Saturday, October 23, 2010

Major storm system next week signals end to dry mild weather..

After 4 weeks of mild dry weather over southern Manitoba with virtually no precipitation over that time, it looks like a major pattern change is in store over the Prairies for the last week of October. A strong storm system over the Pacific will be pushing across the Prairies early next week, and will bring rain, strong winds and even the season's first snowfall over parts of southern Manitoba by the middle of next week. Rain ahead of the system is expected to push into the Red River valley Monday afternoon or evening then continue into Tuesday. By Tuesday evening into Wednesday, the storm system is forecast to intensify over northern Minnesota into NW Ontario, bringing strong northerly winds and colder air into southern Manitoba. Temperatures will fall into the low single digits by Wednesday, with rain changing to wet snow over parts of southern Manitoba, especially over higher elevations west of the Red River valley. The colder air will bring an end to the mild weather that has produced double digit highs every day so far this month. Below normal temperatures are expected for the latter part of the week before returning to seasonal values for Halloween weekend.

This storm system will bring the first significant precipitation over the Red River valley in over 4 weeks. Overall precipitation amounts from this system will vary between 10 to 50 mm, with a 50% chance of seeing at least 25 mm of precipitation in Winnipeg between Monday and Thursday. It's too early to say whether we'll be seeing our first snowfall of the season in Winnipeg by Wednesday, but it's likely that the higher elevations of western MB including the Turtle Mountain and Riding Mountain areas will be seeing some accumulating snow from this storm system. Stay tuned..


  1. I see the models have been trending to colder airmass with this storm system!

    I could see Winnipeg picking up a quick few centimeters of snow on Wednesday!

  2. What about warm air wrapped around the low and latent heat release?

  3. Rob!
    At this point could the winds be aligned to give Winnipeg some LAKE effect snow squalls????

  4. We thought about it today, since water temperatures is +9C. So far GFS model is deeper with the surface low over northern Minnesota compare to Global and 850 mb temperatures higher. (near +2C). By Thursday morning 850 mb temperature should drop to somewhat near -5C, however pressure gradient begin to decrease. It will be interesting week.:))

  5. Latest ensemble forecasts showing a 70% or greater chance of more than 25mm of precipitation with the upcoming system. Besides that strong statement, you'll be hard pressed to find a model that is predicting less than 25mm for southern Manitoba this week. Latest NAM lines up with the GFS in predicting a 966mb system...the deepest I have seen since I started watching weather.

    Main question at this time is whether or not rain will change to snow on Tuesday night. Most models only bring in snowfall over western Manitoba, with the RRV and SE MB escaping with flurry activity during the day on Wednesday. NAM seems to bring more cold air into the system earlier, which could change the forecast. Will be an interesting week to watch the weather (finally)!

  6. The winds on Wednesday could reach wind warning criteria!

    I have never seen isobars that closely packed together!!

  7. Here are some interesting results from the latest model runs:

    Lowest Pressure: 968mb
    Total precipitation: 60-65mm
    Precip type: All rain in eastern MB. Snow (2 to 5cm) and rain in western MB. Mainly rain, with some snow flurries in the RRV.

    Lowest Pressure: 964mb
    Total precipitation: 50mm
    Precip type: Mainly rain in eastern MB, with some snow flurries. Lots of snow (5 to 15cm) and rain in western MB. Mainly rain, with some accumulating snow in southern RRV.

    Lowest Pressure: 963mb
    Total precipitation: 35-50mm
    Precip type: Mainly rain in eastern MB, with some snow flurries. Lots of rain and snow in western MB. Snow is mainly over higher elevations (10 to 15cm), with lesser amounts (2 to 8cm) over lower ground. Mainly rain, with some snow flurries in RRV.

    Lowest Pressure: 967mb
    Total precipitation: 50mm
    Precip type: Mainly rain in eastern MB, with some snow flurries. Lots of snow (5 to 15cm) and rain in western MB. Mainly rain, with some snow flurries in the RRV.

    Bear in mind that this information accounts for the entire storm (Monday-Wednesday/Thursday). It is pretty clear that the RRV and SE MB will be seeing mostly rain with this system. It is likely that all of southern Manitoba will be in flurry activity on Wednesday, but by that time we'll be out of the heaviest precipitation bands. It seems that areas in western MB will see the only accumulating snow...with areas of higher elevation potentially getting significant amounts.

    The models seem to have converged on one solution after days of moving back and forth. The idea is that a low will move out of Alberta into Manitoba tomorrow, then by captured by a low moving up from the US. The merged system will then slowly move up into NW Ontario, before stalling out there for 18-24 hours. Finally, by Wednesday morning the system will slowly start moving towards James Bay. It will be quite an impressive system, with all models bringing the pressure down lower than 970mb!

  8. Thanks for all that info Scott!

    Looks like a "land falling hurricane" on the models! LOL

  9. One quick note...the 12Z GFS deepens this system to a 955mb low. The most interesting part about that is the fact that this thing is 1mb away from being a bomb under that solution. The pressure drops from 978mb to 955mb in 24 hours, a difference of 23mb. For a system to officially 'bomb out' the pressure has to drop by 24mb in 24 hours. Perhaps a bit extreme, but interesting nonetheless (especially when you consider that the 1993 Storm of the Century was 'only' a 960mb low).

  10. 955 mb low!
    Are you kidding me?????

    Anyone want to go wind surfing on Lake Winnipeg?????

  11. A 955mb low would be the lowest pressure ever recorded for a non-tropical system in the mainland US (and Canada?) according to wikipedia.

  12. Special weather statement issued for areas in North Dakota!

    Wind gusts there could reach 50 mph which then would most likely also affect our area!

  13. For all those who enjoy snow, click my name...

  14. This comment has been removed by the author.

  15. Wouldn't you think that the highest possibility of snow accumuation would be at higher elevations ie Dauphin region, not just south of Winnipeg? But with all that said, with our luck here in Winnipeg we're bound to get the best possibility of accumulative snow...

  16. Rob!
    What are you latest thoughts on this storm???
    Rain or snow??
    How strong could the winds be??

  17. Greater rainfall reported along the Red since Midnight(north of Morris ex Winnipeg)

    CWB locations reported:
    Glenlea Station 8.1mm
    St Andrews 12.45
    Petersfield 13.46
    East St Paul 10.67

    MAFRI Selkirk reports 8.89

  18. High wind watch issued for Grand Forks and parts of eastern North Dakota!

    They also believe that rain could change to snow in the Red River Valley along with a chance of accumulating snow!

    Envionrment Canada is calling for a high of 6 C on Wednesday with rain!

    This is a very complex storm and this situation could go either way!!!( snow or rain)

  19. Thanks Dan'l P and Mark Ewen GFK
    Grand Forks & CPC 2010/2011 Winter Outlook identifies several La Nina years of nasty long cold winters, and late spring flood years.
    55/56 his oldest choice is easily the snowiest winter on record for Winnipeg. Like this year, 3.5 Weeks of dry October was sandwiched between heavy precip the first week and snow beginning the last day of Oct not pausing til December. By Xmas 80cms of snow was on the the ground in open areas, and twice that in sheltered yards.

    Unlike this year 1955 precip was 6 to 10 days later.

    -1955 October 1955 EC DATA Report
    Sept 30 to Oct 05 39.6mm
    Oct 06 to Oct 30 2.5mm
    Oct 31 to Nov 08 41.7mm)

    Sept 20 to Sept 25th 36.6mm
    Sept 26 to Oct 24th 5.5mm
    Oct 25th to Oct 28th 15-50mms f'cast

  20. Mr Farms thanks for the heads up for those of us driving to and in the SW MB (Brandon Dauphin Area) The short range outlook of at least a 70% probability of more than 4 inches of snow and 35 Knot winds seems to confirms your conclusions. See the NCEP Hydromet Prediction Center Graphic on my name.

    See also the discussion at


  21. Models very consistent in bringing extremely deep low over International Falls area by Wednesday morning.. with central pressure down to 959 mb from NAM, and 954 mb from the GEM. 60-65 kt low level jet will give potential for warning level winds by Tuesday night into Wednesday over the RRV, with gusts to 80 or 90 km/h possible as winds become better aligned in low levels and colder air starts working in. Gale force north-northwest winds over the MB lakes will bring large waves and possible shoreline erosion problems along the southeastern shores.

    Looks like a good 25-40 mm of rain from most models for RRV from tonight into Wednesday, with locally higher amounts of 50 mm possible. Wednesday looks downright miserable with all that precip, wind and cold temperatures.. The big question is if we will change to snow Wednesday.. which is likely west of Winnipeg, but warmer low level temps in the RRV and east may give us a sloppy mix of wind driven rain and wet snow. If temperatures were a few degrees colder with this thing, we'd have a major blizzard on our hands in the RRV. We could see a slushy accumulation of snow in Winnipeg Wednesday, with significant accumulations possible over the Riding Mtn and Turtle Mtn areas of western MB.
    Hang to your hats.. should be an interesting 48 hours ahead!

  22. Thanks for the update Rob!
    Winter storm watch issued for parts of North Dakota!

    This storm could be a doozy!!!!

  23. Interesting weather setting up for the next couple of days indeed! Just a quick message that I'm blogging on weather! Come visit me at
    feel free to leave a comment too!

  24. I've noticed Portage La Prairie is much cooler than Winnipeg this morning with a NW wind the past while!
    Why is Winnipeg's wind east while Portage is NW????

  25. WOW!
    Blizzard warning issued for area's of central north dakota!

    Also this a lot of rain falling southern Manitoba!
    15mm yesterday
    25 today
    25 tonight
    15 tomorrow!
    Winnipeg could have 70 mm of rain when is all said and done!

    All that dry weather we had to dry the soil before frezze up is now a distant memory!

  26. Amazing! Robs Oct 28/09 blog entry is almost identical to this.

    This is the third consecutive year we have finished October and started the Snow season anticipating a major storm.

    See RobsBlogs Oct 28th 2009 post and comments. Intensifying storm system to bring strong winds, rain and snow to southern MB...

  27. Here we go again, Flood warning issued for Hallock NE MN

  28. This system has officially bombed out!

    Pressure in Hibbing, MN dropped from 993mb yesterday at 12pm to 960mb today at 12pm. An impressive difference of 33mb! The pressure only needed to drop 24mb officially for bombogenesis to occur. If the pressure in Hibbing, MN drops another 2.5mb it will tie the record for lowest non-tropical pressure ever recorded on the mainland US. If the pressure drops lower than that, we will have a new overall record.

    This system has already set a new record for low pressure in Minnesota, why not the whole country!

  29. What a storm this is!
    This is one for the record books!


  30. Record pressure in Hibbing, MN now...?

    As of 12:51 PM:
    Pressure (altimeter) 28.3 in. Hg (958 hPa)
    Pressure tendency falling rapidly - 0.21 inches (7.2 hPa) lower than three hours ago

    Wow, this system is huge! Tornado Watches in Southern Ontario, with warnings along a huge derecho in the east-central united states, to the strong winds and heavy rain expected here, and the blizzard conditions and heavy snow in southwest manitoba and eastern saskatchewan. Massive storm, alright!

    With the passage of this system, is there the potential of snowsqualls to set up, I wonder?

  31. Pressure in Hibbing,MN is down to 958mb, this is now tied for the strongest midlatitude storm in US history. It will almost certainly set the new record for lowest non-tropical pressure in US history. Pressure is forecast to reach as low as 954mb according the RUC at 6pm tonight.

  32. Is that 35mm at ROBs in the last 24 hours

  33. Scott..

    According to Christopher Burt's book "Extreme Weather", the lowest barometric reading on record for the US is 955 mb (28.20") set on January 3, 1913 at Canton, NY and equalled on March 6, 1932 at Nantucket, MA. So it indeed may set a US record.

    A very impressive storm.. central pressure is equivalent to a Cat 2 hurricane!

  34. Bigfork Airport just Northeast of Bemidji is 955.. International Falls is 957, as are Hibbing and Beaudette