I thought that it would be appropriate to now post this, being now within 10 days of commencing the first edition of Montreal Fireworks in practically three years. That said, it was interesting to still be able to post weather analyses over the last two years in an attempt to better understand the extent to which tentatively assigned fireworks days/evenings would have been impacted by weather conditions, whether positively or negatively.

To that end, weather reports will be provided in this thread for each of the nine (9) fireworks days scheduled for 2022. For each display, a discussion of temperature, humidity, rainfall development, as well as wind speed and direction, will be provided. A preliminary report would first be posted approximately 48 hours in advance of a given fireworks day, followed by a finalized report about 24 hours prior to each display time. Additional updates following finalized reports (i.e. on the fireworks days themselves) would be supplied in situations where rainfall and/or thunderstorms are possible, as well as for unfavorable wind speed and direction.

As always, everyone is also more than welcome to share any weather information!

Hopefully, all displays, especially during actual display time, would face ideal conditions.

Trav.

From now, I am going to visit this forum more frequently. I am glad to know that we may rely on your detailed, specific, and accurate weather forecast once again this year!

I suspect the wind speed may be a particular issue this Saturday for the drones. I don't know the specifics, but I imagine these light devices - and the choreography made with them - are particularly sensitive to wind speed.

Fred

The first display of the 36th edition of the Montreal Fireworks Competition will favorably coincide with borderline very warm to hot conditions in what would be part of a near-heat wave event (June 24th-June 26th). Indeed, for the greater Montreal area, a maximum temperature of 29 C to potentially even 30 C will be possible for June 25th. In light of the high humidity, this would further induce a maximum humidex of 35 C by mid-afternoon. Into the late-evening, the temperature value would only decrease slightly, remaining at 26-27 C by display time (humidex of 32 C).

Precipitation development would be restricted as a result of this region being governed by an area of high pressure, though some fair-weather cumulus and high-altitude cirrus patches are favorable. For the evening, the sky should be largely clear with isolated cirrus clusters in the distance.

In the wake of a strengthening area of low pressure ejecting East (which would amplify warm air advection on June 26th), winds should gradually adopt light SE tendencies by late-afternoon and would carry with them speeds of 6-8 km/h. This would allow fairly rapidly building smoke to drift slowly to the right and slightly away of the La Ronde audience. Higher altitude smoke motion should behave in a similar manner. Periods of extensive smoke accumulation, however, would be possible during more energetic pieces of the display and/or if there are moments where smoke-rich products are used.

Another update to follow late this evening (June 24th) or into predawn June 25th.

--------------------------------------------------

Fred – No problem for the weather updates!

Would drones be a part of this opening display? If so, the latest thinking is that the wind speeds should be light enough for good flying conditions.

Trav

The drones are before the display, not part of it - that's why I didn't really cover them in the interview as they're nothing to do with the actual display itself.

Forecast details specified in the previous update continue to be applicable for this first opening display day. As such, presented here are the dominant weather conditions for Saturday, June 25th for the greater Montreal area.

Temperature/Humidity

Very warm to hot conditions continue to be favorable for Eastern Ontario to Southern Quebec for June 25th. For the greater Montreal area, specifically, a maximum temperature of 29 C to 30 C is likely (mid-afternoon). As a result of the borderline high to very high humidity, the highest achievable humidex should be 36 C to 37 C. For the late-evening period, including display time, a temperature of 26-27 C is likely, and with continued high humidity, the humidex value should be 33-34 C.

Precipitation

Rainfall development in this general area is largely limited, as mentioned previously. However, some of the recent surface data does indicate some localized enhanced lift, especially farther North/NE of the island. This would support a narrow window of opportunity for a briefly-sustained and slow-moving isolated non-severe thunderstorm and/or convective rainfall during the mid-afternoon to late-afternoon, when the available instability is maximized. For this reason, a 30% probably of precipitation is included here. Still, mostly clear conditions are favored, especially after sunset. During the evening, a few residual cumulus and distant isolated clusters of cirrus are favorable.

Wind

Wind speeds continue to be rather light to occasionally calm for most of this day, with the except of the mid- to late-afternoon, when speeds are somewhat breezier. Earlier in the day, wind fields are largely in the form of light Westerlies, but by late-afternoon, as a strengthening area of low pressure advances NE, winds should transition to light ESE, at 3-6 km/h, including into the evening. This would allow rapidly building smoke accumulation to travel (very) gently away from the on-site audience, slowly towards the audience on Notre-Dame Street. This would further apply for higher-altitude smoke. Periods of extensive smoke accumulation are favorable, depending on how frequently active this display realistically is. At some points, the smoke can potentially appear near-stationary along low- to mid-level, though the Easterly component in the wind fields would best help the viewing from La Ronde, and for those positioned on adjacent sections of the bridge nearest to La Ronde.

If necessary, another update concerning principally wind speed/direction will be provided by the mid-afternoon of today (June 25th).
------------------------------------

Paul – Thanks for that clarification! Indeed, after reading about your interview previously, I was under the impression that the drones would be used at some point prior to the actual display, and that turns out to be the case!

Trav.

Wind speeds continue to be light during this evening (June 25th). Directional tendencies should still undergo a transition to ESE to SE by early this evening, but speeds should also be slightly stronger (6-9 km/h) to allow the smoke to displace a little faster (clear to the right of and away from the La Ronde audience), which would be helpful during times of larger smoke accumulation. For those on Notre-Dame Street, viewing from closer to the bridge would be most suitable to avoid smoke interception.

Trav.

There was an unexpected twist with the wind during the pre-opening display tonight!

For the audience at La Ronde, the speed and direction of the wind were perfect, blowing the smoke gently towards our right, and keeping the view very clear throughout the show. Then, in perfect synchronization with the end of the display, the wind turned to Westerlies, so we were treated with a smell of sulfur that many fireworks aficionados like!

That was a perfect ending!

Fred

Hi Fred,

Yes, that is quite something! Fortunately, the vast majority of the show carried with it a clear view due to the SE to SSE wind fields, but it is interesting how that alteration occurred so neatly with the end! When winds are so light, they become more subject to localized features (such as terrain), which can suddenly cause them to change direction before their regular flow can be restored.

Trav.

Weather conditions for the second opening display (July 2nd) should largely be ideal. Following what would be a very warm and highly humid July 1st/Canada Day, conditions would quickly favor a much less unstable environment as July 2nd progresses. A maximum temperature of 26.5 C to 27 C is likely for the greater Montreal area by mid-afternoon. As humidity drops to moderate standards, the maximum humidex would be 29 C. By late-evening, the temperature would decrease to 21 C, but with a negligible humidex as a result of mostly low humidity at the time.

Rainfall development would be limited beyond early-predawn as increasing stability unfolds, allowing skies to mostly clear by mid-morning and leaving behind some fair weather cumulus. Later in the day, a weakening cold front will advance South/SE and would provide some lift suitable for an increase in some lower-altitude cloud cover (with clear breaks) overspreading the region at the time.

Winds would largely be in the form of breezy to gusty SW to WSW over a large vertical depth, with (near-) surface speeds of 24-28 km/h (gusts of 35-39 km/h, especially during the morning to early-afternoon). By evening, the SW base speeds would decrease to 17-21 km/h (occasional gusts of 29-32 km/h). As such, the smoke would be moving quite rapidly towards far right-hand sections of the La Ronde audience, though higher-altitude smoke would also sometimes be moving towards right-hand and partially central sections (possibly with some occasional pyrotechnic debris). Significant accumulations of smoke are not expected, especially in light of the borderline low-moderate humidity by late-evening. The display, however, could appear frequently hazy when viewing its right-hand sections. The breezy winds would also induce a slight chill at times for some, especially as the humidity is low.

Another update to follow by tomorrow late tomorrow evening to early-predawn (July 1st-July 2nd).

Trav.

Details mentioned in the above posting continue to largely hold for July 2nd. As such, presented here is the overall weather conditions expected for Saturday, July 2nd for the greater Montreal area:

Temperature/Humidity

Temperatures continue to showcase values that are very warm for the day, despite a gradual introduction of cooler, drier air deeper into the day. A maximum temperature of 27 C is favorable by mid-afternoon, and with continued moderate humidity, the highest achievable humidex would be 31 C. By late-evening, the temperature would decrease to 21 C, with a negligible humidex in light of borderline low-moderate moisture levels (low by display time).

Precipitation

While rainfall would be restricted as a result of an increasingly stable environment beyond the predawn of July 2nd, a secondary but weakening cold front would encourage a layer of low-level cloud during the evening (i.e. post-sunset), with some large clear breaks in between.

Wind

Wind speeds would resolutely follow a WSW to occasionally SW pattern throughout the day over a great vertical depth. Wind speeds would be rather gusty later in the morning through to the mid-afternoon, in particular, but these base speeds would weaken slightly by late-afternoon (though still breezy). Speeds during the late-morning to mid-afternoon would be on the order of 23-27 km/h (occasional gusts of 39-43 km/h) but decreasing to 13-17 km/h (occasional gusts of 22-24 km/h) by near sunset. No significant accumulations of smoke are expected, and the smoke itself would be drifting rather quickly towards mostly right-hand sections (occasionally central partially) of the La Ronde audience. High-altitude smoke would more favorably advance even more quickly over right-hand to central sections of the on-site audience. At some points, some pyrotechnic debris could reach these sections. A slight chill in the air could also be felt by some with the breezy SW to WSW wind flow and lower humidity featured by late-evening.

Another update, if necessary, for wind speed/direction will be provided by the mid-afternoon of today (July 2nd).

Trav.

Reviewing some of the newest data, there have been some indications of somewhat stronger lift (and in light of recent evidence of more vertical definition among some of the current cumulus) ahead of the aforementioned weakening cold front around sunset. This would invite a narrow window of opportunity for sparsely-distributed convective rainfall - typically between 7:30 p.m. and 9:15 p.m. (July 2nd). The probability of precipitation in this situation would be 30%, but if rainfall does occur, it would be brief, as the convective clouds that carry them are fast-moving. The air would cool locally, (to 19-20 C) however, as a result of rain-cooled air, while moistening would send humidity levels to temporarily near-moderate standards. Cloud cover should gradually decrease thereafter with increasing atmospheric stability, though a layer of fair-weather cumulus cloud with large clear breaks between them would be present.

Also, wind speeds would continue behaving in a WSW to SW pattern, though more SW for the late-afternoon to evening. This would allow the smoke to focus more at right-hand sections of the La Ronde audience, though higher altitude smoke would still move more directly towards right-hand and partially central sections, as mentioned above. The pattern would still allow for a fast evacuation of smoke (notably at the highest altitudes), though causing the display to sometimes appear hazy/murky when mostly watching its right-hand portion.

All other details presented above hold constant.

Trav.

For July 9th, an area of high pressure will take hold of much of Ontario and Quebec, leaving dry conditions and largely clear skies. Consequently, the risk for rainfall development would be kept at a minimum. The maximum temperature would be 24 C during the mid-afternoon for the greater Montreal area, and then 21 C during display time. As the humidity would remain low, no real humidex is favored.

Winds would typically be flowing lightly from the North to gradually NNW early in the day, though a transition to WNW to eventually WSW would is likely by mid-afternoon to evening, respectively. Unlike the situation during the last display (on July 2nd), wind speeds would be rather light over the course of the evening, at 4-7 km/h, allowing the smoke, from all altitudes, to drift gently towards right-hand to partially central sections of the La Ronde audience. Although periods of larger smoke accumulation are favored at certain points of the Mexican display, particularly extensive accumulations are not expected in light of low humidity.

Another update to follow late this evening to early-predawn (July 8th-July 9th).

Trav.

Details mentioned in the above posting continue to be valid. As such, here are the dominant weather conditions for the greater Montreal area for Saturday, July 9th.

Temperature/Humidity

A maximum temperature of 24 C is favorable by mid-afternoon, declining to 21 C by display time. As a result of low humidity, a humidex is not relevant.

Precipitation

As the region would be governed by a large area of high pressure, convection would be kept at a minimum. Some modest lift in the area would be suitable for sparsely-distributed fair-weather cumulus, but sky conditions would be largely clear, especially during the evening.

Wind

Winds continue to be in the form of light NNW to NW for the early part of the day. By the afternoon, directional tendencies become more Westerly, but these do transition to more WNW near sunset and beyond. Throughout the day, speeds are largely light, from 7-11 km/h, though breezier during the mid-afternoon before becoming 4-7 km/h over the course of the evening. As such, the smoke would be moving gently (a touch faster at the highest altitudes) towards central to left-hand sections of the La Ronde audience, causing the display to sometimes appear hazy/murky from there, and when the display is viewed to the left, in general. Although periods of larger smoke accumulation are favorable at low- to mid-level, as well as during more active segments of the display, particularly extensive amounts of smoke are not expected due to marginally-sufficient wind speeds and low humidity.

Another update, if necessary, will follow by mid-afternoon today (July 9th) to address evening wind direction.

Trav.

Thank you again, Trav, for this specific forecast.

Is 21 Celsius the forecast for 10pm or an average for the evening? MeteoMedia daily forecast predicts 21 in the evening, but its hourly forecast indicates 18 Celsius at 10pm (and 16 Celsius at midnight, when many people who attend the show at La Ronde are still in transit to go home). I feel that long sleeves or a jacket may be very useful tonight!

Fred

Hi Fred,

Yes, the 21 C would be the estimated temperature for the greater Montreal area at 10:00 p.m. However, since the maximum temperature achieved for today narrowly missed the expected maximum of 24 C, it is necessary to reduce this estimated display time temperature slightly (20 C).

As a consequence of clear sky conditions, low humidity and light winds, the air can more efficiently cool post-sunset. That said, this cooling process is relatively slower over the metropolitan area, and so the temperature should hold at 20 C (17-18 C farther West, over the West Island) during display time. Although cooler, the light winds would generally help to partly mitigate the discomfort induced by the chilled air, though a long-sleeved shirt would, indeed, be useful especially closer to midnight and beyond. This morning’s temperature out here, in the Southwestern portion of West Island, decreased to 11 C this morning, so I would envision a similar minimum here by mid-predawn/overnight tonight (July 10th).

I believe the second half of July would be fairly strong for more regularly warmer than normal conditions, offsetting slightly the cooler first half, though this would begin encouraging more days suitable for thunderstorms. This warmer and much more humid pattern should also prove to hold well throughout much of August, potentially leading to a very warm to hot August, overall.

*Winds continue to be in the form of WNW for this evening (at 4-7 km/h). At times, due to the light nature of the winds, this flow could undergo a transition to WSW during the display, which would allow the smoke to suddenly begin moving more towards right-hand and central sections of the on-site audience, but in either case, central sections would still be intercepting smoke at least partially.

Trav.