There’s been no formal announcement for the recent updates to the bulletin viewer, but I’ve been working away at improving some aspects of it lately. Still working on parsing out some compatibility issues with a few bulletins, so expect to see continued improvements in the coming weeks. But, for now, here’s all the recent updates:
Author: Brad
Brad lives in Winnipeg with his wife and two children and is the founder of A Weather Moment. He has loved weather from a very young age and has followed that passion through his life so far. He received a B.Sc. in Earth Sciences with Specialization in Atmospheric Sciences and is currently employed in the field of meteorology. You can find the author as WeatherInThePeg on Mastodon.
Cooler Weather Arrives
A big change is on the way for Winnipeg and the Red River Valley; after a stretch of hot and humid weather, the jet stream is plunging southwards and will spread significantly cooler conditions across the southern Prairies.
Today’s weather will be dominated by an upper-level low tracking into North Dakota, shunting the jet stream further south and bringing cooler air into the region. Here in Winnipeg, temperatures will climb to around 21°C this afternoon — some 5°C below normal — with northerly winds at around 15-20 km/h. We may see a few showers in the morning, but most of the day should be cloudy with no rain. Skies will clear out late tonight into the early morning hours of Thursday as temperatures dip to a low near 11°C.
Thursday will bring clearing skies as a broad ridge of high pressure builds into the region. Winds will remain light, and with a bit of sunshine highs should be a little higher than Wednesday at around 24°C. There will be a very slight chance of an isolated shower developing along lake-breeze boundaries in the Interlake and drifting south towards Winnipeg in the late-afternoon, but that the chance is low. Skies will be clear Thursday night with a low near 11 or 12°C once again.
Friday will be more of the same; light northwesterly winds under partly cloudy skies with a high near 24°C. Temperatures will dip down to a low near 13°C on Friday night.
Long Range
Saturday will continue the cooler conditions with a high in the low 20’s, but a passing disturbance will bring a slight chance of some scattered showers or thunderstorms. The remainder of the weekend into next week will bring seasonal to slightly below-seasonal temperatures with mixed skies and occasional chances for showers.
Winnipeg’s seasonal daytime high is currently 26°C while the seasonal overnight low is 13°C.
One More Chance for Thunderstorms, Then Cooler Weather Arrives
The heat will stick around for just one more day before a cold front ushers in cooler temperatures that will persist through the remainder of the week. That cold front will also bring the threat of severe thunderstorms to the Red River Valley this afternoon as it slides southeastwards through the region.
Today’s weather focus for Winnipeg & the Red River Valley will be the continued heat and humidity in place and the cold front that will be shunting it out today. Temperatures will rise quickly this morning towards a daytime high near 30-31°C. With dew points still in the 18-20°C range, humidex values will climb into the upper 30’s once again. By early afternoon, a cold front will start slumping southwards into the Red River Valley, bringing with it a risk for thunderstorms.
As shown in ECCC’s thunderstorm outlook, there is a chance for severe thunderstorms over the Red River Valley and southeastern Manitoba.
Going over the MIST ingredients:
- Moisture: Surface dew points near 20°C will provide large amounts of energy for thunderstorms to work with.
- Instability: The high dew points will combine with moderately steep mid-level lapse rates to produce MLCAPE values near 2500 J/kg.
- Shear: Shear is lacking somewhat; 500 mb winds of 30-35 kt layered on top of south to southwesterly surface winds of 10 knots will produce bulk shear values near 25 kt.
- Trigger: A cold front slumping southwards through the region.
The high instability coupled with middling shear but sharp trigger will combine to produce the threat of severe thunderstorms that quickly develop into a multicellular line and move to the southeast.
The primary threat with today’s thunderstorm will be large hail. As shown in ECCC’s outlook, hail up to 5 cm diameter — a bit larger than a golf ball — is possible in the worst storms that form today. Heavy rain will be the second threat as it’s quite likely the rainfall coming out of the line of storms is torrential. Whether or not there’s overland flooding will depend on how quickly the line is moving; at this point, it seems like things will be progressive enough that while the rain will be heavy, it won’t reach severe criteria (50 mm in under 1 hour). There may be strong winds in some of the storms, but it won’t be as common as large hail and heavy rain. There is not a significant tornado threat today.
The biggest uncertainty will be when exactly the thunderstorms start. If they form early, around 1PM or so, then they’ll initiate to the northwest of Winnipeg and move through the city early to mid-afternoon. Should the capping inversion hold longer and storms don’t form until 3-4PM, then it will be likely that the cold front has passed through Winnipeg and the storms fire to the south and southeast of the city. The southern Red River Valley and southeastern Manitoba have a high probability of seeing thunderstorms this afternoon.
Behind the cold front, winds shift out of the northwest to around 20 km/h as skies clear. Temperatures will drop to a low near 17°C tonight.
Tuesday will start off sunny with skies becoming mixed in the afternoon as a weak disturbance moves towards the region. Temperatures will climb to a high near 26°C, but the humidity will be much more comfortable as dew points fall to the 11-13°C range in the continued light northwesterly winds. There may be a slight chance of some isolated showers in the afternoon. Tuesday night will bring some clearing in the evening, but then more organized cloud will begin moving in ahead of a low that will impact the region on Wednesday. Temperatures will drop to around 11°C.
Wednesday will bring cloudy skies and a good chance of showers to Winnipeg and the Red River Valley. It will be a relatively cool day with highs around the 20°C mark and continued light northerly winds. The chance for showers will taper off in the evening with temperatures dropping to a low near 11°C.
Long Range
The remainder of the work week looks quiet with temperatures near-seasonal, if not a bit below. There may be some chances for showers on Friday or Saturday, but it’s still looking a bit unclear at this point.
Winnipeg’s seasonal daytime high is currently 26°C while the seasonal overnight low is 13°C.
The Heat Is On; Thunderstorms Possible Saturday
While July has been relatively pleasant, temperatures have [somewhat surprisingly] been largely below seasonal for much of the month. That’s all about to change as significant heat builds across the region to round out the month.
A developing southerly wind of 20-30 km/h this morning will draw warmer air northwards out of the United States and help push daytime highs up to around the 30°C mark. Skies will remain mainly sunny and humidity in the mid-teens should keep things feeling relatively comfortable. Expect lows to fall to around the 19°C mark tonight with winds continuing out of the south and partly cloudy skies.
Saturday will see a cold front slowly sweeping across the province, bringing with it a severe thunderstorm risk. Before that, though, there will be a hot summer day on tap with highs once again near the 30°C mark under mixed skies. With the southerly winds slowly diminishing and dew points rising to around 19 or 20°C, it will end up feeling quite humid in the afternoon. The cold front will progress eastwards through the day, reaching the Red River Valley mid- to late-afternoon. As it pushes into the valley, it will bring with it the risk of severe thunderstorms.
Going over the MIST ingredients:
- Moisture: Low-level moisture will be plentiful with surface dew points climbing towards the 20°C mark and with deep moisture extending towards 850 mb.
- Instability: Slight to moderate instability will be in place. Mid-level lapse rates leave a bit to be desired with expected values only around 6-7°C/km, but this is somewhat offset by the substantial latent heat available through surface moisture. Depending on the exact orientation of this system, the heights may be rising as the front stalls, which would work against thunderstorm development.
- Shear: Bulk shear values around 25-30 kt will be in place which is on the lower end of values. Low-level shear will likely be weak and mid-level shear largely unidirectional.
- Trigger: The cold front will slowly slump southeastwards, gradually slowing into the evening hours.
The primary threats with any storms that develop will be large hail and damaging winds, although with dew points so high, torrential rain is likely as well. They would move southeastwards through the Red River Valley. The biggest question will be whether or not storms actually develop. The threat will exist generally around the Trans-Canada Highway corridor and south, but we’ll provide an update on Saturday with a new look at the day’s potential.
The thunderstorm threat will diminish before midnight and temperatures will then drop to a low near 17°C under clearing skies.
Sunday will be another hot day with a high near 31°C but more comfortable humidity as the dew point drops back towards the mid-teens. Skies will be partly cloudy and winds will be light out of the east. Winds will shift out of the south on Sunday night and increase to 15-25 km/h, keeping temperatures fairly warm; the overnight low will be just around 19 or 20°C.
Long Range
Temperatures will continue to be warm through the start of next week with partly cloudy skies and highs generally around the 30°C mark. Monday will likely be moderately humid again, but things will dry out on Tuesday as a cold front moves through. The rest of the week looks fairly quiet with near-seasonal temperatures and low humidity.
