Major winter storm takes aim at southern Manitoba..

The well advertised winter storm that we've been following for a week now is getting closer, and snow from the system will be spreading into southern Manitoba this afternoon into tonight, with heavy snow expected over the weekend. A WINTER STORM WARNING is in effect for much of southern Manitoba, including Winnipeg and the RRV, with general snowfall accumulations of 20-30 cm expected across much of the area by Sunday morning, with up to 40 cm possible over portions of southwestern MB. Further east, the storm will likely bring a band of freezing rain or ice pellets towards the Ontario border overnight and Saturday before changing to all snow Saturday night into Sunday.  In Winnipeg, light snow is expected to develop this evening, becoming steadier and heavier after midnight with 5 cm possible by Saturday morning. Snow will continue all day Saturday with another 10-20 cm likely by evening along with northeast winds gusting to 50 km/h at times. Additional snow is expected Saturday night into Sunday morning before the storm gradually moves out with storm totals of 20-30 cm possible across the Red River valley, including Winnipeg.

Projected snowfall accumulations Friday night into Sunday 
(GEM model left, NAM model right) 

GEM snowfall accumulations
Fri evening to Sunday morning
orange area is 25cm+

NAM snowfall accumulations
Fri evening to Sunday
orange area is 25cm+

 

Regardless of the total amount of snow that falls, residents should be prepared for a prolonged period of snowy weather over southern MB beginning tonight, lasting through Saturday into Sunday morning, and gradually tapering off later Sunday. Road conditions will deteriorate as the storm progresses, especially Saturday and Saturday night when the bulk of the snow is expected across southern MB.  Be prepared for much slower travel times and possible road closures. (In fact, I wouldn't be surprised to see the TransCanada closing tomorrow from Winnipeg to the Saskatchewan border) Northerly winds of 30 to 50 km/h will accompany the storm with reduced visibility at times in snow and blowing snow. Improving conditions are expected later Sunday as the storm pulls off. Note that this storm will also be affecting neighbouring southern Saskatchewan, North Dakota, NW Minnesota, and NW Ontario so keep that in mind if you have travel plans to those areas this weekend.   For MB highway conditions and any road closures, visit Manitoba Highways website. 

Follow the storm on radar!  Follow the storm on radar using Radar Viewer from A Weather Moment, which is displaying radar echoes in SNOW mode.  Note that radar imagery on the Weatheroffice website is still on RAIN rates, and will significantly underplay snow intensities. Radar imagery on Weatheroffice is fixed on rain rates nationally until Dec 1st when it switches over to snow rates.

Snowy Saturday on tap.. but how snowy?

Rob's Obs Snow Poll average:  17.2 cm (based on 101 entries)

This is what many roads in southern
Manitoba may look like Saturday

It's looking increasingly likely that a significant snowfall will be impacting southern Manitoba by Saturday, with the season's first widepsread snowfall of the season expected for the RRV and much of southern MB.  Environment Canada has issued a SNOWFALL WARNING for much of southern MB, including Winnipeg, for the potential of 15 to 25 cm of snow Friday into Sunday. Although there remains some uncertainty about how much snow will fall in any one location (including Winnipeg), there are a few things that are looking more likely about this impending snowfall event..

Expected storm position
valid 6 am Sunday Nov 11th
(HPC - NOAA)

- Storm track: Low will be tracking towards Duluth (see image left). That increases odds of heavier snow over SE MB and less snow towards the SK border 
- Precip Phase: Will be an all snow event. With the above storm track, likelihood of mixed precipitation (freezing rain/ice pellets) is reduced over most of southern MB 
- Timing: Snow will be spreading in from the southwest late Friday, persisting through Saturday and Saturday night, then gradually pulling off Sunday. Snow expected to develop in Winnipeg Friday night (midnight or pre-dawn hours Saturday)

Snowfall projections (GEM model)
Friday through Sunday, 5 cm ranges
(yellow line is 20 cm)

Snowfall projections (NAM model)
Friday through Sunday, 5 cm ranges
(orange line is 25 cm)

OK, but what about what everyone wants to know: how much snow will fall in Winnipeg?  Models still have been flip-flopping on that issue, but the consensus is growing that Winnipeg will see around 15 cm of snow in total from early Saturday into Sunday morning.  Model estimates for Winnipeg range from a minimum of 10 cm  to a high of 30 cm, but overall, they seem to converging around that 15 cm mark.  It's likely however that some areas of southern MB will see more than that, perhaps 20-30 cm, including parts of the RRV and SE Manitoba (and possibly even Winnipeg if a heavier snowband hits the city)

Regardless of the total amount that falls, residents should be prepared for a period of snowy weather over southern MB beginning Friday night, lasting through Saturday, and easing off Sunday. Road conditions will deteriorate as the storm progresses, especially Saturday when the bulk of the snow is expected across southern MB.  Be prepared for much slower travel times and possible road closures.  Northerly winds of 30 to 50 km/h will accompany the storm with reduced visibility at times in snow and blowing snow. Improving conditions are expected Sunday as the storm pulls off. Note that this storm will also be affecting neighbouring North Dakota, NW Minnesota, and NW Ontario so keep that in mind if you have travel plans to those areas this weekend.

Winter storm threat increasing for southern MB this weekend.. snowfall amounts still uncertain

Long range computer models are coming into agreement that a significant winter storm will likely be impacting southern MB by Saturday.  Models show a storm system developing over the central US Rockies later this week and tracking into Minnesota by Saturday, bringing a swath of snow across the northern Plains states and southern Prairies. Although models agree on this general premise, there is still some uncertainty about exactly where the storm will track, which will have major implications on where the heaviest snow falls over southern MB. Currently, there are 3 main scenarios that are possible. With each scenario, I give a likelihood of that outcome occurring (purely subjective based on my own analysis and interpretation)

Scenario 1 -  Weaker low tracking near Duluth 

Southern MB impacts:  Colder with less snow over western MB and RRV, more snow over SE MB     
Winnipeg snowfall:  5-15 cm (less snow north and west, more snow south and east)
Likelihood:  25% (Updated Nov 9th) 25%




 

Scenario 2 - Stronger low tracking near International Falls 

Southern MB impacts:  Heaviest snow over RRV and interlake, less snow over SE MB     
Winnipeg snowfall: 15-25 cm (less snow west and east)
Likelihood:  50% (Updated Nov 9th) 55%






Scenario 3 - Strong low tracking near Lake of the Woods

Southern MB impacts:  Heaviest snow over western MB and interlake, less snow over RRV/SE MB with freezing rain or ice pellets possible      
Winnipeg snowfall: 10-15 cm (more snow north and west, less snow south and east)
Likelihood:  25%  (Updated Nov 9th) 20%



 

In all cases, the bulk of the snow is expected to fall Saturday with snowfall tapering off Sunday. Winds will depend on the strength and track of the low, but generally the strongest winds will accompany the area of heaviest snow, which will lead to snow and blowing snow issues.

Model Snowfall projections Friday through Sunday 

GFS model (left), GEM model (right)

(based on 12Z model runs from Tue Nov 6th)

Projected snowfall accumulations
Fri - Sun from GFS model
5 cm ranges, yellow is 20 cm line

Projected snowfall accumulations
Fri - Sun from GEM model
5 cm ranges, green is 10 cm line

I will continue to monitor the situation and have updates as the week progresses. During that time, updated model solutions will hopefully be converging towards a more consistent forecast that I can relay with more confidence. In the meantime, you may want to start making sure you have the winter gear handy for the end of the week, and your vehicle is prepared for winter driving conditions (including snow tires)

A little rain Monday evening then a quiet week. Winter storm threatens southern MB by weekend..

Weather map for 6 pm Monday
showing band of rain and wet
snow pushing across southern MB

A warm front over northern Alberta will push into southern MB Monday bringing a band of precipitation ahead of it. The bulk of the precipitation should fall as rainshowers through the Interlake Monday afternoon into the RRV by evening, with some wet snow mainly north and east of Lake Winnipeg. Further west, the warm front will likely result in some patchy dense fog developing overnight into Monday morning across SW Manitoba especially towards the SK border.

GGEM map for Sunday morning
Nov 11th showing strong
system affecting southern MB 

After Monday, things look generally quiet over southern MB the rest of the week with generally fair weather and seasonable temperatures. By next weekend however, long range models are hinting at a potentially significant winter storm affecting southern MB Saturday into Sunday, with the possibility of heavy snow and strong winds. The storm is still a ways off and there are track and intensity differences from the various models that will have a major impact on forecasting who gets snow and how much. So at this point, all we can say is that the POTENTIAL for a significant snowfall of 10 cm or more exists for much of southern MB next weekend, including Winnipeg. I'll be posting blog updates on this developing situation as the week progresses.  

Meteogram showing various model
output for Winnipeg including
6 hr precip amounts (bottom)  

The chart to the left is a meteogram plot showing various meterological parameters for Winnipeg out to 10 days from UQAM's excellent Meteocentre.com site.  The meteogram is interesting since it plots various model solutions (such as the GFS, UKMET, ECMWF, GLB, etc) as well as previous model runs. It's an effective way to see how models are agreeing, and trends in the expected weather conditions. The meteogram plots MSL pressure (top), 850 mb temperature (center) and 6 hr precip (bottom) Updated Winnipeg meteograms available after noon (12Z meteogram) or after 12 am (00z meteogram).   Meteogram data also available from SpotWx.com            

Some snow moving into southern Manitoba overnight into Friday

Weather map for midday Friday
showing area of snow pushing
into the RRV from the west

A weak weather system over southern SK is forecast to spread an area of snow over southern MB overnight into Friday, bringing some accumulating snow to much of the area.  Snow is expected to move into SW Manitoba overnight, gradually spreading into the Red River valley including Winnipeg by Friday afternoon (see top image). The snow is expected to continue through the evening rush hour into Friday night before tapering off early Saturday. Snowfall amounts are expected to range from 5-10 cm over SW Manitoba to about 2-5 cm in the Red River valley including Winnipeg (see lower image), with the highest amounts mainly south and west of Winnipeg. Little snow is forecast north and east of Winnipeg as the system slides to the southwest of the Red River valley and weakens.

24hr snowfall accumulations (cm)
from RGEM model
valid 7 am Fri - 7 am Sat

Luckily, winds will be light accompanying the system with temperatures near the freezing mark so blowing or drifting snow should not be an issue. Still, this will likely be the first widespread accumulating snow the city has seen since early October, so be prepared for some winterlike driving conditions by late Friday, especially if you're headed west of the city.




11 am Nov 2 UPDATE: Snow has spread over southwest MB this morning with MB highways reporting snowcovered roads west and northwest of Brandon. See recent photo taken on Hwy 16 near Foxwarren..

5:30 pm UPDATE:  Snow over southwest MB has edged eastward to a Portage-Carman-Emerson line. Snow is occurring moderate to heavy at times along and west of this line, with visibilities down to 1 km at times.  Snow will slowly move east into the Red River valley this evening with light snow possible in Winnipeg, although bulk of snow will likely remain south and west of Winnipeg.

24hr snowfall accumulation (mm/cm)
up to 7 am this morning. Note how
close Winnipeg was to swath of
heavier snow to southwest.

Snowfall amounts past 24 hours..

Winnipeg...  dusting
Carman .......  3 cm
Portage .......  5 cm
Winkler .......  6 cm
Brandon ..... 12 cm