Category: Forecasts

Heat & Humidity Builds Through The Weekend; Thunderstorms Possible

Brad Leave a comment

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

Brad Leave a comment

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

Scott Leave a comment

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.

Heat Breaks with Soggy Saturday

Brad 2 Comments

The heat seen over southern Manitoba over the past week will be in place for just one more day before a low pressure system moves through the region on Saturday, bringing soggy weather and cooler temperatures.

Another hot day is on the way for Winnipeg, but humidity will continue to decrease slightly towards more comfortable levels. Winnipeg & area will see plenty of sunshine today with just a few puffs of cloud possible in the afternoon. Winds will be fairly light out of the west-northwest at 15-25 km/h. Temperatures will climb to a high near 28°C. Tonight will bring increasing cloud and light winds as temperatures dip to around 18°C.

A low pressure system will be pushing northeastwards out of Saskatchewan & Montana on Friday night.
A low pressure system will be pushing northeastwards out of Saskatchewan & Montana on Friday night.

Saturday will be an unsettled day as a low pressure system moves through the province. The daytime high will be in the mid-20’s with winds picking up out of the south to 20-30km/h in the morning.

There will be rain on Saturday, however at this point, there’s still some uncertainty on exactly where precipitation will fall. Indications are that amounts will generally be 5-15 mm, however convective elements may produce rainfall amounts up to 30-50 mm in thunderstorm activity.

One potential outcome of Saturday shows two main areas of convective rainfall with up to 50 mm of rain.
One potential outcome of Saturday shows two main areas of convective rainfall with up to 50 mm of rain.

Ultimately we’ll simply have to wait and see how things shape up and what the nature is of the precipitation that develops through Montana and Saskatchewan tonight. We’ll provide updates in the comments below.

Much of the rain will taper off on Saturday evening, leaving us with fairly cloudy skies and a low that falls to around 16°C by Sunday morning.

Sunday will be a bit of a mixed bag. Expect mixed skies and a high near 26°C, however winds will be breezy, peaking out of the northwest at around 40 km/h and we’ll see just a slight chance of some scattered showers. Skies should clear for Sunday night as temperatures head to a low near 16°C.

Long Range

The start of next week looks fairly pleasant with sunny to mixed skies and daytime highs in the mid- to upper-20s. It looks like it will be fairly dry with a ridge of high pressure deflecting things south of the Red River Valley, but that will be sensitive to the exact location that this feature sets up.

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