Saturday, November 19, 2016

Major winter storm bypasses Manitoba.. Winnipeg still waiting for first measurable snow. Next threat for snow Monday night into Tuesday


The first major winter storm of the season blasted
Minnesota and NW Ontario Friday with
blizzard like conditions, but spared Manitoba
(photo along I-94 in Minnesota)
A Colorado low winter storm system tracked across Iowa into southern Minnesota Friday bringing a blast of wintery weather across much of northern and western Minnesota. The storm dropped 20-40 cm of snow across northern Minnesota with up to 60 cm (24 inches) reported near Orr in the far north. The storm also produced strong northerly winds which resulted in blizzard like conditions across much of the western state leading to numerous traffic accidents and some road closures. As the storm moved north, heavy snow pushed into NW Ontario mainly east of Dryden with 30-40 cm reported in Atikokan and Upsala, and 10-25 cm in Thunder Bay. Earlier in the week, models were suggesting this storm could be taking aim at southern Manitoba, but the storm took a track further south and east sparing Manitoba from any major impact. We did however get colder weather on the backside of the storm with northerly winds producing bands of lake effect flurries off Lakes Winnipeg and Manitoba. After a record mild start to November with well above normal temperatures over the first half of the month, temperatures will be closer to normal over the next few days.

When's it going to snow here? 

So after missing this big storm Friday, and missing several snowfalls in October which affected Saskatchewan and Alberta, Winnipeg and much of the RRV are still awaiting their first measurable snowfall of the season. As of today (Nov 18th), Winnipeg has gone 222 straight days without measurable snow, the 4th longest such streak on record here (see table below). Our last measurable snow in the spring was 0.4 cm on April 10th (we had some snowflurries on May 13th, as well as Oct 7th and Nov 2nd, but no measurable accumulation on those days, just a "trace")    

Top snowless streaks in Winnipeg as of Nov 15
records since 1872 (chart courtesy of @jjcwpg)



Next threat for widespread snow across southern MB
will be overnight Monday into Tuesday 

(NAM model valid 6 am Tue morning Nov 22) 

Barring any measurable snow from lake effect flurries tonight into Saturday morning (some areas east and west of Winnipeg are getting some accumulating snow off Lakes Winnipeg and Manitoba), the next threat of snow over southern MB will be Monday night into Tuesday as a low pressure system in Saskatchewan moves east, spreading an area of snow into Manitoba. This will not be a major winter storm like the one that hit Minnesota today, but it may result in our first measurable snow here in Winnipeg and the RRV, with perhaps 2-5 cm by the Tuesday morning commute.      
 

11 comments:

  1. Most guidance continues to show likelihood of some snow moving into Winnipeg and RRV in the pre-dawn hours Tuesday morning with a couple cm possible by the morning rush hour. Temperatures however will be mild, near 0C, so roads should be mainly wet although there will likely be slippery sections on some roads, especially outside the perimeter. The exception to this scenario is Canadian model guidance (both RDPS and GDPS) which keep us mainly dry and have the precip developing mainly north and east of Winnipeg Tuesday. This seems to be an outlier solution, and at this point, I favour us seeing some snow here by Tuesday morning.

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    1. The discrepancy between Canadian (CMC) and other model guidance for Tuesday is forecasting when the precip will surface over southern MB. Most guidance shows precip (snow) surfacing west of Winnipeg early Tuesday and then spreading east through the morning and becoming heavier over SE MB. CMC model guidance is drier, and has the precip surfacing east of Winnipeg Tuesday morning and becoming heavier towards the Ontario border, with very little snow falling here. We'll see if models trend towards a common solution..

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  2. CMC models continue to give very little precip (snow) to Winnipeg with this upcoming system (keep bulk of snow east), while other models still show measurable snow developing over us tonight into Tuesday, with heavier amounts east of the RRV. Progged soundings also suggest precip tonight may be mixed with some ice pellets, freezing rain, or rain depending on surface temperatures above or below freezing. Kind of a messy situation. My best guess is that a mixed bag of precip will develop tonight over the RRV, becoming mostly snow by morning which will then spread over SE MB which should see the greatest snow amounts from this. Overall, I'm thinking about 2-5 cm of wet snow for Winnipeg with 5-8 cm over SE MB. I'll update as new info comes in..

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    1. Note that this system has the potential to surprise on the upside in terms of snowfall. The upcoming setup is known as an "inverted trof" which brings up moisture from the US. Sometimes, this type of setup can lead to bands of heavier snow setting up over an area giving unexpected higher totals. Tough to say where that heavier band may set up, but hi-res models are suggesting possibly just south and east of Winnipeg Tuesday. Note though that a difference of 20 miles or slightly colder temps can mean the difference between 5 cm of snow and 15 cm. Something to keep in mind..

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    2. Based on 12Z guidance, I'm going to up my snow estimate for Winnipeg to 5 to 8 cm, and up to 10 cm for areas south and east of the city. Tricky forecast based on where deformation axis sets up with heavier snow band..

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    3. Latest guidance shows precipitation moving into the southern RRV shortly after midnight and reaching Winnipeg by 2-3 am. Precipitation should be mainly wet snow with some melting at first before it starts to coat the ground overnight. Likely 2-3 cm of snow by the morning commute in Winnipeg, mainly on grassy surfaces.. roads should be predominantly wet and slushy. Precipitation may be mixed with ice pellets, freezing rain or rain over parts of the RRV overnight. Snow continues Tuesday morning in Winnipeg before tapering off by midday, with steadier snow continuing through the afternoon over SE MB (Steinbach, Whiteshell, etc) Snowfall totals should be around 5 cm for Winnipeg with higher amounts of 5-10 cm east of the city.

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  3. Well, precip came in pretty much as expected overnight with quite a bit of "mixed phase" precipitation noted (ice pellets, freezing rain, etc) That helped to keep snowfall amounts down compared to if temps were a little colder and precip was all snow. I've picked up 3 cm of snow as of 10 am mixed with ice pellets, with 5 cm of snow reported over southeast Winnipeg. Snow, or a mix of snow and light rain, is pretty much done here in the city as the area of precip moves NE. Temps climbing to +2C this afternoon so roads will be mainly wet today after a slick start this morning.

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  4. Great forecast a few days ago. I suspect this helps the city with their brine vs no snow from cmc.

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    1. Yeah, CMC models did not do well on this system for Winnipeg, showing little in the city with most of the snow east. The automated forecast for Tuesday had no mention of snow in the city.. just a 40% chance of showers. It's only when human forecasters started intervening in the forecast that snow was mentioned for Winnipeg. That shows the problem of totally automating a forecast based on only one model..

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  5. Rob a memory from 61 62 was arriving by train from the east a few days before christmas and virtually no snow on the ground all the way in. Of course it snowed before christmas, excessively after, and i ( and may others) managed to prang my new VW Beetle in a slow motion rear end collision. Dented hood only .

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    1. You're right Don.. according to EC climate records, Winnipeg only had a trace of snow on the ground as late as Dec 21st, before 4 cm of snow fell on the 22nd. Only 3 cm snowdepth by Christmas Day.. quite meager.

      Note that today, Nov 22, was the latest date on record for Winnipeg's first measurable snowfall of the season. Records since 1872. The previous latest date was Nov 21 1963 when snow started falling in the evening, and dropped about 3 inches by the morning of the 22nd. By lunchtime however, no one was talking about the snow.. JFK was shot and killed in Dallas that same afternoon, Nov 22 1963.

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