Tuesday, November 23, 2010
Here we snow again!
Another day.. another snowfall. The third snowfall in less than a week will be affecting southern Manitoba beginning overnight and continuing through Wednesday into Thursday. A snowfall warning has been issued for much of southern MB including Winnipeg for a general snowfall of 10-20 cm by Thursday. Snow is expected to move into southwest MB this evening and spread into Winnipeg and the Red river valley overnight. Snow will continue through Wednesday with 10 cm likely by evening. Snow is expected to lighten up for awhile Wednesday night but continue into Thursday with another 5 -10 cm possible before tapering off Thursday evening. Easterly winds of 20-30 km/h Wednesday will become light Wednesday night, then pick up from the northwest on Thursday as the system moves east of Manitoba. Northwest winds of 30 to 50 km/h are possible by afternoon or evening which will give areas of blowing and drifting snow over the Red River valley, especially south of Winnipeg.
Posted by rob at 3:40 PM
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Something to keep an eye in terms of snow ratios is the strong warm advection progged particulary on 18Z GFS. Initial busrt of snow tomorrow associated with strong LLJ ahead of main disturbance. Model soundings show a relatively warm saturated layer (temps above -10C) atlaest thru 750 hPa. That is outside the optimal temp range for dendritic crystal growth (-12 to -16 C ?). However it is difficult to tell where best vertical motion resides from the available model data (how much is above 700 hPa in colder air).ReplyDelete
Also have to watch out for the dry slot as Rob mentioned...
Daniel can you tell me what that means? Are you saying that snow amounts might not be what they are stating or that it may be grainier smaller snow flake making the weight of the snow the same but not as deep to loss of fluffiness. Also this dry slot - are you saying Winnipeg might miss some of this snow like so often happens here.ReplyDelete
It basiccally means that the snow will be less fluffy than with the previous systems as Rob mentioned. If there is even more warm advection tomorrow than models advertize than the snow may be even less fluffy.ReplyDelete
In terms of the dry slot there will likely be a snow free period between the warm advection precip and the wrap around snow. It is always hard to predict exactly how it evolves within a particular system.. so its postion will have to be closely monitored.
Latest models runs in fairly good agreement for total precipitation amts through S MB. For Winnipeg, the model range is between 10 and 15mmReplyDelete
(based on NAM, GFS, GEM, ECMWF, HPC, and NAEFS), and in Steinbach the range is also 10 to 15mm. If you figure in a 14:1 ratio, then snowfall totals are in the 14 to 21cm range (6 to 8"). I think snowfall will likely start at a 14 or 15:1 ratio, then decline as low as 12 or 13:1, then rise back up to a 15 or 16:1 ratio by Thursday, giving an average ratio around 14:1.
Models certainly not giving forecasters any breaks when it come to low position. HPC ensembles seem to suggest that the low will be positioned around Kenora, ON by 12Z Thursday. This solution would likely create blizzard conditions through at least the southern RRV, given 40kts winds at 850mb. However, the NAM and GEM stall the low out over S MB/N ND, which would certainly make for much lighter winds over the RRV. The NWS seems to be going with the GFS/ECMWF solution, which is interesting. Hopefully models will come to a common solution tomorrow, as it will have major implications on the weather for Thursday.
A little burst of snow early this morning up the Red River valley gave us a quick cm or two, but now radar shows very little in the way of organized snow over us this morning. Things expected to fill in by this afternoon into this evening as better lift and moisture head our way, with another 5-10 cm possible between noon and midnight. Models continue to advertise well defined dry slot pushing through RRV overnight into Thursday morning before we get some wrap around snow Thursday afternoon with maybe another 2-4 cm. Overall, looks like Winnipeg will be seeing 10-15 cm today into Thursday, perhaps a bit more if we can get some heavier bursts in the snow this afternoon/evening.ReplyDelete
Blizzard conditions looking unlikely for the RRV based on the latest model runs. Models seem to be moving towards a common solution whereby the low stalls out over SE MB, leaving the strongest winds mainly over ND and near the MB/SK border. The wind will likely pick up on Thursday night, but it won't get strong enough to produce blizzard conditions - just blowing snow in open areas.ReplyDelete
Looking at the north dakota radar is showing that nice snow band developing just south of grand forks!ReplyDelete
Steady snow should start around noon!!!
This afternoon commute is going to be CHAOS!
Latest poll consensus is for exactly 15 cm in Winnipeg today through Thursday. Votes are pretty well evenly split between the 10-15 cm group and the 15-20 cm camp, with a few more votes in the 10-15 cm category being cast recently.ReplyDelete
Large area of snow over ND is just moving across the Canadian border as of 11 am, and should be spreading north over the RRV over the next couple of hours reaching Winnipeg by early afternoon. Then it looks like several hours of snow with visibilities down to 1/2 mile at times this afternoon with potential for 5-10 cm into this evening. Latest guidance now backing off on dry slot over Winnipeg, with more continuous snow persisting tonight into Thursday as low slowly moves over SE MB into NW Ontario. That may give us the higher storm totals of 15-20 cm in the city if that pans out. Note also that we can still have falling snow by tomorrow evening as the wind picks up from the northwest, which would bring a period of poor vsbys in snow and blowing snow even to Winnipeg. A complex and evolving system.. let's see how it unfolds..
What a mixed bag of forecasting. EC is saying could receive 10-20 cm of snow into Thursday. Weathernet which has been calling for large amounts of snow have now changed their forecast and calling for 5cm from today till tomorrow afternoon.ReplyDelete
Checking the webcams out of grand forks shows some heavy snowfall rates!ReplyDelete
Visibility down to 0.5 km in heavy snow!
Latest ensemble is giving a 70-80% chance of at least 10mm of precip through Steinbach, Winnipeg, Morden, and Sprague with this system. That should be good for at least 13-15cm when you factor in the ratio.ReplyDelete
Snow is just moving into the city now and will persist through the afternoon. Rates of 1-2 cm/hr being reported in some of the heavier snow bands with vsbys of 1 km or less at times. Brandon has picked up 5 cm in the past 3 hours. I suspect the city will be seeing a good 5 cm by the drive home.. with another 5 cm tonight and another 5 cm Thursday..
Visibility has really gone downhill quickly here in Winnipeg!!ReplyDelete
Traffic gridlock on the ride home anyone???
Environment Canada states near 0 visibility is possible is some of the heavier snow bands.ReplyDelete
Careful out there!
In a "flurry" of last minutes votes, the poll ensemble dropped to an average value of 14.2 cm. Most votes were in the 10-15 cm range with the next in the 15-20 cm category. Good band of moderate to heavy snow moving through now will give us 5-10 cm into this evening before it lightens up tonight for awhile.. then another 5-10 cm possible overnight into Thursday. As daniel noted earlier.. drive home will be a mess today.. probably 2-3X your normal drive time..ReplyDelete
Very heavy band passing through WPG at the moment, close to 0 visibility. Looks like we're in for a good dumping!ReplyDelete
Holy crap is it snowing!! I think you better open that poll up so some of us can change our vote!ReplyDelete
As of 4 pm, I've measured 6.5 cm of new snow since it started earlier this afternoon, 4 cm in the past 90 minutes. 8 cm storm total so far. Heaviest band going through the city right now..ReplyDelete
Hey Rob is this snow going to take a break around 6:00pm or so. Just looking at the radar it looks like it might be taking a break for a short time anyway.ReplyDelete
That heavy burst has hit Steinbach hard as well. We received about 7cm in the past 3 hours, for a total of about 8cm today.ReplyDelete
The snow doesn't seem overly fluffy, so I'm assuming that the ratio is probably somewhere around 12:1, but that is just a guess. I'll figure out the real water equivalent later tonight when the heavy snow ends.
Snow is definitely getting lighter now, although radar still shows echoes to our south so I don't think it will stop completely this evening. However it shouldn't be as heavy as it was this afternoon. We should be close to 10 cm by evening, with another 5 cm or so tonight. Snow amounts on Thursday will depend on where the "wrap around" snow ends up on the backside of the low. Most areas should see about 5 cm Thursday but 10 cm is possible in the wrap around band.
What is this womens intuition thing??ReplyDelete
She never looks at forecasts but out of the blue yesterday says "Can you drive me to work tomorrow and pick me up?"
Oh well, I'd better get going! Double or triple time should get me home by... when??
Only about 5.3mm of liquid in Steinbach for about 9-10cm of snow. That makes for a ratio of around 17:1, which is higher than I expected. Models indicate at least another 6mm of precip for most of S MB by tomorrow evening, so we could be in for a lot more snow.ReplyDelete
Another 2 cm this evening up to 9 pm in Charleswood, on top of the 7 cm this afternoon and 1.4 cm early this morning. Storm total so far: 10.4 cm and still snowing with an interesting line of heavy snow approaching from the southwest. A very light and fluffy snow this evening with light winds.. and a little more convective in nature. Nice and balmy too with -5C temps here while -10 to -20C air floods south of us into North Dakota on the southwest flank of the low.ReplyDelete
That narrow line of convective snow going through Charleswood right now giving large fluffy snowflakes.. dropping almost straight down. Some flakes 1-2 cm wide.ReplyDelete
This is the most snow I have ever seen for this time of year!ReplyDelete
My head is still spinning on how fast winter has settled in this year!
12-13cm of snow in Steinbach at 7:00am this morning. Light snow on the way for the rest of the day as wrap-around precipitation comes through.ReplyDelete
Thanks for the report Scott.ReplyDelete
I've picked up another 5 cm since 9 pm last evening.. 15 cm storm total as of 7 am. 27 cm snowdepth. Looking beautiful out there..
How did the temperature drop so much with a south wind????
Normally a NW wind would do that!!!
Yes, an interesting temperature pattern with this system. All the cold air over western Canada wrapped south of the main low across North Dakota into northern Minnesota overnight into this morning. As the low moved just to our north, we picked up a south wind which drew that cold air northward. Interestingly, mild air is still wrapping around the system to the north and northwest (still -5C in the Interlake area). As our winds shift into the NW shortly, our temperature should actually warm up! (up to -10C or so)
Note also that those NW winds will bring in more of that wrap around snow to our north and west.. so we'll likely pick up another few cm today. Looks like we'll be close to 20 cm when this thing finally winds down..
Rob Is this correct??ReplyDelete
approx 61cm snow last winter at your site (Nov-Mar) all last year and 45 in the last week??
Officially, I measured 66 cm from Nov 2009 to the end of March 2010. November and March last year were virtually snowfree, with only 1 cm or so in each of those months. We basically had only 3 months of winter last year, and even those months had meager snowfalls (only 63 cm over Dec through February) Only 3 significant snowfalls all winter last year (10 cm or more): one just before Xmas, one in January, and one in February. But they were spaced a month apart.. not all in one week! Yes, a very different winter this year!