Tuesday, December 11, 2012

Another round of snow moving in for Wednesday morning commute..


24 hr snow accumulations
from RGEM to Wed evening.
Highest amounts expected
over southern RRV
Another clipper system developing over the western Prairies is forecast to spread an area of snow over southern Manitoba tonight into Wednesday. Snow is expected to spread into southwest Manitoba this evening reaching Winnipeg and the RRV around midnight or shortly after. Snow will increase in intensity overnight with 2-5 cm possible by the morning rush hour.  Plan on extra time for your morning commute as roads will be snow-covered and slippery. Snow will be tapering off by midday Wednesday with total amounts of 4-8 cm possible for Winnipeg, and 10 cm or more possible mainly south of the city.    

87 comments:

  1. I'm quite curious to see where will get the most snow; I think that Winnipeg has a decent chance of seeing awfully close to 10cm tomorrow. Areas north of the warm front will see the most snow, with widespread 3-4" accumulations, with a narrow strip just a little north of the front that could see 4+ inches. With the very tight baroclinic zone both at the surface and aloft with this system, it will be very interesting to see how the interplay between moisture and SLR values play out. Given the fairly cold temperatures I'm place over the RRV, I really wouldn't be surprised to see storm-averaged SLR values as high as 19:1 or 20:1.

    Certainly a challenging system to forecast for given EC's warning criteria (heavy snowfall is 10cm in 12 hours or less).

    I'll have my take on things up on AWM tomorrow morning (as per scheduled), but don't worry, I'm not cheating! I'll be scheduling it tonight before I go to bed :-)

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  2. Oh and as a quick guess, I'm betting that awfully close to Morris ends up being the cutoff between cold weather with 5-10cm of snow to the north and the warmer air to the south with only a few cm of snow.

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  3. Widespread snow across southern Saskatchewan with visibilities generally from 1/2 - 1 mile in snow and local blowing snow. Snow should be spreading into SW Manitoba this evening reaching Winnipeg around midnight - 3 am time frame. Given the cold temperatures and increasing wind, snow will likely be quite fine and crystal like, making it easy to drift or blow around with enough wind.

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  4. Is there a reliable source of observed SLR values around here? Someone pointed me to Cocorahs, but their SWE data isn't very good. Just today one site in Winnipeg reported a SLR of 50:1 while another had 5:1 from yesterday's snow, both impossible readings.

    I suppose Rob your WINNIPEG CHARLESWOOD 2 Cooltap site is pretty reliable, however slow to be updated on the EC site.

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  5. SLR values are hard to come by now that snowfall observations aren't taken at some of our main synoptic sites (such as Winnipeg, Regina, Saskatoon and any automated station). COCORAHS obs are hit and miss, so reliability is not there. (by the way, last evening's snowfall was about 40:1 based on 2 cm of snow melting to 0.5 mm of water.. very dry and fluffy stuff)

    As for me, I don't take SLR values, just snowfall. So the Charleswood 2 snow obs are purely snowfall depth in cm.

    Before things went automated, observers at Winnipeg airport would take snowfall measurements in cm, plus melted equivalent in mm and record the totals in the total precipitation for the day (in mm.) So SLR values were easy to derive back then.

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  6. Rob,

    BTW, thanks for all the great info....really appreciate it.

    Beside tonight's snow, are there any potential big snowfalls on tap for us within the next 7 days or so?

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  7. Current model guidance looks pretty quiet over us for the next week after tomorrow's system. We may get brushed with a light dusting now and then, but no major organized systems forecast over us. Models indicate a stormier pattern setting up south and east of us over eastern NA over the next week.

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  8. Well that's good news...I think everybody besides those snow enthusiasts are tired of these little snowfalls we've been receiving over the past few weeks.

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  9. Getting scary in northern Manitoba, -47 wind chill in Thompson now with temperatures approaching -40°C tonight.. Going to be a long winter..

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  10. Visibility down to 1.5 miles in snow and drifting snow in Brandon. Leading edge of snow approaching Portage La Prairie as of 10:30 pm..

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  11. Snow starting to move into the city. All guidance suggests QPF values of 3-3.5 mm except for RAP. RAP however overdoing extent of precipitation shield with line thru Brandon now. Looks like about 4-5 hours of moderate snow.

    Snow liquid ratios are tricky.. temperatures in best saturated layer are close to -10 C, with colder air near the surface. Hard to give a weighted average without seeing vertical velocity profile (would need to look at some model diagnostic tools), but I would guess around -12 C which yields SLRs around 18 or 19 to 1. Snow will also be falling thru a layer where winds will be in the range of 15-20 kts which could tear up some of the bigger flakes so actual SLRs may be lower.. especially on the back edge of the band. Best guess around 5.5 cm for the city.

    Daniel

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  12. Hey Rob,

    I noticed EC & WN have changed there forecast for the weekend. 5-10 cm on Saturday again???

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  13. 6.4 cm of fresh snow at my place as of 8 AM. 22 cm snow on ground. Still snowing very lightly but looks like it's pretty much done.

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  14. Anonymous.. Right now, the GGEM model is the only model predicting such large amounts for Saturday. All other guidance has very little for the weekend. We'll have to see how things trend over the next few days, but at this point, GGEM is the clear outlier.

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  15. Thanks Rob. Lets hope for no snow

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  16. 6.5 cm here as of 9:15 AM (River Park South). Depth in the yard up to 21 cm with 27 cm in the deepest drift (max depth). Have to use the metre stick soon!

    JJ

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  17. So much for the snow stopping lol.
    Looks like will be here till late afternoon.

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  18. Another 1 cm of fluffy flurries since 8 am.. Up to 7.5 cm now.

    Evidently a local car dealership is running a promotion that if it snows 12 cm today (12/12/12), 12 customers will get $12,000 You can bet a few people hope it will snow all day! (although I don't see another 5 cm for them, but stranger things have happened...)

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  19. 8.0 CM as my place in Windsor Park since the snow began overnight up to Noon today.

    Snow depth in my yard up to 24CM.

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  20. Interesting, John Sauder says we only got 3-4 cm in the city from this system.

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  21. Yeah, what's he looking at... More like 7-8CM snow.

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  22. I picked up another 2.4 cm of very fluffy snow since 8 am, for a total of 8.8 cm since event started. The snow today was very dry.. probably 40:1 stuff... while the snow last night was more like 20:1.

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  23. Hmmm. That Global GEM inverted surface trough over MB on Saturday looks a little exaggerated. It's no wonder the other models don't agree.

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  24. Yup. The new GGEM run is more in line with the other models. The previous run just looked implausible.

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  25. The only difference is that they pushed the inverted trof further east now

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  26. Something wrong with The Forks station? Hasn't been reporting for a couple days.

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  27. Looking at the radar looks like snow is approaching the city. I know they are forcasting flurries but if the radar picture holds together looks more like snow then just flurries for Winnipeg

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  28. Ah yes, the inverted trough was pushed east. It helps to look at an actual weather map!

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  29. Daryl..

    Yes, you're right. Area of steady snow just southwest of the city approaching from the west. Could see a quick 1-2 cm especially across the south part of the city this afternoon.

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  30. Rob,

    What's the situation for Saturday..will we see accumulating snow or just a few flurries?

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  31. At this point, it's looking like just a few flurries for Winnipeg Saturday. Better chance of steadier snow towards the Ontario border and east.

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  32. Wow really coming down in south end right now. Very fluffy so I think a few cm definitely possible.

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  33. What a difference from last year.

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  34. yeah, already picked up 1 cm here in Windsor Park....coming down pretty good right now

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  35. Lol on EC's homepage it shows 15°C right now (above zero!). I wish!

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  36. Really? I'm seeing -15 C.

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  37. I knew it would change back quick so here's a pic in case people missed it. (I'm not crazy)
    http://puu.sh/1Ayc0

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  38. LOL. Hopefully EC hasn't contracted out EarthNetworks/WeatherBug/WeatherFarm to manage their site.

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  39. SPECI CYWG 132032Z 16005KT 2SM -SN VV005 15/ RMK SN8=

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  40. Any idea on how much snow has fallen?
    I bet 3 cm by the time its done.

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  41. I have picked up 2CM here in Windsor Park as of 3:15 PM and still snowing...very slow commute home today.

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  42. 3 cm here in River Park South so far as of 3:40 PM. Wouldn't be surprised if amounts are a little higher in the southern tip of the city due to the fact a band clipped the south tip near 1 PM missing the rest of the city.

    JJ

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  43. Picked up 3CM as well here in Windsor Park as of 4:30 PM. Still snowing as well...may get another 1CM or so before it tapers off early this evening.

    What a difference a year makes...last year we couldn't buy a snowflake....this year it's snowing pretty much every 2nd or 3rd day.

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  44. 3 cm of new snow today in Charleswood as of 5 pm. That makes 17 cm over the past 5 days. Snow depth up to 25 cm now. Wasn't expecting this snowfall today..

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  45. Rob,

    Given the surprise snow today, is there a chance we could get surprised with some snowfall on Saturday instead of a few flurries?

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  46. Surprise snow? You should have listened to this guy:
    "I've been watching the radar this morning and the snow that was in my forecast yesterday has shown up."

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  47. Oh yeah John Sauder....he's right everytime, eh? lol...last i checked he didn't have snow yesterday in his forecast for today.

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  48. Looks like just the odd snowflake even for eastern MB tomorrow.

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  49. Hi Rob, I don't pretend to know anything about meteorology, but can I ask you what would be a good weather site to look at for a relatively accurate and quick reference as to expected snow fall. No disrespect to you and your colleagues, as I usually follow your blog, but I'm in the snow clearing business and often have to get immediate readings to disperse people properly so often I have used the weather Network or accuweather but they are often so indifferent I don't know if I should call people to work or not?
    You by a long shot are more accurate but your a blogger and do this as a hobby, I have income and people depending on me for an income and often need immediate information where would you go for fast updates on a blackberry?

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  50. Anonymous.. Thanks for your interest in my blog. I hope it provides you with some good info to help with your snow clearing business. I try to provide insight whenever I can, especially for the bigger snowfall events.

    I assume you're looking for more specific information on snowfall accumulations and timing? EC will include snowfall amounts in the Day 1-2 forecasts if it's at least 2 cm or more in a 12 hr period. No amounts are ever mentioned after day 2.

    For more detailed information on snowfall timing and accumulations, you may want to try consulting the graphs below the Winnipeg forecast icon on my main webpage. (The two lines labelled "graphs") Click on "48HR" for Canadian model data that includes snowfall amounts out to 2 days, and click on NAM for American model data. These charts are from SpotWx.com and are quite handy to view model data at hourly increments. You can also click on "6day" and "GFS" for snowfall outlooks out to 6 days or more. Now, these are raw model output, but they can give you a general idea of when snow is expected, and how much. Unfortunately, these graphs are flash enabled, which means you can't view them on many mobile platforms. Hopefully, that capability will be there some day.

    Other than that.. check back with my blog whenever you can. I don't always update things as quickly as you may like, but I certainly try to respond to comments or questions whenever possible.

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  51. It's currently 10C and raining in Chicago... they still haven't received any measurable snow this season.

    Windsor was the Canadian warmspot at 7C.

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  52. Just looked at 2 taxpayer funded forecasts for today. One says cloudy and -6, the other says 'fairly sunny' and -11.

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  53. Yeah and on the news this morning they said Wpg 'will warm to -9°C' today. That was just moments after they said it was currently -7°C. Ha!

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  54. Anon- I run Spotwx.com which Rob mentioned mentioned. It will hopefully be working on any mobile device within 1-2 months. Let me know if you have any questions, using the contact link on the site.

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  55. This sunshine is very fuzzy and white, smacking me in the face. A surface ridge does not necessarily sunshine make, despite what you learn in Met 101 class.

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  56. Up to 13.5C in Port Weller in the Niagara peninsula today... pretty mild weather in Eastern Canada.

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  57. Where has the sunshine gone? It seems that the last 3 months have been way cloudier than normal and combined with the short days, makes for a lot of gloom.

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  58. Wow.. another 4 cm of light fluffy snow overnight out of nothing but boundary layer cloud with radar hardly showing anything all night. Last December, we couldn't buy a snowflake.. this year, it's snowing even when we don't expect it. Up to 23 cm for the month now, 66 cm for the season.

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  59. Oh wow only got 1 cm in River Park South, Rob, as of 8:50 AM.

    Incredible that the hoar frost from 3 nights ago is still on a lot of trees. Just shows how calm our weather is right now.

    JJ

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  60. In Windsor park only received 1 cm as well.

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  61. At least 3 cm downtown this morning.. so it looks like highest amounts over central and western parts of the city. Very light fluffy stuff though, probably 40:1 SWE ratios again..

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  62. Anybody know what happened to The Forks station? Hasn't been reporting for a week now, starting to lose a lot of data...

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  63. I heard it was a communication line issue with MTS, but I don't know why it's taking so long to fix

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  64. Canadian warmspot was Grimsby in the Niagara peninsula at 9.2C. It's the time of the year when Niagara is usually a bit milder than Windsor during mild spells.

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  65. Oh no...not the spammers!

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  66. Spammers, lucky us.

    Hey rob, still going to get 2-4 cm of snow within the next 24 hrs?

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  67. Looks like bulk of snow will be slipping mainly south of Winnipeg this evening. But we should see some snow spreading in overnight into Wednesday with a couple cm possible. Another one of these weak systems passing through.. pretty dull stuff.

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  68. Rob:

    I have been following your weather site for 3 years now, and always pleased with the product.

    I'm a leader of a local scout troop. Do you think you would be interested in sharing your weather knowledge with a few keen scouts?

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  69. So what's Thursday's high?

    NAM: -11.1 C
    SCRIBE-Reg: -12 C
    GEM-REG: -12.9 C
    CTV Winnipeg: -13 C
    Env Can: -13 C
    TWN: -13 C
    GEM-GLB: -13 C
    GFS: -13.9 C
    Wunderground: -14 C
    Euro: -17 C
    CBC MB: -17 C

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  70. 1.4 cm of new snow overnight in Charleswood, 25 cm on ground. Heavier axis of snow just to the south and southwest of Winnipeg, with 4-5 cm reported in the Carman and Holland areas overnight. Radar hinting that the band is shifting north a bit and may affect southern parts of Winnipeg by midday.. but better chance for heavier snow just south of the city.

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  71. Anonymous.. Pass me along an email contact and we can discuss details about a talk with your scout group.

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  72. The Euro shows a high of only -17C tomorrow, but cloudy too!

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  73. Rob,

    I've noticed that it's looking pretty chilly for Christmas?

    How cold is it likely too be next week, are we looking temps around -30 C?

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  74. Hey Rob, when are you planning to update your blog? As am curious about how our weather will be over the second half of the week. All of course from your perspective.

    Let me know, thank's.

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  75. 3 cm in River Park South so far

    JJ

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  76. Ho hum, boring weather, boring forecast......yup.

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  77. Yeah, very dull stuff.. getting tired of these daily minor snowfalls that keep adding up. And sure would like to see the sun for a change! Hopefully things clear out for tomorrow, although satpix still show some pesky low cloud hanging around southern MB tonight.

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  78. If it prevents us from getting to -20/-30/-40 everyday, I'd take cloudy and snowy everyday of the winter!

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  79. yeah ill take some cloudy snowy days over those brutal artic highs with temps < -20

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  80. At least it provides a bit of entertainment as some people struggle with the forecast. The overnight low didn't even get down to someone's forecast daytime high, and this morning's temp is already above their high. Blame it on the clouds!

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  81. It's amazing how we just can't clear out in these ridges... Persistent low cloud and boundary layer flurries. I don't mind missing out of the -20c temps, but I'm getting a little sun deprived! Oh well, I see some sunny breaks on the Steinbach webcam.. maybe I should take a quick drive out there to get my vitamin D fix! :)

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  82. Rob,

    What does the weather situation look like through Jan 1st. Any possible storms or just colder and somewhat more sunshine?

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  83. I can't recall such a prolonged period of boundary layer flurries in Winnipeg. We've had episodes of long duration low cloud, but not giving this constant flurry activity. Amazing.. Picked up another 0.6 cm of fluff today, now up to 29 cm for the month, 72 cm for the season. Last year, we had 25 cm of total snow to this point.. with a brown Christmas over much of southern RRV and ND.

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  84. Well, the ECMWF called the low cloud but was about 6C too cold. The NAM was best for temperature, but if memory serves didn't forecast all this cloud. Of the human forecasts, most did OK with the temp (within 2C) except our local CBC.

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  85. Ottawa webcam will be interesting to follow tonight into Friday.. major winter storm heading their way.

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  86. Anonymous.. Current model guidance suggests a pretty quiet pattern over southern MB through the end of December with a more active storm track through the Ohio valley/Great Lakes into eastern Canada. We may see a clipper system by Christmas Eve, but otherwise looks pretty quiet and seasonably cold. Nothing major noted at this point, at least in model land.

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