A Return to Summer?

Brad Leave a comment

After several weeks of weather that resembled fall more than summer, we may begin to see hot weather return.

A Surface Ridge of High Pressure Will Slide Southward on Monday

Monday

Monday

Mix of Sun and Cloud. Slight Chance of Showers.
23°C / 6°C

However, before we see hot weather again in Southern Manitoba, we’ll have to deal with yet another burst of polar air. Another surface ridge will drop down from the north on Monday, which will result in reasonable, but still cool conditions. High temperatures on Monday will be in the low twenties, though there may be some readings in the mid twenties along the International border. There might be a few showers around during the afternoon and evening as cool air aloft generates a bit of instability. The wind will generally be light and from the north, though it will be a bit breezier in open areas.

Tuesday

Tuesday

Mainly Sunny
22°C / 7°C

Tuesday looks to be just a slightly cooler version of Monday. Highs will be in the low twenties once again with with a light northerly wind. Shower activity looks less likely on Tuesday, but there may still be some bubbly cloud cover as the ground heats up during the day.

Wednesday

Wednesday

Mainly Sunny
23°C / 10°C

At this point there is a bit of uncertainty as to how warm Wednesday will get. Some weather models suggest we’ll see temperatures in the mid to upper twenties, while others suggest temperatures in the low twenties are most likely. I’m leaning towards the later of those two scenarios, as I don’t think the warm air will move in quite that quickly. As a result, I’m once again calling for temperatures generally in the low twenties with variable cloudiness through the day. The area with the best chance of seeing some warmer conditions on Wednesday will be portions of Western Manitoba where that warmer air may filter in a bit during the afternoon and early evening.

Long Range

The longer range forecast is where things begin to look more promising. Models suggest that we’ll stand a good chance of seeing high temperatures in the upper twenties on Thursday. If we’re lucky, we may take a run at the 30C mark as early as Friday, but that type of heat looks more probable on the weekend right now. There have also been some hints in the models that this heat may also be accompanied by elevated humidity levels. Given that the model I’m looking at for this (GFS) is notorious for being too humid, I’m not going to get overly caught up on this for now. Once we get closer to the weekend, and more accurate information is available, this part of the forecast can be more appropriately addressed.

Elsewhere in Weather News: August 10th, 2013

Matthieu Leave a comment

Potent Heatwave Strikes China; Possible Typhoon on the Way

A prolonged heatwave has been in place for this whole week and even a part of last week over most of Eastern China, including the megacity of Shanghai. An upper-level ridge centered directly over Shanghai (but covering the whole region) is contributing to abnormally high temperatures in the region. Scorching heat, ranging from the high thirties to low forties, covered the whole region while remaining in place yesterday. Numerous heat alerts were issued by the Chinese government urging residents to limit outdoor activities, spend time in air conditioned buildings and most importantly, to stay well hydrated. Unfortunately the death toll had risen to 10 people as of Friday, with Shanghai hardest hit.

China surface temperatures

Map of Eastern China’s surface temperatures for today at 4pm, dark orange is over 36 degrees Celcius. (Source: Wunderground maps)

Such a potent heatwave in this region is not common – it has been said that this one is the worst in 140 years. On August 7th Shanghai broke its all-time record temperature, recording an official high of 40.8°C. Before the recent heatwave began, the highest temperature ever recorded in Shanghai was 40.2°C set in 1934. Shanghai’s average high temperature for August is 32°C. Drought concerns are now coming into play as water sources are starting to run low in the east-central region of China where little to no rainfall is expected in the coming week while the heatwave continues.

The southern coast of China could be under the gun for some drenching rains associated with an incoming typhoon: Typhoon Utor. Utor has still not passed over the Philippines but it is expected to make landfall to the northeast of Manila as a category two. Following its first landfall, it will continue travelling into the South China Sea though there is still a lot of uncertainty as to whether it will curve north into China’s mainland or simply brush the south coast.

Utor

Infrared satellite image of Utor on Friday evening, and it’s expected track. (Source: CIMSS)

Weather Set to Slowly Improve

Brad Leave a comment

After a few days under the influence of significantly below-normal temperatures, conditions are set to gradually improve as the cold low that has been anchored over Northern Manitoba, Northwestern Ontario and Hudson Bay – for what feels like forever – begins to slowly shift off to the east.

Friday

21°C / 9°C
A few scattered showers in the morning, then a mix of sun and cloud.
Saturday

22°C / 11°C
Mainly Sunny
Sunday

24°C / 11°C
Mainly Sunny

This morning will start with mostly cloudy skies and a few scattered showers through the Red River Valley. These showers will taper off through the morning and should be over by midday. After that, we’ll see a mix of sun and clouds (although there’s a slight chance we might end up fairly cloudy, but I’ll bet on some sunshine) as we climb to a high of only around 21°C. We’ll have a partly cloudy sky tonight as we drop to a low of about 9°C.

Forecast for 700mb heights & winds from the RDPS valid this morning. The orange dashed line represents an upper trough swinging southwards that is expected to produce a few showers Friday morning.

Saturday and Sunday will be fairly nice days. Winds won’t make much of an appearance while much of our cloud cover finally moves off into Ontario and some warmer air finally starts to push back into the region. We may see a bit of a cloudy start to Saturday, but things should quickly turn sunny as we climb to around 22 or 23°C. We’ll drop to around 11°C Saturday night and then climb to a sunny high of 24°C on Sunday.

Moderation, At Last

The NAEFS 8-14 temperature anomaly outlook issued 12Z August 8th.

The NAEFS 8–14 temperature anomaly outlook issued 12Z August 8th. The lack of colours over Manitoba represents a return to seasonal weather is expected.

Long-range forecast models are finally forecasting a return to seasonal weather over the next week or two. With the relocation of the cold low into Eastern Canada, the persistent cold trough that drove our northwesterly winds will also vacate the region allowing milder air to push back in. Like we mentioned on Wednesday, no particularly warm is set to push into the area, but the warm August sun should quickly modify our air mass back towards seasonal values.

Little to no precipitation is expected in the next 5–7 days as broad upper-ridging slowly builds into the Prairies. A couple weak disturbances will have to be monitored, but for now there’s no rainy days in sight.

Fall Arrives Early

Brad Leave a comment

Distinctly fall-like weather will dominate over Southern Manitoba through the rest of the work week as a (unfairly) cold low slumps southwards into Central Manitoba, spreading cool Arctic air southwards across the Red River Valley and into the northern Plains of the United States.

A cold low slumping southwards into Central Manitoba will bring cooler, distinctly fall-like weather to Southern Manitoba. Image depicts 700mb temperatures for midday today.

A cold low slumping southwards into Central Manitoba will bring cooler, distinctly fall-like weather to Southern Manitoba. Image depicts 700mb temperatures for midday today.

Today & Tonight

Wednesday

18°C / 8°C
Mainly cloudy with a chance of showers.

We’ll see mainly cloudy skies today as the upper low continues it’s southwards trek pushing cool, unstable air into the Red River Valley. There may be some drizzle or a few showers to the in the lee of Lake Manitoba and the south basin of Lake Winnipeg this morning, although there may be enough wind shear to prevent any lake-effect precipitation from forming in this cool air mass. Temperatures will climb to only around 18°C today with some scattered showers developing through the day in most areas of the Red River Valley. The clouds and showers will move out in the evening leaving us with clear skies and light winds as we drop down to a temperature of around 8°C.

Thursday & Friday

Thursday

20°C / 11°C
Mainly cloudy with a chance of showers.
Friday

22°C / 9°C
Cloudy with a chance of showers in the morning then clearing.

Thursday will start off nice and sunny but quite cool. Scattered clouds will develop midday before a more organized area of cloud begins work it’s way into the city from the north in the afternoon. The afternoon cloud will limit our daytime high to only around 20°C. By late afternoon or early evening we’ll see a chance of showers move into the Red River Valley as another batch of moisture wraps around the back-side of the upper low and down through the Interlake. The cloud cover will help keep our overnight low a little warmer – close to 11°C – instead of the cooler temperatures of Wednesday night.

Early Friday morning we’ll probably see mostly cloudy skies with a chance of showers. The cloud cover will push out in the mid-to-late morning and we’ll be left with sunny skies and a high near 22°C. Friday night will be cloudy with a low of around 9°C.

Hope For the Weekend?

While some long-range models are forecasting temperatures in the mid–20’s, at this point it doesn’t look like we’ll see a warm-up that quickly. While the cold air definitely begins to push off to the east through the weekend, no particularly warm air is pushing in to replace it. We’ll see gradual warming thanks to the sunny skies, but at the moment a more conservative forecast of temperatures climbing towards the mid–20’s – instead of rocketing past it – is probably a safer bet. At this point it does look like it will be nice and sunny through the weekend, though, so all in all it will be quite pleasant.