Tag: Rain

Spring is in Sight

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The GFS depicts an upper-level ridge building into our region early next week.
The GFS depicts an upper-level ridge building into our region early next week.

Winter-weary Winnipeggers can take solace in the fact that an end to the never-ending winter is in sight. There is increasing confidence that a large upper-level ridge will build into the Central U.S. and Southern Prairies early next week and finally bring some seasonal to slightly above seasonal temperatures to the region. First, though, we’ll have to make it through the rest of the week.

A Cold End to the Week

Cold temperatures will continue to persist through the remainder of the week with well below seasonal highs and lows expected. These cold temperatures are being caused by a large stationary trough of cold air over Hudson Bay that has locked the eastern Prairies into a northwesterly flow that has allowed cold Arctic air to spill southwards, dashing the warm-weather hopes of battered and beleaguered Manitobans.

Wednesday
-2°C / -17°C
A few clouds.

Thursday
0°C / -10°C
Partly cloudy. Slight chance of flurries.

Friday
5°C / 1°C
Late day cloudiness; warming up.

Tonight will be the coldest night for the remainder of the week in the Red River Valley thanks to another push of cold air on the back side of a low pressure system passing to our south. There will be a strong chance of another swath of record low temperatures broken – similar to Monday night – as overnight lows dip some 15-20°C below normal.

Thursday brings a similar high to today, around -2°C, however temperatures just off the ground will be a little bit cooler. This combination will result in stronger low-level instability and we could potentially see a few light flurries develop through the Red River Vally similar to what was seen on Monday afternoon. Overall the risk is very slight, though. Temperatures will drop to a more mild -10°C Thursday night as warmer air begins pushing eastwards.

Friday will be the warmest day so far this week. Temperatures look to climb above the freezing mark towards +4 or +5°C with only a bit of cloudiness to contend with. Winds will be a little breezy out of the southeast to around 20-30km/h, but overall it will be quite a pleasant day with plenty of sunshine. Some cloud will begin streaming in late in the day ahead of the next system pushing towards the region. The cloudier skies will help keep our overnight low fairly warm, with a chance we won’t even drop below 0°C. We may have to contend with some unpleasant weather through the overnight hours, though…

Big Shift on the Weekend

Precipitation amounts forecast on Friday night by the GDPS.
Precipitation amounts forecast on Friday night by the GDPS.

Models are all hinting towards some precipitation on Friday night into Saturday morning as a low pressure system lifts northeastwards through the Prairies. It’s still far too early to speak towards the system in much detail at all, other than saying the bulk of it looks to happen during the overnight period. Some models, such as the pictured output from the GDPS[1] really wind the system up and produce significant quantities of rain or snow while others lift the system much further north with little precipitation development. We’ll have more details on precipitation type and how much of what to expect later on in the week.

The bigger news is that this system marks a significant pattern shift as the upper level ridge we mentioned at the beginning of the article begins developing and pushing eastwards. As it does so, warmer air looks set to flood the Prairies, quickly launching our temperatures back towards seasonal to above-seasonal. Sunday will have temperatures close to normal[2] and we might see it get as warm as the low-to-mid teens on Monday, if we can manage to work past our snow cover.

Multiple days of near-to-just-above freezing temperatures coupled with the strong April sun should do quick work to melt the remaining snowpack across much of the Red River Valley. Melt will be minimal until the weekend, but even one or two days with temperatures in the 5-10°C range will do quick work with much of the remaining snow. Once we can eliminate the snow pack, extremely abnormal cold will be much harder to come by and it will be much easier to see seasonal temperatures.

  1. Global Deterministic Prediction System – Canada’s long-term forecast model.  ↩
  2. Seasonal temperatures for Winnipeg currently are around 11°C for a daytime high and 0°C for an overnight low.  ↩

Snow On The Way

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A low pressure system pushing eastwards across the Southern Prairies and the Northern Plains will spread snow and rain into Southern Manitoba today.  Amounts are not expected to be significant in the Red River Valley – especially in areas near the international border – but it will be one of the first “snowy” days of the year.


Total forecast precipitation (liquid-eqivalent) from Friday morning to Saturday morning.
Total forecast precipitation (liquid-eqivalent) from Friday morning to Saturday morning.

Today

Friday

2°C / -2°C
Cloudy with light snow beginning this afternoon.

Precipitation will begin pushing into the southern Red River Valley later this morning and into the northern half of the valley, including Winnipeg, this afternoon as the low pressure system begins working it’s way into the region.  Precipitation will fall mainly as snow through the northern half of the Red River Valley while in the southern half of the valley some light rain will be more likely. Naturally there will be a transition zone somewhere in the central RRV where amounts will not be too significant with only a cm or two falling here in Winnipeg at most.  Further south, up to a 3–4mm of rain could fall.  Light snow will taper off in the evening leaving behind a chance of some flurry activity through the overnight hours.  We’ll see a low dipping just below 0°C.

The Weekend

Saturday

2°C / -6°C
Mainly cloudy; chance of flurries.

Saturday will be a mainly cloudy day with a slight chance of flurries throughout as cool, somewhat unstable air continues to push south behind the low.  No significant accumulations are expected and we’ll climb to a high of around 2°C.  The winds will be a somewhat gusty 30km/h out of the northwest through the day.  Through the overnight things will be mainly cloudy, although a few breaks in the cloud are expected, as we dip to a low of about –6°C.

Sunday

-2°C / -13°C
Mixed skies; slight chance of isolated morning flurries.

On Sunday skies will improve while temperatures do not.  We’ll see a mixed sky with a high of only –1 or –2°C.  A few light flurries may be possible in Winnipeg in the morning as we may be just grazed by a weak system passing through the Interlake.  Cooler air will continue to filter southwards through the day and drop us to a very chilly –12 or –13°C on Sunday night under mainly clear skies.

After that, a fairly sunny, cool and quiet week is ahead next week as a large arctic ridge dominates the weather over the Eastern Prairies.

Seasonal Weather Ahead; Unsettled Pattern Developing

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We’ll see a reprieve from the cold snap across Southern Manitoba over the next few days as temperatures return to more seasonal values, however with that comes the development of a more unsettled pattern that will bring multiple chances for rain or snow to the region over the next week.

Wednesday

6°C / -1°C
Warming up with a few clouds.
Thursday

7°C / -1°C
Mostly cloudy.
Friday

6°C / -2°C
Light snow changing to rain likely.

We’ll see a comparatively beautiful day today with temperatures climbing up to around 6°C under a mix of sun and cloud. The warmer temperatures are thanks to a breakdown of the high-amplitude jet stream that has been in place over North America over the past week and a bit. As the pattern flattens out, it will allow warmer air to push back into Southern Manitoba, which in turn allows us to enjoy non-freezing temperatures. The milder temperatures will stay with us through the remainder of the week.

Thursday (Halloween!) will bring cloudier weather as a weak front aloft begins moving into the area. Temperatures will climb up to around 7°C by the afternoon, making it the warmest day we’ll see this week. Cloudy skies will persist through the night as we drop to around –1°C. Things look to stay nice and dry for the trick or treaters!

Precipitation accumulation expected through the day on Friday, courtesy the NAM.
Precipitation accumulation expected through the day on Friday, courtesy the NAM.

Friday has a good chance of bringing us some light snow or rain. There’s good agreement that a disturbance will slide down from the northwest on Thursday night, pushing into the Red River Valley through the morning hours on Friday. Precipitation may begin as light snow, but should switch over to rain by midday at the latest. No significant amounts are expected; models are only producing a 2–5 mm water-equivalent of precipitation, so it will be relatively light activity. The precipitation looks to move in fairly early in the morning and will last through much of the day before tapering off around supper time or shortly thereafter. We’ll see a high of around 4 or 5°C and an overnight low of around –2°C.

The Weekend Ahead

Cloudy skies will persist through much of the weekend as a more unsettled pattern develops. Daytime highs look to stick around the low single-digits and overnight lows dropping to a couple degrees below zero. The next chance for precipitation looks to push in on Sunday night through Monday as a system pushes through the region bringing snow to the Interlake and possibly areas further south as well. More on that later in the week.

Late-Season Thunderstorm Risk Kicks off Dreary Weekend

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A powerful low-pressure system pushing northwards out of the Dakotas that will bring copious amounts of rainfall to SE Saskatchewan and Western Manitoba will also bring a risk for thunderstorms, perhaps even an isolated severe thunderstorm, this evening in advance of an occluding cold front. This will mark the start of a somewhat dreary weekend for the Red River Valley that will be marked most notably by a wet & windy Saturday and a very cool, albeit sunny, Sunday.

Thunderstorms Possible Today

Friday

19°C / 12°C
Mainly cloudy. Chance of showers with the risk of a thunderstorm late in the day.

We’ll see a mainly cloudy day today with relatively nice temperatures as we sit in the warm sector of the low pressure system pushing into the province. Despite the cloudy weather, we should see temperatures climb to around 19–20°C for a high with south-easterly winds to around 30km/h.

We may see a shower early this morning as the warm front pushes through and brings us into the warmer air, although a majority of the activity will be off to our west. If anything manages to push into Winnipeg, it will be relatively short-lived. After that we’ll see no chance of precipitation until later in the afternoon or the evening as a cold front begins pushing into the Red River Valley from the south.[1]

Event outlook for Friday, October 11th.

Event outlook for Friday, October 11, 2013.

While we sit under cloudy skies, this would be a good time to note that the weather to our west will be decidedly different. Rain will push in early this morning and spread NNE through the day, hitting areas west of the Red River Valley and Lake Manitoba the hardest. In total, anywhere from 35–75mm of rain is expected, with the lesser amounts closer to the Red River Valley and the higher amounts running along the Saskatchewan border then towards Lake Winnipegosis with enhanced precipitation near the Riding Mountains as upslope enhancement in the north-easterly winds amplifies the amount of rain. Environment Canada has rainfall warnings out for many regions in Western Manitoba, and you can check here to see if your region is covered by one and find additional details.

As the cold front approaches the Red River Valley this evening we’ll see considerable destabilization of the mid-levels coupled with an extremely strong 60–70kt 500mb jet beginning to poke it’s nose north of the border. The Red River Valley will lie in a fairly diffluent area aloft with strong convergence along the cold front as it pushes northwards. Limited surface moisture will constrain SBCAPE values to only a mere 400–500J/kg, but the extremely strong dynamics, in particular the strong directional and speed shear, may help promote the growth of strong-to-severe thunderstorms along/just ahead of the cold front.

This all is highly dependant on either enough destabilization occurring or enough convergence occurring along the cold front. At this point, I think that the southern Red River Valley will see the strongest storms with a lesser risk of strong storms further north here in Winnipeg. By the time the front reaches us, it seems like it will be a band showers and/or thunderstorms with less organization than when things initiate in the Dakotas. If any of the storms do become severe, the main threats will be large hail and strong winds. There will be a very small risk of a few weak tornadoes with these storms, but I believe that will be most likely in North Dakota with the odds diminishing fairly rapidly as you push northwards through the Red River Valley.

The showers/thunderstorms will push through overnight as we drop to a low of around 11 or 12°C.

Wet & Windy Saturday

Saturday

↘ 6°C / 2°C
Cloudy with showers. Windy. Temperature dropping through the day.

Saturday in Winnipeg will be marked by wet and windy weather as we move onto the back-side of the Colorado low and see some wrap-around rain and gusty northwesterly winds move in.

The rain will likely be somewhat showery in nature – in that we won’t see solid rain all day long – and there’s some uncertainty on how much we’ll see exactly, but around 5mm seems like a relatively safe bet at this point. If the system is a little faster than forecast we could end up with almost nothing as the rain would fall further north, and if it’s slower than forecast we could see closer to 10mm as we end up under the wrap-around rain for even longer.

The wind will be the main weather story though. Here in Winnipeg we’ll see winds 30–40km/h out of the northwest with gusts up to 60km/h, but it will be a significantly different story for those on the lakes. Winds over the lakes will increase to nearly 50–60km/h on Saturday with gusts as high as 90km/h, which will produce fairly sizeable waves. If you have a home or cottage on the southern or eastern shores of the lakes, you’ll want to make sure you make any preparations you might have to and prepare for some strong wave action and howling winds for Saturday and Saturday night.

With those strong winds will come falling temperatures; here in Winnipeg we’ll likely see temperatures fall to around 5 or 6°C by the end of the day as colder air pushes in on the back-side of the low. Skies will clear and winds will lighten overnight as we drop to around 2°C for our overnight low.

Sunny but Cool Sunday

Sunday

9°C / -2°C
Sunny. Cool.

Sunday will see the return of the sun, but the price we’ll pay is significantly cooler weather than we’ve been having over the past week. Daytime highs on Sunday will top out at only 9 or 10°C and it will be a slow climb to get there. Temperatures will likely drop well below 0°C on Sunday night with a hard frost likely as temperatures dip to around –2°C.

This will also mark the transition into a cooler pattern. Daytime highs will remain around 10°C through much of the week.

  1. It sounds odd, but this system is essentially sideways with the warm front and cold front both moving from south to north.  ↩