Tuesday, October 02, 2012

Storm system to bring significant rain.. and (gasp) snow.. to Red River Valley and SE Manitoba Thursday into Thursday night.

4 km hi-res NAM image valid
15Z Thursday morning. NAM is
most aggressive on storm intensity
and snowfall over southern MB
A major storm system is forecast to develop over the eastern Dakotas Wednesday, tracking into northern Minnesota Wednesday night into NW Ontario Thursday. This system is poised to bring the most significant precipitation to the Red River valley and SE Manitoba in several weeks, and the moisture will be most welcome.  Current model guidance is showing anywhere from 10 to 50 mm of precipitation may fall with this storm system Wednesday night through Thursday and Thursday night. The problem is there are indications that some of this moisture may fall as snow, and the snow could be significant over portions of the RRV and SE MB, as well as neighbouring northeast ND, northern MN and NW Ontario.  Rain from this system is expected to spread into southern MB from North Dakota Wednesday night and continue Thursday, with increasing northerly winds bringing colder air into the system as it tracks towards Lake of the Woods. Rain will likely mix with or change to snow Thursday into Thursday night, with some slushy accumulations possible.  The changeover to snow is still difficult to predict, since models differ on the strength and track of the main storm system, and the intensity of the associated precipitation. If the changeover to snow occurs earlier in the day Thursday as some models suggest, snowfall could be significant over portions of the RRV and SE MB. Whatever the case, it will be an important system to monitor over the next day or two. Stay tuned.

UPDATE 2: Winter storm warning in effect for southeast Manitoba, including Steinbach, Whiteshell and Sprague regions. 10-20 cm of snow possible Thursday into Thursday night with up to 30 cm possible in Sprague region.  Winter storm warnings in effect for northeast ND including Grand Forks, as well as northwest Minnesota for possible 6-12" of snow. 

UPDATE 1:  NWS Grand Forks has issued a winter storm watch for northeast ND and northwest Minnesota up to the Canadian border for potential of 6" (15 cm) or more of snow Thursday into Thursday night. Special weather statement issued for the Red River valley and southeast Manitoba for potential early snowfall. A special weather statement is in effect for Kenora and Red Lake for possible 5-10 cm of snow or more Thursday night into Friday.

27 comments:

  1. NAM continues to defy the odds of probability with what amounts to a blizzard over the Red River valley Thursday. I'm still discounting it, but its been darn consistent, and GEM continues to trend towards a slower and wetter solution for us. Could it be.. a snowstorm developing Thursday for Winnipeg and RRV?

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  2. Winter storm watch issued for NE ND and northern MN Thursday into Thursday night.. special weather statement for possible 5-10 cm of snow or more for Kenora-Red lake areas. Still trying to get my head around a snowstorm this early in the season after 15 straight months above normal.. but Mother Nature knows how to keep things interesting.

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  3. 12Z NAM coming more in line with other models taking heaviest precip over SE MB. Hopefully maintains that trend.. not quite ready for a big snowfall just yet. Still could see some decent accumulations over SE MB and towards Ontario border.

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  4. Rain overspreading North Dakota at this hour, with a changeover to snow noted over far SW. Rain should continue to spread east northeast towards MB border this afternoon into tonight, reaching Winnpieg overnight or early Thursday. Heaviest precip expected south and east of Winnipeg.

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  5. Noticed that Winnipeg is under that special weather statment

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  6. Winter storm warnings coming according to the 2pm PASPC update.

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  7. Winter storm warnings out for areas just southeast of Winnipeg Thursday including Steinbach, Whiteshell, and Sprague regions. Rain changing to snow overnight and becoming heavy Thursday. 10-20 cm of snow expected with up to 30 cm possible over Sprague region. Strong northerly winds and heavy wet snowfall will cause poor visibility and travelling conditions, as well as put stress on tree limbs and power lines.. Winter storm warnings out for neighbouring northeast ND and NW Minnesota.

    Winnipeg forecast to be on the western edge of the heaviest precipitation, with rain changing to snow Thursday, and a couple cm of slushy snow accumulation possible by Thursday night.

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  8. Is there any reason why EC didn't bother issuing a watch when the NWS did down south?

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  9. To think at this time last year we were basking in record heat in the low thirties.

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  10. According to radar, rain shield has pushed up to the south perimeter of Winnipeg as of 9 pm. Some light drizzle being reported at the airport, likely from a weak band of lake effect coming off Lake Winnipeg into the city on a 010 flow. Light rain should be pushing across the city over the next few hours. About 5 mm of rain so far along the US border according to Weatherbug data.

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  11. Rain is mixing with snow in the south end right now.

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  12. Still some differences in the models even this close to the event.. GEM doesn't change fully to snow until tonight with little accumulation, while GFS/NAM change it over as early as this morning with ~ 30 cm.. A wait and see game.

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  13. Snow starting to stick on the grass in Charleswood.. a little heavier snow over eastern suburbs of Winnipeg. Snow really increases east of the city with reports of 10-15 cm over SE corner of province.

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  14. Hi Rob, My wife is saying this is too early for snow in Winnipeg. I'm telling her Winnipeg has had snow in September. Who's right? Thanks, Chris in Westwood.

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  15. Chris.. Yes, Winnipeg has had measurable snow in September, as early as Sept 24 1984 (6 cm)

    But I'd have to say you're wife is right.. it IS too early. :)

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  16. Hi Rob,

    I'm back with one of my occasional questions. I still read the blog almost daily and enjoy the conversation - much more civil than on a lot of the news blogs.

    As I understand it the 'normal' highs and lows that EC provides are based on a 30 year rolling average. And as I am well aware readings were not always at the airport, but were at other sites in earlier years.

    Now if we looked at the weather data going back to the 1870's and figured out daily normals based om that data, how much lower would the normal highs and lows be than the figures from EC's 30 year averages? ie How much have we heated up since record keeping began here?

    I hope you follow my thinking.

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  17. I will slap the next person I hear saying ''only in Manitoba'' lol!

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  18. This system must've put all of ND's radars with their new dual-pol capabilities to the test. Will be interesting to see how it performs for the rest of fall and winter.

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  19. >> Anonymous said...I will slap the next person I hear saying ''only in Manitoba'' lol!

    No kidding. Have people already forgotten about last October's major snowstorm over New England that caused so much damage there? Hey, snow happens here in October, even this early.. but it won't stick around. So take it in for what its worth.. an interesting meteorological anomaly!

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  20. Joe..

    30 year normals have increased substantially here in Winnipeg since the late 1800s, mainly for the winter months. Average winter temperatures in Winnipeg in the late 1800s were around -18.4C.. now the average is -14.5C, about 4C warmer.. a significant amount for a winter average. Summers though have only gone up from 17.8C to 18.4C, so not a large difference there. By far, the biggest difference in our averages has been over the winter months. Simply put, our winters are nowhere near as cold as they were in the late 1800s, while summers are just a bit warmer. In fact, we had warmer Julys on average in the 1930s and 1940s than we do now..

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  21. Hi rob,

    Couple of Questions...

    With this cooler than normal weather expected to persist into next week, are we done with the warmer temps as in 15C-20C daytime highs?

    Also, supposedly with the upcoming el nino although weak in nature and the record arctic sea ice melt which is expected to delay the start winter, what's with all this below normal weather suddenly?

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  22. It's been snowing all day in Winnipeg, at least where I am, but almost all melted on contact.
    For data purposes, where do you put this type of precip, in rainfall or snowfall? If snowfall, how do you measure in centimetres when none is accumulating?
    Hopefully that makes sense..

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  23. Anonymous said.. >> With this cooler than normal weather expected to persist into next week, are we done with the warmer temps as in 15C-20C daytime highs?

    For the time being, yes.. we won't see temps back in the 15-20C range over the next week or so. However, we should be moderating back to near normal temps in the mid teens later next week, and in fact, CPC hints of warmer than normal temperatures possibly returning by mid October. Now, it'll be getting less and less likely for us to see 20C temperatures after mid October.. but it can happen. We've had 20C+ temperatures in Winnipeg as late as Nov 5th.

    >>With the upcoming el nino although weak in nature and the record arctic sea ice melt which is expected to delay the start winter, what's with all this below normal weather suddenly?

    Remember, we will always go through periods of below normal weather, even during generally warmer than normal patterns. Above normal doesn't necessarily mean above normal every day.. just warmer on average over a certain period.

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  24. Anonymous said...>> It's been snowing all day in Winnipeg, at least where I am, but almost all melted on contact. For data purposes, where do you put this type of precip, in rainfall or snowfall? If snowfall, how do you measure in centimetres when none is accumulating?

    Good question. If it's snowing all day and none is accumulating, you would record a "Trace" as snowfall (in cm) and put the melted equivalent (in mm) as total precipitation. For example, today I recorded 1 cm of snow but 15 mm of melted precipitation (rain and snow together).

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  25. Quite the intense band of what is likely snow off to the northeast of Winnipeg coming off Lake Winnipeg through Grand Beach to Milner Ridge area. This looks like a deformation axis precipitation band enhanced by lake effect moving slightly westward towards Beausejour. Could be seeing heavy snowfall rates in that band.

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  26. In 2009, we had 10 cm of snow on Oct 9th off Lake Manitoba. After that, we didn't get a good snow until Christmas, so who knows, this doesn't necessarily mean an early winter!

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