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 Montreal Fireworks Forum —› General —› Weather Cooperation (or not) for Summer 2013.
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Posted: Jun 1, 2013 23:48:56

Hello everyone,

As we have (quickly) arrived in the month of June, I thought that it would be appropriate to post the weather thread.

As always, weather reports/updates will be posted prior to each fireworks night, including some preliminary details from as far as two days in advance. The reason for this is that there is often too much uncertainty to provide more meaningful forecasts beyond two days ahead for a specific time frame. Reports will include temperature, humidity (moisture), wind speed and direction, and, if necessary, the risk for precipitation (rainfall/showers). I will try to keep details brief and concise, but if/when the potential for severe weather exists, a little more elaboration and additional updates, as needed, will be provided. Everyone is also more than welcome to share any information.

I continue to regularly post weather updates on my Facebook profile, largely when extreme weather is likely. If you would like to follow me there from time to time, please feel free to visit my profile:

https://www.facebook.com/travis.moore.5074?ref=tn_tnmn

For those that are interested, my Spring-Summer 2013 weather outlook (posted on St-Patrick’s Day) can be found here:

https://www.facebook.com/notes/travis-moore/winter-2012-2013-and-a-loo k-ahead-to-spring-summer-2013/10151528552166346

In summary, I am anticipating a very humid end-Spring to Summer period for 2013, with an enhancement in the number of thunderstorm/severe thunderstorm days. Temperatures should generally be slightly above normal for each of the warmer months, though the number of days reaching 30 C or more could be slightly reduced relative to what was observed in 2010, 2011 and 2012. Precipitation should follow near to above normal tendencies, but locally well above normal patterns will occur due to the nature of thunderstorms.

Here’s hoping for ideal weather conditions for all of our participants of 2013!

Trav.


Posted: Jun 21, 2013 21:18:48

Mother Nature may have decided to play a role as soon as with the inaugural display of the season. I am looking forward to read your weather forecast, especially specific information for late night.

Fred


Posted: Jun 21, 2013 22:50:22   Edited by: Smoke

First, let me welcome everyone to the first official day of Summer (it arrived early this morning - June 21st - 1:04 a.m. EDT).

A warm front will gradually migrate into E. Ontario to S. Quebec during the day Saturday (June 22nd), producing widespread rainfall across these regions ahead of it. Current and recent model runs have come more into an agreement concerning the overall nature and timing of the front, and the associated rainfall coverage. Given the timing of the warm front, periods of rain are most likely to occur during the late-morning through to the afternoon hours, followed by mainly cloudy conditions for the late-evening period. General cloudiness and rainfall will act to maintain near-constant maximum temperatures of 20-22 C throughout the afternoon period. It will likely feel sticky, as well, and temperatures should hover between 18-20 C during the evening hours.

What is possibly more concerning to me, however, is the combination of high humidity and light winds shown for the evening hours, especially following the afternoon showers/periods of rain, when the air is more saturated. At this point, winds are projected to be coming out from the NE/NNE at about 8-11 km/h during the late-evening, so this could prompt smoke to be moving gently to the left of the audience at La Ronde. This would affect those on the bridge in sections over Notre-Dame, and over the river while, at times, obstructing the view for those stationed at the Old Port.

I would still like to analyze the newer model runs from tonight as they come in to confirm the above information, so I will provide another update early tomorrow. Once the warm front lifts farther North with time, a heat wave (in the technical sense) may emerge for many areas of E. Canada, beginning on Sunday (June 23rd).

I apologize for the delayed initial update, as I was awaiting for the models to show a consensus concerning the risk of precipitation for tomorrow.

Trav.


Posted: Jun 22, 2013 01:03:57

The newest model runs from this morning (June 22nd) have recently arrived and follow general trends shown by previous runs. However, the new data presented does warrant some revisions to the above mentioned information for precipitation coverage and timing for today, and, to some extent, maximum temperatures. As such, here are the most likely conditions to predominate for today:

Temperature/Humidity

Maximum temperatures will likely reach 23-24 C during the afternoon, owing to some pockets of afternoon solar heating. Evening temperatures in the metropolitan area should be anywhere from 20-21 C. Humidity will be high throughout the day, and borderline high-very high by the late-afternoon/evening, making it feel like 27-28 C during that time frame.

Precipitation

As mentioned previously, periods of rain/showers are still expected to occur. However, the newest model runs indicate that most of this rainfall should take place by through most of the morning hours, largely around and after dawn. Into the afternoon, mainly cloudy conditions should prevail, but because of the potential for some brief, isolated breaks of solar heating, combined with increased moistening, there will be a slight risk for isolated air mass thunderstorms and/or convective showers. Into the late-evening, convection should cease, and skies will remain mostly cloudy with some clear breaks.

Wind

Wind speeds remain light from the ENE to eventually NE (late-evening to overnight) at 9-12 km/h (slight change from 8-11 km/h). As such, winds will be “gently” pushing the smoke to the left of and away from the audience at La Ronde and instead affect viewers on Notre-Dame/de Lorimier street, as well as those on the bridge overlooking those streets. This may occasionally affect viewing at the Old Port, as well. Note that periods of smoke accumulation could occur due to the high humidity and generally light winds.

If necessary, I will provide another update well before the display today.

Trav.


Posted: Jun 22, 2013 15:58:01

MeteoMedia has just updated tonight forecast, increasing probability of showers from 30% to 60%-70%.

It's a shame that few people will likely attend the Australian debute display.

Fred


Posted: Jun 22, 2013 16:32:43

I'm still optimistic that the bulk of the rain will be over around 5/5:30pm.

So long as there is a bit of wind, we should be fine tonight.

Paul.


Posted: Jun 22, 2013 16:55:57   Edited by: Smoke

Just to provide an additional update, periods of rain/showers should largely come to a close following dinner time (near 7:30 p.m. EDT) this afternoon (June 22nd), with the bulk of the precipitation coming to a close shortly. This means that the risk for (deep) convection will be minimal later this afternoon, and temperatures will remain closer to 18-19 C, coupled with continued borderline high/very high humidity. Persistent rains throughout the afternoon are the result of the aforementioned warm front becoming more quasi-stationary, allowing precipitation to linger for an extended period of time. Edit: Skies will remain mostly cloudy this evening.

As per my previous postings, the combination of high humidity and very light winds (recent projections of 6-9 km/h) could generate conditions for periods of heavy smoke accumulations and may deteriorate viewing, especially for those positioned on Notre-Dame street (and nearby streets) - winds are expected to be more from the East to ESE, so the smoke should be very slowly moving away from the audience at La Ronde (and occasionally "slightly" to the right) later this evening, though it will build up quickly, especially from low-level effects. These conditions will also be accompanied by more saturated surface and near-surface air following the morning-afternoon rain/showers.

Trav.


Posted: Jun 22, 2013 19:12:10

If it is not too late, I would suggest having the umbrellas handy (or some form of head covering) for the evening, as the degree of lift, as well as the near-saturated nature of much of the lower atmosphere, is supportive for continued scattered precipitation development throughout the evening (despite what recent projected radar imageries have shown). Otherwise, it will be mainly cloudy, as was originally stated.

All other conditions remain constant.

Trav.


Posted: Jun 25, 2013 16:08:04

Trav: I need a forecast for Knowlton for Saturday evening. Environment Canada and MeteoMedia have divergent forecasts right now - the former says rain and 19C and the latter 40% chance of thundershowers and 26C - quite the difference. I'd like warm, dry and sunny please for my Canada Day show Plus it would be good if it's dry at La Ronde on Friday evening for Team England's debut in the competition.

Cheers,

Paul.


Posted: Jun 27, 2013 01:37:26

Weather conditions for England's display this Friday (the 28th) are generally expected to be unsettled. A broadening upper-level trough will likely be developing across Ontario and Quebec by tonight (June 27th), allowing for a developing area of low pressure in the U.S. to travel North along the jet stream.

Latest model guidance is somewhat divergent, but there has been some agreement that the bulk of the associated rainfall for Friday will occur during the early-morning hours (slight risk of non-severe thunderstorms at this time) through to the mid-afternoon, which will be followed by mainly overcast skies into the late-afternoon/evening hours. However, a few lingering showers are still possible for the evening due to continued lift.

With the lack of daytime heating, and because of wet conditions and gusty NE winds, temperatures will be restricted from rising to seasonal/above seasonal values. Instead, maximum temperatures could only reach 17-18 C and will drop slightly by the evening to 15-16 C. Winds will continue to be breezy into the evening hours from the NE, making it feel chilly (enhanced by cool evening temperatures). As such, light jackets will likely be required for many (something that bothers me to say at the end of June). Humidity should remain at moderate levels throughout Friday. Breezy NE winds should generally push smoke quickly to sections of Notre-Dame street nearest to the bridge (and affecting those on the bridge near and overlooking the street). For those positioned at La Ronde, the smoke should predominantly be moving to your left and away. Wind speeds may be marginally strong into the early-evening, so that is something to be monitored in the newer model runs.

Another update to follow later today/early tomorrow.
-------------------------------------------
Hi Paul,

For Saturday evening/late-evening in Knowlton, temperatures are expected to hover around 18-19 C (afternoon high of 24-25 C), along with relatively high humidity. A few convective showers and scattered non-severe thunderstorms will also be possible along a stationary front that will affect locations mostly East of Montreal. Latest model guidance, however, suggests that convection will be most active during the afternoon hours. Skies should remain partly cloudy during the evening, and winds could become very light from the WSW at 4-7 km/h.

If necessary, I will provide another update as the newer model runs become available.

Trav.


Posted: Jun 27, 2013 09:27:56

Thank you for this forecast, Trav, and we stay tuned for updates as we may experience severe weather conditions tomorrow.

For sure, that would be a nightmare for many people - including Paul, who must be at Knowlton Saturday - but I wonder whether we are going to experience a premiere in the Montreal International Fireworks Competition history. Meteomedia predicts winds around 30 km/h for Friday evening, with gusts reaching 50 km/h. Specific forecast is not available to distinguish early and late evening, and we have often experienced more severe winds in early than in late hours.

There hasn't been any cancelled or postponed show since 1985. While Six Flags had, a couple of years ago, a policy to postpone a show to the next day in case of poor weather conditions, I think it has been dropped because too difficult to implement given the number of organizations involved in the event (police, fire service, public transportation system, etc.). Now, the policy is that fireworks are displayed rain or shine, but may be postponed for security reasons.

So I think that we must be alert for any cue from the organizers today and tomorrow morning. They may have to take a tough decision.

Fred


Posted: Jun 27, 2013 09:32:16

I'm sure that by 10pm tomorrow night thing will be fine. Funny that it's always England that experiences bad weather in their participations (recalling the strong winds during the last Kimbolton display a few years ago that lead to a the latest ever start).

I think things will be better for me on Saturday (I hope!). Every year it's the same thing: eyes glued to the radar!

Paul.


Posted: Jun 27, 2013 09:49:57   Edited by: fredbastien

I'm sure that by 10pm tomorrow night thing will be fine. Funny that it's always England that experiences bad weather in their participations (recalling the strong winds during the last Kimbolton display a few years ago that lead to a the latest ever start).

Yeah, that was in 2003. Paul, you wrote this in your report:

Weather became the dominant issue for this display. The team lost half a day of setup due to heavy thunderstorms. Then it was hot for a day, then grey and humid. The weather threatened to do its worst but it appeared everything would be OK. Suddenly, at 9:30pm, very strong wind came out of nowhere. So strong that it was difficult to hear the announcements for a while. Unfortunately, the wind was blowing directly at the audience. Then the thought that the unthinkable could happen: cancellation. As the time inched towards 10pm, the wind didn't diminish. Everyone waited nervously. Then an announcement that the display would be delayed by 25 minutes until the wind, as confirmed by the meteorologists at Dorval airport, would subside enough to allow the display to be fired safely. Just after 10pm, the wind died down a lot. Darryl Fleming came to see me at 10:20 and commented that I would have something interesting to write here! Then the wind increased and once again diminished. Finally, an announcement that the display would start. Expectantly people awaited the countdown from 10. But nothing, just silence. Then a slow handclap from the audience. A minute passed. Would it be canceled? The wind seemed to be picking up again. But finally, the countdown took place and the display started at 10:27. At around 10:40, heavy rain started, frustratingly because the period from 10:00 until 10:30 was completely dry. I put a small umbrella over my notebook and battled on regardless, trying to write even though I couldn't see, both because the notebook was covered, and my eyes got ash and rain in them. But after about 10 minute, the rain more or less stopped and it didn't detract from the display too much. What a way to celebrate my 100th display!

And I clearly remember the (false) announcement that the display was going to start, as the famous "Que tombe la nuit, que la fête commence" was pronounced. Following a moment of silence, the incredible Michel Lacroix catched the movie theme of that display and resumed with these words: "Nous vous avions promis Une soirée au cinéma, alors prise 2! Que tombe la nuit, que la fête commence! 10, 9..."

Fred


Posted: Jun 27, 2013 15:20:17   Edited by: Smoke

Canadian displays also had their share of bad weather in the past, but it is quite the coincidence that England is expected to potentially face a near-similar scenario to a decade ago. Still, I believe the strongest of the winds will occur during the afternoon hours, and, unlike 10 years ago, the winds are not projected to be directed toward the audience at La Ronde, but rather closer to those on the bridge, and those on Notre-Dame street. Overall wind speeds for the evening, however, are still questionable. Rainfall during the late-morning to mid-afternoon hours will likely be abundant.

I will have another update prepared for later on.

Trav.


Posted: Jun 28, 2013 03:03:36

A strengthening area of low pressure moving in from the South is expected to bring copious rains and strong winds to S. Quebec. As such, here are the most probable weather conditions for Friday, June 28th for the Montreal area (and surrounding locations).

Temperature/Humidity

Temperatures throughout today will remain unseasonably cool across much of S. Quebec due to ongoing NE/NNE winds, thick cloudiness, and rainfall. Maximum temperatures will likely only reach 17-18 C, with evening/late-evening temperatures cooler at 13-14 C. Humidity levels will be moderate. Please dress warmly.

Precipitation

Periods of rain are still expected to occur throughout today, with the heaviest of rain occurring from the mid-morning to early-afternoon period. Following this, mainly cloudy conditions will persist into the late-afternoon to the evening, with scattered showers lingering for the late-afternoon. By evening, overcast skies should prevail, with the continued possibility for scattered showers (mostly for the early-part of the evening).

Wind

Winds will be gusty from the NE to NNE through most of the day, with highest speeds occurring during the late-morning to mid-afternoon period. Top gusts and sustained winds during the this time will be between 48-52 km/h and 28-33 km/h, respectively. Into the late-afternoon to evening period, wind speeds should diminish progressively and significantly, especially into the evening, with general speeds closer to the 11-14 km/h range by late-evening and overnight. Dominant wind direction has recently been shown to shift a little counter-clockwise by the late-evening, however, due to a progressive retrograde motion exhibited by the associated area of low pressure. As such, winds should be coming out more from the North to NNW by late-evening, causing the smoke to move towards the adjacent bridge, and to the left of those at La Ronde. Some periods of smoke accumulation will be possible due to saturated air, but the winds should typically be strong enough to frequently push away the smoke.

That’s the way the weather should generally work. In summary, mainly cloudy conditions should dominate for the late-evening, with the continued possibility for lingering scattered showers, especially for the early part of the evening, so have an umbrella (or some form of adequate head covering) handy. Though winds will diminish, they will still be enough to chill the air, so also bring a jacket for the evening.

I will provide an additional update, if necessary, should wind and/or precipitation tendencies show significant changes for the evening (especially since some model divergence still exists for this time frame).

Trav.


Posted: Jun 28, 2013 14:36:47

I just wanted to provide an update concerning wind direction for this evening. Because the current area of low pressure is retrograding somewhat more quickly, the wind direction should undergo a transition by early this evening. Previous model runs were showing more SW/SSW wind tendencies beyond midnight, but this is now illustrated to occur a little earlier. As such, winds should change from the current NE/NNE patterns to SSW to SW patterns by a little past dinner time (6:00 p.m.) and should remain for the duration of the evening - this should now push smoke to the right of the audience at La Ronde (left for those on Notre-Dame), though possibly occasionally affecting extreme right-hand sections if becoming more Southwesterly. Wind speeds remain identical, however, but are slightly less at 10-13 km/h. Some periods for smoke accumulation are possible (mostly at low-/mid-level), though not to the same extent as what was seen with Australia's display. Also, evening temperatures should remain steady at 14-15 C. All other conditions remain constant, and, as mentioned previously, rainfall should largely come to a close into the mid-afternoon, leaving mostly cloudy conditions, and a few possible lingering isolated showers until the late-afternoon/early-evening.
-------------------------------
Paul, weather conditions remain similar to what was previously posted for your display tomorrow in Knowlton. The only difference is that forcing for convection is more associated with a surface warm front, and the current upper level low, for the afternoon. Isolated severe thunderstorms are more possible to your East/NE. Also, wind direction is more SW/SSW for the evening, and temperatures for the afternoon are closer 22-23 C. At approximately what time is your show expected to begin? 10:00 p.m.?

Trav.


Posted: Jun 28, 2013 15:14:21

Thanks for the update Trav! Yes, showtime for me is 10:00pm. We start the setup at 1pm so hopefully it will be mainly dry. There's no danger of setting any trees or grass on fire this year! What wind velocities can we expect? The past two years had completely calm conditions, which is not good for a fireworks display.

Paul.


Posted: Jun 28, 2013 17:10:07

Scattered convective showers and isolated thunderstorms are most likely during the afternoon hours ahead of a cold front (not warm front, as I erroneously mentioned in the previous post) before it transitions to more stationary status to your East later in the day. Convection should gradually dissipate near, and a little after dinner time tomorrow.

As for the wind patterns, you may dealing with a third year in a row where winds are very light (though not quite calm)! Wind speeds are expected to be light at 4-7 km/h, and from the SW/SSW around the time when your show begins, as well as the surrounding hours.

No problem for the update.

Trav.


Posted: Jun 30, 2013 21:57:22

Canada Day forecast:

Temperature/Humidity

Afternoon temperatures will likely reach 23-24 C for the afternoon tomorrow for most of S. Quebec, with moderate humidity. Evening temperatures should remain steady at 20-21 C (except 18-19 C for the late-evening), along with continued moderate humidity levels.

Precipitation

Precipitation is generally not expected – however, cloud cover will gradually increase as the day progresses, especially into the early-afternoon and onwards.

Wind

Winds will generally be slightly breezy throughout the day at 12-16 km/h from the NE (occasionally NNE) and will increase steadily in speed near midnight and onwards.

Trav.


Posted: Jul 3, 2013 23:59:24   Edited by: Smoke

Weather conditions for Hong Kong/China's display on Friday, July 5th, are expected to be the polar opposite of what had been observed for England's performance. After a cool and very wet June 2013, temperatures are projected to be consistently above-seasonal for at least the next several days, beginning today (July 3rd), courtesy of a Bermuda High that recently developed in the Atlantic. As such, for the first time this year, a fireworks day/night will very likely experience more Summer-like weather.

There is some divergence in the latest model guidance concerning overall cloud coverage for Friday, thus leading to two somewhat different maximum temperature scenarios. At this point, daytime highs for Friday are shown to reach as high as 30-31 C, but if extensive cloud cover develops into the afternoon, then highs will be closer to 26-27 C. In either case, however, very high humidity will be present, making temperatures feel like the mid to upper 30s C. By the late-evening, values should remain closer to 23-24 C, with continued very high humidity, causing it to feel more like 29-30 C. Skies should be partly cloudy for the evening.

Because of the increasingly buoyant atmosphere over the next few days, a few isolated convective showers and non-severe thunderstorms could develop during the afternoon hours. No lifting mechanisms are associated with convection, suggesting that it is largely dynamically-driven (through daytime heating) and should, thus, be fairly sparse and dissipate into the late-afternoon to early-evening periods. A few isolated organized lines of thunderstorms, however, could develop during the afternoon on Friday in E. Ontario to S. Quebec.

Wind direction should be largely in the form of Southwesterlies, pushing smoke towards right-hand sections of the audience at La Ronde. Wind speeds, though, are expected to become breezy (and occasionally gusty) into the late-afternoon to evening hours, but it is still a question as to how windy.

Another update to follow by later tomorrow/early-Friday.

Trav.


Posted: Jul 5, 2013 02:33:50

Conditions specified in the above post remain largely constant. As such, here are the most likely weather patterns for today, as well as this evening (July 5th):

Temperature/Humidity

The persistence of the Bermuda High will circulate very warm and humid-rich air into much of the Eastern North American continent. For S. Quebec, temperatures will likely reach 29-30 C during the afternoon hours, along with very high humidity, making it feel as hot as 36-38 C. By the late-evening, temperatures should remain at 24-25 C in the Montreal metropolitan area, but the continued very high humidity will make it feel closer to 32-33 C (though somewhat regulated by the breezy SW winds – see wind section).

Precipitation

Convection is expected to become enhanced into the afternoon hours in association with a moderately unstable atmosphere. Due to atmospheric dynamics, convective showers and thunderstorms should be sparse in coverage, but enhanced wind shear fields could support a few organized clusters of thunderstorms, and isolated severe thunderstorms, in the afternoon. Like yesterday (the 4th), convection should be most active throughout the afternoon and slowly subside by late-afternoon into the early-evening. Skies should remain partly cloudy with some mid-level cloud clusters for the evening.

Wind

Like previous runs, latest model guidance projects gusty winds developing into the afternoon hours, where sustained speeds and top gusts could reach 21-25 km/h and 34-38 km/h, respectively. By evening, wind speeds should diminish slightly to 16-19 km/h, with gusts closer to 31-34 km/h (marginally close to the 40 km/h threshold). Wind direction remains Southwesterly, pushing smoke quickly towards the right of the audience at La Ronde, but also towards (extreme) right-hand sections of the audience there. Winds will also provide some relief for those who cannot tolerate the very high humidity.

That’s the way the weather should work. In summary, a breezy evening, with very high humidity, warm evening temperatures, and partly cloudy skies.

*I will provide another update concerning wind speed for the evening hours early today.

Trav.


Posted: Jul 5, 2013 15:14:32

Winds continue to be breezy throughout this afternoon. However, sustained wind speeds for this evening should be a little less than what had been previously shown, with a more suitable range of 12-15 km/h (from the SW). Speeds should begin to slowly diminish by around dinner time.

With respect to convection, recent model runs have favored continued isolated convection until early this evening (more gradual scattered coverage for this afternoon, especially into upstate New York), owing to a high shearing and unstable environment to promote some development. Thus isolated showers and non-severe thunderstorms remain possible until early this evening, followed by partly cloudy skies for the late-evening.

On another note, today is the 14th anniversary of S. Quebec's violent electrical storm, called a derecho (a fast propagating and elongated cluster of powerful thunderstorms capable of producing widespread damaging straight-line winds over a span of hundreds of kilometers). This system caused large-scale damage in association with the winds and produced continuous lightning that was enough to mimic daylight. Top sustained wind speeds rivaled those of a near-category 2 hurricane. The July 5th, 1999 thunderstorm is certainly the most powerful thunderstorm that I have ever witnessed to this day.

Trav.


Posted: Jul 11, 2013 01:07:25

Following the passage of yesterday evening's (July 10th) cold front, a broad area of high pressure is slowly following behind from the NW. This area of high pressure will be the weather maker until the end of the weekend and, as such, will influence tomorrow's (Friday, the 12th) patterns.

Friday's weather is expected to be fair, with plenty of sunshine, light to moderate NNE winds, borderline low-moderate humidity, and stable air. As a result, no precipitation is expected for the Spanish display, and we should instead have pleasant evening conditions.

Late-evening temperatures should be around 20-21 C in the metropolitan area, along with borderline low-moderate humidity (so no significant humidex). Winds should be light (8-11 km/h) from the NNE, so the smoke will be generally blowing gently clear to the left of the audience at La Ronde and headed to adjacent sections of the bridge (sections near the park and over the river). For those at the Old Port, smoke could periodically affect viewing.

Another update will be provided later today/early-Friday.

Trav.


Posted: Jul 11, 2013 08:55:30

For once, the weather should be fully cooperative. That is great!

Fred


Posted: Jul 11, 2013 10:58:41

Hi Fred,

Yes, weather conditions should be mostly good for the Spanish display. However, the only aspect that concerns me for the evening is the lack of wind - above, I had mentioned light winds of 8-11 km/h, but newer projections have consistently indicated near-calm conditions.

In any case, I'll have another update prepared later on to address this.

Trav.


Posted: Jul 12, 2013 02:01:47

As mentioned in the previous update, high pressure will be the dominant weather factor for the day today (July 12th) across S. Ontario through to S. Quebec. As such, the patterns stated previously are still largely constant. Here are the dominant conditions for the Montreal area:

Temperature/Humidity

Maximum temperatures for today should reach 25 C, with low humidity, though humidity levels will rise slightly by the end of the day. By late-evening, temperatures will likely drop to 20-21 C for the metropolitan area (a little cooler outside the city), along with borderline low-moderate humidity. As a result, no significant humidex is forecasted. A formal heat wave may occur for both S. Ontario to S. Quebec, beginning Sunday, July 14th, with warming/moistening beginning tomorrow (the 13th).

Precipitation

No precipitation expected. Skies should remain mainly clear, including for the evening.

Wind

This is where it becomes tricky. Winds will be light throughout the day from the NNE at 9-12 km/h. Latest and recent model guidance have suggested very light to calm wind speeds by the evening to late-evening hours, consistent with the center of high pressure in close proximity to our location. Maximum speeds are 2-4 km/h. Under such conditions, smoke build-up is likely, especially during the more active segments of the display, and along low- to mid-levels. Directional tendencies are NE (occasionally ENE) for the evening, so the smoke should occasionally be moving very slowly towards those on the bridge nearest to the river, as well as for those on Notre-Dame street near the bridge. Folks at the Old Port could also have viewing inhibited by smoke. At times, smoke could be near-stagnant. For those at La Ronde, the overall wind direction could sometimes be of assistance, as smoke would be moving very slowly to your left and away, with build-up mostly in those directions. Fortunately, however, the humidity will not be high to contribute to additional accumulations.

In summary, a pleasant evening, with tolerable temperatures, borderline low-moderate humidity, and very light NE winds.

If necessary, I will provide an additional update concerning wind behavior (speed and direction) early this afternoon.

Trav.


Posted: Jul 12, 2013 16:23:14

The most recent model data shows a "slight" increase in wind speeds for this evening, with maximum speeds around 4-7 km/h. This should very gently push the smoke to the left of those at La Ronde and head towards the bridge, and towards sections of Notre-Dame street just South of the bridge. Periods of smoke build-up are still likely, mostly near the bridge.

I will also increase the late-evening temperature in the metropolitan area slightly to 21-22 C.

Everything else mentioned previously still remains.

Trav.


Posted: Jul 16, 2013 09:01:52

Just a note for Trav - yesterday was the hottest day in Montreal (9.6 cooling degree days - average temp for 24 hours was 27.6) since July 14th last year, when we had 9.8 cooling degree days (average temp was 27.8) - though yesterday's high temperature was just a bit higher than July 14th 2012.

Paul.


Posted: Jul 16, 2013 13:00:28   Edited by: Smoke

Hi Paul,

Thank you for sharing this! Indeed, the absolute maximum temperature for the Montreal area for yesterday (July 15th) slightly exceeded that of July 14th, 2012. Outside the city, towards the airport, however, last year's maximum on July 14th remains slightly higher than yesterday's, where the absolute maximum was recorded at 33.3 C on July 14th, 2012 (yesterday, it was 33.1 C), along with a daily mean (daily maximum and minimum averaged) of 28.1 C (so, 10.1 cooling degree-days). In either case, though, both today's, and especially tomorrow's (July 17th) maximum temperature may be enough to be the hottest since July 14th, 2012, and possibly beyond that.

Other than that, the highest daily means remain with August 1st, 1975 and July 21st, 2011, where the means were 30.3 C and 30.0 C (12.3 and 12.0 cooling degree-days), respectively, at the airport. The absolute maximum temperature, at the airport, on August 1st, 1975 was observed at 37.6 C, and on July 21st, 2011, it was 35.6 C (tied with July 22nd, 1955 for the warmest temperature to occur in the month of July). On both days, humidex values were close to 50 C. July 1955 was the warmest July in recorded history and included a monthly maximum average of virtually 30 C (17 of the 31 days reached 30 C or more)!

And it appears that we have now officially attained heat wave status for the Montreal area, as it recently surpassed 30 C today, and, thus, making it three consecutive days where daytime highs reached 30 C or more. Powerful thunderstorms, however, may occur later tomorrow afternoon/evening across E. Ontario to S. Quebec, and again late-day Friday (July 19th) in S. Ontario to S. Quebec, just before a cooling into the weekend.

Trav.


Posted: Jul 17, 2013 08:28:19

Trav,

where do you get the figures for downtown from? McTavish station reported 32.3max and 27.6 mean for July 15th, at least in the daily figures: http://www.climate.weatheroffice.gc.ca/climateData/dailydata_e.html?ti meframe=2&Prov=QUE&StationID=10761&dlyRange=1994-07-26|2011-10-17&Mont h=7&Year=2013&cmdB1=Go

Just curious,

Paul.
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