Friday, March 28, 2008

Spring break begins with winter storm

Well, it's looking more and more likely that a significant winter storm is going to be affecting Southern MB this weekend, particularly for areas north and west of Winnipeg Saturday afternoon through Saturday night. With this weekend marking the start of spring break in southern MB, the storm could put a damper on travel plans for some people especially later Saturday. The details..

A storm system over Montana Saturday morning will move northeast and intensify as it moves over SW Manitoba Saturday evening. Snow from this system will spread over much of southern MB by midday Saturday, becoming heavy at times Saturday afternoon into Saturday evening. The snow will likely be mixed at first with some rain over the Red River valley and SE Manitoba Saturday afternoon, including Winnipeg before it changes to all snow by Saturday evening. Further west, the precipitation will likely stay as all snow with heavy snow possible west of Portage Saturday afternoon. So if you have travel plans to the west Saturday, it would be advisable to leave Winnipeg as early as possible Saturday before the heavy snow develops by early to mid afternoon. For Saturday night, the band of snow should taper off in Winnipeg and the Red River valley as a dry slot pushes in, while heavy snow will be persisting north and west of Winnipeg through the Brandon, Dauphin, McCreary and Interlake areas. These areas will likely see the heaviest accumulations from this storm system with 20 to 30 cm possible by Sunday morning. Here in Winnipeg and SE Manitoba, amounts should be less (perhaps 10 cm) since there will be some melting precipitation at first, and the area of snow will not persist as long as areas further north and west. However if the warm air is less pronounced, or the system is slower.. Winnipeg could see heavier amounts of snow through Saturday night. All in all.. should be an interesting system to watch over the next day or two, and could add an extra element to Earth Hour tomorrow evening (lights out between 8 and 9 pm... maybe Mother Nature will do it for us!)


  1. What are the chances that this system could be a complete bust???
    If they are calling for 3 C for a daytime high tomorrow will the snow even stick??

  2. I think that is unlikely, this system has been in the forecast for quite a while now, a last minute switch just doesn't seem reasonable. This system is also developing today, so I don't think that overall system will change at all. Although precipitation amounts and exact track are always variable factors.

    About the +3 temperatures...The ground is still frozen (besides the top couple centimeters during the day) and with the cold ground most will probably stick. Furthermore with the freezing mark in the upper atmosphere veering well south of us as the system comes in at its fullest, most precipitation will be snow. Rain is just possible as it approaches, in the first stages of its impact.

    Some of that was my opinion, what do others think about snow amounts? I think Winnipeg will see 15 to 25cm and areas west should see 20 to 30cm. Eastern Manitoba will be on the fringe so it could end up being 15 to 25cm there, or only 5 to 10cm we will have to wait and see.

  3. The bust potential for this storm is highest along the US border, over the red River valley (including Winnipeg)and SE MB. These are the areas where enough warm air could mix in to give more rain than snow and keep overall accumulations down. But this is a wild card at this point, and I wouldn't bet on it. It only a takes a degree or two difference to give you snow instead of rain, so I'd be cautious about downplaying things for Winnipeg at this point. Hence the winter storm watch. I think it's pretty much a given that areas from Brandon through McCreary to Fisher Branch will see a decent snowfall from this thing by Sunday morning with a good 20-30 cm in that swath. For Winnipeg, we could see anywhere from 5 cm if we get more rain to 15 cm if its mainly snow.

  4. I dislike the heavy snow falls with these temps. It makes it almost impossible to move. The stuff comes out of the snowblower like a sausage machine

  5. WOW
    That radar return is looking mighty impressive!
    I wonder if it is going to be a rain /snow mix or all snow.
    Well I guess we will find out in a hour !!!

  6. So far in Winnipeg it is all wet snow.. (I will be "camped" out in Winnipeg (St. Boniface)for the weekend, so no reports from Steinbach.)

    ...This leads me to believe that we will see just snow here. The temperature just fell from 2 to 1 degree, and the wet snow might cool the air a bit further. Upper air temperatures will be below zero through the entire event, and as long as the surface temperature doesn't rise I don't think we will see much rain. Some wet accumulations are already forming, I am interested to see this system develop some more, as to where the heaviest line of snow will set up.

    The GFS and Global model(s) both show Winnipeg just along the heaviest line. The PASPC discussion suggested that the system may be tracking slightly farther South than expected, which would shift that heavy line right into Winnipeg. We are about to enter a small dry slot as of 2:40 p.m. and beyond that looks like more heavy snow.

    This is definitely a good weekend for weather enthusiasts!

  7. Well, it's certainly been an interesting day in Winnipeg today with precipitation battling between wet snow and rain into this evening. Rain has now changed to wet snow in the city as of 8:30 pm (during Earth Hour!), and starting to give a slushy accumulation. Still some good echoes on radar, so we may still get 5-10 cm out of this thing tonight. Conditions worse to the west of Winnipeg with the TransCanada now closed from Brandon to SK border.

    Note convective line of showers in North Dakota with tops to 30000 ft generating some lightning strikes near the SD border!

  8. Today certainly stretched my forecasting abilities, an indication I still have lots and lots to learn. Overall it was a good experience, luckily we got some kind of big snowfall this winter. In Steinbach our largest snowfall still looks to stand at 9cm for the winter, unfortunately this winter seemed especially poor. Spring is just around the corner(meteorologically) and the snow should be gone shortly. By the end of this week I think winter should finally be behind us, and April will hopefully bring warmer temperatures.

    By the way, we still need to see which poll answer from the previous question will be correct.

  9. Scott..

    These types of system are the most challenging to forecast.. for the experienced and beginners alike! You're always learning in this business!

    Very windy conditions setting up this evening in the southern Red River valley with southerly gusts to 85 km/h at the CWB site in Dominion City, and gusts to 83 km/h at Hallock MN. Doppler radar indicating 70 kt southerly low level jet at 5000 feet, some of which is surfacing this evening possibly due to that convective band coming through. Impressive system with a lot of dynamics!

  10. What an intense band of snow that passed thru before 10 pm to around 11:15 pm. With such strong warm air advection and low level jet... it would have been a good set up for nocturnal tstorms if there was a bit more moisture and warmth. Seems like the very strong dynamics and large scale ascent cooled the column off enough for a change to all snow after waffling between frozen and liquid precip.

    As the forcing and band moves off...temps may climb as we will tap mild air down in N Dakota and Minnesota on a SE flow ahead of the low and the cold front. A lot of this snow/slush may gone by the morning... atleast I hope. The last we need is for all this gunk to refreeze as colder temps move in.

  11. Sorry..that last post was me... dont know how the heck that happened lol.. anyways good nite.

  12. Okay..this is getting silly... somehow my google account name was changed. Last two posts were from me Daniel. Sorry for the multiple postings.


  13. Downtown Winnipeg this morning (Sunday) has some serious wind gusts. I'd estimate it maybe around up to 60KM/h, Windows are rattling heavily in my apartment building.

    WFP Current Conditions says the winds are 38MPH.

  14. Well, after it was all said and done, ended up with about 3 or 4 cm of wet slushy snow here in Winnipeg, and around 5 mm of rain for a total of 10 mm in melted precipitation for this event.

  15. I was just looking at the precipitation accumulation from yesterday, and noticed something interesting.

    Winnipeg received 17.5mm (Airport) and 21.8mm (Forks). Brandon on the other hand received 16.2mm, Dauphin 5mm, Carberry 14.3mm, Melita 6.2mm, Virden 6.2mm, McCreary 10.9mm, and Minnedosa 16.2mm.

    It turns out Winnipeg received more precipitation than all these other regions that were supposedly right in the track of the storm. Is it possible there was lots more accumulation overnight? I am curious to see how much snow accumulated in the above regions in Environment Canada's statement later today. If it would have been a couple degrees colder, we could have been dealing with 20cm of snow!

  16. Scott..

    Those readings from Winnipeg (both airport and Forks) look suspiciously high.. and I suspect they were overcatching precipitation due to the presence of nipher snow shields still being on the precipitation guage. These snow shields act like larger funnels that make more accurate readings for snowfall during winter . However if they're still on in the spring, they will overestimate rainfall by as much 2 times due to the overcatchment area. These shields are usually removed by early April. That's some of the problems with relying on auto-station reports without proper quality control being done. Looking at other sites around Winnipeg (unshielded) showed results more in the 10 mm range during the storm.

    Other auto-sites in western MB may have underreported precip amounts due to clogged gauges with the wet snow.. tough to say. I see several climate station reports (taken by real live humans!) of 15-20 cm of snow through the Riding Mtn/Minnedosa/Dauphin/Arborg areas .

  17. I am not sure... maybe 15 - 20 mm is not out of the question for yesterday. The snowfall rate was phenomenal at times and the water content of the snow was extremely high. Is it possible the very strong winds caused some stations to underestimate precip totals?

  18. I read the PASPC discussion this afternoon, and it said that 30 to 40cm of snow fell in and around the Riding Mountains! I can agree with both comments, the snow was very heavy at times, but yet it seems unlikely 20mm fell in Winnipeg.

    I thought Environment Canada would post a report of snow totals today. Do they still do that?

  19. AWCN11 CWWG
    Summary weather statement issued by Environment Canada at 3:06 PM CDT
    Sunday 30 March 2008.

    Summary of severe weather events and forecasts from 8.00 AM CDT
    Saturday to 8.00 AM CDT Sunday.

    An intense weather system tracked through southern Manitoba on
    Saturday and into early Sunday morning leaving a trail of wet heavy
    snow to many areas. The southernmost part of the province,
    Including the City of Winnipeg escaped the significant amounts as
    temperatures remained warm enough to allow the falling snow to melt
    throughout much of the event. The heaviest snow extended through
    The Riding Mountain park region across Lake Manitoba into the
    Central Interlake region. The heavy snow and strong overnight winds
    produced widespread poor driving conditions. A number of highways
    were closed including the Yellowhead and portions of the
    Transcanada. The wet heavy snow and winds also combined to produce
    power outages in the Lake Manitoba area.

    Here is a summary of notable reported accumulations:

    Brandon 12 cm
    Neepawa 18 cm
    Strathclair 30 cm
    Rossburn 18 cm
    Dauphin 20 cm
    Carberry 10 cm
    Amaranth 25 cm
    Alonsa 35 cm
    McCreary 25 cm
    Steep Rock 15 cm
    Ashern 30 cm
    Lundar 10 cm