Your Canada Day forecast:
In the wake of the severe weather triggered by Monday evening's (June 28th) strong cold front, cooler air has, as expected, settled into Eastern Canada from the Hudson Bay and is expected to last for a couple of days longer (today included) due to a sharp trough in the jet stream. As such, this trough does play a role in governing Canada Day's weather before Summer-like conditions make their graceful return. Here is what to generally expect in most of Southern Quebec for Canada's 143rd birthday:
Temperature/humidity:
With the trough persisting and with an area of strong high pressure advancing in, daytime highs will continue to struggle in surpassing 20 C, and overnight lows will likely hover around the mid teens (a little cooler in the the lower double digits towards the Eastern Townships during the late evening-overnight period). Temperatures are suppressed due to breezy Northwesterly winds, and the same holds true for humidity levels (low). Equipt a light jacket or sweater if you plan to be out long just before and following dusk - it will be a chilly, if not cool, night.
Precipitation:
Instability will continue to linger into Southern Quebec for Canada Day because of the wrap-around effect of the low pressure system situated (strengthened by the trough) over central Quebec, and so widely scattered showers (brief if you encounter any) during the afternoon hours are possible, particularly when advancing Eastward into the Eastern Townships and towards Quebec City - otherwise simply a mix of sun and cloud, much like today. As a result of high pressure moving in, though, the chance for instability becomes lower into the very late evening-overnight, and I thus believe there will be mostly scattered low to mid level cloud by that point in time. Saturation levels are low at the surface and aloft by late day, but a little higher as you head East and Northeast of Montreal during the very early evening/late afternoon, resulting in a continued slight risk (still at 30-40%) for scattered showers for these hours in those areas. Chance of showers for the day is 30% in most of Southern Quebec.
Winds:
As mentioned previously, winds are principally coming out from the Northwest to later West-Northwesterly (WNW) at speeds in the moderate range at 17-23 km/h, though diminishing to 12-15 km/h (same directional range) by late evening-overnight. With the low humidity, the winds will provide a little chill when they blow, especially considering the direction(s).
***If you plan on heading to Ottawa, weather conditions are similar to Montreal, and so the evening should be ideal for the fireworks there, just on the cool side.
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Two tornadoes were confirmed by Environment Canada with the squall line on the evening of June 28th, one of which touched down in the West Island in Saint-Anne-de-Bellevue (roughly 8 km Southwest of where I reside) and the other just to the North of Montreal in Mascouche, roughly 30-35 km North of the city. Both tornadoes were registered at F0 strength (the weakest), but though at the lowest end of the Fujita scale, winds are, most assuredly, powerful enough to do some damage to trees (some large) and property, which was indeed the case for both areas affected. Fortunately, no injuries or fatalities were reported. An F0 is capable of winds of up to 116 km/h.
There were apparently numerous observations of funnel clouds that evening and earlier in the afternoon in both Ontario and Quebec, though I suspect many of the these reports had mistaken them for scud formations. As previously explained in the above post, scud clouds are clouds that commonly develop underneath the shelf cloud due to the powerful downdrafts forcing the warmer, moister air ahead of the storm to rise and condense into additional funnel cloud-like formations. Because of their ominous appearances, and the way they hang or droop beneath the shelf cloud, they are often erroneously identified as funnel clouds. Scud, however, can sometimes point to rotation, and therefore the presence of mesocyclonic activity, if or when they exhibit circular motion below the base. Wind shear, which are winds that change in speed or direction (or both) with increasing elevation, was also quite high that day, which prompted many appearances of funnel clouds.
Here is a picture shot from Saint-Anne-De-Bellevue:
http://www.theweathernetwork.com/your_weather/details/620/2899137/3/ca qc0142?ref=ugc_city_thumbs
I'll be heading down there to survey the damage.
Edit: And Tyler, it's a real pleasure to see and hear from you again, my friend.

No problem, as always, for the forecasts and analyses.
Trav.
