Saturday, September 06, 2014

Enjoy the summerlike weekend.. an early blast of fall coming by Tuesday

Say goodbye to summer this week!
850 mb temperature map shows blast of cold air
flooding across the Prairies by late Monday
It was a lovely Saturday over southern Manitoba as afternoon sunshine and southwest winds pushed temperatures well into the 20s across the RRV, including a high of 25.3C in Winnipeg, about 5C above normal for this time of year. Sunday looks just as nice with sunshine and light southerly breezes pushing afternoon temperatures back to the 25C mark again.. perfect weather to enjoy the Broadway ManyFest street festival, the annual Bombers-Riders Banjo Bowl game, or any other late summer outdoor activities. Enjoy it while you can because there are BIG changes coming in the weather this week across the Prairies. An unseasonably cold airmass will be barreling down from the Arctic early this week, bringing a blast of well below normal temperatures from Alberta to Manitoba. This colder airmass will be ushered in by a cold front pushing across southern Manitoba late Monday into Monday evening. Temperatures in the 20s Monday afternoon will plummet Monday night, with temperatures on Tuesday struggling in the 10-13C range along with cloudy skies and brisk north winds, making it feel more like October than September. The cold weather will persist the rest of the week with cloudy skies, patchy light rain or drizzle, and temperatures only in the single digits to around 10C.  That's a good 10C below normal for this time of year.  If that wasn't bad enough, higher elevations of western MB (such as the Riding and Duck Mtns, Turtle Mtn, etc) may even see the season's first flakes of .. *gasp*.. SNOW by mid week! (Very early, but not unprecedented for those higher elevations) The saving grace is that clouds and wind may prevent a widespread killing frost during the week for the remainder of southern Manitoba, but if there are any areas that clear at night, frost will be a major concern during mid to late week. So enjoy the summerlike Sunday.. a taste (or more like a heaping serving) of fall is on the way!

22 comments:

  1. Rob, really interested in what you think this winter is going to be like?? Do you think that it is going to be another very cold and snowy winter? I sure hope not, we have had are fair share the past 2 winters.

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    1. Last winter was one of the coldest in over 100 years. Statistically, it would be very unlikely to have a winter as cold or colder than last year, Not that it can't happen, just extremely unlikely. Other than that, I have no idea how this upcoming winter will be.. I was hoping for a strong El Niño to develop but it looks like they're backing off on that prediction. That makes it a lot more difficult to predict what kind of winter we'll have.

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  2. I know I'm in the minority here, but I wait all year for September. It's mu favourite month of the year. Warm days cool nites, incipient fall colors, few bugs, nites are quieter and longer. The prospect of October in September is a double bonus! I love sleeping with the window open especially when it cold outside. I have a fan outside the window on a portable "workbench" helping to pump in the cold air. Sometimes my room is only +12°C in the early AM. Thanks for the great news Rob and thanks for posting it here again. Chris in Westwood.

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    1. Glad you'll be enjoying the early taste of fall Chris! I love September too, but more for days like today! What a gorgeous day! I would love this weather into October!

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    2. I share your love of Sept genrrally and the cool nights but would not give up our beautiful summers to live elsewhere.

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  3. Models indicating cold front will be pushing across Winnipeg Monday a little earlier than initially thought. Looks like front will be moving through between noon and 3 pm, at which time winds will shift from southerly to north, and temperatures will drop from midday values of 22C to 12C by evening. A pleasant start to the day with a chilly finish!

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  4. Elevated convection this morning on a weak LLJ ahead of the front. Next area of precipitation will move in tomorrow afternoon and evening as an area of midlevel forcing develops behind the surface front.

    These showers will merge with an area of steady, moderate rain associated with a developing Colorado low on the east side of the deepening upper trough. NAM is furthest NW with track of surface low - moving it from the Twin Cities up through the Keweenaw Peninsula of Upper Michigan. Light precipitation backs into SE Manitoba under this scenario.

    ECMWF, and to a lesser extent GFS, are not as deep with the upper trough and more progressive with the system. As a result they track the low further SE.. La Crosse WI to Sault Ste Marie with precipitation shield only affecting SE N Dakota. Will have to monitor model trends as there is still lots of uncertainty regarding the evolution of the current pattern.

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  5. Current Winds and lake Wpg level wreak havoc on Southern Basin Winds of 20 knots 40Km onshore near gimli
    Lake levels and recrds graph last two years
    http://wateroffice.ec.gc.ca/report/report_e.html?mode=Graph&type=realTime&stn=05SB006&dataType=Real-Time&startDate=2013-04-09&endDate=2014-09-09&prm1=46&y1Max=&y1Min=&max1=1&mean1=1&prm2=-1&y2Max=&y2Min=

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  6. Colorado low sitting down in Kansas right now is progged to track to just SE of the Twin cities by early tomorrow morning. Moderate rain falling from south and east of a Grand Forks to Warroad MN line with light precipitation echoes far southern RRV and SE Manitoba. Another area of light showers over SW Manitoba and Saskatchewan. Cloud line over S Interlake at this time.

    Positions of these features should remain relatively steady over night, as the low tracks NE. 3-5 mm of rain possible Emerson to Sprague by tomorrow morning. Mid level push of drier air sags south by around 7 am.. possibly giving us clear skies in Winnipeg. With wind speeds staying up however.. temperatures will have a hard time bottoming out.

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  7. What a mess in Calgary this morning. 10-15 cm of heavy wet snow overnight has caused considerable tree damage with lots of power outages. Out of season snowstorms can have the same impact as a major ice storm.

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  8. Tough call on frost tonight in southern MB due to variable cloud cover, winds and lake influences. Any place that stays clear tonight will have a frost risk as dewpoint temperatures are at or below freezing and afternoon temperatures only in low double digits. Areas downwind of the lakes should stay above freezing as well as places that have some cloud cover. Much of RRV has cleared this evening however there's an area of cloud spreading in over SW MB that should insulate areas along and south of TransCanada overnight. Areas that stay clear have the greatest frost risk overnight as winds drop off tonight.

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    1. Lots of cloud over most of southern MB tonight.. so that should minimize the frost threat for most areas...save for the colder valleys or areas that manage to clear out for a few hours overnight. As of 10 pm, temps mainly in the +6 to +8C range, with Minnedosa the cool spot at +4C.

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    2. Tomorrow night (early Friday) could be a more widespread frost threat over southern MB as cool ridge builds in.. Cloud cover will again dictate extent of frost, but models are indicating more breaks in the cloud tomorrow night than tonight. Something to monitor..

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  9. Rob How much moderation will the absolutely drenched soil east of 59 and particularly east of Hwy 12 see. I ask for two reason. Circled that area north of Hwy 44 yesterday and it is drenched. And golfed yesterday morning at Coppermine where Lee River meets Lac du bonnet and it was one of the most plesant days this year . Despite the forecast However to emphasize the point, in many places the course which is built on granite was like walking on a water bed..Wonderfully dust and pollen free air.

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    1. Don.. Elevated soil moisture does help to reduce frost severity compared to dry soils..and this could be the difference tonight between frost and no frost in any wet area. Tonight is another tricky forecast due to the extensive cloud cover today and how much of that will dissipate tonight. The feeling is that these clouds will at least partially clear allowing for temps to drop to the freezing mark overnight, but it will be contingent on how quickly and widespread the clearing is. Sustained cloud cover in any area will reduce the frost threat which would be good news for crop growers if that happens.

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  10. Rob What is it about Elie topography that makes it the focal point of so much weather Havoc. The only fire tornado in Manitoba to result in death that I know of. The only or
    first f 5 tornado in Canada and the ten miles of Hell Snow Squalls from lake Manitoba in November which turn the TransCanada Highway into an instantaneous whiteout Deathtrap.

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    1. For snowsqualls, Elie lies in a perfect spot between Portage and Winnipeg to get NW squalls off Lake Manitoba with a maximum fetch (330 wind direction) This wind direction can often result in the most intense squalls because they're lined up perfectly with the orientation of the lake for the longest fetch. Once the lake freezes, then Elie can be in line to get a lot of blowing snow with those 330 winds blowing snow off the south end of Lake Manitoba into the western RRV. Other than that, Elie is no more prone to wild weather than any other spot in southern MB.

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  11. Although theElie Strawboard plant was often the scene of fires the baales of straw that resulted in the tragic filre tornado death was near winkler

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  12. http://m.theglobeandmail.com/news/national/bizarre-fire-funnel-throws-manitoba-man-to-his-death/article1038979/?service=mobile

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  13. Arctic high over SW Saskatchewan is progged to drop into western S Dakota by dawn tomorrow. Locally, lower level flow turns from NW to more W or WSW (at 850 hPa) by around 1 am. Area of fairly solid stratus over western Manitoba and eastern Saskatchewan trying to hold on. Region of more broken stratus and cumulus over the interlake and Winnipeg. Model relative humidity fields not doing a great job handling current low clouds.

    It looks that at least some broken cloud may persist tonight - leading to local variations in temperature by morning. Whatever remains of those low clouds off to our west should start oozing eastwards towards the RRV by the later half of the night. That combined with a westerly, downslope flow of 5-10 kts from the surface to 925 hPa should keep temperatures from really bottoming out. Hopefully only patchy, light frost in cold prone locations by morning.

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  14. That fire tornado was near Winkler not Elie

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  15. Winnipeg and much of southern/eastern RRV spared from frost by a small band of cloud that hung around most of the night. Frost more extensive over western RRV and Pembina Valley areas (Carman, Treherne, Manitou, etc) with clearer skies and lows of -1 to -3C. Most of SW MB spared from frost due to another area of low cloud that persisted all night, fortunately for them. Patchy frost through the Interlake regions inland from the lakes. Harder freeze over much of southern SK overnight where skies were clearer and no major lake influences (-1 to -4C)

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