Today is off to a cold start after a cold front passed through the Red River Valley yesterday morning, ushering in winds up to 70km/h and some mixed-phased showers as the cooler air mass moved into the region. The cool-down will be short-lived, fortunately, as seasonal to above-seasonal temperatures will return for today & through the weekend.
Today and tomorrow’s dominant weather feature will be a ridge of high pressure that will move through the region over the coming two days. With it in place, daytime highs will be cool at a seasonal or slightly below-seasonal 9–10°C. Winds will be light, and both tonight and tomorrow night will see overnight lows dipping below the freezing mark to around –2°C.
The GDPS surface wind forecast for midday Sunday shows a core of stronger winds as a result of the outflow from the ridge of high pressure to the east.
Sunday will see a sunny start to the day, but a bit of cloud push in for the evening and overnight hours. The biggest weather issue of the day will be strong southerly winds that develop as surface winds accelerate out of the ridge of high pressure to our east and are aided by the strong temperature gradient as warmer air moves in aloft.[1] As such, winds will increase–likely midday–to around 40–50km/h out of the south with some gustiness on top of it. It won’t be severe-level winds, but it will certainly be a windy fall day. Temperatures will be slightly warmer at around 14°C, kept lower than the air moving in over us would suggest by the cool outflow winds at the surface.
The winds will taper off in the evening and temperatures will head to around 6°C for an overnight low under partly cloudy skies.
The Week Ahead
Next week is looking fairly unremarkable for the most part. There appears to be a slight chance of some rain mid-week, and other than that, it’s nothing but sunny to partly cloudy skies and seasonal to slightly above-seasonal temperatures. Lovely weather for the second half of October.
Additionally, multiple models indicate the likelihood of enhanced anticyclonic curvature to the pressure gradient over the Red River Valley which, if true, will act to enhance the wind speeds. ↩
The warmer-than-seasonal warmth in place over Southern Manitoba will last just one more day before a cooler air mass works its way into the region behind a cold front that will push through on Thursday.
Today will bring seasonal weather to Winnipeg & the Red River Valley, albeit with a bit of a breezy wind. Under mainly sunny skies, the temperature will climb to around 15°C, which is nearly 5°C above the seasonal average high of 11°C for this time of year. Winds will pick up through the day and be fairly windy out of the northwest with sustained winds climbing to 30–40km/h with gusts to around 50km/h.
Temperatures will dip to around 4–5°C tonight with skies becoming partly cloudy before morning.
Thursday will be quite an unpleasant day that will see a cold frontal passage that will bring in blustery winds and falling temperatures. The day will start off with partly cloudy skies and temperatures climbing to around 10–11°C by midday. Winds will be windy out of the northwest at around 30km/h with some gustiness on top of that. As the cold front passes through in the afternoon, we’ll see mixed-to-cloudy skies develop with a very slight chance of some showers along the front as it passes through. No significant accumulations are expected. Winds will remain blustery with winds remaining at 30–40km/h with gusts as high as 60km/h.
Looking at the forecast 850mb temperatures, the passage of the cold front on Thursday is quite obvious.
As the front passes through, temperatures will drop to around 6°C in the Red River Valley. They’ll continue to drop as winds taper off and skies clear, heading towards an overnight low near –2°C.
Friday will be a pleasant, but cool, day. Winds won’t be much of an issue and temperatures will climb to around 7°C under mainly sunny skies. The low on Friday night will once again be around –2°C under clear skies.
Unremarkable Weekend Ahead
Looking ahead to the weekend, there doesn’t appear to be much to say about it. Through the weekend temperatures will climb back towards seasonal values with a bit of wind on Sunday. No significant precipitation is in store for the region.
Next week looks to have a bit of variability to daytime highs and a couple chances for rain as a slightly more unsettled pattern develops.
It will be a very windy Thanksgiving as a strong low pressure system ushers in potentially damaging winds. By the time you’re reading this your loose objects will probably already be in your neighbour’s yard!
Monday
Today will not be the most pleasant Thanksgiving, as rain and strong winds wreck havoc outdoors. A strong low pressure system and corresponding pressure gradient will generate high to extremely high winds over southern Manitoba on Monday. The highest winds are expected Monday morning, when sustained speeds of 60-80km/h, and gusts to 100km/h or more, are expected. The period of extreme gusts likely won’t last more than a few hours, but during that time it will certainly do some damage, not to mention the fact that you’ll have a lot more leaves to rake!
A strong pressure gradient (shown above as tightly packed black lines called isobars) will bring very windy conditions to southern Manitoba on Monday
Today will also be rather soggy, as moderate rainfall occurs in association with this low pressure system. Today’s rainfall amounts will likely be around 5-15mm in the Red River Valley. You’ll have to wait until at least Tuesday for all those wet leaves to dry out!
Tuesday
Tuesday will be much calmer than Monday. Temperatures will climb into the mid teens under mainly sunny skies. Winds will remain breezy from the west, but they will feel light compared to Monday!
Wednesday
Wednesday will feature much the same weather as Tuesday. Temperatures will be in the low to mid teens under mainly sunny skies. Winds will be breezy from the north-west, but once again it will feel like nothing compared to Monday.
Long Range
Long range models continue to show a strong signal for warmer than normal weather through the end of October. Hopefully this will continue to be the trend as we move into winter due to the effects of El Nino.
After a pleasant, summer-like start to the week, the weather is set to turn more unsettled as a disturbance rolls through Southern Manitoba tonight. Fortunately, the agitated weather will only bring temperatures back towards seasonal values before we see the heat move back in through the weekend, setting Winnipeg & the Red River Valley up for a hot start to next week.
Today will be a fairly pleasant day in the Red River Valley. There’s a slight chance of some shower activity early this morning as a trough passes through the region, but afterwards we’ll see the cloud begin to clear out through the remainder of the morning leading to just a few clouds this afternoon through the region. Daytime highs will climb to around 21°C–but with significantly less humidity than yesterday–with winds initially out of the northwest at 20–30km/h tapering off through the morning.
The more significant weather will roll into the province this evening as a low pressure system lifts northeastwards out of North Dakota and pushes across southern Manitoba. An area of showers, likely with thunderstorms embedded, will develop across southern Saskatchewan and northeastern Montana and spread eastwards through the night, pushing into southwestern Manitoba early in the evening and then spreading into the Red River Valley and Interlake through the remainder of the night. As is typical with systems that involve convection through the night-time hours, model solutions are a little scatter-shot as to what the outcome will be. Overall, it appears that the bulk of the precipitation will pass to the north of Winnipeg, however some models are coming up with solutions that bring significantly more precipitation into the region.
This simulated RADAR image from the NAM forecast valid on Thursday morning shows a band of heavy, convectively-driven rain over Winnipeg & the Red River Valley.
The NAM-based solutions all tend to produce fairly strong, convectively-driven rainfall over the Red River Valley late tonight into Thursday morning. With PWAT[1] values near 35mm, the rainfall could be quite intense, however strong winds aloft should be moving anything that develops along at a fairly decent clip, meaning overall rainfall accumulations shouldn’t be excessive with around 10–20mm in any heavier precipitation that develops. Outside of thunderstorms/heavy rain cells, the more general rainfall amounts from this system should be around 2–5mm or so in regions south of the Trans-Canada Highway, and closer to the 5–10mm range for areas northwards.
This forecast sounding for Winnipeg from the NAM for Thursday morning indicates heavy rain or thunderstorms may be possible.
Temperatures will dip to around 14°C tonight. Thursday will see a high near 15°C with winds increasing out of the northwest to 40 gusting 60km/h in the afternoon. A chance for showers will persist through the remainder of Thursday under mainly cloudy skies.
Friday will bring calmer weather to the region with mainly sunny skies and a high near 19°C. Winds shouldn’t be too bad at around 15–20km/h.
Warmer Weather Returns on the Weekend
Our cool-down to seasonal temperatures will be short-lived, however, as warmer weather is set to build back into Manitoba through the weekend. The upper-level trough that will bring us our unsettled weather will push off to the east and a zonal flow is forecast to quickly develop across the Prairies, pushing in warmer air aloft that will begin to bump our temperatures back upwards. Saturday looks to have a high around 20°C, while Sunday will see the mercury climb towards the mid–20’s.
This forecast of 850mb temperatures from the GDPS shows temperatures pushing into the upper teens on Monday morning.
The GPDS is forecasting 850mb temperatures pushing into the upper teens through Monday, which would equate to temperatures in the upper 20’s as long as we see the sunshine. Afterwards, it looks like we may see a couple more disturbances roll through in the remainder of the week, bringing temperatures back towards seasonal.
While we will have occasional cool-downs, long-range forecasts continue to forecast above-normal temperatures through the remainder of September.
