Tag: Severe Thunderstorms

State of the Climate – A Stormy Summer 2016

Julien Leave a comment

Summer 2016 will be remembered for its intense and frequent thunderstorm activity which caused several tens of millions of dollars in damage across the Prairies. Manitoba experienced its fair share of the action with multiple damaging wind, flooding rain, tornado and damaging hail events – the most some areas have seen in years. Humidity was high, which possibly was one factor that helped fuel a more intense season. Temperatures were pleasant – not too hot and not too chilly. In fact, temperatures averaged bang on normal in Winnipeg.

Average or TotalDeviation from NormalRank Since 1873
High Temperature24.6°C-0.1Equal to median
Mean Temperature18.4°C0.0Tied 65th warmest
Low Temperature12.2°C+0.2Tied 47th warmest
Rainfall231.5mm-16.0 (-6%)63rd rainiest

Overall, it was a wet summer, except for a few isolated locations. Winnipeg’s airport actually saw slightly drier than normal conditions from June to August, but this was mainly a result of a dry August when storms mostly missed the location. June and July were wetter than normal.

Wet Summer For Most

Thunderstorms were a regular occurrence throughout not only southern Manitoba but also Saskatchewan and Alberta this summer. Severe thunderstorms occurred almost daily across the Prairies with only a handful of days seeing no severe weather.

Thanks to the active weather, rainfall amounts were above normal throughout most of the three Prairie provinces. Only localized portions of northeastern Manitoba, central Saskatchewan and southwestern Alberta saw below normal rainfall. The wettest areas relative to normal were the southern Red River Valley in Manitoba, southwestern Saskatchewan and southeastern and northwestern  Alberta. The following two maps from Canada Drought Watch show percent of normal precipitation and precipitation percentiles for the season since April.

The highest rainfall totals from April 1 to September 8 in southern Manitoba were along the US border in the Killarney to Sprague area where 500 to 750 mm of rain fell. A secondary area of heavier rainfall also occurred east and northeast of Winnipeg with 500 to 650 mm. Letellier took top honours with a whopping 752 mm at the Manitoba Agriculture station. 18 days saw over 20 mm of rain as rounds of heavy rainfall occurred almost every few days. Farmers regularly faced overland flooding on their fields as a result. Other high rainfall totals in the area included Green Ridge with 630 mm, Vita 563 mm, Altona 568 mm, Killarney 520 to 550 mm, Steinbach 530 mm and Morden 490 to 550 mm. High rainfall totals also fell in the Whiteshell area where heavy rains at times caused serious flooding. About 620 mm of rain fell in Falcon Lake and 572 mm in Hadashville during the period. All the above rainfall totals are via Manitoba Agriculture, Manitoba Fire and Cocorahs.

In Winnipeg, rainfall was slightly above average at the airport between April 1 and September 8 with 365 mm. Average for the period is close to 340 mm. Higher totals fell in other parts of the city however, with 420 to 470 mm in western and southern sections.

Year of Severe Thunderstorms and Tornadoes

A total of 16 tornadoes occurred in Manitoba this year; 1 in May, 2 in June, 5 in July and 8 in August. This is up from 11 tornadoes last year and the most tornadoes in a year in a couple of decades (the 1980’s to early 90’s was a busy period). Manitoba also had the most tornadoes in Canada this year. There were a number of multi-tornado-day events including 4 on August 8 and 3 on July 20 and August 3.

There were many notable hail and wind events this summer across southern Manitoba, too many to list. As a result, I have prepared a list below of what I believe were the top 5 events of the summer.

Top Thunderstorm Events

I have listed, in chronological order, what I believe were the top thunderstorm events of the summer in southern Manitoba

June 24/25 Derecho

A rare derecho event occurred from the evening of June 24th into the overnight on June 25th. A severe thunderstorm complex moved in from Montana and raced across southern Manitoba. A derecho is one of the  most intense thunderstorm events with respect to wind. By definition, it is a thunderstorm complex that produces winds of at least 50 knots (93km/h) along a swath at least 400 km long and whose life span exceeds 6 hours. In addition, no longer than 2-3 hours must pass between successive wind reports. These criteria were met during the June 24/25 event. The following map shows AWM`s Convective Outlook Verification for the event and is included here to show where the severe events were recorded.

Verification of the AWM Convective Outlook for Junes 24/25, 2016
Verification of the AWM Convective Outlook for Junes 24/25, 2016 with hail and wind reports overlaid. Additionally, flooding due to rainfall was reported in several locations within the slight risk region.

Winds in excess of 90 km/h occurred in a swath from Melita to Carberry to Carman to Saint Adolphe with the derecho. Melita was pummelled with a maximum recorded gust of 124 km/h! Trees, fences and homes suffered damage. Gusts over 100 km/h occurred in Deloraine (102 km/h), Waskada (107 km/h) and Carberry (102 km/h), and gusts over 90 km/h occurred in Killarney (96 km/h), Somerset (90 km/h), Ninette (90 km/h), Carman (93 km/h), Morris (91 km/h), Sanford (90 km/h) and Saint Adolphe (92 km/h). Damage was widespread and significant with snapped trees, crop damage and other property damage. Streets in some areas were littered with branches and debris the next morning.

A narrow jet (sting jet?) of winds between 90 and 110 km/h also occurred in the Brandon area behind the massive thunderstorm complex around 4 am. This was a very interesting occurrence because these winds occurred behind the storms and would be a great case study project. Brandon airport recorded a gust of 106 km/h with the event. Forrest, just north of Brandon, recorded a gust of 98 km/h. Trees were snapped and uprooted, which caught many by surprise because there was no thunder or lightning and only light sprinkles occurring at the time.

Wind was not the only severe weather with the storms. Toonie sized hail occurred south of Killarney and nickel sized hail in Winnipeg. Flooding was a problem as well. 80 to 100 mm of rain fell in the Killarney area with a swath of 50 to 80 mm northeastward to Elm Creek. Winnipeg received 25 to 40 mm with highest amounts in southern and eastern sections. Estimated wind gusts near 80 km/h also occurred in the south end as the city was brushed by the strongest winds to the south. Another swath of 50 + mm fell from Selkirk southeastward to Falcon Lake. In fact, the Falcon Lake/West Hawk Lake area received an incredible 140 to 160 mm of rain. Flooding was severe with some highways underwater and closed. Lake levels in the area were unusually high.

July 20 Supercells / Long Plain Tornado

A series of severe thunderstorms developed in southwestern Manitoba and southeastern Saskatchewan after 4 pm and raced eastward through southern Manitoba in the evening.

The storms dropped up to tennis ball sized hail in extreme southeastern Saskatchewan before entering into Manitoba. In Manitoba, numerous funnel clouds were seen with the storms west and southwest of Brandon. Two of these became landspout tornadoes near Hartney. With no damage reported, these were rated EF-0. The main story initially was the hail with toonie to tennis ball sized hail from the Melita to Brandon areas. The City of Brandon was hit hard with hail up to golf ball sized, wind gusts over 80 km/h and up to 40 mm of rain in 1 hour.

The supercells then continued eastward with incredible wind gusts and a damaging tornado south of Portage la Prairie. A summary of wind gusts is provided in the following table:

LocationMaximum Wind Gust (km/h)
Portage Southport138
Selkirk115
Mountainside110
Winnipeg Int'l Airport107
Elm Creek107
Starbuck101
Gretna96
Cartwright95
Carberry94
Deerwood93

The area south of Portage was worst hit with winds over 130 km/h recorded. Widespread and significant damage occurred with trees toppled and uprooted and buildings damaged. A supercell tornado also occurred at the Long Plain FN and New Rosedale Hutterite Colony south of Portage. Buildings were shifted off their foundations, roofs ripped off homes, hydro poles toppled, cars flipped, sheds and farm buildings destroyed and trees were again toppled and uprooted by the tornado. Debris was scattered across fields downwind. The tornado was rated an EF-1. According to CBC, about 150 homes were damaged and some residents remain displaced in September. A video of the tornado from a distance exists here. A timelapse of the storm coming in Winnipeg exists here.

The storm then raced east toward the Winnipeg area. The storm was one of the most ominous storms ever seen with a massive shelf cloud, nearly-constant flashes of lightning and a sky that was almost completely green. Damaging winds occurred with a gust of 107 km/h at Winnipeg International Airport and 115 km/h in Selkirk. Significant damage occurred with trees toppled and some buildings damaged. A roof was partially ripped off an apartment building in north Winnipeg. An estimated 1 million dollars in damage also occurred to a U of M professor`s equipment at the St. Andrews airport. Wind damage also occurred in the Beausejour, Anola, Treherne, Elie and Elm Creek areas. According to Manitoba Hydro [CBC], at peak, 32,000 Manitobans were without power, about 20,000 of which were in Winnipeg.

August 3 Tornado Outbreak

A series of supercell thunderstorms developed in southwestern Manitoba and North Dakota in the afternoon and persisted through the evening. The storms produced numerous tornadoes with three tornadoes in Manitoba: at least one tornado near Glenboro, one tornado west of Morden  and a landspout tornado near Margaret.

The town of Glenboro was lucky as a tornado narrowly missed the town. A tornado formed south of the town after 5 pm and the storm continued to produce a tornado for close to half an hour as it continued northeastward and crossed highway 2. The tornado at one point was a massive wedge tornado northeast of town. Farm sheds and buildings were damaged or destroyed, trees were uprooted and hydro poles were toppled by the tornado. Video of tornado exists here. The storm also dumped 57 mm of rain in 1 hour in Glenboro and 54 mm in 1 hour in Holland to the east. Peak rainfall was just north of Glenboro with a 79 mm storm total recorded at a Weather Farm station.

The Morden area was hit hard by storms moving up from North Dakota. A wind gust of 111 km/h was recorded at the airport. Streets in the city were littered with twigs, branches and toppled trees and shingles were ripped from roofs. Streets were also flooded after 30 to 50 mm of rain fell. A tornado was also seen west of the city in pictures, but no damage directly related to the tornado was ever reported.

Wind damage also occurred in Portage la Prairie, Plum Coulee and Gretna thanks to wind gusts between 80 and 95 km/h.

Storms danced around Winnipeg during this event with only a few mm of rain recorded. Lightning was spectacular however. The storms had just scraped the south end. Saint Adolphe, a short drive south of Winnipeg, recorded 54 mm of rain in 1 hour and a wind gust of 92 km/h. Branches were taken down and some minor flooding was reported.

The low pressure system responsible for the thunderstorms on August 3 also produce slow-moving thunderstorms in the wrap-around portion of the system north of Dauphin. 150 to 190 mm of rain fell in the Ethelbert area in just 6 hours. Flooded fields were reported.

August 8 Tornado Outbreak

Supercell thunderstorms developed in Saskatchewan and moved into southern Manitoba southwest of Riding Mountain National Park, producing the largest tornado outbreak of the year in terms of number of tornadoes. Four tornadoes were confirmed, two of which were rated EF-2 and two rated EF-0. The storms, which tracked from Russell to Erickson, also dumped hail up to tennis ball sized.

Waywayseecappo FN was hit by one of the EF-2 tornadoes. Several homes were damaged or completely destroyed. A school bus was also flipped on its side. Hail up to golf ball sized also fell with the storm. Some residents were evacuated after the storm.

A summary card produced by AWM for the August 8, 2016 tornado outbreak.
A summary card produced by AWM for the August 8, 2016 tornado outbreak.

The other tornadoes were south of Russell, near Elphinstone and near Erickson. The one south of Russell was rated an EF-0 based on tree damage. The one near Elphinstone was also given an EF-0 rating due to no reports of damage. The tornado near Erickson was rated an EF-2. A long swath of forest about 500 metres wide was completely flattened (seen thanks to aerial photos from CBC) and bark ripped off trees. Swirls could be seen in the forest from above, confirming that a tornado indeed produced the damage. The tornado also damaged homes and other buildings in the area. The storms continued southeastward after the last tornado, but weakened.

High Humidity

With an average dewpoint temperature of 13.7°C, summer 2016 tied with 2005 for third most humid summer since 1953 in Winnipeg. Some might think this stat is a little surprising because the summer really wasn’t that hot. In fact, temperatures were only near normal overall and very hot days were few and far between. This was probably a good thing because otherwise, the high humidity combined with hotter temperatures would have made the summer much more unbearable.

July 20 saw the peak humidity of the summer when dewpoint temperatures rose to the 24 to 27°C range across southern Manitoba, breaking records. At Winnipeg Int’l Airport, dewpoint peaked at 25.9°C, the second highest dewpoint reading on record since 1953. The record is 26.1°C on July 17, 1966. Dewpoint temperatures reached an amazing 27°C in Carman, Winkler, Portage, Altona, Beausejour and Minnedosa. The highest reading was in Carman at 27.4°C. The heat and humidity together produced humidex values in the mid 40`s.

Hottest Day of the Year Was Outside of the Summer Season

Consistent with few very hot days this summer, the hottest day of the year was actually outside of the summer season. A high of 35.2°C on May 5th was the hottest of the year and the earliest date to reach the highest temperature of the year on record since 1872. It was also only the 12th time that our hottest day of the year was in May. The high of 35.2°C was also the earliest occurrence of temperature over 35.0°C on record since 1872. Previous earliest was May 8, 1874 with a high of 35.0°C.

RankDateHigh
1May 5, 201535.2°C
2May 7, 189134.4°C
3 (tie)May 13, 193233.3°C
3 (tie)May 13, 197732.6°C
5 (tie)May 19, 194835.0°C
5 (tie)May 19, 199234.2°C

Warm Year and September so Far

The January to August period averaged 5.5°C in Winnipeg, tied with 1999 for 13th warmest on record since 1873. September so far is averaging just over 2 degrees above normal, making this the 14th warmer than normal September in the last 16 years. September has been and seems to continue to be warming at a rapid pace. In fact, September has warmed 1.0°C in the last 20 years, 0.7°C in the last 10 years and 0.5°C in the last 5 years, showing that warming for the month has accelerated in recent years. The 30-year 1987 to 2016 average for September is 13.4°C, up from 12.9°C in the 1981-2010 normal and the warmest Septembers have been on record. There is certainly no guarantee that this warming trend will continue forever, but what is interesting is how rapidly the month has warmed and how rare it has become to experience a chilly September.

Risk of Storms to Start the Week

Scott Leave a comment

This week will start out with another risk of severe thunderstorms across southern Manitoba. On the bright side, conditions prior to the storms will be warm.

A low pressure system moving into southern Manitoba will bring a risk of severe storms to the region
A low pressure system moving into southern Manitoba will bring a risk of severe storms to the region

This Week

Today will be a warm and increasingly humid day across southern Manitoba. High temperatures will generally be in the upper twenties, although some locations may reach the 30C mark. The increased humidity will push humidex values into the mid-upper thirties. The approach of a strong low pressure system will result in a stiff southerly wind developing across southern Manitoba. Wind speeds in the Red River Valley will be 40 km/h gusting to 60 km/h by late afternoon. Other portions of southern Manitoba will also be windy, but with speeds perhaps a bit lower than those in the RRV. This same low pressure system will bring a risk of severe storms to most of southern Manitoba as a cold front slices into this warm, humid air mass. All hazards will be possible with storms that develop, with the primary risks being large hail and damaging wind gusts. Tornadoes will be possible with any storms that remain isolated, although the tornadic risk is somewhat lower than last Wednesday.

AWM Day 1 Convective Outlook for August 8, 2016
AWM Day 1 Convective Outlook for August 8, 2016

Models hint at an organized convective system perhaps developing out of the afternoon/evening storms. Should such a scenario play out, the Red River Valley and southeastern Manitoba may be at risk for more widespread damaging winds from the evening into the overnight period.

Moisture: Surface dewpoints of 17-21 C are expected across southern Manitoba, with 850 mb dewpoints of 12-15 C by early evening. Moisture is expected to be well mixed within the boundary layer, giving a 100-mb mean mixing ratio of approximately 12-13 g/kg.

Instability: The aforementioned well-mixed boundary layer will sit beneath mid-level lapse rates of approximately 7 C/km. Steep low-level lapse rates will be present owing to the well-mixed, and relatively deep boundary layer. Resulting MLCAPE values will be near 2000-2500 J/kg across south-central Manitoba by early evening. Early evening instability will generally be poor in the Red River Valley and points east, with MLCAPE of 1000 J/kg or less. However, by the late evening period (03Z onward), MLCAPE/MUCAPE will increase to near 2000 J/kg in the region.

Wind Shear: A 50 kt 500-mb jet streak pushing into SW Manitoba will be preceded by approximately 40 kt of westerly flow over southern Manitoba. Except near the surface warm front, surface winds will generally be southerly, and as a result will not enhance the effective bulk wind difference (EBWD) in a notable way. The result will be EBWD values of 30-40 kt across southern Manitoba, with locally higher values near the surface warm front. More interestingly, a strong southerly low-level jet of 30-40 kt is expected over south-central Manitoba by late afternoon. This will result in 0-1 km wind shear of 15-25 kt. Effective storm relative helicity values will also be strong, at 250-400 m2/s2 during the evening. Low-level shear and helicity are also expected to benefit from the decoupling of the boundary layer by mid-late evening, as the LLJ increases to 45 kt by 0300 UTC.

Trigger: The primary trigger for deep convection Monday evening will be a cold front moving in from eastern Saskatchewan and a warm front extending eastward from a low pressure system near the MB/SK border. Forcing for ascent will be quite strong, especially over western Manitoba, where a potent shortwave trough will help knock down heights by the afternoon. The combination of the low-level mesoscale ascent with the surface fronts and mid-level ascent from the incoming shortwave should easily be able to trigger storms by late afternoon across western Manitoba.

Discussion: Severe thunderstorms are likely to develop across western Manitoba/central Interlake beginning Monday afternoon. Initial storms will likely be a mix of supercells and multicell clusters, owing to the strong forcing. Any initial cells that are able to maintain relatively unpolluted surface-based inflow will present a tornado risk, owing to the strong low-level shear/helicity and steep low-level lapse rates. All initial severe cells will be capable of large hail and damaging wind gusts. As the evening progresses, some models hint at upscale growth/cold pool mergers leading to the development of a bowing system over the southern interlake, or adjacent regions. Should such a system develop and have a significant line-trailing cold pool, it would tend to move ESE/SE, potentially impacting Winnipeg, the Red River Valley, and southeastern Manitoba. A system will a less pronounced cold pool may take a most easterly track, primarily avoiding the Red River Valley. Latest models suggest a well-organized, cold-pool driven MCS is the less likely outcome. The overall risk is slight for all of southern Manitoba. A future moderate risk is possible should a forward-propagating system become more likely.

The cold front which triggered today’s storms will pass through the Red River Valley early Tuesday, likely bringing with it some showers and/or weak thunderstorms. After the front clears the region, skies will begin to clear, allowing temperatures to climb into the low twenties by afternoon. Winds will be northerly at 20-30 km/h behind the front.

Wednesday’s forecast remains fairly uncertain at this point. Models hint at the potential for rain across much of southern Manitoba, though the amount and duration of this rain is quite uncertain. Some models bring significant rain to the region, while others bring only light showers. It appears regions along the international border may be at the highest risk for significant accumulations, though that could change as new data becomes available. Outside the rain, skies will be mainly cloudy with temperatures near 20C. Winds will be easterly at 20-30 km/h.

Long Range

The long range forecast shows little change in our pattern over the next couple weeks. Expect to see 1 or 2 weather systems rolling through our region every week, with stormy conditions associated with the passage of each system. Between systems we can expect generally pleasant conditions, with temperatures near to above-seasonal values.

Potent Severe Thunderstorm Threat For Manitoba

Brad 1 Comment

A low pressure system tracking eastwards through Saskatchewan will bring a potent severe thunderstorm threat to Southern Manitoba today. The development of severe thunderstorms capable of producing damaging hail and winds, torrential downpours, and tornadoes is expected this afternoon over portions of southwestern Manitoba. These thunderstorms will then track eastwards across the Red River Valley & the southeastern corner of the province through the evening hours.

Hot and humid weather will return to Winnipeg today as temperatures soar to the 30°C mark while dewpoint temperatures climb towards the 20°C mark in the Red River Valley courtesy a gusty southeasterly wind of 30-40 km/h that will develop midday. This hot and humid weather will serve as the pressure cooker for severe thunderstorm development as a low pressure system tracks into the province this afternoon.

Through the morning hours, a few isolated thunderstorms are possible across the southwestern and south-central portions of the province, but they aren’t expected to be particularly notable. By early to mid-afternoon, the “main event” will start with thunderstorms developing along a north-south line west of the Red River Valley. Through the late afternoon into the evening, these thunderstorms will move eastwards across the Red River Valley and southeastern Manitoba.

These thunderstorms will be capable of producing large and damaging hail, dangerous straight-line winds exceeding 100 km/h, and torrential downpours capable of flash flooding. In the early hours of the system, over portions of southwestern Manitoba and possibly extending into the western Red River Valley, these thunderstorms will also be capable of producing a tornado.

Going over the MIST ingredients for convection:

  • Moisture: Dewpoints climbing into the 20-23°C range will combine with moderate vertical extent as an organized moisture feed advects into the province from the Dakotas.
  • Instability: Significant moisture coupled with moderate mid-level lapse rates to produce MLCAPE values 2000-3000 J/kg. MUCAPE values of 1500-2000 J/kg will continue overnight into northwestern Ontario.
  • Shear: Significant speed and directional shear will be in place over the province with textbook-quality looping hodographs present under 50-60 kt of 0-6km bulk shear will practically guarantee supercell development upon storm initiation and will be completely supportive of upscale growth into the overnight period.
  • Trigger: A frontal wave passing by the province and associated low pressure system and trough will provide ample lift and convergence to trigger thunderstorm development.

As storms develop, they will very quickly begin rotating and mature into supercell thunderstorms. These storms will very quickly develop hail and severe wind threats. Low lifting condensation levels coupled with the strongly veering hodographs and notable low-level CAPE also suggests a tornado threat for the first few hours of the storm life-cycle. This will most likely be constrained in an area from Brandon to Winnipeg along the Trans-Canada Highway and then south to the American border.

The severe thunderstorm threat will continue eastwards with the line through the evening into Ontario.

AWM Day 1 Convective Outlook for August 3, 2016
AWM Day 1 Convective Outlook for August 3, 2016

The thunderstorms will track eastwards through the evening hours, with Winnipeg most likely seeing the activity between 8PM and 1AM.

Winds will diminish tonight behind the thunderstorm activity as temperature dip to around 17°C.

Update: EC Event Summary

Environment Canada has issued a summary of the severe weather that occurred across ‪#‎MBstorm‬ yesterday. The highlights are two confirmed tornadoes, loonie to quarter sized hail, wind gusts up to 111 km/h, and 4″ of rain!

Weather summary for Manitoba
issued by Environment Canada
at 5:04 a.m. CDT Thursday 4 August 2016.

Discussion.

An intense low pressure system tracking across the Prairies brought
widespread severe weather to much of southern Manitoba on Wednesday.
Two tornadoes have been confirmed, and numerous reports of heavy
rain, damaging winds, and large hail were also received.

The following reports have been received by ECCC meteorologists
(event times are approximate):

A funnel cloud was reported 8 km north of Hartney at 5:00 pm CDT.

A brief tornado was reported near Margaret at 5:10 pm CDT. No damage
was reported with this tornado.

A larger, longer lived tornado was reported 10 km west of Baldur at
5:20 pm CDT. It tracked northwards towards Stockton where a large
shed was destroyed shortly after 5:30 pm CDT.

ECCC meteorologists continue to investigate these and other
unconfirmed tornadoes.

Hail reports:

Loonie sized hail at Brandon at 6:05 pm CDT.
Quarter sized hail at Shoal Lake at 9:20 pm CDT.
Loonie sized hail at Wasagaming at 10:10 pm CDT.

Peak wind gust reports:

111 km/h at Morden at 7:26 pm CDT.
93 km/h at Portage la Prairie at 7:10 pm CDT.
92 km/h at St. Adolphe at 9:05 pm CDT.
85 km/h at Gretna at 7:46 pm CDT.
74 km/h at Winnipeg Airport at 9:45 pm CDT.

Rainfall totals in millimetres:

Erickson 104
Neepawa 75
Glenboro 66
St. Adolphe 64
Holland 56
Ethelbert 53
Fisherton 53
Morden 53
Killarney 50
Souris 49
Cypress River 45
Elm Creek 43
Snowflake 43
Winnipeg The Forks 2.7
Winnipeg Airport 1.4

Environment and Climate Change Canada meteorologists are actively
seeking pictures or videos from Wednesday's severe weather events
and further damage they may have caused. Should you have any
information regarding these events or to report severe weather at
any time, please call 1-800-239-0484, email storm@ec.gc.ca, or tweet
#MBStorm.

Please note that this summary may contain preliminary or unofficial
information and does not constitute a complete or final report.

End/PASPC

The Rest of the Week

Thursday will be a cooler day with a high near just 21°C with gusty northwesterly winds at 30-40 km/h. There will be a slight chance of some showers as the wrap-around from this low moves across the province. The humidity will be flushed out of the province making for more comfortable conditions. Temperatures will dip to 13°C Thursday night with clearing skies and diminishing winds.

Friday will be a pleasant day with winds out of the northwest at 20-30 km/h, highs in the mid-20’s and mainly sunny skies.

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

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.