Tag: Rain

Winnipeg Dodged The Weekend Rain, But Another Chance On The Way

Brad Leave a comment

Winnipeg managed to eke out a fairly pleasant Sunday with a cloudy morning giving way to sunny breaks in the afternoon as temperatures climbed up into the low 20’s. Showers that had the potential to impact the city ended up splitting as they entered the Red River Valley; one area headed to the north and across the Interlake while a second area of showers moved through North Dakota. Another chance for rain is on the way, though, with a low pressure system forecast to move through the region on Tuesday.

Attention now turns towards a developing low pressure system in Wyoming that will organize through the day today, strengthen tonight, and then move through the region on Tuesday.

Today will bring increasing cloud cover, particularly through the afternoon, but otherwise will be a pleasant day with a high near 22°C and relatively light winds. Tonight will bring mixed to cloudy skies with a low near 12°C as the low pressure system builds into North Dakota.

Tuesday’s forecast has a lot of room for error, but we’ll take a stab at broad generalities here. The short version: expect cloudy skies with a very good chance of seeing rain and/or thunderstorms beginning mid- to late-morning and tapering off in the late afternoon or early evening. Winds will pick up out of the north to northwest through the day to around 40 km/h as the low pressure centre moves through the Lake of the Woods region. Temperatures will top out near 15 or 16°C and drop to a low near 7°C on Wednesday night.

Some forecasts hint as much as 25-40*mm* of rain in the Red River Valley on Tuesday.

The long version: everything begins on Monday night as an area of thunderstorms develops across western North Dakota on the northern side of the surface low. These storms should expand in coverage through the night, spreading east-northeastwards along a warm front draped southwest-to-northeast across the state. This area of convective rainfall will spread into southwestern Manitoba late Monday night into Tuesday morning, then spread eastwards into the Red River Valley. At this point, there may be thunderstorms still embedded in the area of rainfall, but that risk will diminish through the morning. The rain will move eastwards through the day, then taper off in the late afternoon. With the convective nature of the rainfall, accumulations may end up being highly variable, but overall it seems like 10-20mm is quite likely, with higher amounts possible on a more localized level.

Now this is all fairly prone to error; primarily, a strong low-level jet is expected to develop across South Dakota along the eastern quadrant of the low, which may end up being a foci for thunderstorm development and rob this system of moisture that would have travelled further northwest or pull this system eastwards slightly faster, possibly causing the rain to pass to the southeast of the Red River Valley.

On Wednesday, the winds will remain gusty out of the north with temperatures climbing to a high, optimistically, near 11°C. Skies will start off fairly cloudy, but gradually break up a bit for the afternoon. Significant clearing will likely hold off until the overnight period as temperatures drop to a low near 2°C.

The remainder of the week looks dry with highs slightly below-seasonal and a fair amount of sunshine.

Winnipeg’s seasonal daytime high is currently 20°C while the seasonal overnight low is 5°C.

Winter Storm Brings Snowy Monday to Southern Manitoba

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A developing winter storm will bring moderate-to-heavy snowfall to southern Manitoba beginning early Monday morning. The storm system will primarily affect the Red River Valley and areas east, bringing a fair amount of wet, heavy snow to the region.

Monday’s main story will the snow that moves across the region, supported by a developing low pressure system lifting northeastwards through the Dakotas. The area of snow will rapidly develop overnight, first across western North Dakota, then expanding quickly northwards.

The snow will fall throughout much of the day in the Red River Valley, and into the evening over southeastern portions of the province. It will fall mainly as snow, except for the far southeastern portion of the province—particularly in the Sprague area—where it may become mixed with ice pellets or rain as warmer air wraps in just north of the low.

AWM Snowfall Outlook for Monday April 24, 2017

By the time the snow tapers off this evening much of the south-central and southeastern portion of the province will see between 5-10 cm of snow. The Whiteshell region will likely see 10-15 cm of snow.

Potential Forecast Issues: There are a few potential sticky spots for the forecast. The first hinges on temperatures, which are largely expected to be hovering near the freezing mark. If things end up a bit warmer, snowfall totals will be reduced, either due to lower snow-to-liquid ratios and increased melting/compaction of the snow, or via greater mixing of rain. If temperatures end up dropping a bit cooler than expected, snowfall amounts will bump up a bit, but the greatest impact would be in Sprague, which would go from “near 10 cm with mixed precipitation” to “10-20 cm of heavy snow.”

The most likely snowfall amount for Winnipeg is likely in the 7-10 cm range, with a very small chance of creeping up to 11 or 12 cm. While this may seem like a pretty notable snow, it’s not very significant in the grand scheme of things and doesn’t even register on the top 10 largest daily snowfalls after April 15th:

Top 10 Largest Daily Snowfalls After April 15 (Winnipeg 1872-2016)

RankSnowfall AmountDate
121.1 cmMay 1, 1967
220.8 cmApril 27, 1966
320.3 cmMay 19, 1931
420.0 cmMay 9, 2002
520.0 cmMay 11, 2004
617.3 cmApril 24, 1937
716.5 cmApril 25, 1960
815.2 cmMay 20, 1882
914.0 cmApril 19, 1996
1013.0 cmMay 5, 1938
Snowfall records produced by Rob's Obs.

Winds will pick up out of the northeast early Monday to around 30 km/h and remain at that strength for quite a while, gradually shifting to the north by Monday evening and then persisting through Tuesday until tapering off on Tuesday night. Temperatures will drop to a low near -3°C on Monday night, climb to a cloudy high near +3°C on Tuesday and then drop back to a low near -6°C under mixed skies on Tuesday night.

The cloudy skies and cooler temperatures will slow the snow melt over the region, and as a result the snow will likely stick around longer than Friday’s snowfall did. However, the sun should poke a bit on Wednesday which, when combined with a slightly warmer high near 4°C, should be enough to melt the snow.

We’ll be keeping an eye on new runs of weather models as they roll in later tonight and update this post if there’s a significant shift in the snowfall forecast.

Long Range

Cooler-than-normal temperatures will persist through the remainder of the week with daytime highs of 5-9°C remaining below the seasonal average of 14-15°C.

Winnipeg may see some more rain or snow on Thursday as a large low pressure system lifts into Northern Ontario and may spread precipitation westwards into Manitoba; this seems relatively unlikely, but it’s worth being aware of as an outside possibility.

Things should settle down for the weekend with a return towards seasonal temperatures, however long range models show the potential for another system Sunday night into Monday that could bring more rain and snow into the region.

Winnipeg’s seasonal daytime high is currently 14°C while the seasonal overnight low is 1°C.

One More Day of Warmth Before A Big Cool Down

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Winnipeg and the Red River Valley will see mild temperatures today, but a sharp cold front will sweep through the early Saturday, bringing unsettled conditions and much cooler temperatures.

A southwesterly flow aloft will draw mild air into the Red River Valley today, eventually sending daytime highs into the mid-teens this afternoon. Before that, however, there will likely be fog patches throughout much of Southern Manitoba. Areas that see fog will likely see some cloudier skies through the morning as the fog lifts, but it should subsequently burn off leaving much of the region under sunny skies. Winds will also be light, so all in all it should be a beautiful day.

Change is afoot, though. Cloud will move in overnight as a cold front slumps southwards through the province. It will move through very early on Saturday morning, ushering in northerly winds to around 30 gusting 50 km/h and sending temperatures to a low near +2°C. As the front moves through in the morning, it will support an area of precipitation that will begin as rain, but possibly change over to snow mid-morning.

The GDPS is forecasting a swath of 2-5 mm of precipitation across southern Manitoba on Saturday.

The precipitation will end midday as winds begin to ease and temperatures climb to a high near 6°C. There’s a decent chance that the cloud cover will break up a bit in the afternoon let the sun shine through. The wind will diminish on Saturday evening as the temperature drops to a low near -2°C with some cloud cover beginning to move in.

Sunday will bring mixed skies to the region as Saturday’s disturbance departs and the next one develops in Alberta. A reprieve from precipitation, temperatures will climb to a high near 6 or 7°C with light easterly winds. Cloud coverage will increase in the evening as the next system approaches, bringing with it a chance of showers for Sunday night. Temperatures will drop down to a low near 0°C.

Long Range

The start of next week will bring more unsettled weather as a major storm system tracks near the American border. Uncertainty exists on the track of the low, and with a fairly sharp boundary to its precipitation, that leads to a wide range of potential precipitation amounts.

The GDPS clips Winnipeg with a major system that tracks along the American border early next week.

We’ll have updates closer to the event on what exactly we can expect from this system.

In the wake of that low, Winnipeg and the Red River Valley will see a stretch of calm weather with below-normal temperatures until the end of the week, when another system may impact the region and bring more rain and/or snow to the province.

Winnipeg’s seasonal daytime high is currently 13°C while the seasonal overnight low is 0°C.

Spring Warmth Returns Alongside Showers

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After a brief cool-down that followed a wet end to the weekend, spring-like weather will return as mild temperatures return alongside some unsettled weather.

Temperatures are on their way back to near-seasonal today as daytime highs climb to around 12-15°C across the Red River Valley under fairly sunny skies for much of the day. There will be increasing cloud, particularly through the second half of the afternoon and early evening, spreading into the Red River Valley ahead of a low pressure system moving towards Manitoba. Winds will be pleasantly light out of the southeast. Expect temperatures to drop to a low near 4°C tonight under mostly cloudy skies.

On Thursday, a low pressure system tracking across the province will result in cloudy skies for Winnipeg showers developing through the Red River Valley beginning midday. Rainfall amounts look fairly low at just a couple mm, however higher amounts are possible in any heavier showers that might develop. Temperatures will be a bit cooler than Wednesday with highs near 11°C. Some clearing should work into the region on Thursday night as temperatures dip to a low near +2°C.

Showers are likely across the Red River Valley on Thursday
Showers are likely across the Red River Valley on Thursday

Friday will bring a return to the nice weather with clearing skies and a high near 15°C. A cold front will sweep through the region overnight into early Saturday morning, bringing more cloud into the region alongside some northerly winds. Temperatures will dip to around 3°C.

Long Range

Saturday will be fairly cloudy with a chance of showers through the first half of the day as the cold front clears the region. Temperatures will see a return to below-normal with highs topping out in the mid-single digits. Winnipeg will likely see sub-zero lows once again on Saturday night.

Sunday will bring more cloud back into the region through the day as another disturbance approaches the region. Temperatures will remain cool with highs in the mid- to upper-single digits. More showers are possible, however whether or not Winnipeg will see them depends on the exact track the disturbance takes.

Winnipeg’s seasonal daytime high is currently 12°C while the seasonal overnight low is 0°C.