Slight Chance of Showers Saturday Evening

A system tracking across the Rockies into Alberta will slide quickly across the Prairies, brining increasing cloudiness to Winnipeg and the RRV Saturday afternoon with a slight chance of showers in the evening. For more info, read on!

12Z 21 October GEM-REG 3 hour precipitation accumulation valid at 00Z Sunday (Saturday Evening)

Overnight a low pressure system will track across the Central Prairies towards Manitoba with a developing N-S trough intensifying as it moves eastwards. As it enters The Pas and Norway House areas on Saturday, Winnipeg and the RRV will see increasing clouds and a strengthening southerly wind to 30-40 km/h. As the trough swings through Winnipeg in the late afternoon and early evening, we’ll see a slight chance of a shower or two. The bulk of the precipitation should stay north of the city, closer to the low, where there is more significant lift. All models bring the edge of the rain close to Winnipeg, though, so it certainly isn’t out of the question for us to end up getting 2-4 mm out of an hour or two of rain. It seems most likely, though, that late afternoon and the evening will be overcast with a scattered shower or two.

After this system passes through, we’ll enter a stagnant pattern for a couple days with daytime highs just below 10°C and overnight lows slightly below 0°C.

Ensemble 500mb Theta-E
Ensemble Mean 500mb θe

The next chance for significant weather looks to be next Tuesday night / Wednesday morning as a rather sharp 500mb cold trough swings across the province. This will present us with a slight chance of flurries overnight, but shouldn’t amount to too much. More on that next week.

Have a great weekend and enjoy these crisp fall days!

Significant Rainfalls On The Way for Tuesday

A low-pressure system approaching Manitoba will rapidly develop this evening as it enters the province, bringing one of the most substantial widespread rainfalls of the last several months. The largest amounts will lie along a narrow axis called the deformation zone which makes these events hard to predict: a slight change in the track of the low can cause shifts in the placement of the deformation zone. So where will Winnipeg lie? What can other areas of the Red River Valley expect? Click through to find out!

12hr. Rainfall from the GEM Regional Model, valid 00Z Wednesday Evening

This system is slowly built into Southern Alberta through the night last night, and is now beginning to quickly move eastwards across the Prairies. Currently, the system is fairly weak, giving only light showers to many areas across Southern SK/AB, however a shortwave ejecting onto the Prairies from the Canadian Rockies will slidealong the US/Canada border this evening and overnight and will be able to tap into warmer air aloft over the Eastern Prairies and a pool of extremely cool, Arctic air over the Northwestern Prairies.

The combination of a powerful shortwave with access to these two air masses will result in a rapidly deepening low pressure system. Currently, the low sits just east of Regina and has a central pressure of about 100.8kPa. By mid-morning Tuesday, the low will sit over the Southern Red River Valley with a central pressure of 99.5kPa, which is a significant drop in pressure over 12-18 hours.

Rain will push into SW Manitoba by this evening, with a few scattered showers across the Red River Valley before midnight. Rain will intensify and build across the RRV into SE Manitoba overnight as the system really starts tapping into some of the cooler air across the Northern Prairies. The deformation zone will become quite apparent by tomorrow morning, which will make the precipitation forecasts easier, but right now it’s looking like it will set up just over or the southeast of Winnipeg.

So! What does this all mean?

Rain will push into Winnipeg and areas south overnight and be quite intense at times. Widespread amounts through these areas will likely be 5-10mm overnight, with the chance of some higher amounts over the Western Escarpment. Tomorrow will be quite an active weather day, with continuous rain for much of the RRV and strong winds with gusts as high as 70-80km/h from the north. These strong winds will likely cause some localized erosion on the lee beaches of the lakes which are still dealing with high water levels.

Areas south of Winnipeg will see an additional 15-25mm of rain tomorrow with few areas getting as much as 30mm, as will the Whiteshell. Winnipeg itself, however, will be trickier. If the deformation zone sets up to the southeast of us, we’ll likely only get perhaps 5-10mm. If we end up under it, or it moves to our NW, we could see substantial amounts of rain. Right now, the likely scenario is 10-15mm, with the potential for amounts as high as 30mm.

The system will clear out by Wednesday and we’ll be left with daytime highs in the mid to high teens for Wed/Thursday as we sit in cooler air behind the cold front associated with the system. By the end of the week, another upper ridge begins to build into the Prairies which will push sunshine and warm temperatures back into Southern Manitoba. Currently, it looks like we’ll see highs in the mid-20’s by week’s end.

So enjoy that (most of) you’ll be at work tomorrow during our kind of miserable day, and we’ll all enjoy the sunshine and warm temperatures in another taste of summer this weekend!

Canada’s Ozone Tracking in Jeopardy (Along With Many EC Programs)

Canada’s Ozone Tracking in Jeopardy (Along With Many EC Programs)

Record Setting Heat Across the Prairies

Summer has decided to hang on and not leave us quite yet, bringing record-breaking heat to much of the Canadian Prairies. A large upper ridge build into the region on Tuesday and Wednesday, pushing the jet stream all the way up to the 60th parallel which has allowed a hot, dry southwest flow to remain in place over Alberta, Saskatchewan and Manitoba for days on end. Records have fallen left in right, with some of the highest daily quantities of records being broken at once over the last two days.

How long will this heat stay with us? How hot is it going to get? Click through to read more!

On Wednesday, September 7th, 22 record highs were broken across Alberta, Saskatchewan and Manitoba:

Daily Record Temperatures set September 7, 2011

Location New
Cold Lake 30.4 27.8 1998 1953
Fort Chipewyan 27.0 25.0 1937 1884
Fort McMurray 31.0 28.3 1949 1944
Jasper 29.6 29.1 1998 1943
Whitecourt 29.1 26.7 1949 1943
Saskatoon 33.4 31.5 1990 1892
Collins Bay 28.0 18.8 1980 1972
Hudson Bay 30.7 30.2 1990 1943
Key Lake 30.0 21.5 2005 1977
La Ronge 29.6 27.7 1980 1923
Meadow Lake 30.2 28.5 1998 1924
Melfort 31.7 31.5 1980 1902
Nipawin 33.0 32.2 1934 1927
North Battleford 33.0 32.2 1893 1880
Rosetown 32.6 32.0 1991 1937
Stony Rapids 27.0 22.7 2005 1960
Fisher Branch 29.7 29.5 1980 1977
Gimli 28.3 27.9 1980 1944
Lynn Lake 29.0 23.9 1980 1952
The Pas 30.3 29.4 1934 1910
Thompson 27.6 24.5 1990 1967

Of note on this day:

  • North Battleford broke a daily record high temperature that was set in 1893, a record 118 years old.
  • Many record highs were broken by at least 2 or 3°C, and some by nearly 10°C.

On Thursday, September 8th, 22 record highs were broken across Alberta, Saskatchewan and Manitoba:

Daily Record Temperatures set September 8, 2011

Location New
Cold Lake 30.8 29.8 1981 1953
Coronation 32.2 31.2 1981 1928
Fort McMurray 32.1 30.4 1981 1944
High Level 27.4 26.3 1995 1967
Jasper 30.0 29.8 1998 1943
Sundre 26.9 26.0 1994 1985
Waterton Park 28.3 28.0 1994 1966
Saskatoon 34.1 33.5 1981 1892
Collins Bay 24.6 24.1 1981 1972
Hudson Bay 31.7 30.2 1990 1943
Kindersley 33.2 32.8 1981 1913
Leader 34.2 33.5 1981 1924
Nipawin 32.8 32.2 2003 1927
Stony Rapids 24.1 22.3 2003 1960
Fisher Branch 32.1 32.0 2003 1977
Gimli 31.1 30.0 2003 1944
Island Lake 28.1 25.2 2009 1971
Lynn Lake 26.6 23.6 1980 1952
Pinawa 30.7 30.5 2003 1964
Sprague 30.9 29.4 1932 1915
The Pas 30.3 27.5 2003 1910
Thompson 28.0 25.8 2003 1967

And today, September 9th, 2011, 18 records were broken:

Daily Record Temperatures set September 9, 2011

Location New
Edson 28.7 27.8 1963 1910
Fort Chipewyan 30.0 27.0 1981 1884
Fort McMurray 32.7 32.4 1981 1944
Jasper 30.4 27.2 1944 1943
Sundre 28.9 25.8 2006 1985
Waterton Park 28.5 27.4 2006 1966
Whitecourt 29.7 29.0 1981 1943
Collins Bay 28.0 23.0 2003 1972
Hudson Bay 31.7 29.0 1998 1943
La Ronge 31.0 26.6 1994 1923
Nipawin 32.1 29.2 1981 1927
Stony Rapids 29.1 22.0 2006 1960
Fisher Branch 31.8 31.5 1982 1977
Gimli 31.1 31.0 1982 1944
Lynn Lake 31.1 26.6 2003 1952
Sprague 31.9 30.0 1931 1915
Swan River 31.7 30.0 1998 1908
The Pas 30.7 26.8 2003 1910

This record-setting heat is all thanks to an impressive upper ridge that has built into the Prairies. This is a feature located high in the atmosphere that causes a large area of air to subside (move downwards). Combined with the fact that they build up from the south, they bring a lot of warm air along with themselves, and often result in a large area seeing sunny skies, light winds and hot, dry weather.

The upper ridge will remain in our area for the next couple days, with daytime highs remaining in the low 30°C range. Winnipeg has an honest shot at breaking our daily record high temperature tomorrow which sits at 32.4°C. Things will abruptly change next week however. On Monday a low pressure system will pass by to our north and drag a cold front down across the province. Through the following days, a large ridge of high pressure will build in from the northwest, bringing significantly cooler temperatures than the past week:

GFS Temperatures Valid 06Z Thursday 15 Sept
GFS Surface Temperatures Valid 06Z Thursday 15 September

Currently it looks like next Wednesday and Thursday will be the coldest of the days, with highs struggling to get as high as 15°C. While the last week has been a beautiful late-season blast of summer, fall is set to make an aggressive entrance early next week.