Tag: Windy

Labour Day Brings Windy, Cool Conditions and Chance of Showers

Brad Leave a comment

The passage of a cold front this morning will usher in strong northerly winds and bring scattered showers to the Red River Valley as a blast of Arctic-sourced air spills southwards into the region. The cool conditions will stick around for the first half the week, but temperatures are set to soar again heading into the weekend!

There’s no getting around it: today is going to feel positively fall-like as a cold front moves through this morning and blasts Winnipeg and the Red River Valley with winds of 40-50 km/h and gusts up to 70 km/h as a surge of Arctic air spreads southwards in its wake. Temperatures will reach a high of just 19°C today under mixed skies with widespread showers as an upper-level trough swings through behind the front.

With such strong winds in the region, if any thunderstorms manage to develop, they will have the potential to produce severe wind gusts in excess of 90 km/h. Additionally, marginally severe hail1 is possible due to very low freezing levels, but larger quantities of small hail would be more likely from any thunderstorms that could manage to develop today.

RPDS 10m Wind Speed Forecast valid 21Z Monday September 4, 2017
Strong winds (pink) will be in place over the Red River Valley Monday afternoon.

Winds will ease tonight as temperatures head to a low around 9°C under partly cloudy skies. Tuesday will continue to be windy out of the north to northwest at 30-40 km/h with gusts up to around the 50 km/h range, but skies will be sunnier and no rain is expected. Temperatures will be similar to Monday with highs around 19°C. Tuesday night will be quite chilly as temperatures dip to a low near 5°C or so as a large ridge of high pressure moves into the region.

Wednesday will mark the start of a turnaround back towards positively summer-like heat. Winds will be light out of the west under mainly sunny skies as temperatures climb to a high of 21°C. While it’s not a huge improvement from Tuesday’s temperatures, it marks the departure of the large ridge of high pressure bringing the cool temperatures as it slumps off to the south. In its absence, the upper-level ridge that is bringing very warm temperatures to western Canada will begin to work its way across the Prairies.

Long Range

NAEFS 8-14 Day Temperature Anomaly Forecast — Valid September 11-18, 2107
NAEFS 8-14 Day Temperature Anomaly Forecast — Valid September 11-18, 2107

Temperatures are set to soar through the latter half of the week with highs in the upper 20’s on Thursday and Friday, then potentially reaching the 30°C mark on the weekend. Temperatures are then expected to remain above-normal through the remainder of next week. Additionally, there’s essentially no chance for rain from Thursday onwards through next week in current forecasts as persistent upper-level ridging shifts the storm track well to our north.

Winnipeg’s seasonal daytime high is currently 21°C while the seasonal overnight low is 9C.

  1. EC³ condensers severe hail to be the size of a nickel (21mm) in diameter or larger. ↩

Showers on Friday, Long Range Shifts To A Nicer Outlook

Brad Leave a comment

A low pressure system and cold front moving through Manitoba today will bring morning showers or thunderstorms to the Red River Valley and a follow-up chance for rain this afternoon. Once this system clears out, there’s good news ahead as the long-range forecast has shifted to a more optimistic outlook!

To start Friday off Winnipeg & the Red River Valley will see cloudy skies with a good chance of showers as a line of precipitation moves into the region from the west. That line should be through by 8 or 9AM, and then Winnipeg will be left with cloudy skies and a breezy southerly wind near 30 gusting to 50 km/h as temperatures climb towards a high near 24°C. Then, around 2-3 PM, the threat for thunderstorms will redevelop — primarily for Winnipeg south to the US border and areas east — as a cold front moves across the region. Strong thunderstorms are likely with this front with the potential for isolated to scattered severe storms. The main threat with this afternoon’s thunderstorms will be large hail between the size of nickels and loonies alongside gusty winds. Things will calm down this evening as the wind swings around to the northwest and temperatures head to a low near 13°C.

PASPC Day 1 Thunderstorm Outlook valid September 1, 2017
The PASPC Thunderstorm Outlook highlights well where severe thunderstorms are possible today.

Late Saturday night into early Sunday morning, it appears a weak disturbance will roll through the region. It will mainly bring a bit of cloud to the region but there will be a small chance of some early morning showers on Saturday. Once it moves out, though, Winnipeg will be set for a beautiful day as weak ridging moves into the area, bringing mainly sunny skies, light winds, and temperatures in the mid-20’s.

GDPS Surface Temperature Forecast valid 21Z Sunday September 3, 2017 with annotations
A low pressure system passing through Manitoba on Sunday will bring warm temperatures to the Red River Valley

Another low pressure system is then forecast to move across the Interlake on Sunday, drawing very warm air eastwards and pushing daytime highs up in into the low 30’s. Winds will be breezy out of the south at 30-40 km/h, and Winnipeg can expect partly cloudy skies. Temperatures will then dip back to around 13°C again on Sunday night with a breezy northwesterly wind.

Long Range

The long-range forecast is looking much better than it appeared it would be earlier this week! While a potent shot of cold air is expected to slide southwards behind Sunday’s system, dropping high temperatures on Monday and Tuesday into the upper teens, the cool weather is now expected to be short-lived. Instead of being stuck on the edge of a large upper-level trough as an upper-level ridge sits over BC, models have moved towards a more progressive pattern, allowing the ridge to push eastwards relatively quickly. This means a return to seasonal temperatures by mid-week instead of week’s end.

Otherwise, fairly quiet weather on tap for next week.

Winnipeg’s seasonal daytime high is currently 21°C while the seasonal overnight low is 9C.

Another Cool, Showery Day Before A Slow Warm-Up

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A shortwave rolling across southern Manitoba today will bring cloudy skies, cool temperatures, and a good chance of more rain showers through the afternoon. The remainder of the week will bring more sunshine and a slow return towards seasonal temperatures.

Extensive cloud moved into southern Manitoba overnight and will persist for much of today as an upper-level disturbance called a shortwave moves through the region. As it swings through, it will likely be supporting an area of showers that will move into the Red River Valley later this morning and move out mid- to late-afternoon. Rainfall amounts will generally fall in the 5-10 mm range throughout the main area of rain in the Red River Valley, however a narrow line of 10-20 mm accumulations may set up somewhere along the path of the shortwave as it moves through the valley.

RDPS 12hr. QPF valid 00Z Wednesday August 23, 2017
An area of showers will produce accumulating rain across a swath of Southern Manitoba today.

The cloud and rain will make for quite a cool day with high temperatures climbing to only the upper teens. Winds will be easterly wind at just 10-20 km/h. The rain and cloud will clear out this evening as a ridge of high pressure moves into southern Manitoba.

Thursday will be a relatively pleasant day when compared to Wednesday; expect mainly sunny skies, winds out of the southeast at 15-25 km/h, and a high near 23°C. Thursday night will continue clear with a low near 12°C.

Friday will bring seasonal temperatures back to the Red River Valley, but a developing low pressure system over the western Prairies will produce gusty southerly winds over the Red River Valley. The day will start off sunny, but become partly cloudy midday with winds increasing to 30-40 km/h out of the south. Highs will be near- to slightly above-seasonal in the mid-20’s.

GDPS 10m Wind Forecast valid 21Z Friday August 25, 2017
An area of breezy southeasterly winds will develop on Friday from Lake Manitoba southeastwards across the Red River Valley into Northern Minnesota.

More cloud cover will move in later in the day as a trough approaches from Saskatchewan. Expect a low in Winnipeg near 15°C on Friday night with winds gradually diminishing.

Long Range

Saturday will bring a cloudy day to the Red River Valley as a trough swings through the region. There will be a slight chance of showers or thundershowers as it moves through. There may be a few sunny breaks late in the day, but expect cloudy skies to return Saturday night with another slight chance of showers or thunderstorms.

Sunday will see things gradually improve with near-seasonal temperatures returning alongside some sunshine. The start to next week looks to bring near to slightly above-seasonal temperatures to Winnipeg with a fair amount of sunshine.

Winnipeg’s seasonal daytime high is currently 24°C while the seasonal overnight low is 11°C.

Warm With A Chance of Thunderstorms, Then Turning Drier

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The weather returns to slightly warmer than normal summer fare for Winnipeg to start the week with highs in the upper 20’s and mild lows. It will also be relatively dry, with the only significant chance for rain coming on Monday night as a cold front slowly moves through the Red River Valley.

Today will be a warm and windy day in Winnipeg as breezy southerlies bring summer heat and slightly muggy conditions to the Red River Valley. Skies will become mixed fairly early in the morning as the south-to-southeasterly winds ramp up to 30-40 km/h. These gusty southerly winds will bring mild temperatures into the region, pushing daytime highs just short of 30°C. In addition to the warmth, these winds will maintain the slightly humid conditions in place with dew points remaining in the 16-18°C range. Closer to the cold front — primarily over the southwestern corner of the province but also possibly into the western Red River Valley — moisture will pool and dew points will likely rise into the low 20’s, making for quite a muggy day in those areas.

A potent low pressure system over western Saskatchewan will spread gusty southerly winds across the Red River Valley on Monday afternoon.

By evening, a cold front will be pushing eastwards into the Red River Valley, bringing with it a chance of showers or thunderstorms to much of southern Manitoba.

Going over the MIST ingredients:

  • Moisture: Dew points will climb generally into the mid-teens, but elevated moisture is expected near the cold front as moderate southerly winds enhance moisture pooling ahead of the front. Moisture is also expected to be moderately deep, extending to roughly 850 mb.
  • Instability: Moderate mid-level lapse rates on the order of 7-8°C/km will combine with the low-level moisture to produce MLCAPE values of 1500-2000 J/kg.
  • Shear: Shear will be somewhat lacking with only 25-30 kt of 0-6 km bulk shear; this is fairly low and may be the real limiting factor in any thunderstorm activity that may develop.
  • Trigger: A pronounced cold frontal trough moving eastwards will provide the focus for any convective development.

Overall it seems that there will be enough energy available for severe thunderstorms, but the lack of shear will throw a wrench into the certainty of a large-scale severe weather outbreak.

The highest risk for severe weather in southern Manitoba will be over the southwestern corner where scattered thunderstorms first fire up along the cold front. These storms will have the potential to produce significant hail and strong winds. While an isolated tornado is possible, it won’t be an elevated threat with today’s thunderstorms. As the cold front moves eastwards through the evening and spreads the thunderstorm threat into the Red River Valley, the threat shifts towards favouring strong winds. Temperatures will bottom out overnight around 18-19°C with the winds tapering off.

This simulated RADAR image from the 3km NAM model shows a forecast of thunderstorms for the Red River Valley on Monday evening.

The weather then settles for Tuesday and Wednesday as a broad ridge of high pressure builds into the Prairies. Skies will clear and remain mainly sunny for much of Tuesday and Wednesday as temperatures climb to highs near 27°C both days. It will remain slightly humid with dew points remaining in the mid-teens through the middle of the week. With that humidity remaining in the region, it will keep overnight lows in the mid-teens as well.

Long Range

Gradual upper-level ridging will build into the Prairies late this week and into early next week, bringing continued mild weather and low probabilities of rain. The odd system may slide across southern Manitoba from the northwest, returning temperatures back to seasonal alongside a chance of showers. Overall, though, it appears Winnipeg and the Red River Valley will be entering into a fairly dry pattern.

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