Hello everyone,

As we have reached the month of June, I thought it would now be appropriate to post this thread.

For each of the fireworks displays this Summer, weather reports will be posted here, including a preliminary outlook two days in advance of every display date, followed by finalized forecasts for either later on the day preceeding fireworks days, or early on the fireworks days themselves, if necessary. I will try and keep details short and concise and will commonly focus on temperature, humidity, precipitation (if applicable), and wind (speed and direction). In cases where the potential for thunderstorms, particularly severe thunderstorms, exists, some further detail will be provided. You are also, of course, more than welcome to post weather updates, but be sure to pay particular attention to the aforementioned meteorological factors.

As mentioned previously, I also use Facebook to provide weather information. As of last Summer (2011), I have been more regularly posting weather updates on my Facebook profile, mostly for severe weather events of any kind across S. Quebec. As such, you are also invited to follow me there, especially when the likelihood for severe weather becomes elevated. The page can be accessed here:

http://www.facebook.com/#!/profile.php?id=738801345

Finally, for those interested, I have posted a detailed Summer 2012 outlook, as well as a review of this past Winter, on my Facebook page. This review can be retrieved using the following link:

http://www.facebook.com/#!/notes/travis-moore/winter-2011-2012-and-a-l ook-ahead-to-spring-summer-2012/10150727374171346

In short, I am anticipating a warm (normal) Summer for 2012, just not as warm as what was seen over the last two years (2010 and 2011). This suggests a slight decline in the number of days reaching maximum temperatures of 30 C or more, as compared to the previous two Summer seasons. Additionally, I believe that we could witness an increase in the number of severe weather days across Ontario and Quebec, corresponding to potentially above normal thunderstorm activity - this could imply locally average to above average precipitation for the Summer months.

Note that I released this review around mid-March, but what I had stated then remains unchanged until now. However, I have been monitoring the equatorial Pacific SSTs (sea-surface temperatures) over the last few weeks, and some model projections have exhibited signs that a weak El Nino may emerge by the end of this Summer, and onwards toward Winter 2012-2013. If El Nino conditions do persist in time for the latter part of the Summer and thereafter, this could spell a reduction in the number of Atlantic tropical cyclones that develop. Additionally, this could also have more positive implications for our upcoming Winter, although it has yet to be seen how both the North Atlantic and Arctic Oscillations will behave at that time. That said, I am not entirely convinced that El Nino will, in fact, dominate, as there is much uncertainty in the model projections. At this point, it appears equally probable that either neutral or weak El Nino conditions will prevail for the end of Summer and beyond, so that is something to keep an eye on for the coming months. If neutral conditions are dominant, it could result in near-normal Atlantic tropical cyclone activity, as well as a more typical upcoming Winter. Still, the climate models demonstrate an overall consensus of warming SSTs (toward positive anomalies) over the coming months, but it's now simply a question as to "how much" warming will actually unfold. In either case, our past La Nina episode has dwindled since the latter part of April, and near-neutral conditions will likely be present for the remainder of the Spring, and for much of this Summer, before any potential transitions occur in the equatorial Pacific.

Here's hoping for ideal weather conditions for all of our participants of 2012!

Trav.

Trav: any updates on the weather for Saturday? Also, I'm doing my Canada Day show on Sunday 1st in Knowlton again - would it be possible to get a weather forecast for that?

Thanks!

Paul.

I have not made a close verification of this, but I believe the 2012 debute display is the latest on the calendar since the start of the competition in 1985. So it seems that we are lucky and, instead of cold weather often experienced on early- or mid-June opening displays, we should enjoy summer conditions, with sun, heat and humidity. I can't wait for Trav's detail reports. In such circumstances, I suppose the big question mark is about wind force and direction.

Fred

At this point in time, the weather should be okay for Japan's display on Saturday evening (June 30th), as compared to what previous prognostics were indicating in terms of instability. That said, because of the positioning of the area of low pressure at the time, I am closely monitoring wind patterns for the day, as they may become unfavorable for folks at La Ronde, more so for spectators on the right hand side of the grandstands. Winds could also be quite gusty during the afternoon period (maximum gusts potentially near 45-47 km/h), though I am expecting them to subside by the evening.

I will provide a more preliminary overview of the weather situation later today. As Fred mentioned, wind tendencies are questionable!

Paul, for Canada Day across S. Quebec, convective showers and isolated clusters of thunderstorms may be possible late in the day due to a passing cold front, which will act to, once again, decrease temperature and humidity values in time for Monday. Humidity itself should be high, and winds are expected to switch to Northwesterlies by the evening period. Maximum temperatures should reach 26-28 C. Still, I would like to keep an eye on this weekend altogether - with the newer model output arriving today into tomorrow (the 29th), it will be easier to finalize these conditions.

Fred, I think you may very well be correct in stating that this is the latest that the competition has ever commenced. There is also a good likelihood that last year's opening date could be the second latest! Could this be a new trend?

Trav.

The current area of low pressure, centered over Northern Quebec, will likely remain nearly stationary for today (Friday) into the Canada Day weekend. Consequently, this weather system will govern patterns for this time period for both S. Ontario and S. Quebec, continuing to bring very warm to hot temperature values, borderline moderate-high humidity, and variable SW to WSW winds speeds to these regions.

For Japan's display on Saturday, the newest model projections indicate very warm temperatures and continued borderline moderate-high humidity. Because of a passing cold front moving through this morning, humidity levels will decrease somewhat during the afternoon hours and will be held constant thereafter into Saturday, producing humidex readings into the low 30s Celsius (high 20s C by the evening). The latest surface analysis, however, reveals a secondary cold frontal wave descending from the NW into Saturday. The front itself, though, is shown to be relatively weak in nature (as per convergence strength), so I don't expect widespread convection with this system. Still, partly cloudy skies (towering cumulus clusters) could be generated by the late afternoon period into the evening here in S. Quebec with a few isolated convective showers and non-severe thunderstorms (concentrated mostly to our North). Once this front passes through, it will push humidity levels down to more moderate levels in time for Canada Day, along with temperatures closer to seasonal (24-25 C).

Winds (speed and direction) are still something that need to be monitored for Saturday evening. The latest surface analysis continues to exhibit SW winds for early Saturday into the afternoon hours and becoming gusty (top gusts at about 45-47 km/h with sustained speeds between 33-36 km/h) for the afternoon period. By the evening, directional tendencies may shift to WSW, along with lighter sustained speeds at around 17-21 km/h (further decreasing to 11-15 km/h by late evening). This would suggest that the smoke could be blowing towards mostly the right hand sections of the grandstands at La Ronde. However, some simulations are showing Northwesterly patterns by late evening, which would push smoke to the left, although it would head towards spectators on the bridge adjacent to the park. As such, it is still required to wait for the models to come more into agreement.

That's the way the weather should generally work for today into the weekend. I will provide a finalized report later today (for Canada Day and Saturday), although an additional update may be necessary early Saturday for winds and potential precipitation.

Paul, for the evening of Canada Day in Knowlton, winds should generally be light (8-11 km/h) from the WSW, though breezier Westerlies (15-19 km/h) will likely take place during the afternoon period. The probability for precipitation is now less, as the cold front will have gone through Saturday night, East of Montreal, leaving mostly pleasant conditions for Canada Day. Maximum temperatures should be around 24-25 C, coupled with moderate humidity. Temperatures decline to 18-20 C by late evening, along with near-constant humidity levels. Again, I will post finalized details later today, just in case of any changes, but this should give a good overview as to what to likely expect.

Trav.

Apologies for the delay!

After reviewing the latest model runs, these are the conditions that will likely be prevalent through Saturday (June 30th) across S. Quebec. An analysis for Canada Day is also prepared in the following section, though it is possible for some adjustments to be made into tomorrow.

June 30th

Temperature/Humidity

Temperatures are still expected to remain very warm/hot for daily maximums for Saturday, where values may attain as much as 29 to 31 C. Humidity levels are also within the moderate-high range, making it feel into the 30s C (33-35 C), mostly for the early to mid parts of the afternoon before a secondary cold front advances from the NW later in the afternoon to the early evening. Late evening temperatures should be closer to 24-25 C (as much as 26-27 C in the metropolitan area), along with moderate humidity, generating a humidex of about 29-30 C.

Precipitation

As mentioned previously, a secondary cold front will be advancing from the NW later tomorrow afternoon into the early evening, generating increased cloudiness by mid afternoon, along with a few possible isolated convective showers and non-severe thunderstorms. The greatest area of convergence/moist convergence along and ahead of the cold front is still shown to be North of Montreal, so I am expecting greater likelihoods for more widespread storm initiation over those areas. Precipitation for Southern portions of Quebec (Montreal included) should generally be more isolated in nature, so a 30% probability is in order for the late afternoon-early evening period. Instability should subside by the late evening time frame with building convective inhibition.

Wind

The current area of low pressure has not shifted positioning significantly from previous simulations. As such, winds are expected to still be largely coming out from the SW through tomorrow and will be gusty throughout the afternoon, with maximum gusts between 47-51 km/h and sustained between 33-36 km/h (highest sustained winds and gusts should occur between 1:00-4:00 p.m. Speeds should subside with the onset of the evening as the system slowly migrates East, declining to as much as 17-21 km/h (gusts at 27-30 km/h) and further down to even as low as 7-11 km/h by late evening. In terms of direction, winds are shifting more to NW tendencies for the early to late evening (more from the WSW by mid to late afternoon), so this could gently displace smoke towards the left hand sections of the grandstands, as well as possibly left hand-most parts of the central section. Smoke may also influence those on the bridge just adjacent to the park and behind (going East). Some smoke accumulation may take place during more active sections of the display due to the combination of lighter winds and moderate humidity.

In summary, borderline moderate-high humidity and very warm to hot temperatures will be present for Saturday. Isolated convective showers and non-severe thunderstorms (30% probability) are possible for the late afternoon and early evening period due to a passing secondary cold front. Winds are gusty for the day and are mostly from the SW but could change to WNW to NW tendencies by late evening, pushing the smoke to left hand sections of the La Ronde audience. Speeds also die down significantly by the evening, which could lead to some occasional smoke build up. If necessary, I will provide a brief update concerning the winds early tomorrow.
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Your Canada Day forecast:

Temperature/Humidity

With the passage of the secondary cold front later Saturday through S. Quebec, maximum temperatures for both Montreal and to the East/NE will likely reach 25-26 C with continued moderate humidity, making it feel closer to 28-30 C. By late evening, temperatures decline to 19-20 C, along with near-constant humidity (humidex not significant).

Precipitation

Generally comfortable conditions should prevail for early to mid sections of the day. However, newer (and a few previous) prognostics indicate a developing upper level trough following the departing surface low. This trough will enhance instability for the mid-afternoon period for Western/SW sections of Quebec, producing isolated convective showers and a few possible non-severe thunderstorms. The risk gradually pushes East by the late afternoon to early evening period, but instability should gradually cease thereafter with nocturnal cooling, leaving predominantly partly cloudy skies. Precipitation may become more scattered in association with this trough, so a 40% probability for W/SW sections of the province (considering also the timing during the afternoon) is appropriate, as well as for areas East and NE of Montreal towards Sherbrooke and Quebec City, though decreasing to 30% by the early evening. In either case, expect increased cloudiness by the afternoon - this increase is also supported by mid level analyses showing elevated relative humidities at those levels of the atmosphere.

Wind

Winds should be breezy throughout the late morning to afternoon period for Southern and Eastern/NE Quebec. Wind direction should be primarily from the West, but should begin to change to Northwesterlies by the evening for the Montreal area to WNW to the East of the island. Speeds also uniformly decrease by the evening to 5-11 km/h for the aforementioned regions.

Trav.

As expected, a few isolated convective showers have developed ahead of the cold front and will continue to do so to the NW while pushing SE over the next few hours. Again, most of the thunderstorms, and even severe thunderstorms, lies to our NE.

In terms of winds, they should remain as Northwesterlies for the duration of the evening, although models now indicate slightly higher wind speeds at 12-15 km/h, which would facilitate smoke clearance a little more.

Enjoy the show by Japan!

Trav.

As this upcoming area of low pressure slowly advances Eastward, both S. Ontario and S. Quebec will slowly resume a very warm/hot and humid air mass for tomorrow (Friday, July 6th), with temperatures locally attaining as much as 34-36 C, along with humidity values ranging in the high 30s to low 40s C. However, as a cold front pushes in from the WNW by late tomorrow afternoon, clusters of convective showers and thunderstorms (a few of which may reach severe criteria) could develop along and ahead of it. It's still questionable, however, how widespread convective activity will become. Consequently, the best chance for any convection to take place across S. Quebec should span from late Friday afternoon to the pre-dawn hours of Saturday. This also suggests that humidity levels will be declining to moderate values for Saturday, along with maximum temperatures closer to 26-28 C (late evening temperatures should decline to 22 C). I am additionally keeping an eye on a secondary cold frontal wave descending quickly from the NW, which may have some influence later in the afternoon, although this is not suggested in current model simulations.

One aspect that I am closely watching is the wind, mostly in terms of direction. By Saturday evening, winds may be blowing toward central and right hand sections of the audience at La Ronde. Once the cold front moves toward the SE, winds will gradually shift to West-Southwesterlies Saturday morning and oscillating between WSW to straight Westerlies for the mid afternoon to evening time frame. Wind speeds themselves should be breezy through the morning to afternoon and early evening periods, with sustained speeds between 23-27 km/h (ocassional gusts of 34-37 km/h). Wind speeds should decrease to 15-19 km/h by late evening.

I will provide an update for later tomorrow, and, if necessary, early Saturday afternoon, to confirm prevailing conditions.

Trav.

Weather conditions described in the previous posting remain similar for the day tomorrow, although there are a number of additional details that I'd like to incorporate. As such, here are the updated forecast details for Saturday, July 7th:

Temperature

Temperatures continue to remain very warm through tomorrow, with maximum values reaching as high as 27-28 C. Humidity levels, however, are reduced to borderline moderate/high levels, and so humidex readings should be around 31-32 C during the afternoon period. By late evening, temperatures decline to 22 C (as much as 23-24 C in the metropolitan area), along with mild humidex readings around 25-26 C (moderate humidity by late evening). Both temperature and humidity further decline into the overnight period, as cooler and drier air progressively settle in.

Precipitation

Model simulations continue to show that the greatest potential for convective activity remains for tonight into the morning hours, although the frontal wave will likely generate increased cloud cover and a few rain showers tonight toward the early afternoon. Following 2:00-2:30 p.m., the sun should slowly make more more appearances as the front slides SE. The simulations also continue to display a secondary cold front (as mentioned in the previous posting) descending quickly from the NW by late tomorrow afternoon. This front is relatively weak, however, and so the threat for defined convection should be minimal. The increased cloud cover early in the day associated with the previous front will also limit stronger instability. Still, this frontal wave could produce some brief increased cloudiness during the late afternoon, along with a few isolated showers (30% probability) distributed across S. Quebec and E. Ontario. The speed and timing of the front suggests that any instability associated with it should cease by the late afternoon-early evening period - this is also further supported by decreased relative humidities at mid levels of the atmosphere, as well as changes in surface/near-surface wind direction by the late afternoon (see next section).

Wind

Latest surface analysis projections remain fairly close to what had been illustrated in previous runs in terms of both speed and direction. However, newer analyses show that winds are shifting direction by the late afternoon period, where West-Northwesterlies and Westerlies become straight Northwesterlies. With this directional shift, winds should be pushing the smoke towards the "left" of the audience at La Ronde, although the extreme left hand section of the grandstands could occasionally be affected. Those positioned on the bridge behind the park (near the ramp and heading East) would be most influenced by smoke. In terms of the progression of directional tendencies through the day, winds become Westerly by the morning hours and transition to the WNW by the early afternoon. By the late afternoon period, winds should be more from the WNW and, into the early evening, from the NW. Speeds will be greatest from the late morning to early-mid afternoon, with sustained speeds at 23-27 km/h (occasional gusts between 31-34 km/h). The breezy nature of the winds is expected to continue into the late afternoon to early evening period at 19-23 km/h (occasional gusts at 27-30 km/h), and then to 18-21 km/h by the late evening.

That's the way the weather should generally work. To recap, warm temperatures should be present for the evening period, coupled with moderate humidity and breezy conditions from the NW. Isolated showers (30% probability) are possible during the late afternoon with the approaching secondary cold front but should gradually subside by the onset of the evening.

Trav.

As this potential heat wave continues to build across S. Ontario and S. Quebec, expect temperatures to attain borderline hot to very hot standards, as well as high to very high humidity, for both today (Friday) into the weekend. As mentioned previously, for a "heat wave" to emerge in Quebec, maximum temperatures must reach 30 C or more for at least three consecutive days, and seeing that we struck an hourly maximum of 31 C yesterday (the 12th), and given the potential temperature distribution for today and tomorrow, I have reason to believe that this weather pattern will, indeed, become a formal heat wave for many parts of S. Quebec.

Saturday's (July 14th) weather conditions will be a part of this pattern. Consequently, temperatures across E. Ontario and S. Quebec could locally reach as high as 34-36 C for daytime highs, along with high to very high humidity, making it feel as warm as 42-43 C. Evening to late evening temperatures will also remain quite high, largely because of the elevated atmospheric moisture content. As a result, values may remain around 28-29 C, especially in the metropolitan area, while the humidity will make it feel around 34-35 C. Conditions should also remain mostly dry for the evening, although I am monitoring an upper-level disturbance South of the border for early in the day - this should remain South into New York, but I'd still like to keep an eye on it in the newer model runs from today. The greatest chance for enhanced convection and severe weather is late Sunday night through the day Monday.

There seems to be a general agreement about wind tendencies in the model runs, where all are exhibiting SW to SSW patterns for the day (except WSW for the late-morning to mid-afternoon) into the evening period. Winds are breezy during the late-morning through most of the afternoon at 15-19 km/h but subside to 8-11 km/h by the evening. Some projections, however, are showing continued Southwesterlies into the evening, while others show a shift to the SSW direction. In either case, smoke from the fireworks should be blowing to the "right" of the audience at La Ronde, but it remains a question of how much to the right.

I'll provide an update later today Saturday's weather conditions.

Trav.

After reviewing the latest model analyses from today (Friday), overall conditions remain largely unchanged from what had been described in the previous posting. As such, here are the prevailing weather conditions for Saturday, July 14th for the Montreal area.

Temperature/Humidity

Because of an advancing area of low pressure moving in from the West, and a strong, dominant area of high pressure that has been centered over the North Atlantic for the last while, the resulting circulation of warm, moist air will push maximum temperatures to locally as hot as 33-35 C (a touch less from previous forecasts) during the mid-afternoon, along with continued very warm to hot temperatures during the late-evening period at 28-29 C, especially in the metropolitan area. Humidity levels are also remaining borderline high to very high, making it feel around 38-39 C during the mid-afternoon and 35-36 C throughout the evening, consistent with slightly rising humidity levels later in the day.

Precipitation

The models continue to show mostly dry conditions across S. Quebec, with roughly 30-40% relative humidity values at mid-levels of the atmosphere and suppressed/weak instability. As I had also expected, the upper-level disturbance (an upper-level trough) that I had mentioned previously is still shown to stay farther South of the border into extreme S. New York and southward. Weak instability may produce a few isolated cumulus clouds with limited vertical development during the afternoon, but skies should remain mostly clear.

Note that these conditions will quickly change into Sunday (the 15th) afternoon-evening, as enhanced convection becomes more prominent with an approaching cold frontal wave and preceding shortwave trough (this system is shown to move in a little faster, as compared to previous runs). As a result, convective showers and thunderstorms (some possibly becoming severe thunderstorms) may develop through the afternoon-evening period. Also note that this front will not sharply cut temperatures and humidity into the work week - this will likely occur by the end of the week (Thursday and Friday) as another cold front pushes through.

Wind

Wind tendencies (speed and direction) remain mostly constant in the newer projections. However, it appears that winds, after coming out from the WSW (early to mid-afternoon) to SW (morning and late-afternoon), should transition to South-Southwesterlies (SSW) by the late-evening period. Wind speeds still remain light but are slightly higher at 9-12 km/h. As such, smoke should be gently blowing to the right of the audience at La Ronde (left of the audience positioned on Notre-Dame street), although some smoke accumulation could occur during more active segments of the display due to the high humidity present.

That’s the way the weather should work. To summarize, very warm and humid conditions for Saturday evening, along with light SSW winds and a few scattered cumulus clouds. If necessary, I will post a brief update concerning the winds early tomorrow afternoon, at the very latest.

Should be another enjoyable July-like evening.

Trav.

Consistent with the information posted above, it is no surprise that Environment Canada has issued a high heat and humidity warning over much of S. Quebec. I would not rule out the possibility of humidex readings reaching as high as 42 C this afternoon. I personally adore this weather, but for those who have little tolerance for this kind of heat and humidity, it is important to remain indoors in an air-conditioned environment and to stay well hydrated (preferably with water). It is also important to stay out of the sun between 11:00 a.m. to 4:30 p.m., not only with respect to the heat, but also due to the high UV index forecasted for today.

As for the winds this evening, they are still expected to behave in patterns specified in the above posting. For everything else, please refer to the above post.

Trav.

It's been great, this year, not to have to look at the radar for storm threats before heading over to La Ronde!

Enjoy this great summer weather everyone!

Paul.

Indeed, the weather has been treating fireworks days well so far this year. Conditions for Tuesday evening (the 17th) are a little tricky, however, as convective showers and thunderstorms may develop across S. Quebec ahead of the aforementioned cold front (which will lead to a sharper cooling by Wednesday). It's still a little early to say how strong thunderstorms (if any) will become, though.

More details later tomorrow.

Trav.

Mentioned previously, this current heat wave will gradually subside as a cold front associated with the next area of low pressure passes through S. Quebec and S./E. Ontario Tuesday night. As a result, temperatures and humidity levels decline by Wednesday morning, with the cooler and drier conditions persisting towards early Saturday (the 21st) - overnight lows for both Wednesday and Thursday night may be as cool as 12-13 C for parts of S. Quebec (Montreal included, mostly outside the city). Until then, expect continued hot and humid weather until overnight Tuesday, including temperatures as high as 27-28 C (feeling closer to 34-35 C with the borderline high to very high humidity) in the metropolitan area for Tuesday evening/late-evening.

Note that periods of convective rains and thunderstorms (some potentially severe) are possible through the morning to afternoon period due to the low’s warm front, while the risk during the late-afternoon to evening period is attributed to the passing cold front. The atmosphere, at this point, is shown to be moderately unstable (for various reasons) through the early evening period and persisting (though weaker) into the early-overnight hours.

With this upcoming secondary area of low pressure intensifying as it travels ENE, relatively strong gusts of wind will likely develop during the late-morning to early-afternoon hours, where speeds are sustained between 27-31 km/h, while occasional gusts may reach as high as 42-45 km/h. Wind speeds (and gusts), however, are shown to decline by the late-afternoon to early evening hours to 19-23 km/h (occasional gusts between 29-32 km/h) and further to 14-18 km/h by late evening. Winds shift to various directions through the course of the day, consistent with the ENE progression of the low. Winds first begin from the SSW during the morning hours and then transition to the SW for the early to mid-afternoon period, becoming WSW by late-afternoon and Westerly for the early-evening period. By late-evening, models indicate a shift to NW tendencies, but the challenge is forecasting how quickly the previous Westerlies will undergo this transition. As a result, some projections show Westerlies throughout the evening (which would push smoke towards the audience at La Ronde), or a change to the NW (pushing the smoke to the left of the audience, although occasionally affecting extreme left sections of the grandstands).

In any case, a more careful examination of newer prognostics is essential to have a better overview of Tuesday evening’s weather conditions, especially in terms of wind patterns and atmospheric instability. Additional updates may be needed into early Tuesday, as well.

Trav.