Tag: Benign Weather

A Graceful Return to Form

Brad Leave a comment

A quiet week is ahead weather-wise as an upper-level ridge over the region dominates the weather for the remainder of the week. No precipitation is anticipated for the rest of the work week while temperatures slowly climb to above-normal values.

Wednesday
19°C / 4°C
Sunny

Thursday
20°C / 9°C
Sunny

Friday
24°C / 12°C
Partly cloudy

The next few days will be mainly sunny with just a few more clouds working in on Friday. No rain is expected. Daytime highs will start near 19°C today and climb to 24°C by Friday. Overnight lows will remain chilly tonight with lows just near 4°C, but then push towards above-normal of 9–12°C.

Long-Range Outlook

Overall, the weekend is looking quite nice. Temperatures will be in the low-to-mid 20’s with overnight lows in the upper single digits. Some showers or thunderstorms will be possible along a weak cold front draped across the province – likely north of Winnipeg through the Interlake – but at this point anywhere along or south of the Trans-Canada Highway looks fairly dry.

Heading into the start of next week, though, some models are hinting at the possibility of another – albeit weaker – Colorado Low impacting southern Manitoba. The GDPS[1] is forecasting a very rainy Monday with elevated convecting drenching Southern Manitoba with over an inch of rain. The NAEFS[2] takes a more middle ground approach and pushes a weaker system a bit further east, with our region being grazed and getting something in the 5–10mm range. The GFS[3] produces the weakest solution with an even weaker low pushed even further east with little-to-no impact on Southern Manitoba.

It’s too early to say too much about that system other than we’ll be sure to keep an eye on it as we head into the weekend. There are numerous factors which make it look not nearly as bad as the storm we had over the long weekend, so even though it may be the 3rd Colorado Low in 2 weeks, it may not be a significant issue for the region.

  1. Global Deterministic Prediction System – The Canadian long-range forecast model.  ↩
  2. North American Ensemble Forecast System  ↩
  3. Global Forecast System – The United States long-term forecast model.  ↩

Seasonal Weather Returns

Scott Leave a comment

We’ll see seasonal weather return this week after a chilly weekend. Temperatures will climb into the mid to upper teens by midweek.

Monday will remain cool as we stay in a northerly flow behind a departing low pressure system
Monday will remain cool as we stay in a northerly flow behind a departing low pressure system

Monday

Today will remain below-seasonal, but temperatures will warm somewhat over the weekend’s values. High temperatures should climb into the mid teens in the Winnipeg and Brandon areas. However, areas closer to the US border will remain under thicker cloud cover and will struggle to reach double-digits. The wind will be brisk at 30 km/h from the north.

Tuesday

Tuesday will be a nice day, as temperatures climb into the mid/upper teens under mainly sunny skies. Winds will be light as high pressure settles in over the region.

Wednesday

Wednesday will be similar to Tuesday, but there will likely be a bit more cloud cover as a system passes to our south. Temperatures will be in the upper teens under a mix of sun and cloud and light winds.

Long Range

It appears that temperatures will continue to warm through the end of the week. However, long range models hint at another weather system passing to our south next weekend, which may once again draw down some cooler air from the north. In general, models suggest that our weather will hover near normal values for the next couple weeks.

Pleasant Weather Returns

Brad Leave a comment

Winnipeg will see a reprieve from the below-normal temperatures this weekend as the ridge of high pressure that’s brought the cooler weather shuffles off to the . In its place, a southerly flow will return warmer air to the region with temperatures climbing back to near the seasonal mark.

Over the next few days, no significant weather is expected in Winnipeg or the Red River Valley. Today will start off with some lingering cloud that will clear out through the day. Temperatures will climb to a high of around 13°C with a light southeasterly wind. Expect a low near 0°C under clear skies tonight.

Saturday will bring mainly sunny skies, light southeasterly winds and a high near 16°C. Saturday night will see a low near +2°C with a bit of cloud cover.

RDPS forecast Temperature for Friday Afternoon
The RPDS weather model is forecasting highs climbing above 15°C in Winnipeg on Saturday afternoon.

Sunday’s high will also be near 16°C, however with a few more clouds than Saturday. The temperature will drop to 7°C or so on Sunday night with increasing cloudiness overnight.

Cold Trough over Manitoba & Ontario

Cool And Sunny, Becoming Unsettled

Brad Leave a comment

Temperatures will be stuck well below-normal for late April through the remainder of the week as a stationary long-wave trough locks Manitoba into a pool of cold Arctic air. To make lemonade of it, skies will at least be quite sunny and winds light making things comparatively pleasant to how the week started.

The next two days will be very similar and very quiet weather-wise. Both today and tomorrow will bring mainly sunny skies, light winds and high temperatures near +5°C. Tonight will be another brisk evening with a low near –7°C while tomorrow night will bring slightly warmer temperatures with a low near –3°C. All of these temperatures are well below normal, though. Daytime highs will be about 8°C below normal[1], a far cry from the 10–15°C above normal we saw last week, and overnight lows will be 4–8°C below normal.[2]

RDPS 500mb Winds valid 12Z April 22th, 2015
The 500mb wind pattern Wednesday morning shows a highly amplified ridge over Alberta & the Western Arctic diving into a very deep trough over Manitoba & Ontario.

By Friday, the stagnant ridge-trough pattern that has set up over North America will begin to break down. Throughout the day, Southern Manitoba will increasingly come under the influence of a trough of low pressure stretching from a low tracking through South Dakota to a low lifting through Alberta. Out ahead of the South Dakota low, it’s likely that some flurries will develop along the US border in southwestern Manitoba and spread east along border regions through the day. At this point, it looks highly probable that any flurry activity will remain south of Winnipeg. That being said, Winnipeg will see increasing cloud cover and a fairly cool high of just 4°C. Clouds should clear out Friday night with a low near –4°C.

Long Range: A Shift To a Wetter Pattern?

The long range forecast is a little tricky at this point, however we can break it down into two categories of uncertainty: timing and weather pattern. The second there’s a fair amount of confidence in; the timing, however, is a lot more difficult. The current long-wave weather pattern over North America is known as a blocking pattern. These weather patterns are very stable configurations of the jet stream and other upper-level features that result in stagnant weather patterns; these can be stretches of hot, dry weather in the summer[3] or long periods of well below-seasonal temperatures.[4]

Weather models are quite good at forecast what sort of weather pattern may develop when the blocking pattern breaks down, however they are generally quite poor at the actual timing of the break-down. This is because to shift these very stable features, significant changes in the long-wave pattern have to develop across huge distances, and those changes can be very difficult to forecast accurately.

That being said, we should start to see our current weather pattern break down this weekend, driven by an approaching low that will drive a wedge into the elongated upper ridge over the west coast as well as the retrogression of an upper-level low[5] from Ontario. As this happens, cool weather will blanket much of the Prairies – although it won’t likely be any cooler than we’re seeing now – and it looks like there will be an increased chance of precipitation through the Southern Prairies, perhaps even multiple low pressure systems coming through.

All to say it’s going to go from cool and dry to cool and, quite likely, unsettled through the coming weekend. Looking even further ahead, it does look like next week we’ll see a return to seasonal temperatures.

  1. Normal daytime highs for late-April in Winnipeg are around 13°C.  ↩
  2. Normal overnight lows for late-April in Winnipeg are around 0°C.  ↩
  3. Under what’s known as an omega block.  ↩
  4. This happens when an area gets stuck underneath a cold trough; this is what’s happening over Manitoba right now.  ↩
  5. A low pressure system “retrogrades” when it’s motion becomes opposite that of the usual motion; in our case, it’s when a low moves from east to west instead of west to east.  ↩