Friday, September 26, 2008

Nice stretch of weather coming up..

Looks like some pleasant fall weather coming up over the next few days into next week as a large upper ridge begins to build over western Canada early next week. This upper ridge will bring sunny warm and dry conditions to Alberta and Saskatchewan much of next week, with some of that weather moving into southern MB by Tuesday.

In the meantime, skies have cleared across southern MB today behind a weak cold front that moved across the region this morning. High pressure will build into southern MB tonight giving clear skies and diminishing winds.. with some patchy frost possible by early Saturday.  This high pressure system will bring ideal fall weather on Saturday with plenty of sunshine and light winds, making those afternoon highs of 17 degrees feel even warmer.  On Sunday a low pressure system moving through the Interlake regions will spread an area of cloud and scattered showers across central and southern MB. This system is now forecast to move further north than earlier expected, thus the threat of rain will be lower for Winnipeg and areas south. As a result, we may get by with a rainfree weekend here.  

Once this system passes to our east, clearing skies and seasonable temperatures are expected over southern MB for Monday and Tuesday with more sunshine and even warmer temperatures likely by Wednesday as the western ridge builds east.  Some models are indicating that this ridge will collapse over the eastern Prairies by late next week allowing cooler air to return over us again, while the Cdn GLB model keeps us dry and warm right through next week.  It's still a long way off to say one way or another.. but in the meantime, enjoy the fine stretch of weather coming up!        


  1. Dew points have dropped dramatically in Winnipeg this afternoon, from +6C to +1C between 2 and 3 pm as those northerly winds bring in drier air from a high pressure system over northern SK. Lots of subfreezing dewpoints to our northwest under that ridge of high pressure which will be over us in the morning. With clear skies tonight and winds dropping off, this will give a good chance of frost outside the city core and away from the lakes. Overnight lows tonight should range from zero or -1C at Winnipeg airport to +4C at the Forks.

  2. Great news Rob...

    Those low dewpoints are just another reminder that winter is coming.

  3. First official freeze at the Winnipeg airport this morning, with a low of -0.5C. Just a touch of frost here in Charleswood with a low of +1.4C.. so the growing season continues for most of the city, especially downtown with a low of only +5C at the Forks. On average, frost arrives some 2 weeks later in the downtown core than at the airport site

  4. First off, good call on the overnite lows for the Winnipeg area Rob. A few observations...

    Interestingly, it stayed above freezing in the open country sites NW of the airport. Stonewall, Grosse Isle, and Rosser did not drop below freezing last night. With a light NW flow those sites, which are slightly higher elevation, seem to get better cold drainage. That cold air gets hung up at YWG with the infrastructure to the SE perhaps blocking its further progress (cold air damming). Some scattered locations like fannystelle and brunkild also saw light frost.

    It is also interesting how just like the past Saturday... the core of cold 850 MB temperatures and very low dewpoints lagged well behind the front. At one point yesterday there was nearly a 20 C spread in dewpoints from Winnipeg to Fargo. The low dewpoints never quite made it into N Dakota before dawn and they were spared freezing temperatures. Its amazing how often set ups like these occur... the latitude around Grand Forks almost seems to be a 'magic line' I just wish Winnipeg could benefit by having that 'line' nudge up a bit further north.

  5. Band of showers moving just north of Winnipeg this morning with even some lightning detected within the band..

    Clouds will be with us through the morning with a chance of showers, then we should get into some sunshine this afternoon as a dry slot pushes in from the west.

    A cloudy start Monday gives way to partly sunny skies in the afternoon, and then the rest of the week looks amazing with models now agreeing that the large upper ridge over Western Canada will slowly build east through the week. This will give us a nice sunny and mild stretch this week with highs of 20 degrees or better Tuesday through Friday. A great week to get in those last holes of golf!

  6. Range of lows on Sept 27th across the city of Winnipeg and nearby sites from a variety of weather stations. Note the frost at the airport was the only official freeze in the Daniel noted due to localized cold air drainage the airport site.

    Winnipeg Airport..... -0.5
    SanfordPWS........... -0.4
    BBY East ST Paul..... 0.2
    CWB Sanford.......... 0.3
    CWBNorthWinnipeg..... 0.6
    NE of Bird's Hill.... 0.7
    CWB Oakbank.......... 1.1
    CWB Rosser........... 1.3
    BayerStonewall....... 1.3
    Charleswood.......... 1.4
    CWBWhyteRidge........ 1.8
    GorillaWhyteRidge.... 1.9
    CWBFortGarry......... 2.0
    CWBEastStPaul........ 2.2
    St Vital............. 2.2
    DeaconsWTP-SEWpg..... 2.4
    RiverHeights......... 2.9
    WhyteRidgeSchool..... 3.5
    Winnipeg Forks....... 4.7
    U of W downtown...... 5.1
    CWBDowntownHQ........ 5.6