Upper-level flow forecast for this evening over Central North America from the GEM-GLB. Of note is the shortwave pushing out of Alberta. This feature will flatten the upper ridge over Southern Manitoba and bring some unsettled weather to SW MB on Sunday.
Rainfall will continue to be spotty and elusive over the Red River Valley as warm temperatures persist and and upper-level ridging maintains it’s hold over the Eastern Prairies. While numerous systems trek through Alberta and Saskatchewan into Northern Manitoba over the next few days, mainly sunny skies are in store for us as we head into the weekend with daytime highs generally around 28°C across much of the Red River Valley. Humidity levels will be lower today and through the weekend than they were on Thursday, however overnight lows will still remain relatively warm in the high teens.
On Sunday, a low pressure system will move eastwards out of Saskatchewan through the Interlake region. Models are suggesting that a band of nocturnal thunderstorms will push into Southern Manitoba on Saturday night and push eastwards before dying around mid-morning. It’s far too early to know where these storms will actually occur, so we’ll be sure to provide updates in the comments. After that band of thunderstorms falls apart, the rest of Sunday actually looks quite nice with clearing skies in the RRV and a high near 30°C.
Next week looks to start off quite pleasant with little chance of precipitation in the RRV until mid-week.
Southern Manitoba will quickly heat up to be extremely hot for the later half of this week, while any rain/thunderstorms will remain fairly elusive through the Red River Valley.
You might need one of these on Thursday.
A strong thermal ridge will start pushing it’s way into Manitoba toady with 850mb temperatures of 22-24°C. This will really crank up the heat over the Red River Valley. Today will be our coolest day over the next few days, with temperatures “only” climbing to 27°C with light winds from the north. There will be some clouds around today and a very slight chance of a shower or two late this afternoon as the warm front starts pushing into Southern Manitoba. Winds will shift to the south overnight tonight, with a low around 18°C.
The southerly wind should help clear the air of any haze and smoke that’s remaining in the Red River Valley, which will allow the full power of the sun to help cook the atmosphere on Thursday. 850mb temperatures will climb towards the mid-20’s, which will help surface temperatures easily climb into the mid-30’s. Two uncertainties exist to the daytime high:
Moisture. The higher the dewpoint is, the more energy it takes to heat it up. That makes it harder to reach really high temperatures when the dewpoints are high than when the air is dryer. For Thursday, the NAM currently predicts dewpoints to be right around 20°C, the GFS pumps dewpoints up to nearly 25°C, and the GEM has them right around 22°C.
Wind direction. Winds will be southerly to start the day, however a weak trough pushing across the RRV should start to shift the winds to southwesterly. When a southwesterly wind is in place over the RRV, it helps to increase daytime highs by a few degress as the wind downslopes over the western escarpment and heats up a little bit. The air often drys out a bit in this process as well, which aids in helping the temperatures increase a bit.
Should the moisture end up being on the lower side and we do get a southwest wind in place over the the RRV, temperatures could potentially shatter our previous hottest day of the year. Models indicate temperatures of 37-40°C are possible over the southern RRV, while temperatures of 34-37°C can be expected over the northern RRV. I’d be very hesitant to say we’re going to hit 40°C in Manitoba on Thursday, especially with dewpoints in the 20’s. It will certainly be an extremely hot day, and when the temperature and the dewpoint are taken into consideration, widespread humidex values of 40-45 will be seen across Southern Manitoba with the potential for isolated spots to see even higher values. Either way, it’s almost certain we’ll see temperatures at least in the low-to-mid 30’s over the RRV, with humidity making it feel much closer to the low 40’s.
Things will cool off a bit on Friday as some less-warm air filters in aloft. 850mb temperatures are expected to drop to a more modest 15-20*deg;C, which will cap daytime highs to “only” 30 or 31°C. Dewpoints should also be a good 3-5°C lower, making it a slightly more comfortable day.
There’s a slight chance of a shower or thundershower on Thursday evening over the more northern portions of the Red River Valley, although any activity will likely stay in the Interlake region. Our chances for showery weather increase into the weekend as cooler air beings to inflitrate it’s way in aloft while down here at the surface we remain near the nose of a thermal ridge. Highs will remain in the high 20’s through the weekend.
More warm to hot weather is expected for this week. Our hot spell continues…
You’ll be seeing a lot of this again this week.
High temperatures through the first few days of the week are expected to be in the mid to upper twenties in Southern Manitoba. No irriguous weather is in the forecast for this period, save for perhaps some rain this morning from a passing thunderstorm complex and a chance for some more showers late this afternoon and through the evening as a bit of cooler air filters southwards on the back-side of the low exiting the province today.
As we move into late week models hint at the potential for another heat wave. The generally accepted definition of a heat wave in North America is three or more consecutive days with high temperatures of 32C or greater (90F or greater). Temperatures of this magnitude may be possible from Thursday through Saturday of this week. In addition, dew points are expected to rise through the latter half of this week, which when combined with the hot temperatures will produce humidex values in the low-to-mid 40s! Since this forecast extends fairly fair into the future weather-wise, it may change somewhat as the week progresses.
As has been the case for much of the last month, long range modelling shows no end in sight to our hot weather. It looks like July should end just as it started – HOT!
Significant flash flooding struck Japan this week due to severe thunderstorms that remained nearly stationary for several hours over the southern island of Kyushu. The stationary boundary collided with warm, moist air from the Pacific igniting the thunderstorms and continuing for nearly 24 hours now, from Thursday afternoon to Friday night causing tremendous amounts of rain to fall over the same areas.
Surface map of Japan with stationary boundary in red and flash flooding region talked about in green box. Effective 1pm Friday, CDT. (Source: Japan Meteorological Agency)
According to the Japan Meteorological Agency, a record of 500+mm (20 inches) fell in Aso and Kumamoto City in less than a 24 hour period overnight Thursday, causing severe mudslides in the area. In all, 15 people have died as a result of the flash floods and mudslides, with 11 still reported missing. Authorities have sent out search teams, where it is safe to do so, to find the missing or buried. As of Friday night, they have found eight survivors buried in the mudslides. The severe mudslides forced people to shovel their way out of houses and to wade through thigh-deep mud to make their way around. Thankfully 68,000 people had been evacuated from the area prior to the storm, avoiding additional casualties. Among the damage, about 22,000 households lost power, train services were shut down, many roads were inaccessible, and rice crops were severely damaged.
First responders searching for survivors where a mudslide destroyed homes. Taken in Minamiaso, Japan. (Source: Reuters)
Road covered in mud and cars left over by the flash floods in Kumamoto City. (Source: Jiji Press)
Unfortunately the stationary boundary is not going anywhere any time soon and is forecast to continue to spawn thunderstorms for the next three to five days as the warm, moist air continues to collide with it and the mountains. Another 100+mm is forecast for Saturday in the region once again, with even a slight chance of tornadoes added to the mix. Friday night, heavy rains warnings (including ground-loosening and inundation) and flood warnings were still in effect with an advisory (watch) for severe thunderstorms in the region.
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