Friday, December 25, 2009

Snow and blowing snow moving into southern MB.. travel conditions to worsen

The next wave of snow from a strong winter storm system over Iowa is spreading over southern MB this morning from the southeast. Visibilities will be lowering through the day as gusty north winds to 50 or 60 km/h combine with falling and fresh snow to produce blowing and drifting snow. This will make for poor travelling conditions today into tonight across southern MB highways, especially through the Red River valley (see Pembina webcam for latest conditions). Travel is not advised this morning across most ND highways and a few over southern MB. Consult MB highways and ND highways for latest road information.

54 comments:

  1. Civil Emergency For ND

    Interstate 29 closed from CDN border down to SD border. Plows have been pulled and zero visibility is occurring in this area!

    Finally...a real storm...

    Some banding occurring in SE MB.

    Slantwise Convection Rob/Dan-GF?

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  2. Things are getting really nasty even here in Winnipeg!!!

    Some heavy snow bands will move in to Winnipeg soon and with winds already 40-60 visibility will drop below 1 km!!

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  3. How long is this heavy wind going to last?

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  4. NAM indicates the strong winds will begin to slowly subside overnight. Tomorrow you can probably look for wind speeds around 30km/h, but not as gusty. Long story short, conditions will continue to deteriorate as the day goes on.

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  5. Measuring snow will be difficult to say the least!

    Areas where I live the wind has already piled up some good drifts of a foot or so!!!!

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  6. Look at the CTV webcam..... WHITEOUT!

    Airport is down to 1 km in snow and wind at 11:51!

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  7. It looks like near blizzard conditions will moving into the Winnipeg area very shortly and lasting a hour or so!!!

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  8. I continue to be mystified as to why visibilities aren't lower across southern Manitoba right now. We certainly have the winds.. gusting to 60 km/h, we have fresh snow, and we have falling snow.. yet visibility at Winnipeg airport has never officially hit blizzard criteria of 1/2 mile or less. Webcams around the area show reduced vsbys in snow and blowing snow, but nothing really bad. Even in eastern ND, vsbys at GFK and FAR aren't as bad as I thought they'd be. The only thing I can see is that we're not in a cold advection type setup (at least in the east) where you get more efficient low level mixing which can kick up the snow and blowing snow. Note that vsbys are lower to the west of RRV where it's colder. Things are still bad.. but I was thinking there'd be more extensive 1/4 mile or less vsbys out there. Interesting..

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  9. The snow may be quite sticky with high moisture content which is limiting blowing some what?

    It is interesting to note the edge of the deformation band appears to be sharpening... it is snowing rather heavily just SE of the city with lighter returns over the airport. Returns have backed to a Carman-Gimli-Bissett line. NAM appears to have a decent handle on current QPF and prints out roughly 15 mm water equivalent with higher amounts just south of the city.

    An incredible moisture fetch off the Gulf Stream passing over Cape Hatteras arching thru the Great Lakes to N Minnesota.. never saw anything like it before. NAM/RUC depict warm air at 850 hPa affecting us, however northerly surface winds have allowed for a shallow cold layer to slide underneath. They are both also very aggressive in wrapping warm, dry air from the NE of all places (!!) by midday tomrrrow.. this looks to me almost like an 'inverted dryslot' They show above zero temperatures at 850 hPa backing into the Pinawa and Bissett region.. needless to say temperature trends will be very interesting over the next 24 hours with cold core driving into central plains.

    Overall precip totals will be dictated by:

    1) the behavior of heaviest band of precip now just SE of the city

    2) how soon and if we are affected by the strange dry slot working in from the NE

    I suspect we may see a sharp cut-off in accumulations across the Winnipeg region. I wouldn't even be surprised if areas NW of YWG see only 10 while areas just SE of the city get 20.

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  10. Daniel.. The snow doesn't seem to be that sticky, at least at the surface. It's certainly dry enough to blow around and drift, but there doesn't seem to be enough airborn snow to really reduce vsbys, at least for a sustained duration. I see that warm air to the east has changed the snow at Kenora to freezing rain and ice pellets now. Goes to show you the impressive circulation with this beast.

    Tough to measure the new snow out there, but I estimate another 5 cm or so today based on how much my snowdepth's gone up. Heavy drifting with bare spots in some areas.. 30 cm drifts in others. Drifts are hard packed due to the wind. As you say, probably higher amounts just southeast of the city.

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  11. Only had 6cm here so far today. That brings storm total up to 9cm.

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  12. I'm estimating about 7 cm here in Charleswood as of 5 pm.. 13 cm storm total so far. Lots of blowing and drifting, but visibilities not too bad. I think I even felt some minor ice pellets out there out there at 5 pm..

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  13. Spokes of dry air intrusions and ragged bands of precip showing up on RADAR... this is often typical of these large storms in their later stages.

    Models have poor handle on warm, dry wedge working into SE Manitoba right now. Main band remains south and east of Winnipeg.. in fact it is hardly snowing in Garden City, YWG, St James etc.

    I suspect the main band will continue backing a bit and reorient itself more along a west to east axis perhaps affecting southernmost Winnipeg. I think accumulations will be very hit and miss probably starting to mix in with ice pellets by overnite. Other areas may just see lite freezing drizzle or flurries.

    Tough to say.. there is also a chance precip may start to fill again, we'll see.

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  14. Hi

    As for vsbys...the snow water ratio was a bit higher than climo. I know early this morning when working most sites were having estimates of 12:1 or 11:1 even. So that would account for a bit less vsby issues as suspended blowing snow not as bad. But drifting is terrible down here...Probably 13-15 inches at my house since 3 am (when the main snow began). Snow drifts cover my front and side doors up about 3 1/2 feet.

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  15. Heavier returns showing as new band backs in from Ontario... may suggest freezing rain or bright banding.

    So far areas of the city west of Main and north of Portage have seen very little new accumulation.. I would be surprised if YWG has even received 5 cm. We'll if this new band will be able to penetrate further NW into the city proper.

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  16. 11-12cm storm total so far in Steinbach. I expect another 5 to 10cm by tomorrow evening, which should bring our storm total up around 20cm...what I was expecting. I think parts of Winnipeg will be in the 15 to 20cm range, while other areas could be significantly less. I wouldn't be surprised to see some totals around 30cm in the Modern area.

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  17. Another note..

    We got 1-2 hours of ice pellets this evening. Probably the same band that went through Kenora earlier.

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  18. Rob!

    I think this storm pretty much panned out as expected in term of snowfall amounts and wind!!!

    What took me by surprise in the amount of heavy drifting!!

    Like you said some bare spots on the ground with 1 foot drifts in other spots!

    So I guess it will be next to impossible to get a snow amount????

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  19. Officially 15.7 inches on Christmas at NWS Grand Forks. This is on top about 3.5 inches which fell on Thursday.

    Now GFK airport which does have contract observers is wide open and their measurements there were way off and likely incorrect. They only recorded 5.7 inches for Christmas Day.

    Trust me the 15.7 is indeed correct for where I live.

    Dan

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  20. Very difficult to get a precise snowfall measurement out there because of the drifting. Officially at Winnipeg airport, they had 3.5 mm of melted snow on the 24th, and 8.0 mm on the 25th for a total of 11.5 mm melted snow up to midnight last night. Assuming an 11:1 snow/water ratio, that translates to about 13 cm of new snow Thu-Fri which pretty much agrees with what I measured. Ice pellets mixed in last night as well which kept down the amounts and the blowing/drifting.

    So kudos to those who picked 10-20 cm on the snow poll!

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  21. I measured a 24-25th total of 16cm in Silver Heights, but the drifting makes this measurement suspect. Parts of my yard are wind blown down to the grass with 60cm drifts of snow on my driveway. Why couldn't it have been the otherway around?

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  22. About 14cm in Oak Bluff in sheltered areas from the wind. But yeah, I have drifts over 4 feet in my yard...actually one is about 6 feet...and some of my yard has grass showing...so yeah...definitely a wind driven snowstorm...but a storm nonetheless.

    I'm curious...they should have issued at least a weather warning for this especially with the freezing drizzle/rain/ice pellets.

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  23. Only 12cm storm total here. Nearly impossible to measure snow...in many cases there is less snow now than before the storm.

    We certainly missed most of the action. The models had another sad performance in my area, but better around Winnipeg. The models were predicting a minimum of 20cm, but closer to 25cm with the snow ratio. In reality we got 10 to 15cm at most. GEM was the most accurate for southern Manitoba, something to bear in mind for future storms this winter.

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  24. Hi Justin.. welcome home!

    I'm calling it 15 cm total here in Chwd.. which seems like a fairly consistent number for the Winnipeg area.

    As for no weather warning for Winnipeg.. technically, we didn't meet any weather warning criteria over the past 2 days. Snowfall never exceeded 10 cm within 12 hrs or 15 cm in 24 hrs, visibility was never below 1/2 km at the airport for at least 4 hrs (which pretty much represents a rural area outside the city) and ice pellets itself is not a weather hazard (unlike freezing rain)

    However, there were certainly travel impacts, although no roads were ever closed in Manitoba. This event probably could be best handled by a generic "weather advisory" for weather conditions having impacts on the public, but falling short of warning criteria. However EC does not issue advisories like NWS does. It's either warning, or nothing. In this case, conditions fell below warning criteria, so no warning statements were issued and weather details would have been covered in the public forecast. Note also, that EC issued a special weather statement on Wednesday to highlight the potential impacts of this storm to southern MB.

    These events always bring up the question.. what is "significant weather".. and what minimum criteria are required to issue warnings to the public? Are current criteria sufficient? Should they be changed? You have to find a balance between having warning thresolds that are too weak which results in overwarning events, or too stringent so that you miss potentially significant weather.

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  25. 22.5 inches of snow in grand forks!!!

    WOW!!!

    Can anyone tell me if that is a record for the most snow ever for a storm in that area?????

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  26. Its virtually impossible for models to resolve where mesoscale bands like those that affected us will set up... so you always have to take QPF values with a grain of salt. Hopefully those bare spots will allow for some dynamic/thermodynamic feedback as we have seen in the past. Whenever wind drives snow into localized drifts and exposes bare ground over large areas or mixes in dirt into the snowpack... the albedo can be significantly reduced.

    We will transition into an active NW flow pattern as vigorous jet energy amplifies upper ridge over Alberta and carves deep trough over central and eastern Canada absorbing remnants of that huge low. Models suggest at least 3 shots of arctic high/clipper 'couplets'.

    Initial arctic outbreak to occur Monday during the day.. watch for abnormal temp trends (falling during day). First high moves quickly off to the SE by Tuesday morning sparing us from bitter overnite lows, but N Minnesota could be in for some cold morning temps. Temps should recover rapidly ahead of a weak , slow moving low that passes thru on Wednesday.

    Then another lobe of cold air rotating around main vortex builds south as first low intensifies over great lakes. GEM is further west with this outbreak and shows surface high dropping thru Alberta giving us 490 dam thickness (of 500 to 1000 hPa layer). GFS on the other hand drops the high down thru Manitoba with 850 hPa temps of approx -18 C. The latter scenario allow for strong inversion to set up over new deeper snowpack and produces bone chilling lows of -32 to -35 C over pockets of S Manitoba Friday morning.

    The roller coaster will continue as more significant clippers will roll thru on Sunday and then Tuesday of next week... here we go.

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  27. So much for the drying out of the RRV. At least the Xtreme cold is on hold.

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  28. SB Extreme Cold was temporarily on hold

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  29. Preliminary ND storm totals on my name.

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  30. Oops my name for snow totals

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  31. daniel P

    In regards to your question about most ever in a storm for Grand Forks...I dont know. I am off work for a few days. I will check when I return to work on Tuesday. I think the final storm total is 25.1

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  32. Im curious if anyone else got lots of freezing rain cause in the southern part of the city we got eough to make our driveway very trecherous and its parctically shear ice. Just curious to know because some of you guys were talking about ice pellets but not so much freezing rain. And just to report for the southern part of the city i would estimate (hard to tell with blowing snow, snow drifts) we got around 12-14cm of snow and in our yard 3-4ft snow drifts.

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  33. Look out for the cold front tonight!

    Tonight will feel very cold with that strong north winds compared to this past storm with it's milder temperatures!

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  34. Mr Farms..

    I noted some ice pellets in Charleswood Friday evening, and I heard there was some light freezing rain reported just east of Winnipeg. I also noted webcams in the south end of Winnipeg and Steinbach were also icing up Friday evening. So you definitely could have picked some up. I didn't notice any freezing rain, but the ice pellets were giving a thin layer of ice on the windshield and front of my car when I was out driving Friday evening. Maybe the strong winds were causing the ice pellets to break on contact, release their liquid water which would then freeze up in the -5C air.

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  35. Question for Dan-GF..

    I noticed that NWS Grand Forks recorded 15.7" of snow on Dec 25th with a water content of 0.50" This would give a snow:water ratio of about 30:1, which seems awfully high for this storm (which was giving more like 11 or 12:1 ratios) Are those numbers correct, or is it difficult to do a straight water:snow correlation due to the strong winds Friday that gave severe blowing and drifting?

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  36. The guidance or output statistics for GEM (SCRIBE?) performing poorly for next week and do not match raw model output. I suspect the MOS is not 'seeing' strong inversion/ shallow cold layer setting up. It doesn't seem to warm us up enough for Tuesday either with - 6 C 850 hPa overhead..

    Large 1040 mb arctic high builds down across the prairies later part of the week.. guidance running far too warm. With all the fresh snow cover and with potential for high to be directly overhead of Saskatchewan/SW Manitoba Friday morning I would expect very cold temps possibly well into the -30s.

    We will have to see how cold temps get in N Alberta and Saskatchewan by later Tuesday into Wednesday to get a better handle on exact lows. Rob what's your take on this?

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  37. Rob!

    Wind forecast for Winnipeg tonight is 20 km/h

    Portage wind forecast tonight is 30 -60 km/h

    I wonder why such the huge wind speed difference between such a short area????

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  38. Daniel.. I suspect UMOS guidance may be a bit positively biased by the recent mild temperatures over southern Manitoba, and is not capturing the depth of the Arctic air as you suggest. Very odd for southern MB to see two days of howling north winds on the backside of a major storm system in late December, and our temperatures stay in the minus single digits the whole time.

    So yes, the UMOS guidance may need a few days of more normal weather to get a batter handle on our temps. Take Tuesday night for Winnipeg for example.. "Clear. Temperature steady near minus 18" Well, not likely. Temperatures in winter in clear skies do not stay steady.. they drop. The only way temperatures stay steady in winter is with cloud, or winds, or both. So either that steady -18C is wrong, or the forecast has missed cloud cover or wind moving in Tuesday night to maintain that steady temperature trend.

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  39. daniel p.

    I suspect those gusty winds for Portage/RRV are mainly for this evening with a cold front coming through.. but Winnipeg may see gusts to 40 or 50 km/h this evening as well (Gimli gusting to 40 km/h past hour)

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  40. It agree, this remarkable idea is necessary just by the way

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  41. That was quite the cold front that passed through last night!

    Temperatures are really struggling today!!

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  42. Enjoyed the real meaning of windchill this morning.

    In Brandon 24th to 26th and it was nothing like this.
    Fields adjacent to Highway 1W on the 26th from Portage to Wpg were bare except near tree cover on the river banks. Brandon area has about double (Wpg) snow on open ground (15-25cms) with no bare patches.

    In retrospect, Hwy 1W was not as bad as other years. No cars in ditch by late Xmas eve, nor boxing day aft. Absence of trucks had a lot to do with it I suspect. Travel time was 5 mins longer than normal 2 hrs. Manitoba Road Condition website is a great improvement and contained up to the minute accurate info both days

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  43. Rob

    Your question about the water equiv for NWS GFK...yes it would be an estimate. I wasnt working that day...but the measuring snow and its water equiv is a very interesting subject.

    We have a SRG and every 6 hrs we bring it in and melt the snow. In a wind situation it will not catch all the snow. Now we are told we can only report what we catch...even though we know it is not all of it and underdone.

    Dan

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  44. Rob

    The whole snow measuring and reporting liquid content has been a big mess since the NWS went to automated systems in the 90s. The automated systems were put in place to support the FAA, and then after the fact it was like "uh oh how do we know report snowfall since we replaced the manual observers with automated ones". In some cases, the FAA hired contract weather observers like the ones we have located at GFK. The augment the ASOS obs at GFK every 6 hours for their snowfall/snow depth. The AWPG (all weather precipitation gage) that was put in with the ASOS is supposed to be better but still underperforms in wind. But regulations say we must adhere to what the automated system says and to what our SRG collects. In the past we used to fudge the data a bit..but no longer.

    Now for Fargo...there is no snowfall observer at the airport. Instead we supplement all winter precip by using a cooperative observer in North Moorhead (close enough to be climatological the same). His observed data and snow depth is used as the official data for Fargo airport.

    For many other sites that used to have snowfall data, there is none now. So the whole snowfall climatology has kind of been hosed.

    But I did check for NWS FGF...we can adjust our snowfall for the wind but must report what fell in the SRG. Thus the discrepency.
    Also the snow depth we measure at NWS is in an open field. Thus our snow depth is often way lower than in town in protected areas. Same for GFK airport whose measuring area is highly exposed.

    Sorry for the long winded discussion.

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  45. Rob!

    How is December doing so far in terms of averages for snowfall and temperatures???

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  46. Has anyone noticed all the blowing snow in the air today???

    Those winds are really making it nasty cold out there!!

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  47. Thanks for the info Dan..

    We have the same issues with snow measurements north of the border. Snowfall at most airport sites in the Prairies is non existent, with only melted water equivalent reported by the automated gauge. Airport observers will sometimes include snow amounts in remarks, but it's hit and miss. Brandon is the only airport in the southern Prairies still taking snowfall measurements. There seems to be better snowfall observations at airport sites in Eastern Canada where snowfall is a bigger issue for snow clearing contracts. But overall, snowfall climatology in this country has taken a beating since automation. The best snowfall data now comes from our trusty co-op climate observers who give us daily snowfall and snowdepth data through the winter. Without them, we'd have no record of actual snowfall in the Prairies.

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  48. Back! I'm dissapointed i missed out on this storm! The first big storm and i miss it. Because in Brandon, no snowfall, not even a snowflake when i was there on the 25th, neither on the 26th. Some drifting snow but nothing much.
    Now i come back here greeted by a half meter drift carved by those nasty winds Winnipeg got. My bush also got squashed by the weight of the snow and wind. Don't know if it will survive =Þ

    Did environment Canada issue any official snowfall amounts? I missed them.

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  49. As of yesterday, Winnipeg airport is around -14.8C for the month, which is just slightly below the December average of -14.4C. Snowfall at my site is 18.8 cm, which is close to the average of 19.8 cm for the month. So overall, the month will turn out just about average in temperature and precipitation, although it was well below normal the first half, and above normal the second half.

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  50. jewels.. most places over southern and southeast MB picked up between 10-20 cm of snow over the two days. There was about 15 cm in total for Winnipeg. Scott mentioned 12 cm in Steinbach. Higher amounts of 20-25 cm likely over southern and western RRV. Snowfall difficult to measure due to the heavy drifting which made it seem like we got more snow than we actually did.

    I was impressed by the snow clearing operations after this storm. City did a great job in my opinion. Most major streets were plowed within a day, and side streets within 2 or 3. I guess they were just itching to get out there after going so long without snow!

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  51. Ya i was very impressed to see how clean the roads were. Kudos to those snowplow workers.

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  52. It was interesting that Brandon snow didn't seem to drift . Cars in large parking lot xmas eve had about 10 cms on the roofs and it was still there Boxing day even though some nasty wind gusts xmas day .

    Driving in from the West, Headingley South and Charleswood (as usual) appeared to have far more snow than the Ridges and Fort Garry. The trees and dicthes perhaps or is there another reason Rob?

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  53. You know from that storm we didn't get much snow in accumulation. It was mostley blowing so hard that there was these grass patches in my area starting to apear. But then there were drifts that were getting as tall as I am! Crazy!.

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