Category: Forecasts

Unsettled Weather to Start The Week

Brad 3 Comments

A series of low pressure systems will bring two rounds of unsettled weather to the province before calmer weather moves in for the second half of the week.

Today will be a continuation of the humid weather that moved into the region on the weekend with muggy dewpoint values near 18°C persisting as temperatures climb to a high near 27°C. Skies will remain mostly cloudy through the day, although a few sunny breaks might be seen.

The main weather focus for the day will be thunderstorm potential. Any remaining thunderstorm activity from overnight will clear out this morning, but it won't be much of a reprieve before a new batch of thunderstorms develop along a slow-moving cold front sweeping across the Red River Valley. There will be a slight risk of severe thunderstorms with today's activity; primary threats will be large hail and torrential downpours, but a smaller threat of damaging winds also exists.

The RDPS hints at significant rainfall accumulations of ≥ 40-50mm possible after today's thunderstorms.
The RDPS hints at significant rainfall accumulations of ≥ 40-50mm possible after today’s thunderstorms.

The thunderstorm activity will clear out through the afternoon and evening hours from northwest to southeast across the Red River Valley & SE Manitoba. Skies will clear out, temperatures will drop to a low near 16°C, and the humidity will begin to be flushed out overnight.

Tuesday will be a beautiful day throughout the Red River Valley as temperatures climb to a high near 29°C. Winds will be breezy out of the west at 20-30 km/h. Expect a low near 16°C on Tuesday night.

The weather on Wednesday will be under the influence of the next low pressure system moving into the region. Through the day, showers will begin spreading into Southern Manitoba beginning in the southwest corner of the province in the morning, spreading into the Red River Valley through the afternoon, and then onwards towards the Ontario border in the evening.

There's still quite a bit of uncertainty on the main precipitation swath, so we'll be keeping an eye on this one as it develops. That said, best indications are for the heaviest accumulations over Parkland Manitoba with up to 25-30 mm of rain, and then lesser amounts south and eastwards as the rainfall takes on a more transient nature.

Long Range

The remainder of the week and heading through the weekend looks quite dry with mostly sunny skies and daytime highs in the mid-20's, so after the system clears out on Thursday morning, there should have plenty of pleasant days ahead!

Winnipeg’s seasonal daytime high is currently 26°C while the seasonal overnight low is 13°C.

Heat & Humidity Builds Through The Weekend; Thunderstorms Possible

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Heat and humidity will build back into Southern Manitoba this weekend, bringing both mid-summer warmth and the returning threat for severe thunderstorms.

Today will be a beautiful day for Winnipeg & the Red River Valley as a ridge of high pressure exiting the region continues to bring mainly sunny skies. Winds will remain light out of the south as temperatures climb to a high near 27°C. Tonight, under a few clouds, temperatures will dip down to near 14°C.

The weather pattern will begin to change on Saturday as a low pressure system developing over the Prairies begins drawing warmer, more humid air northwards into Manitoba. Daytime highs will be similar to Friday, around 27°C, however the humidity will begin to become a little more noticeable by the end of the day as the dewpoint climbs to the 16 or 17°C mark. Alongside the increasing humidity will come a slight chance of some late afternoon or early evening thunderstorms. The severe potential looks fairly limited at this time, as does the overall ability for any storms to organize, so while an isolated strong-to-severe storm may be possible, no widespread or organized severe threat is expected.

Temperatures will then dip down to around 17°C on Saturday night with a few clouds.

Dewpoint temperatures climbing to near the 20°C mark will make for a muggy Sunday.
Dewpoint temperatures climbing to near the 20°C mark will make for a muggy Sunday.

Sunday will see the warmest air move into the Red River Valley alongside an increment in humidity. Daytime highs will climb to near the 30°C mark along with dewpoints rising to near the 20°C mark, making it feel quite muggy. Humidex values, a "feels like" temperature that combines temperature & humidity values, will be in the upper 30's, making for quite a hot day. Skies will be mixed, and a breezy southerly wind will be in place through the Red River Valley at 20-30 km/h.

Sunday night will be a warm one with temperatures dropping only to around 20°C. A threat for thunderstorms return with a likely severe threat. Over 2500 J/kg of MLCAPE will be in place over parts of the province, alongside 35 kt of bulk shear and strongly veering wind profiles. This suggests an all-threats severe hazard, including a tornado threat in the early hours of storm initiation over Southwestern Manitoba. As the thunderstorms progress eastwards, the threat will likely shift to strong wind and large hail.

Long Range

Next week is looking like a return to more unsettled weather. Uncertainty exists with the thunderstorm system at the end of the weekend, with some models suggesting a slower progressing system that would result in more of a rain/storm threat on Monday instead. After a brief reprieve from that system, another one looks to be on the doorstep for mid-week that will bring another chance for rain and thunderstorms. Following that, the week will end off slightly cooler than seasonal.

Winnipeg’s seasonal daytime high is currently 26°C while the seasonal overnight low is 13°C.

Hot, Dry Weather Ahead

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In what seems like an almost unbelievable stroke of luck this year, hot and dry weather will continue throughout the second half of the work week for Winnipeg and the Red River Valley.

We finally get a bit of a break here at A Weather Moment with not just one, but two (!) short blog posts in a row as a ridge of high pressure dominates the weather over the Red River Valley.

Today and tomorrow will both be pleasant days with daytime highs near 25 and 27°C respectively and overnight lows near 13°C. Winds will be fairly light out of the north both days. Skies will be partly to mainly sunny.

By Friday, a low pressure system pushing eastwards across Saskatchewan will begin spreading cloud across Southern Manitoba. While some shower activity is possible over southwestern Manitoba, nothing is expected here in the Red River Valley. Temperatures will climb to a high near 28°C with winds fairly light out of the south. Lows will be near 16°C on Friday night.

Long Range

The weekend brings back the potential for some wet weather as a slow-moving low pressure system moves across the region. There's still a fair amount of uncertainty associated with this system, however, so this will be more of a generalized outlook.

The GDPS is forecasting a swath of 10-35mm near the US border Friday night through Saturday night.
The GDPS is forecasting a swath of 10-35mm near the US border Friday night through Saturday night.

Current guidance suggests the development of a slow-moving area of rain through North Dakota on Friday night which will have the northern edge extending into Southern Manitoba. This system will very slowly move eastwards through Saturday, spreading rain across the Southern Red River Valley. Guidance suggests that the bulk of the rain would leave the region on Saturday night with 10-35mm of rain having fallen in the heaviest hit areas on the Canadian side of the border. Sunday would then bring just a slight chance of showers.

Again, there is a substantial amount of uncertainty associated with this system at this point and a slight shift north or south could dramatically alter the amount of precipitation expected.

Winnipeg’s seasonal daytime high is currently 26°C while the seasonal overnight low is 13°C.

Calmer and Drier to Start the Week

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We will be in a much drier and calmer pattern early this week as an upper ridge of high pressure build over western North America. This should provide many areas an opportunity to dry out after what has been an exceptionally wet pattern over the past two months.

An upper ridge of high pressure over western North America will bring drier weather to southern Manitoba
An upper ridge of high pressure over western North America will bring drier weather to southern Manitoba

This Week

Today will be a nice day in southern Manitoba. High temperatures will climb up near the 30C mark in most areas under mainly sunny skies. Winds will be westerly near 20 km/h, offering a bit of natural air conditioning from the heat of the day.

Tuesday will see a bit of a cool-down from today as a cold front brings a cooler air mass to the region. However, it won’t be a significant cool-down, as high temperatures will remain in the mid twenties. Winds will shift to northerly at around 20 km/h. Skies will be a mixture of sun and cloud as some high-level cloud moves through the region.

Wednesday will see temperatures once again in the mid twenties under a mixture of sun and cloud. Winds will be light as we sit within a slack surface pressure regime.

Long Range

The long range forecast shows us remaining under the influence of high pressure aloft until at least the end of the week. This should generally mean warm and dry conditions, although the odd thunderstorm cannot be ruled out. It doesn’t appear that an organized precipitation should be expected until next week, although some models hint at perhaps a semi-organized convective system affecting border regions midweek. However, it’s too early to say if such a system may transpire.