Sunday, February 08, 2009

Freezing rain, rain and wet snow Monday into Tuesday..

A winter storm watch has been issued for much of southern MB for Monday into Tuesday as a complex storm system in the US plains spreads a messy mix of wintery precipitation into the area. The storm system is expected to spread an area of freezing rain into Southern MB overnight into early Monday morning which could make the morning commute treacherous un untreated roadways. Freezing rain may last for several hours with significant icing possible in some areas Monday.. possibly 5-10 mm of ice or more. This may be enough to cause damage to tree limbs and power lines with power outages possible. By afternoon, the freezing rain is expected to change to rain, mixed with wet snow at times, over the Red River valley and southeast MB as temperatures rise above zero.. while wet snow will likely prevail over western areas. Rainfall could be in the 5-15 mm range across southeast MB Monday into Monday night while snowfall amounts of 10 cm of more are possible further north and west. Precipitation is expected to gradually change to snow over all areas Tuesday into Wednesday as colder air wraps into the system.

Considerable uncertainty remains in the timing, precipitation amounts and precipitation phases with this system. This is an unusual storm system for this time of year in southern MB.. typically storms with such a mixed variety of weather don't hit southern MB until March or April. As such residents are advised to stay tuned to updated watches and warnings on this developing situation.


  1. This storm has the potential to be the most significant icing event here in the Red River valley/southern MB in quite some time. Worst case scenario would be for 10-20 mm of rain Monday into Monday night with surface temperatures remaining at or below freezing through the period. That would cause some serious problems. Still by no means a certainty.. but the possibility is there.

  2. I was looking at the Storm Prediction Center outlook for tomorrow and they show the "thunderstorm area" extending all the way into North Dakota!

    That shows that the system will have very intense shield of moisture that will be thrown into the cold air.

    Environment Canada insists that Winnipeg area will be in the warm sector on Monday....we will see

    NWS in grand forks still show the 32 F line running through Grand Forks which would put all of Southern Manitoba into a heavy ICE!

  3. Winter storm watch has been upgraded to a freezing rain warning for much of Red River valley and SE MB. Look for freezing rain to develop by dawn Monday and continue Monday morning before changing to rain by midday. 5 to 10 mm of ice possible followed by another 5 to 10 mm of rain. Wet snow to follow for Tuesday into Wednesday. Ice accumulations may be more or less depending on when surface temperatures climb above freezing Monday.

  4. Latest NAM has a band of freezing rain moving into Winnipeg by 4 am.. changing to light rain or drizzle by 8-9 am. I think frzg rain will last longer.. probably through midday. Get the de-icing salt and sand ready for those walkways and steps in the morning. I've put out my standard rain gauge in the backyard to see how much rain we get with this event. (My weather station rain gauge is frozen up at the moment)

  5. Rob!
    How much accumulation of heavy wet snow do you see possible as this system pulls away Tuesday night??

    NWS is calling for 6 - 8 inches for the Devils Lakes Basin!

    One thing is for certain!
    There is gonna be a lot of moisture falling the next 48 hours!
    25 mm total accumulation is not out of the question!

  6. The ensemble is giving a 40% chance of more than 25mm of precip in the RRV and SE MB. That is a very bold statement from a model that is traditionally very conservative.

    The NAM shows high temperatures of 0 for Winnipeg, and +1 for Steinbach. Although the NAM usually does very well with these strong advection situations, I am not as sure about this one. If history is a guide the NAM should nail this, but since this scenario is so strange, I wouldn't be surprised if failure prevailed.

  7. I don't think we'll be seeing much heavy snow here in the RRV.. maybe 5-10 cm at most as the system pulls out. Heavier snow will be further west of us, west of the Pembina escarpment.. where 10-20 cm is possible Monday through Tuesday night.

    Such a nice evening out there with a full moon.. hard to believe all this mess will be moving in within 12 hours!

  8. Rob!
    The temperatures have been lowered by environment Canada to - 9 for overnight lows.
    So I assume that will have an impact on how much longer it takes for the temps to get above zero tomorrow???

  9. Large area of rain has now formed in South Dakota and heading into North Dakota!

    Looks like even some heavy convective rain bands forming on the eastern edge of the precipitation shield!

  10. I was concerned about those convection bands. They will drift north as extremely weak convection or convective remnants. If that is the case we might as well throw all our forecasts out the window, because those convective bands will be very hit and miss.

  11. P.S. I am thinking about 3 to 8mm of ice accretion for Winnipeg, and 3 to 6mm of ice for Steinbach. If surface temps stay below or around freezing all day like many models are showing we may be in for the "Ice Storm of the Century". Although unlikely, it is possible.

  12. NWS radar out of north Dakota is showing some yellows and even some oranges in the rain shield!

    Does that mean that rain is very heavy or is it showing that as ice??

    Does the NWS radar have a "snow mode" like we have or they just have one setting on their radars?

  13. Travel Not Advised on most highways in Southern Manitoba including several road cloasures as of 3am.

    Ice Covered, Extremely Slippery areas, Travel @ own risk, Emergency and Towing Services may be unavailable.

    Quite the dire road warning message.

    This is a decent icing event to say the least!

    Haven't seen the roads this coated with ice in years

  14. The trees around here in my area are shining with ice!

    I surprised at how quickly the temperatures have risen above zero!

  15. Picked up 6.4 mm of freezing rain in this first wave. Very slippery out there but the ice is starting to melt a bit as temperatures rise above zero. I too am surprised how quickly our temps rose above zero.. I thought we'd be near or below freezing through midday. Looks like a lull in the perecipitation much of today with just some very light rain or drizzle, then a second wave of rain moves in by the drive home into tonight.

  16. I picked up 9.4mm. It took about 90 days to get that much liquid prior to today. Basically it is like adding 20 to 30cm to our snowpack, assuming the average ratio for this year.

    ...And there is more to come.

  17. The streets around my house are solid ice. The ice is about a .25" - to .5" thick, which was helped somewhat by the layer of snow that was already present. It is hard to walk around, never mind driving.

  18. Oh boy we missed 20-30 cm of snow. That is a real dissapointment for this time of year. If the moisture is gonna come it would have been nice if it was snow rather than rain.

  19. Rumble of thunder SW of the City limits. I heard it, dog heard it, friend called me a minute after asking if I heard it...definitely odd...

  20. How much rain/freezing rain fell over the Red River Valley from here South to Fargo.?

    I'm just curious how these amounts will change the current flood projections. It seems like we had a decent amount, with more to come.

    The precipitation shield is lighting up big time South of us.

    This is so rare, I wonder how many times this has happened before.

    I was skating this morning on my streets in Oak Bluff with my neighbour shooting a puck around.

    Oh yeah, did anyone else hear any thunder around 8:50am? I checked the lightning detectors, and they picked up nothing...

  21. Justin..

    Generally looks like a good 10-15 mm of rain trough the valley up to 5 pm (I've had about 10 mm here in Chwd) with another batch coming through this evening and tonight (maybe another 5-10 mm) This will give totals of 15-25 mm over the RRV by the time it tapers off Tuesday.

    Not sure how this will affect flood forecasts.. certainly is a lot of rain for this time of year (in fact, unprecedented) but perhaps it's early enough that the impact will not be as severe had it occurred during flood season. But this certainly will elevate the flooding risk I'm sure.

    By the way, many of EC rain gauges have a nipher shield attached to them until April to help in snowfall measurements. These shields will overcatch rainfall in the winter months, so rainfall amounts from EC stations may be overestimated from Nov-April. For example, the Winnipeg airport AWOS gauge recored a nipher-assisted 16 mm up to noon, while a non-nipher gauge at the same spot recorded 9 mm. Something to keep in mind when looking at rainfall amounts from some of these stations.

  22. Winnipeg airport recorded 26.5 mm of rain up to midnight yesterday which would be a new February rainfall record for Winnipeg. However, this was overestimated by a good 50% thanks to an attached nipher shield. The non-shielded Forks gauge reported 13.7 mm, and I picked up 14 mm. Other unshielded gauges around the city were generally in the 10-15 mm range.. so that 26 mm is definitely an overestimation.