Most of what is stated in my previous post still provides a good overview for this coming evening's forecast, but I'd like to give a few updates.

Winds are still behaving mainly in a Southwesterly fashion, but during the late afternoon-early evening period, they tend to be in the form of West Southwesterlies. I'm thinking, though, that these will gradually give way to true SW winds by the time the fireworks are set to begin. Either way, you'll likely notice the smoke passing off to your right for viewers at La Ronde, but, again, smoke would be moving towards the extreme right end, or towards the right part of the seating area (if mostly WSW winds), in general. Both TWN and EC are currently forecasting Westerlies during the evening, but I suspect that they will change that. We all seem to agree about the wind speeds for the evening: 18-23 km/h (occasional breezes closer to the 30 km/h mark). Winds will likely pick up this afternoon following much more light conditions during the first half of the day.

Precipitation wise, again, steadier rains should give way to more on and off showers for the afternoon and into the evening, though I think the low should depart by around 9:00 p.m. towards the Northeast. Thundershowers/t-storms (non-severe) are possible in the afternoon, especially if the sun gets some opportunity to shine through. I don't anticipate storms developing to anything near what we saw last Saturday, however - there's simply not that much energy to work with, and moisture levels aren't as high.

That's what the atmosphere should mostly have in store for us. In summary, we're looking at a breezy evening with gusts at no more than 35 km/h in the afternoon hours. Widely scattered showers and thundershowers are possible in the afternoon, but things should generally improve as we head into the late evening. During the very early evening, showers and t-showers are still possible, but at a lower chance of about 30-40%. Temperatures should hold at about 17-18 C, but it may feel a touch cooler due to the overall breezy winds. Moisture levels are actually dropping to moderate levels, so it wouldn't feel too humid.

I'd still like keep tabs on the winds, particularly direction, just to be on the safe side. If necessary, I'll post an additional update. If not, then breezy WSW to Southwesterlies will dominate the evening. If things play out the way I think they will, we should be in for an alright late evening.

Trav.

Good evening,

It would seem that we have an interesting weather setup for Canada's display. I'm currently keeping a sharp eye on a strong low pressure system coming in from Western Canada (will eventually become merged), perhaps in time for Saturday night. At this point in time, most of the models are indicating that the showers and storms could arrive overnight Saturday under current speed. The majority of the day Saturday should be following a mix of sun and cloud, with warm temperatures and relatively high humidity along with the chance for convective showers in the early morning thanks to a trough, which may also bring some good storm activity Friday (tomorrow) night. With the system moving in, its approaching warm front will actually keep temperatures very warm into the evening hours (as much as 22-23 C) and begin to boost moisture levels a touch further as well. Towering cumulus clouds will become more numerous in the late afternoon-early evening due to an increasingly unstable atmosphere, so it is a possibility that convective showers and storms could develop in Southern Quebec (I'll keep tabs on the strength of these storms if the likelihood increases of them coming through by the evening). We're essentially dealing with two systems - one departing early, and the other possibly coming in much later Saturday (timing is key here). It's a very buoyant kind of atmosphere on Saturday, much like it has been this past week.

I don't think folks at La Ronde will have to worry about smoke flying towards them this time. Instead, with the position of the low by that time, people viewing on Notre-Dame, possibly De Lorimier and the Eastern portion of the bridge may have to contend with it, which is why I'm considering to relocate myself to avoid poor viewing conditions. Wind tendency appears to be variable between the East and Southeast, so De Lorimier/Western Notre-Dame might be a better bet, especially if Southeasterlies prevail. The expected speeds at the moment are a little tough to forecast, but I believe they could pick up a good deal during the late afternoon and onwards, which is important since humidity levels will be quite high.

Once I receive newer models or synoptic charts to work with, it'll be easier to confirm these conditions, but, as always, the information presented here should serve as a rough guideline in what to possibly expect.

Trav.

Hello everyone,

What was mentioned in the above post for Saturday evening (the 25th of July) still is accurate. As the models are still projecting, the system's cold front moving in from Ontario shouldn't be affecting Southern Quebec until roughly just after midnight and onwards with clustered bands of rainfall and widely scattered thundershowers/thunderstorms (some possibly becoming strong), so that's good news. Though it will likely be partly to mostly cloudy with cirrus and towering cumulus clouds, I wouldn't rule out the possibility of preliminary widely isolated showers developing by very late evening (since places like Ottawa and Cornwall have that risk). Once more, humidity levels will be at about high standards and temperatures should remain just above 20 C during the evening (as much as 23 C). During the day itself, we'll be dealing with a mix of sun and cloud, though more cloud than sun because of the previous system departing and later on because of the cold front associated with the coming system from the West. The best chance for severe weather tomorrow is in Southwestern Ontario.

The winds are, again, more of a concern for viewers on Notre-Dame and nearby streets this time. Winds, in general, will be relatively light for most of the day, though I think they will pick up just slightly by early evening to about 14 to as much as 16 km/h. Directional tendency is still mainly Easterly to East-Southearterlies (ESE) for the day, but there is some indication that there could be more of an ESE shift by very late afternoon into the evening instead of just Easterly - this is preferable since the smoke would be directed more to our left. Either way, we are still likely looking at variability between E and SE for the evening, so for those of you watching on Notre-Dame, to get some better viewing and to avoid large amounts of smoke, the closer you are to the bridge is the better (West of the bridge is ideal). Those on the bridge, the closer to the park you are, the better. This is quite ironic since we were dealing with the same kind of problem when Royal was here in 2003. Winds will gradually shift and stay at more S to SW by later Sunday, and this will be responsible for the continued very warm and humid weather for the next while.

That's the way Mother Nature is governing the atmosphere. In summary, we're dealing with the chance for preliminary isolated showers for late Saturday evening followed by more pronounced bands of rains and storms around 11:30 to midnight and onwards. Partly to mostly cloudy skies will dominate the evening, otherwise. Winds are generally light, though I think they will pick up to adequate values by early evening. Average winds are Easterlies for the day (evening included).

Just for the record, this is the seventh display, and I haven't yet been able to forecast entirely pleasant weather for a Saturday (including ideal winds). What an unsettled Summer this has been. For those of you interested in knowing why Summer 2009 has been the way it was, feel free to give me a shout.

Trav.

Well, I wasn't at all surprised that such powerful thunderstorms developed in Southern Quebec last night and yesterday, and I was expecting this sort of scenario to come about for about 60 hours or so prior to the storms. What a storm we had here last night. Here's a screenshot I took of the radar imagery while I was tracking the weather for several hours - it's a crappy shot, but Montreal is where all the red is. Parts of the West Island and the South Shore got hit particularly hard.

http://i18.photobucket.com/albums/b132/Rain12/CIMG1647.jpg

The same strong slow-moving cold front was involved along with a huge amount of CAPE (convective available potential energy), plenty of moisture/humidity, and the sun made an appearance in the later afternoon, which served to boost instability. It should be apparent that the sun's appearance in signaling pleasant weather is deceiving on a typical day with an unstable atmosphere. In fact, much like for the storms that erupted before China's display, the sun also played a big role in firing up the storms on the evening of the 26th of July. Once you have even a small amount of time for sunshine, that's really all it takes when the right atmospheric dynamics are there.

Here's some video that I took:

The thunderclaps and booms:

http://www.youtube.com/watch?v=cgOXbKEL-Eo&feature=channel_page

http://www.youtube.com/watch?v=UgfL4AVg7Mo&feature=channel

The storm entering the West Island from the SW:

http://www.youtube.com/watch?v=NFUnFxowTw4&feature=channel

http://www.youtube.com/watch?v=GpiNdn1MKEU&feature=channel

The storm departing to the NE:

http://www.youtube.com/watch?v=mppq-QU7S3A&feature=channel

http://www.youtube.com/watch?v=G-OJ3RGsBbg&feature=channel

Storms may fire up again today and this evening, but will likely be non-severe in nature - we'll still keep an eye out, though, for the odd isolated severe cell. The best chance for severe weather has shifted Eastward along the cold front today and for tomorrow. Expect continued very warm and humid conditions this week, along with the risk for storms due to a trough. The chance for severe weather may come into existence once more tomorrow (Tuesday) late day into the evening, overnight and through most of Wednesday for Southern Quebec for more and less the same reasons as last night - doesn't mean we will automatically see severe weather, but merely that the conditions are favorable to the development of strong storms during this time.

Trav.

I justly thought about you last night. I took a look to MeteoMedia website as soon as possible following the thunderstorm and the radar picture was awesome, with a lot of red and pink. Fortunately, it was not a fireworks night!

Fred

Hi Fred,

Indeed, the radar imagery was very impressive on the evening of July 26th. The reds, particularly darker reds, and pinks indicate locally flash flooding rains (in excess of 50 mm per hour), damaging winds, hail, and oftentimes frequent lightning (an occurrence every 0.5-8 seconds). Those colors can also sometimes indicate rotation within the updraft area of the storm, which implies a possible mesocyclone (a precursor to a possible tornado). However, usually you would have to revert to Doppler radar to actually confirm or detect any rotation, or if it has been reported by civilians, weather watchers or spotters in the form of wall clouds or funnel clouds.

Again, as stated in the previous post, we could see some strong storms forming today (the 29th) up until late this evening (perhaps even stretching into the early overnight). We had some decent storm activity very late evening yesterday and around midnight to about 2:00 a.m. There's just so much energy and humidity out there today (probably the highest moisture levels so far this year). I love it. Most of the severe storms currently are to our West and Northwest.

Still keeping an eye on Saturday.

I justly thought about you last night.

That's nice to hear.

Trav.

Good afternoon,

For the first time in 7 weeks, we will likely finally see a Saturday having an atmospheric setup that is free of unsettled weather and conducive to virtually pleasant, mostly sunny, and humid conditions thanks to a beautiful South to Southwesterly flow pushing into Eastern Canada. As a result, we will see a few clouds developing through the day along with, again, warm and fairly humid weather, even lasting well into the evening hours. Highs should reach the high 20s C, while staying as warm as the low 20s in the evening with continued moderate to high levels of moisture.

The only thing that we really need to watch right now are the winds. Overall, I think they will be light in nature and staying predominantly out from the SW. However, it is possible that we will see a Southerly shift as well as breezier conditions by the late afternoon. This would be ideal.

The weekend, in general, is looking good, though Saturday is the best day to make any plans since a cold front associated with the next low will possibly be affecting Eastern Ontario and Southern Quebec by late afternoon and evening on Sunday and into Monday, producing showers and thunderstorms (I know the forecasts aren't showing that yet, but you may see the change later on). Friday (tomorrow) is good, in general, though a passing trough may cause a few scattered showers to develop in the afternoon.

Trav.

Just to provide an update for the winds on Saturday night (tonight), again, we're dealing with a Southwesterly to Southerly flow, but I'm thinking that the winds will shift to more SSW to possibly straight Southerlies by late afternoon to early evening as the low pressure system draws closer. Either way, this means that smoke would be blowing predominantly to the right for viewers at La Ronde (left for those on Notre-Dame). Wind speeds are maintaining light status, but should be at about 12-16 km/h by late afternoon and evening.

As mentioned, temperatures are reaching Summer-like values to as much as 28 to possibly 29 C with moderate humidity, making it feel like the low to even mid 30s C. Moisture levels should hold constant during the evening hours, and temperatures will stay above 20 C during this time (21-23 C). A few cumulus clouds will form here and there during the afternoon due to mild convection, but the air is definitely stable overall (wow), although that will quickly change late day Sunday.

For everything else, please refer to my previous post as it is still accurate.

Weather's fantastic for team USA.

Trav.

P.S. Perhaps we may see some scattered showers or even a thunderstorm tonight (Friday night), again, because of the same passing trough that I spoke of.

Just to update, winds will be closer to 10 than 15 km/h this evening. Everything else remains the same.

Heading to Ontario, but I'll be back this afternoon.

Enjoy the show!

Trav.

The forecast for our final entrant is a little tricky for tomorrow (Saturday). I'm still carefully watching a system that is tracking Eastward into Ontario and Quebec. Given the model outputs, I'm thinking that we'll get away with a good Saturday, but some of the simulations are in a disagreement with the actual timing of the approaching warm front associated with the low during the evening hours in our region - some are predicting the front reaching as far Northeast as Eastern Ontario at this time, while we see partly cloudy to increasing cloudiness here in Southern Quebec by the late afternoon and evening. Others suggest the same, but additionally the risk for preliminary showers/light rainfall during the late evening. I'd still like to monitor the overall speed of the front for the next 12 to 18 hours as this determines everything. Most of the model runs should come up with a general consensus as well.

Winds seem to be behaving in a near-identical fashion to what we had seen during the American display - that is, light Southwesterlies to a gradual Southerly shift (though possibly even Southeasterlies) by late afternoon and early evening. Winds should be at about 9-13 km/h for the evening. What we have is high pressure situated over the Atlantic (rare this Summer) along with this coming low from the United States, both helping to circulate warm moist air from the Gulf into much of Eastern Canada, and hence the Southerlies - this is why Sunday is likely going to be quite sticky and humid, along with the risk for some possibly strong storms later in the day.

Temperatures tomorrow evening won't be quite as warm as last Saturday during the American show, and will likely be hovering at about 18-20 C, compared to the 24-25 C seen last week in the metropolitan area (22 C in the suburbs). Moisture levels will slowly increase during the evening-overnight period, however.

I'll have a final update later today (Friday) to confirm these conditions, particularly with respect to the possible precipitation during late Saturday evening. It is with a fair possibility that precipitation should hold off until the early overnight, but again, it's important to keep tabs on the overall speed of the warm front.

Trav.

I hope that Mother Nature will wait until midnight before sending us these preliminary showers. Other than that, it would be a nice day and a comfortable evening.

Heavy rain and scattered thunderstorms in Quebec City since 6:30am this morning...

Fred

Just to provide a weather update, as most of the model outputs are now in agreement, I believe any precipitation forming ahead and along that warm front should arrive by the later overnight hours, as will the generally cloudier skies. The system has actually slowed somewhat due to that area of high pressure stationed out over the Atlantic hindering its movement, so the earlier simulated sky conditions have now shifted as much as a few hours ahead. Consequently, we will still see some increasing cloud beginning to move in during the evening and early overnight, but those preliminary showers should start by mid-overnight and onwards, while more possible steadier bands of rain on and off for the day Sunday. Rains seem to be more pronounced as far Northeast as Trenton, Ontario during the early evening hours Saturday. In all, we should get away with a nice and pleasant Saturday in Eastern Ontario and here in Southern Quebec.

Wind tendency still is maintaining a Southwesterly pattern for most of the day, but I still suspect a shift to the SSW to possibly straight Southerlies by the late evening and eventually South-Southeasterlies overnight. Either way, you should see the smoke moving slowly to your right for those at La Ronde (left for viewers on Notre-Dame), much like last week. Winds are overall light in nature, but will be a little more breezy during the day before transitioning to more of a light status by very late afternoon and through the evening. Again, speeds during the evening are likely 9-13 km/h.

Ambient temperatures are still expected to be close to what I had mentioned before, which is 18-20 C in the late evening, though closer to 17-18 because we're having a fair amount of sky, low moisture, and relatively light winds present, a combination favoring slightly more radiational cooling. Moisture levels are steadily rising during the late evening-overnight period, but are overall fairly low (in part why both tonight and last night being so uncomfortably cool). Once that warm front comes through mainly Sunday, though, you guys will realize how humid it will be - in fact, Sunday-Monday could be one of the most humid days (feeling almost into the low 40s C with the humidity) we've seen this Summer - I really haven't seen an atmospheric setup quite like this for the entire season. Temperatures overnight Sunday and Monday may remain as high as 25 C. Some thunderstorms may become rather powerful later Sunday through to early Tuesday, though for different reasons - we'll keep an eye on that. There's a heck of a lot of moisture, energy, very warm to even hot temperatures, and even some decent helicity levels (wind shear) present during this period - all conditions for inviting strong storms to fire up and even for rotation within some of them.

Hi Fred,

I saw the heavy rains and isolated t-storms you spoke of this morning passing through the Quebec City area and East-Northeastward on radar - some very impressive downpours there at the time. These rains you've experienced were a part of a trough that was associated with the strong low pressure system situated out over the Maritimes currently. Atmospheric troughs usually enhance instability to some degree because they allow for cooler air to migrate Southward into mid levels of the atmosphere, reducing the ambient temperature at that level and near the surface, and ultimately increasing the likelihood for unsettled weather in whatever affected area(s).
---------------------------------------------------
EDIT: In other weather-related news, an F2 tornado was confirmed in association with a severe thunderstorm near Mont-Laurier, Quebec back on Tuesday when that cold front came through. An F2 is considered strong or significant and can possess winds of up to 252 km/h. To put that kind of speed into perspective, it's more than enough to rip rooves off from homes, uproot large trees and turn large objects into missiles.

Trav.

Good evening,

I suppose these are going to be the last couple of weather reports for the 2009 fireworks season.

With respect to the closing show, well as I'm sure all of you can already see in the forecasts, it's likely going to be a typical Summer day Saturday, much like it has been for the last couple of days or so. The long stretch of very warm/hot and humid weather is the result of high pressure held firmly in place in much of Eastern Canada and out over the Atlantic. This is why I had mentioned later in my previous post that I haven't seen an atmospheric setup quite like this for the Summer. I must say that I'm quite pleased with the results.

The long stretch of this typical Summer pattern may qualify as a true heat wave (three consecutive days of 32 C or more), and high pressure in the area will suppress heavy convection since the air is sinking as opposed to rising. This very warm and humid airmass will likely stick with Eastern Canada until most of Tuesday at this point before a cold front moves through late day and into Wednesday and delivers potentially severe thunderstorms. Until then, expect highs in the very high 20s to even low 30s with progressively more and more humidity as we get into tomorrow and then the weekend, making it feel into the high 30s C to possibly the low 40s C. Overnight lows will remain anywhere between 21 to as much as 24 C, along with continued high humidity. A developing system South of Hudson Bay will remain North and travel Northeast because of the jet stream.

As such, we should therefore see a very warm and humid Saturday evening with generally light winds coming out from the Southwest. Mild convection will be present under the influence of high pressure, so a few cumulus clouds will form here and there. Evening temperatures in the metropolitan area may be as high as 25 C and feeling into the low to possibly mid 30s C with the humidity. Wind tendency should remain as Southwesterlies, so smoke will be moving off in about the same direction as was seen during both the American and South African performances. I'd still like to keep tabs on the speeds, however, especially since they're light in nature and the fact that moisture levels are rather high by this weekend. If the speeds remain at or close to the values I'm currently seeing in the model runs, then we should be in for a perfect Summer evening for the closing.

I'll have a final update later tomorrow to confirm the wind conditions. Enjoy the weather, everyone - make up for some lost time.

Trav.

Good evening,

To provide an update for the wind velocities, well, the models are still in an agreement in showing Southwesterlies as the dominant direction for Saturday, though some variability between the WSW and SW through the day, but mostly SW to even a slight South-Southwesterly (SSW) shift by the evening. Therefore smoke, again, should be moving off mostly to the right slowly for viewers at La Ronde (opposite for viewers on Notre-Dame). Speeds are expected to be at about 15 to as much as 19 km/h in the afternoon, but will gradually diminish to lighter status by the early evening to about 8 to no more than 13 km/h - I noticed similar wind patterns over the last 48 hours - it's common with high pressure areas. Speeds, though, should be adequate to move the smoke out fast enough most of the time. A smog advisory could also be issued for the Greater Montreal area tomorrow as well with these kinds of conditions, much like the case today.

Temperatures will remain very warm in the evening, much like it is right now as I write this. I anticipate potentially 27-28 C during the early evening and then gradually to 25-26 C by late evening, especially in the metropolitan area. Moisture levels are high, so it will feel like the high 30s C in the afternoon and low 30s C throughout the evening. With very mild convection, we'll see a few clouds developing here and there, but will become mainly clear in the evening due to the loss of the sun.

That's the way Mother Nature is governing the atmosphere. Another typical Summer night on the way - how appropriate to conclude the 25th anniversary.

Trav.

Just thought I'd provide a final set of weather updates, even though it's not going to be a major display this coming Saturday. Your forecast for Saturday (the 22nd of August) is calling for somewhat improving conditions following this rather unsettled weather pattern in place for both today and tomorrow.

What we are currently dealing with is a vigorous low pressure that has a large amount of upper level support. The cold front, then, associated with this low is quite powerful, and I'm not sure if you've heard, but a fairly large tornado and severe thunderstorm outbreak has struck Southern Ontario (one possible fatality and widespread damage) this afternoon and is continuing to do so as it moves further to the Northeast. Here in Montreal, we face the risk for some thunderstorm activity, some of which may be severe later tonight and through tomorrow (Friday) as that same cold front comes through. There is a lot of moisture, convective energy and instability in the atmosphere, so it's possible for severe weather to develop in Eastern Ontario and Southern Quebec tonight and until, I'd say, the early evening hours tomorrow as the cold front continues to travel in this direction.

As this system moves further Northeastward towards the Maritimes, it will likely merge with Hurricane Bill, who is tracking further North and will eventually curve to the Northeast thanks to this deep upper level trough of low pressure in the polar jet. This may have some influence on the weather on Saturday depending on how much this merged system remains Westward. However, regardless, I'm thinking that things will become increasingly fair by the afternoon and evening with temperatures remaining close to 20 C along with light Southwesterly winds Saturday evening. As the area of high pressure dominates Ontario and Quebec by Sunday into Monday, it will possibly invite unseasonably cool, but pleasant conditions stretching for a few days, though overnight lows may be a little on the chilly side.

A final update will come tomorrow (Friday) evening to confirm these conditions, but in the meantime, once more, be aware that we have the risk for some potent storms for the next 24 hours. It's important to remember that this doesn't necessarily mean that we will in fact see severe weather, but rather that conditions are favorable to their development for this time period. Environment Canada will appropriately issue watches and warnings if they become necessary.

Trav.