As per my last posting, a cold front is expected to affect S. Ontario through to S. Quebec into the afternoon hours of today (July 19th), as well as into the evening and early-morning of Saturday, July 20th (mostly for E. Ontario and S. Quebec). It is this cold front that will end our persistent heat and high/very high humidity in time for the weekend, with the most noticeable changes occurring on Sunday, July 21st. Before this cooling, however, strong thunderstorms could occur through the aforementioned time frame. Model data suggests atmospheric dynamics supportive of defined bands of fast-moving squall line thunderstorms that are capable of heavy rains, small hail, frequent lightning, and locally damaging winds.

For Saturday evening’s (July 20th) display, temperatures are expected to drop to 19-20 C by the late-evening hours in the metropolitan area, along with humidity values reduced to borderline low-moderate levels. Because of an upper-level trough behind the principal cold front, a few isolate showers could occur during the early- to mid-afternoon hours, though precipitation should become suppressed by the late-afternoon and evening. Some synoptic lift into the evening should promote a few clusters of low-level cloud.

Winds will be gusty through most of the day Saturday, especially during the afternoon hours. Latest model guidance suggests top sustained wind speeds for the afternoon hours of 27-32 km/h, with occasional gusts of 42-46 km/h. Dominant wind direction is WSW during the afternoon. By dinner time, gusty winds should slowly subside, though winds will remain breezy into the evening, at 14-18km/h (occasional gusts of 23-26 km/h). A shift in wind direction is expected to occur by the late-afternoon to evening period, where NW tendencies are simulated. As a result, accumulated smoke should be moving quickly to the left of the audience at La Ronde but also periodically affecting extreme left-hand sections.

Another update to follow.
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Paul, I apologize for the late response, as I was pre-occupied in preparation for a thesis defense (which went well ).

From what I understand, data collected at the McTavish weather station is representative of the downtown area. Climate data can be compared here:

http://www.theweathernetwork.com/weather/historical-weather/canada/que bec/montreal

Typically, when comparing/analyzing daily/monthly/annual climate averages for various cities, Environment Canada uses those datasets from the nearest airport. That said, it is always interesting to examine data pertaining to weather stations within a specific area for comparative purposes, such as comparing urban vs. suburban temperatures, or assessing local precipitation variability.

Trav.

I am glad to read this weather report. First, because we should enjoy great conditions for the display on Saturday night (while pyro crews may experience bad conditions to setup everything).

Second, I want to congratulate you, Trav, for your MA thesis defense! That is a fantastic news!

Fred

Second, I want to congratulate you, Trav, for your MA thesis defense! That is a fantastic news!

My congratulations too! We're very privileged to have our our meteorologist here at montreal-fireworks.com - your forecasts are always accurate!

Paul.

Weather conditions specified previously are still mostly constant for this evening’s display. As such, here are the dominant patterns for the Montreal area for today (July 20th).

Temperature/Humidity

Following the passage of the cold front early this morning (and yesterday's severe thunderstorms), temperatures will steadily decline as the day progresses and put an end to our enduring high heat and humidity. As such, temperatures are expected to drop to 20-21 C for the late-evening period into the metropolitan area (cooler outside the city). Humidity will remain at moderate levels, creating a slight humidex of 23-24 C.

Precipitation

Following the passage of the front, an upper-level low could generate a few isolated showers during the afternoon hours. By evening, skies should be mostly clear, with some isolated clusters of low cloud due to some lift present.

Wind

Winds are projected to be breezy throughout the day behind the cold front, with top sustained winds occurring during the afternoon hours at 27-32 km/h, and gusts of 42-46 km/h, from the WSW and West. Winds should slowly subside by dinner time, and progressively more into the evening. By late-evening, winds should remain slightly breezy, with speeds of 14-18 km/h (occasional gusts of 24-27 km/h – gusts are more applicable to the early-evening). A directional shift is expected to occur by a little after dinner time, where more WNW to eventually NW (by evening) are shown, consistent with high pressure advancing from the NW. This should allow smoke to quickly move mostly to the left of the audience at La Ronde, as well as occasionally to extreme left-hand sections.

That’s the way the weather should work. In summary, a mostly breezy evening is expected (mostly the early-evening), with warm temperatures, moderate humidity, and a few cloud clusters at low-level.
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Paul and Fred, thank you both so much for your congratulations and comments! They are much appreciated!

I took some footage of the severe thunderstorms that occurred on both July 17th and July 19th and wanted to share it here - I recommend using earphones to hear the natural sound of the thunder!

http://www.youtube.com/watch?v=9uMxyhBX5wY&lc=gkepyUtRT9BI7FzqxSt-gthE Yj2DgNqPuCrb6EKMJgg

http://www.youtube.com/watch?v=lH-sNwI1y2c

Cheers,

Trav.

Weather conditions for the Croatian team are expected to be near-similar to those present during the American display, as another large anticyclone (high pressure system) advances into S. Ontario into S. Quebec behind the passage of today's (July 23rd) cold front.

With the influence of high pressure, temperatures for late-evening Wednesday (July 24th) are expected to be on the cool side (16-17 C in the Montreal metropolitan area), especially with the breezy winds present. Humidity levels will be low, and no precipitation is expected.

Winds will likely be breezy throughout the day at 19-24 km/h, especially during the afternoon hours. Into the evening period, speeds should diminish (but still slightly breezy) to 12-16 km/h - similar to those speeds during the American performance. However, directional tendencies have been Westerly to WNW in recent and current projections, both during the afternoon to evening hours, consistent with the general positioning of the area of high pressure relative to our location. Consequently, smoke could be moving quickly towards the audience at La Ronde directly, with some tendency towards left sections. Slightly breezy winds will occasionally provide a chill in the air.

Another update to come, mostly in terms of wind direction.

Trav.

As per the previous update, high pressure has now slowly settles into S. Ontario and S. Quebec. As a result, conditions mentioned previously still remain identical. Here are the dominant conditions for the Montreal area for this evening (July 24th):

Temperature/Humidity

Temperatures are expected to be cool for the evening to late-evening period, with values declining to 15-16 C for the metropolitan area (cooler outside the city). Humidity levels will be low, so a humidex is not applicable. A light sweater/light jacket will likely be necessary for some, especially after sunset.

Precipitation

No precipitation expected. A few isolated low-level cloud clusters should be present for the late-evening.

Wind

Winds will be breezy throughout the afternoon at 18-22 km/h (occasional gusts of 29-32 km/h). By dinner time, winds should slowly subside and become lighter at 9-12 km/h in time for the evening to late-evening period. Directional tendencies are largely in the form of West-Northwesterlies for the day, with a shift to NW status by the mid-afternoon, which should endure into the late-afternoon and through the evening. As such, smoke should be blowing adequately to the left of the audience at La Ronde (right for those on Notre-Dame), heading towards the adjacent sections of the bridge. At times, smoke may affect extreme left sections of the La Ronde audience. Light winds will occasionally provide an additional chill in the air.
That’s how the weather should generally work for today. In summary, a cool evening, with relatively light winds, low humidity, and a few isolated low-level cloud clusters. Beyond dusk, a light sweater/light jacket will likely be necessary for some.

Trav.

Mother Nature may deserve a Special Jupiter for diversity of weather conditions this year! It's incredibly cold today, for late July. For sure, I will bring a light jacket tonight.

I hope for great flame effects, great enough to warm the audience!

Fred

I hope for great flame effects, great enough to warm the audience!

Cienfuegos holds the record for that during their show in 2003: http://montreal-fireworks.com/cgi-bin/rep.cgi?head2003,argentina03,tai l2003

Paul.

I recall the flame effects used during the closing show of 2009 to also be memorable.

More breaks in the current cloud deck should occur near dinner time and onwards, though cloudy skies during the evenings on days like this would be welcomed, as they assist to regulate the amount of cooling that occurs following dusk. Regardless, it will most certainly be an unseasonably cool evening.

Fortunately, more seasonal and humid weather should resume by the weekend, and on and off into the following week.

Trav.

I will also reduce the wind speeds for late this evening slightly to 7-10 km/h.

Trav.

An area of low pressure advancing from the West is expected to boost temperatures and humidity levels to more Summer-like standards in time for the weekend, just before a cooling by late-Sunday (July 28th). As a result, it is this system that will be the weather maker for this coming weekend, and, thus, for the Canadian display scheduled for Saturday (July 27th).

Models are still somewhat divergent in terms of the overall timing of the low's Eastbound cold front on Saturday, but there has been some agreement that associated rainfall and non-severe thunderstorm activity should occur until a little after midnight and onwards, while mostly cloudy conditions (mid-level cloudiness) endure for the evening. Temperatures for the afternoon should attain more seasonal values, with maximum highs of 27-28 C, along with high humidity levels, making it feel closer to 33-34 C. Temperatures for the late-evening should remain at 22-23 C (humidex of 27-28 C) in the metropolitan area, so it will likely be quite the contrast from what was witnessed during the Croatian display.

Winds are expected to be rather light, however, at 5-8 km/h throughout the day, and into the evening period for Saturday. This may generate periods for smoke accumulation (mostly at low- to mid-levels of the display), especially with the high humidity present. That said, recent sounding data has indicated a variation of Easterly to ESE directional tendencies for the evening, so smoke build-up may become more important for those viewing on Notre-Dame street as it moves gently in that direction (slowly away from those stationed at La Ronde).

Another update will follow.

Trav.

Little change has occurred with respect to the information presented in the above posting. As a result, here are the dominant weather conditions for Saturday, July 27th for the Montreal area:

Temperature/Humidity

Maximum temperatures should attain 27-28 C by the mid-afternoon hours, along with borderline moderate-high humidity levels, making it feel like as much as 33-34 C. By the late-evening period, temperatures should decline to 24-25 C in the metropolitan area, with continued borderline moderate-high humidity, generating humidex values of 27-28 C.

Precipitation

A few convective showers/rainfall and non-severe thunderstorms are generally not expected until the mid-overnight period and onwards into Sunday (July 28th), owing to a cold front moving in from the West. A few thunderstorms, however, may be reaching severe limits for late-day Sunday. The afternoon for today should be mostly sunny, with a few high-level cirrus clouds and isolated low-level cumulus. That said, in advance of the front, mid-levels of the troposphere will gradually become saturated, prompting largely mid-level partly cloudy skies into the evening.

Wind

Winds are expected to be mostly from the ESE (occasionally SE) for the afternoon and will be light at 9-12 km/h (an increase from the 5-8 km/h specified in the above post). Identical tendencies are shown for the evening hours, although there is slight shift to Easterlies by the late-afternoon/early-evening. As a result, smoke should be blowing adequately away from the audience at La Ronde directly, though, as a consequence, towards sections of Notre-Dame street closest to the firing site (i.e. North of the bridge on Notre-Dame street), causing the display to appear murky from those vantage points. For those on Notre-Dame street, the closer you are positioned to the bridge (and Southward), the better, since winds could occasionally be from the ESE. However, viewing will still likely be difficult.

That’s the way the weather should generally work. In summary, a pleasant evening, with gradually partly cloudy skies at mid-levels, warm temperatures, light ESE/East winds, and borderline moderate-high humidity.

Trav.

Edit: *Also, for those interested, the overnight low following the Croatian display (so, the early morning of July 25th), though not a record for the absolute coolest minimum temperature to take place for the month of July, it was the third coolest minimum temperature to occur in recorded history for the Montreal area for July 25th.

Weather conditions for the final entrant (Italy) should be largely ideal, as well as for the day Wednesday (July 31st), in general.

Two lows, one to our SW, and the other to the NW, coupled with high pressure centered over the Atlantic, will be the dominant weather features for the day Wednesday. Convective showers/rainfall and thunderstorms (some isolated severe thunderstorms possible) associated with these lows should occur until into Thursday (August 1st) ahead of an advancing cold front from the West.

Latest sounding data indicates maximum temperatures of 26-27 C for much of S. Quebec on Wednesday, along with late-evening values of 23-24 C. Winds should be mostly SSE in overall tendency throughout the evening, with speeds at 7-10 km/h. As such, smoke should be blowing slowly clear to the right of the audience at La Ronde (left for those on Notre-Dame), so all major vantage points should benefit from wind patterns. Humidity will be mostly borderline moderate-high, making afternoon temperatures feel as warm as 31-32 C, while late-evening humidex values should be 27-28 C. Skies should remain mostly clear into the evening, with a few clusters of high-level cloud (cirrus). Cirrus clouds should also be present for the latter part of the afternoon.

Another update to follow.

Trav.

What had been stated in the above post still remains largely constant. As such, here are the dominant weather conditions for the Montreal area for today, July 31st.

Temperature/Humidity

With the two lows moving in from the West, temperatures are expected to rise to more seasonal standards today, with daytime highs locally as high as 28-29 C, and generally moderate humidity, making it feel like as much as 32-33 C. Evening/late-evening temperatures should be closer to 25-26 C in the metropolitan area, with humidex values of 29-30 C.

Precipitation

No precipitation expected. Skies should remain mostly clear through the day and into the evening, with a few isolated high-level cirrus and low-level cumulus. Convective showers and isolated non-severe thunderstorms will likely occur ahead of a passing cold front from the West for the afternoon of August 1st.

Wind

Winds will be slightly breezy throughout the afternoon at 12-16 km/h, and from the SW (eventually SSW by late-afternoon). Into the late-evening period, winds should become lighter at 7-10 km/h, with a slight directional shift to straight Southerlies (occasionally SSE). As a result, smoke should be moving slowly and clear to the right of the audience at La Ronde (left of those on Notre-Dame street). Some periods of smoke accumulation may occur at low- to mid-levels of the display, mostly when the display becomes more active and mostly towards the right (for those at La Ronde). The general wind direction favors all major vantage points.

That’s the way the weather should generally work. In summary, a pleasantly/very warm evening, with moderate humidity, light Southerly winds (occasionally SSE), and mostly clear skies (a few isolated high-level cirrus and low-level cumulus clouds). Overall conditions should make for the most ideal weather of the season, since all major vantage points benefit from the general wind direction (combined with all other factors in place).

Trav.

These are perfect weather conditions for an anticipated display!

Fred

These are perfect weather conditions for an anticipated display!

Almost perfect, given that periods of smoke accumulation, as noted above, did occur due to the light winds present!

For Saturday, August 3rd, an upper-level trough to the NW will generate scattered showers and partly cloudy skies across S. Quebec, along with unseasonably cool temperatures. Maximum temperatures for the day should attain 21-22 C, and late-evening values should drop slightly to 19-20 C in the metropolitan area (cooler outside the city). Humidity levels are moderate throughout the day (becoming borderline low-moderate for the evening), but temperatures are low enough that a humidex will not be significant. Precipitation should gradually subside by the late-afternoon, leaving partly cloudy skies for the evening period.

Winds will be largely breezy for the afternoon at 19-23 km/h, with occasional gusts of 28-32 km/h, producing a slight chill in the air. Directional tendencies are mostly in the form of West-Southwesterlies. By evening, wind speeds should decrease to light standards at 10-13 km/h, and more from the SW. As a result, the smoke should be moving fairly quickly towards right hand sections of the La Ronde audience. Wind speeds should still be high enough to produce a slight chill. There is some divergence amongst models with evening wind direction (i.e. SW vs. SSW), though, so this will need to be monitored in the newer runs. However, there is agreement as to the lighter winds in time for the evening period.

Unfortunately, it will likely not feel Summer-like for much of the first week of August, since the aforementioned upper-level trough has been projected to be persistent over much of E. Canada during this time. A nice warming, however, could occur for the 7th and 8th.

Another update to follow.

Trav.

Weather conditions remain generally similar to what had been specified in the previous posting. However, some modifications are necessary with respect to precipitation and, to some extent, wind patterns. As such, here are the dominant patterns for today (August 3rd) for the Montreal area, and for the final display of 2013.

Temperature/Humidity

Temperatures will be unseasonably cool for today, with maximum temperatures of 22-23 C, along with moderate humidity. By the late-evening period, temperatures will drop to about 20-21 C in the metropolitan area, along with continued moderate humidity. Because temperatures are generally low enough, the humidex is not significant.

Precipitation

As mentioned previously, a persistent upper-level trough will continue to produce scattered convective activity, in the form of scattered showers and non-severe thunderstorms, for the afternoon period. Precipitation development could continue into the early-evening time frame due to some lift and low instability present, though coverage should become more sparse (30% P.O.P.) and mostly subside by late-evening. Partly cloudy skies should be present throughout the evening.

Wind

Winds will be gusty for the afternoon at 20-24 km/h, with occasional gusts of 29-33 km/h. Directional tendencies are projected to be in the form of West-Northwesterlies (occasionally from the WSW) by the mid-afternoon hours and becoming more Westerly for the evening period (a change from the SW specified previously). Wind speeds for the late-evening period should decline but remain somewhat breezy at 12-16 km/h (occasional gusts of 23-26 km/h, mostly for early in the evening), producing a chill in the air. As such, the smoke should be moving quickly towards the audience at La Ronde directly, with some occasional tendency towards right-hand sections.

That’s the way the weather should work. In summary, a breezy evening, with somewhat cool temperatures, partly cloudy skies, and a risk for isolated showers early in the evening.

And so concludes the weather reports for Summer 2013!

Trav.

As such, the smoke should be moving quickly towards the audience at La Ronde directly, with some occasional tendency towards right-hand sections.

Thank you for this very relevant update, especially for that special evening.

Furthermore, I also want to acknowledge your outstanding contribution to this forum, once again this year, with useful, specific, and accurate weather forecast. I really appreciated and hope to benefit of your expertise next year!

Fred

Thank you very, very much, Fred! It is always a pleasure, and I am pleased to know that the weather forecasts were useful!

Trav.