Heat and humidity return along with severe weather for Tuesday

The next few days (things are uncertain for Wednesday so I will do a post on Tuesday evening about Wednesday's potential) will be very active in southern Manitoba with the help of heat and humidity fueling thunderstorm potential, get ready because it is going to be hot!

Severe Weather risk map July 19, 2016

Heat on Tuesday in the mid 80's or high 20's

Dewpoints soaring into the low 20's to mid 20's by afternoon in southern Manitoba.

The day Tuesday looks very unstable hot and humid,high temperatures will soar into the high 20's along with humidex readings in the high 30s to low forties combined there will be a chance for extreme heat warnings by Tuesday morning. Things will get really interesting in the afternoon and evening as a trough of low pressure approaches from the west.

Moisture: No shortage of moisture dewpoints will be advecting northwards along and ahead of the frontal system with values of 18 to 25C, PWATS of more than 1 inch or 50 to 70mm is likely.

Winnipeg Indicies CAPE and lifted index along with shear

Brandon Severe weather indicies for the next few days

CAPE INDEX for Tuesday

Lifted Index for Tuesday

Instability: No shortage of it (above) CAPES will be on the order of 2,000 to 5,000 J/Kg with afew places getting above 6,000. Lifted indicies getting from -7 to -13. This will be sufficent enough for explosive thunderstorm development come mid afternoon,, capping may be an issue though.

EHI for Tuesday at 5pm

Supercell composite for Tuesday afternoon

Significant Tornado Index July 19

Storm relative helicity july  19

Shear: High amounts of shear are available on Tuesday with a lot of Storm Relative Helicity available from 200 to 600 m2s-2, EHI of 5 to 8, and supercell composites from 12 to 25. Bulk shear from 50 to 60knots. This should be sufficent for the formation of dangerous supercells and possible tornadoes.

Trigger: Cold Front arriving from the west and a LLJ cranking up from the south ahead of the front.

Summary: Tomorrow will be a dangerous day weatherwise, a cold front will move through mid afternoon to mid evening, with serious CAPE levels there will be explosive thunderstorm development mid afternoon and evening. A high risk is present in the Western half of the province, and a moderate risk points east into the whiteshell. I expect storms to fire by around 4pm (if the cap doesnt hold) in western Manitoba where a high risk is present all modes of severe weather will be possible with huge discrete supercells likely early on, posing a risk of tornadoes and there could be a few touchdowns.  It will likely grow into a southeast or eastward moving MCS after organizing itself.  In both instances there will be a risk for very large hail up to golfballs and baseballs at best or soccerballs, yes soccerballs given extreme high CAPE, torrential flooding rains, ground scraping wall clouds and shelf clouds, winds in excess of 100km/h and frequent dangerous lightning. The risk for a few spinups or tornadoes will be present in the Red River Valley and Winnipeg by late afternoon and evening with the system, though not as high as a risk as the western half of the province. Western Manitoba mainly a afternoon event and the Red River Valley/Winnipeg, Eastman a late afternoon and evening event. Storms should clear by midnight for most. Remember this is subject to change and Justin on Manitoba weather centre should have updates through the day, I will be volunteering at the fringe festival in Winnipeg tomorrow 11am until 4pm at the patio or the beer tent feel free to stop by and say hi if you want.

I will have a quick update in the comments section by late afternoon and another post on Wednesday's potential late Tuesday Evening once storms clear. Remember to tweet reports to #mbstorm on Twitter and follow them there too!