Cool and Rainy Tuesday Brings an End to Late Fall Warmth

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A cold front will bring cool and rainy conditions to southern Manitoba today as it ushers near-seasonal temperatures back into the region.

ECMWF 24hr. Precipitation Accumulation Forecast valid 12Z Wednesday October 23, 2024
Much of southern Manitoba will receive rain from a cold front crossing the region today.

The weather today will be a rather marked change from yesterday. Instead of beautiful sunny conditions with warm weather, a cold front will bring clouds and rain to Winnipeg along with much cooler conditions.

Rain will begin mid-morning today and last into the early afternoon. Winnipeg will likely end up with 5–10 mm of rain before it tapers off, but there’s a small chance that it might drift just a bit north of the city, lowering our amounts. Other than that, moderate northwest winds of 30–40 km/h will spread into the region this morning and persist through the day. These cool winds will send temperatures falling into the afternoon, dipping down to 3 or 4 °C by the end of the work day.

Those northwest winds will continue into the evening. As temperatures fall, lake-effect precipitation is possible off of Lake Winnipeg and Lake Manitoba. As temperatures continue to drop overnight, it could result in a few snow flurries moving through the Red River Valley. The best chance for snow, though, will be in the lee of Lake Winnipeg where bands of lake-effect snow will likely last through the night.

Temperatures will drop to around -1 °C overnight in Winnipeg with winds dying off.

With a ridge of high pressure moving through the region, Wednesday will bring mainly sunny skies as the lake-effect cloud clears out. Temperatures will climb to a high near 10 °C with southerly winds picking back up to around 30 km/h.

A weak frontal wave moving through the region on Thursday night with bring cloudy skies back to the area. This will help keep temperatures a bit warmer; Winnipeg should see an overnight low in the low single digits rather than dipping below freezing. Those southerly winds will also drop off overnight.

Expect clearing skies on Thursday with light northwest winds picking up. Temperatures should again climb to a high around 10 °C. Heading through the night temperatures will dip down to around freezing under clear skies.

Long Range Outlook

A broad area of high pressure will build into the Prairies from the west through the weekend as a weak upper ridge builds in the west. This will bring sunny to partly cloudy skies to southern Manitoba with seasonably mild highs in the 10 to 15 °C range. Overnight lows will range from sub-freezing back to the mid-single digits.

Looking even further ahead, early indications that Halloween this year will be much nicer than last year’s. Rather than temperatures near -9 °C with 20–30 km/h winds making it feel closer to -20, early signs point to an evening with temperatures around +1 °C and winds near 20 km/h. This is obviously subject to change since it’s a ways away yet, but there are few large-scale patterns that suggest we’ll see a drastic snow/cool-down before Halloween this year. Hopefully that forecast can hold!

Today’s seasonal daytime high in Winnipeg is 8 °C while the seasonal overnight low is -2 °C.

Seasonably Warm Temperatures Returning Later This Week

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The Winnipeg area will see one more cool fall day before warmer weather begins to push back into the region again.

RDPS 2m Temperature Forecast valid 21Z Thursday October 17, 2024
An upper ridge will spread warmer temperatures back into southern Manitoba this week.

A stubborn high pressure system will keep cooler temperatures in place across southern Manitoba today. After a frosty start to the day, winds will pick up out of the south into the 20 to 30 km/h range today with daytime highs around the 10 °C mark this afternoon. Things will begin to change tonight, though, as an upper low to our east begins to move off and an upper ridge starts to build across the Prairies. With warmer temperatures beginning to spread into the southern Prairies, temperatures will only dip into the mid-single digits tonight. Winds will persist out of the south around 20 km/h.

The Winnipeg area will have mainly sunny skies for much of the rest of the week. As the upper ridge builds in, daytime highs will climb close to 20 °C with southeasterly winds gradually strengthening up to 40 gusting 60 km/h for Thursday. Overnight lows will climb towards the upper single digits.

Long Range Outlook

A low pressure system will push through the province on Friday, bringing a chance of showers that will be highest east of Winnipeg and cooler temperatures. Daytime highs will dip back into the low teens for Friday and Saturday, the former bringing cloudier skies to the area while the latter is much sunnier. Another push of warmer weather is possible for Sunday and/or Monday, then the upper pattern begins to change.

Cooler temperatures and a chance of rain is possible in the first half of next week, returning the region back to seasonal temperatures.

Today’s seasonal daytime high in Winnipeg is 10 °C while the seasonal overnight low is 0 °C.

Unsettled and Windy Weekend Gives Way to Warmer Weather

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After a cold start to Friday morning, temperatures in southern Manitoba will jump back to seasonably warm values, though the weekend will end with blustery conditions and cooler temperatures after rain showers move through on Saturday.

RDPS 2m Temperature Forecast valid 21Z Friday October 4, 2024
Despite a cold start to the day, a low pressure system over the western Prairies will push warmer temperatures back into southern Manitoba today.

Despite a frosty start to the day for many places in southern Manitoba, temperatures will quickly bounce back to above-seasonal values today. A low pressure system developing over the western Prairies will begin spreading warmer air eastwards into Manitoba. Southerly winds will pick up into the 30 gusting 50 km/h range today with sunny skies and an afternoon high in the upper teens. Those winds will continue right through the night as the low tracks through Saskatchewan, keeping temperatures mild with lows in the low teens.

Despite being relatively warm, Saturday will be a bit of an unpleasant day. The main driver for the weather will be a low pressure system crossing through the Interlake, with an energetic cold front that sweeps through later in the day. The day will start with increasing cloudiness as moderate southerly winds continue across the region. Temperatures will climb back into the upper teens as rain spreads into western Manitoba. There’s a small chance of some midday showers in Winnipeg, but the better chance for rain will develop later in the afternoon as a cold front sweeps through. Winds will shift from southerly to westerly and strengthen to 50 gusting 70 km/h as rain wraps into the region.

RDPS 10m Wind Forecast valid 21Z Saturday October 5, 2024
Strong westerly winds will blast through southern Manitoba on Saturday afternoon behind a cold front that sweeps through the region.

The rain will taper off overnight as temperatures head to a low in the mid-single digits. The winds will continue through the night, shifting to the northwest and gradually easing into the 30–40 km/h range by Sunday morning. By the end of the night, the main area of rain will be well to the east of the Red River Valley, but a couple bands of lake-effect showers may linger in the lee of the lakes into Sunday morning.

Sunday will be a cooler day with northwest winds of 30 gusting 50 km/h and a high in the low teens. Skies should clear for the afternoon bringing sunshine back to the region. Temperatures will dip close to freezing on Sunday night with clear skies and easing winds.

Long Range Outlook

Next week will bring warmer conditions back to southern Manitoba as the upper low over western Hudson Bay retreats northwards and upper ridging is able to redevelop over the Prairies. Much of the week will bring daytime highs in the upper teens or low 20s with overnight lows near the 10 °C mark. The week should also be dry with no significant precipitation in the forecast.

Today’s seasonal daytime high in Winnipeg is 14 °C while the seasonal overnight low is +2 °C.

Cooler Weather Settles In

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Just like that, fall weather has arrived in the Red River Valley with temperatures over 10 °C cooler than seen on the weekend.

RDPS 2m Temperature Forecast valid 12Z Friday October 4, 2024
The first freeze of the season could arrive by Friday morning.

Today marks the start of fall weather in southern Manitoba, courtesy a much cooler air mass brought in by yesterday’s cold front and very gusty winds. This change reflects a major shift in the large-scale weather pattern; the upper ridge over the Prairies has collapsed, and a quasi-stationary upper low is becoming established over the western coast of Hudson Bay. This change will result in a more west to northwest flow aloft over Manitoba, ushering in seasonal conditions for this time of year.

The result will be a week filled with daytime highs in the mid-teens and overnight lows dropping into the 0 to 5 °C range with a risk that we may see the first frosts of the season.

For a bit more detail, today will bring cloudier conditions with lighter winds than yesterday. A high pressure system passing to the south will spread southwest winds of 20 to 30 km/h into the region as temperatures climb into the mid-teens. A weak disturbance slumping southeastwards across the Prairies will keep conditions cloudy tonight; this will ensure that the overnight low stays mild (for this week) at around 10 °C.

Another cold front will sweep through on Wednesday, bringing gusty northwesterlies and cooler temperatures back to the region. With the cooler temperatures moving in and the prolonged northwesterly flow, some lake-effect showers may develop. Winds will likely keep these north of Winnipeg, but worth noting the possibility for areas in the northern Red River Valley.

A ridge of high pressure will push into the province behind the front, bringing clearing skies and sending overnight lows to near-freezing for the rest of the work week. A widespread freeze could be possible over southern Manitoba overnight Thursday into Friday morning.

Long Range Outlook

A moderating trend will develop over the weekend across southern Manitoba with daytime highs heading back towards the upper teens. Overnight lows will also follow the warming trend, likely heading back into the 5–10 °C range through the weekend.

The region will see variable cloudiness, but little to no precipitation is expected.

Today’s seasonal daytime high in Winnipeg is 15 °C while the seasonal overnight low is +3 °C.