Our Hot Week Set to End with a Bang!

(Information Provided by Brad from A Weather Moment)

Temperatures are ready to soar for the rest of the week as a heat source from the Gulf of Mexico builds into the southern portion of the province. Everyone across all of Southern Manitoba should begin to prepare for a potentially dangerous end of week powerful low pressure system that will threaten the first significant severe weather outbreak of the season.


850mb theta-e (a form of measuring temperature) chart valid for 06Z Thursday 07 June. 

The above picture with the red arrows very well depicts the advection of a warm Gulf of Mexico airmass into our region, (theta-e is basically a form of measuring temperature). A southerly flow aloft, aided by a long wave trough over British Columbia to our west and a blocking high to our East will bring us the hottest days we have experienced this year, throughout the rest of this week. Temperatures are expected to reach the 25C to 30C range through the second half of this week.       

Postion of fronts and weather at 00Z Friday

 A weak low pressure system will move through Southern Manitoba throughout Thursday night, ahead of the main upper level feature. Even though dynamics don't look to great for severe weather, a line of thunderstorms will likely develop during the late afternoon and evening hours they will intensify aqnd slowly move east-northeastwards. While tornadoes will not be likely with the storms on Thursday afternoon/evening, CAPE values near 1250 to 1750 J/kg combined with Lifted Indicies near -5 and 20 to 30 Shear should be enough for large hail according to Brad. The possible slow moving nature of the line of storms could produce a risk for heavy rainfall with as much as 30+mm falling over a short period of time. While showers will be common over the southwest portion of the province on Thursday, the chance for showers does extend eastwards through the Red River Valley in the afternoon. Most of the precipitation will fall with the thunderstorms that will develop in the evening.

Although this is still 36 hours away and things could change a lot between now and then. According to Brad "models still are having a hard degrading the blocking pattern that is in place right now ,and some are much more progressive with features and some are much slower."  If things end up more progressive than the look now, there may be a small storm threat for Thursday night.

Thunderstorm Outlook for Night 2 (00Z to 18Z June 08).

Brad says " That taking into account the various speeds, the current area that might see storms on Thursday afternoon/evening looks to be the area bounded from the US border north to Brandon, up towards Dauphin/Swan River, then eastwards across the Interlake and southwards down the eastern Red River Valley. Storms will exit through the Central/Northern Whiteshell. Friday will yet again be another warm day;debris cloud left behind from Thursday Night's convection should clear around lunch time which will hopefully allow the sunshine to warm us to the mid to high 20's. Dewpoints look to build in the afternoon pushing up to the 18C or 19C degrees making it feel quite humid. The main frontal system is set to move in on the weekend, and what a system it looks to be.


SPC Day 4-8 Severe Thunderstorm Outlook

According to Brad "We’ll be under the influence of two strong shortwaves that will push copious amounts of instability over Southern Manitoba. CAPE values look to exceed 2500 J/kg and potentially be as high as 5000-5500 J/kg; this, combined with a weak cap north of the warm front and favorable shear profiles looks to point at a potent setup for severe thunderstorms with high probabilities of (extremely) large hail, strong winds, and elevated risks of tornadoes." From My perspective it looks like this setup will be similar to June 22nd and 23rd 2007 tornado event that featured Canada's first F5 Tornado in Elie and that also resulted in 6 other dangerous tornadoes in Southwestern Manitoba.

More Details will be available throughout the next couple days on Twitter and some on my blog post on this potentially serious Storm Outbreak.