Wednesday, September 23, 2009

September sets new heat record... big cooldown expected Sunday

The summer-like weather of September 2009 will be one for the record books. With a maximum temperature of 26C Wednesday, Winnipeg registered its 17th day in September with temperatures of 25C or higher. This eclipses the previous September record of sixteen 25C days set back in 1940. And it looks like we'll add a couple more to the total before the week is through as temperatures of 25C or more are forecast both Thursday and Friday. This is in stark contrast to a very cool July, the 5th coolest on record, in which Winnipeg saw only ten days of 25C or more. In fact, September 2009 will finish with an average temperature greater than July, the first time that has ever happened in Winnipeg since records began in 1872.

The warm weather has been persistent for the past 3 weeks over southern MB with every day this month above normal so far. But changes are on the way. A storm system is expected to cross southern MB Sunday, which will draw in much cooler air Sunday into Monday on strong northwest winds. This will bring the first spell of below normal temperatures in over 3 weeks, with the risk of a widespread frost by Tuesday morning. The cool outbreak however should not be enough to offset this September finishing as the warmest September on record in Winnipeg as well as most of southern MB.

18 comments:

  1. Let the northwest winds begin! At least until an arctic high goes by. :-)

    That being said we'll see what happens, could be interesting.

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  2. Rob!

    Do you see the potential for damaging winds on Sunday/ Monday???

    Some of the models are showing a very tightly packed wind field!!!!

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  3. Wind warnings are required for sustained winds of 60 km/h or more, or gusts of 90 km/h or greater. I don't think they'll be that strong here in Winnipeg Sunday night into Monday morning, but we'll come close.. maybe 50 gusting 70 km/h. GFS indicating that the core of the strongest winds (50 kt jet at 850 mb) will move over SE SK into the RRV of ND early Monday. This would bring the strongest winds over southwest MB into the southern RRV near Emerson where wind warning criteria may be reached. Of course, this can change as we get closer to the event. Of some concern would be the strong northwest winds on the southeast shores of Lake Manitoba and Lake Winnipeg which could produce high waves and local beach erosion Sunday night.

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  4. Rob
    These cold weather forecasts are the first by you this month without a trailer of the cooler weather will be short lived as above normal temperatures are forecast to return by mid to late week.

    What and when does Octobers first system bring us?
    Can we look forward to relatively great weather in the days after.

    PS I like artwork .

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  5. Rob Thanks for the Lake Wind Warning Sept (Remember 2005) thru Nov are the worst months for these events. and the lake is dangerously higher in Sept as they are right now.

    Jim

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  6. Real time and Historical Lake level info (and RRV) is available at http://scitech.pyr.ec.gc.ca/waterweb/formnav.asp?lang=0

    or link on my name.

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  7. Jim..

    From what I'm seeing, the jet stream/storm track shifts south of us through the first week of October which will mean near to below normal temperatures and a greater liklihood of precipitation events every 2-3 days.. rain at this point. After that, I have no idea what Mother Nature has in store for us. Keep in mind as well that long range models have been having a tough time trying to predict the transition from the well above normal pattern to below. This gives me less confidence in the model's solutions over the next couple of weeks.

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  8. I'm officially declaring today a perfect weather day. Clear blue skies, 26 degrees, light winds, and low humidity. It doesn't get better than this..

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  9. Drumheller, AB recorded 34.8 C yesterday. Insane!

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  10. 28.7C so far today in Steinbach, a full 13 degrees above normal.

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  11. The latest model runs show us getting blasted by a 60kt jet streak at 850mb on Sunday evening. This will likely bring winds of 50 G 70, with higher winds possible in localized areas. Areas in the RRV may reach wind warning criteria.

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  12. Latest NAM showing 50-60 knot 850 mb winds over the MB lakes by Sunday evening with strong cold advection over warm lake waters. This could easily produce 100 km/h wind gusts along the southern and eastern shores of Lake Manitoba and Lake Winnipeg Sunday night.

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  13. It looks like the latest GFS is still consistent with a very strong cold front on Sunday!

    Sunday will be a interesting day to say the least!

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  14. Better enjoy today and tomorrow because it is all going downhill after!

    I'm sure we will get some more nice days in October but for the next few weeks looks like a cool and wet pattern!!!

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  15. I was reminded today that the worst storms for the south end of lake Winnipeg follow a few days of North winds. The south end of the lake is particularly low following days of South winds The hourglass shape has meant the lake is high (full) at the Top (North) End and water levels low at the South end.

    Theoretically Sundays forecast strong winds could produce greater damage if the wind changes to North today and pushes some of that water into the south basin before Sundays gales.

    A Sunday shift in direction .. less damaging

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  16. Not wishcasting just information

    Jim

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  17. Jim

    Wind shifts into the north Sunday morning on Lake Winnipeg, but the strongest winds aren't until evening. So lake levels in the south will be rising all day before the strongest winds kick in. Still looking at 40-50 kts in the low levels mixing down to the lake surface (70-90 km/h gusts) producing big waves and possible shoreline problems Sunday night.

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  18. Will be interesting to see if we can hit 25C again tomorrow. GEM is cooler than the NAM, showing only 10C at 850 mb tomorrow with a high in Winnipeg of only 21C. NAM is showing 15C at 850 mb with less cloud, which would give us another 25C day. If so, that would make 20 for the month, double July's amount.

    25C or not, that will be the last of the 20 degree temps for awhile. It was great while it lasted!

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