Unsettled Weather in Store Next Week

Having broken the 30° barrier another time in the 2010 summer, summertime sun will give way to more unsettled weather next week.

A weak cold front will pass across Southern Manitoba tonight, bringing with it a very slight chance of showers (most likely nothing) and moving us into a cooler airmass for tomorrow, which should be a mostly cloud day.

By Monday morning, a warm front (shown above in the 850mb temperatures) will be positioned SW-NE across Southern Manitoba, extending from a surface low positioned in central North Dakota.  For several days, as the low moves northeast along the baroclinic zone, scattered showers will ride along the warm front.  Each night, there exists a potential for non-severe nocturnal thunderstorms in the RRV and east near the intersection of the warm front and a weak 850mb jet extending up into Southern Manitoba.  Most of the energy associated with the 850mb jet will remain in the states, so I don’t think that any severe weather will be on tap.

Get out and enjoy tomorrow, Sunday through Wednesday will be cooler (think low 20’s for highs) and rather unsettled, with mainly cloudy skies with occasional sunny breaks and showers lurking around during the days, with areas of organized precipitation occurring overnight. on Sunday night and Monday night.

A Few Showers Tomorrow, Then Summer Returns!

Showers will move across Southern Manitoba tomorrow as a weak Alberta Clipper moves through the province. Then, summer returns.

A quickly-moving wave currently over the Alberta/Saskatchewan border will move southeast across Saskatchewan and then veer East and head across Southern Manitoba tomorrow. Along the way, it will lose a fair amount of energy and as a result, we can expect scattered showers or rain tomorrow for a good chunk of the Red River Valley. It looks like there will be very little potential for any convection with the passage of this system.

After this system moves out of the province Tuesday night, winds will slowly veer and start blowing out of the south again. It will not take long for summer to return with daytime highs in the mid-to-high 20’s by the end of the week. Dewpoints will also rise to the mid-to-high teens by Sunday as well, which will solidly cement us as “back in summer.”

As for active weather, after tomorrow, it looks like the next rainy days could be Saturday or Monday, but that’s a long ways out and we’ll wait and see what sets up. Enjoy the warmer weather that’s on the way later this week!

A Rainy Weekend; Sunny Next Week?

Photo from Mike O’Flaherty to CJOB

Winnipeggers were woken by a severe thunderstorm on Friday morning around 5:40AM.  The storm ripped through Winnipeg leaving torrential rains in it’s wake.  Rob wrote an excellent summary of some of the damages that occurred in Winnipeg, including flooded underpasses, power outages, and explosive manhole covers.

Later that day, convection fired up through the RRV and brought another round of heavy rain.  Winnipeg had only heavy rainshowers that caused some localized flooding.  There was another tornado report out of Steinbach, however.  Looking through the damages, I’m highly doubtful that it’s a tornado.  While they’ve had more than their fair share of strong wind events this year, it’s a little ironic that we get more false tornado reports out of one of the only storm-ready communities than a lot of other places it seems.

Now moving on to this weekend’s weather for Winnipeg.

A large upper low positioned north of Winnipeg is bringing huge amounts of rain to the province.  A heavy rain warning exists for Grand Rapids right now, with Environment Canada expecting between 50-75mm of rain.  Through today, rain will wrap around the upper low and spread into the northern RRV by early afternoon.  The models are vary slightly in the exact positioning, but by this evening, areas in the RRV north of Morris can expect rain.  The upper low sinks to the SE overnight, drawing the wrap-around precipitation further south, and most communities within the RRV should expect a fairly rainy Sunday with unseasonably cool temperatures with daytime highs only in the mid-teens.

After this system clears out on Sunday night, the northern half of the RRV will see somewhere from 10-20mm of rain, while the southern half will see more along the lines of 5-10mm, perhaps as high as 15mm.  Following this system should be a relatively unremarkable week.  Cooler temperatures will be the name of the game, with daytime highs around 20 degrees.  The current forecast is for sunshine, however don’t expect completely clear skies as while we may be in a cooler airmass, we still have a strong August sun, which will likely produce lovely cumulus-filled afternoon skies.

One last thing to watch out for in the deceptive Environment Canada “a sunny week!” forecast is the fact that Winnipeg will be under a northwest flow for the duration of the week.  The weather has a sneaky habit of throwing little shortwaves down in a northwest flow that the model doesn’t pick up very well, and should any of these happen (as is even being hinted at for Monday evening), we could easily see another batch of showers and/or thunderstorms.

So instead of thinking this coming week will be a beautiful sunny week, wear thicker shirts, bring a jacket, and don’t be surprised if it ends up more unsettled than the forecasts are hinting at right now.