg has gone 19 consecutive days below normal as of today (August 6th) with temperatures more reminiscent of late August or September than mid summer.  The upper vortex is forecast to slowly drift east into Ontario over the weekend, with a gradual moderating trend expected over southern Manitoba into next week.