Hot Weather Building In; Severe Storms to End Week?

Hot, increasingly humid weather will begin working it’s way back into Southern Manitoba as a southerly flow at the surface, advecting moisture northwards from the US Plains, combines with an upper ridge over the Prairies that will work to crank up the heat.

Model winds at 500mb showing the strong upper-level ridge forecast over the Prairies on Thursday.

Model winds at 500mb showing the strong upper-level ridge forecast over the Prairies on Thursday.

Today

Wednesday

28°C / 15°C
Sunny.

We’ll see a pleasant day today with sunshine dominating the skies and a light northwesterly wind. Temperatures should climb up to around 27°C while the northerly winds keep the humidity down making it a very comfortable summer day. Skies will remain clear overnight as we drop to a low of around 15°C. There will be a very slight chance of a thundershower or two in the Red River Valley through the afternoon hours, but if they do develop they’ll most likely be tied to areas along the western escarpment and northwards towards Riding Mountain park. There would be a very marginal chance of any of these storms becoming severe; if any were to the main threats would be heavy rain and large hail.

Thursday & Friday

Thursday

30°C / 19°C
Sunny & increasingly humid.

The heat will build a little more on Thursday, but the real big difference will be the humidity which will become very noticeable as the winds shift around to the south on Wednesday night and allow the dew point to start climbing. They should reach the mid-to-high teens by Thursday evening which, when combined with our expected daytime high of 30°C will make it feel more like the mid-to-high 30’s. No storms are expected as a strong cap keeps everything in line.

Friday

28°C / 14°C
A mix of sun and cloud; showers or thunderstorms with passage of cold front. Very humid until front passes.

Friday will be the most active day of the week as ample heat and humidity are in place ahead of a moderately strong cold front that will work across Southern Manitoba through the day. It looks likely that storms will initiate on the front fairly early in the day (perhaps even by late morning if nocturnal storms don’t just march out of North Dakota and continue through the day) and pose the risk of becoming severe as they will have ample energy available to them.

High CAPEs combined with ample bulk shear (0–500mb bulk shear values are expected to be in the range of 50–60kt) will allow storms to organize quickly and introduce the threat for large hail and strong winds. Shear values are generally running parallel to the front, which means slow frontal motion could produce training thunderstorms that may produce localized flash flooding. The threat for tornadoes looks fairly low given that winds right near the surface may not be able to move into a favourable direction due to the orientation of the front and tilt of the entire system. While tornadoes can never be ruled out of severe thunderstorms, at this time it doesn’t look like the threat should be considered one of the primary threats for Friday.

The day may be more cloud than sun depending on how convection develops to our south and west on Thursday night, but we should see a high temperatures anywhere from 25°C to 28°C before the front comes through. The passage of the front will bring northerly winds which will flush out a lot of the humidity that will have built up over the prior days which should make things quite a bit more comfortable. Things will clear out overnight as we drop to a low in the mid-teens.

The Weekend

Looking ahead to the weekend, we’ll see plenty of sunshine return with highs climbing in the 27–30°C range with comfortable humidity. It looks great. Keep tuned here and to our team on Twitter (@WeatherInThePeg, @steinbachwx and @lovestormsMB) for updates and thoughts on Friday’s severe weather potential. Until then, enjoy summer!

Stormier Weather Ahead

Rainfall expected on Monday night.

Rainfall expected on Monday night from the RDPS.

Unsettled weather will mark the start of the week as multiple disturbances move through Southern Manitoba in quick succession. A weak trough will push across the Red River Valley late this afternoon and through the early evening associated with a low pressure system moving through Northern Manitoba. That will quickly be followed up by a disturbance moving out of North Dakota through Southern Manitoba as well.

Today

Monday

28°C
Mainly sunny.
Monday Night

18°C
Increasing cloud. Rain with thunderstorms likely overnight.

Most of the day will be pleasant today as mainly sunny skies dominate and the temperature climbs to around 28°C. Clouds will develop a little later in the day as the trough line approaches and we’ll see a slight risk of a thunderstorm in the evening. At the same time as our slight risk of a thunderstorm, a more organized area of thunderstorms will be developing in North Dakota supported by an upper-level disturbance. This area of storms looks to expand into an area of rain with a few embedded thunderstorms as it moves northeastwards into Southern Manitoba and will likely bring rain with a decent chance of some storms through the overnight period to the Red River Valley. The rain could be quite heavy at times, with accumulations potentially reaching the 2” (50mm) mark. There’s still a little disagreement in the models regarding the development of this system, so we’ll be sure to keep an eye out in case it looks like this rain won’t develop. With how things look now, it seems likely that the rain would reach Winnipeg late overnight and move off by mid-day on Tuesday.

Tuesday

Tuesday

23°C / 13°C
Showers tapering off by the afternoon then clearing.

We’ll see a cloudy start to the day with showers likely as long as the convection in North Dakota develops as expected. They could still be quite heavy at times in the morning, so we’ll probably be off to a very wet start to the day. Things should taper off as the main support for the rain pushes into Northern Ontario by the early afternoon hours and then we’ll see sunshine work it’s way out. A few hours of afternoon sunshine should help push our temperature up to around 23°C by late afternoon. On Tuesday night we’ll see mainly clear skies with temperatures dipping to 13°C as we move into a slightly cooler air mass.

Wednesday

Wednesday

28°C / 15°C
Sunny.

Wednesday will mark the turnaround back into a hot weather regime. Sunny skies will dominate as we climb to a high of 28°C with fairly light winds. The sunny, warm weather will be thanks to a upper-level ridge building into the Prairies. We’ll drop to a low around 15°C on Wednesday night under clear skies.

Rest of the Week

The rest of the week will be increasingly hot as a southerly flow redevelops over the eastern Prairies and begins bringing Gulf moisture northwards into the region again. This will be marked by daytime highs near 30°C and increasingly humid air building into the Red River Valley. We’ll have more details on Wednesday, but at this point it looks like the second half of the week and the weekend will be marked by hot, humid sunny weather with a low risk of seeing any stormy weather.

Generally Nice Weekend In Store

A generally nice weekend is in store, with the exception of possible rain or storms on Saturday.

Areas outlined in red over Manitoba are forecast to be between 27 and 29C by the NAM model

Friday

Friday

Mainly Sunny
28°C / 18°C

Today will be another beautiful day in Southern Manitoba. High temperatures will be in the upper twenties under mainly sunny skies. The wind will be fairly light and from the north.

Saturday

Saturday

Mix of Sun and Cloud. Chance of showers or thunderstorms.
27°C / 15°C

Saturday looks to be the only possible wrench in the weekend forecast. It appears that skies will be a mix of sun and cloud or mainly cloudy on Saturday with a chance of rain and risk of a thunderstorm. Any storms that roll through will be non-severe, but possibly enough to cause disruption to outdoor activities. It is possible we may entirely avoid rain and thunderstorms on Saturday, so hopefully that will be the case. If we steer clear of precipitation, temperatures on Saturday may reach the upper twenties in Southern Manitoba. However, if it stays cloudier then highs will end up in the mid twenties.

Sunday

Sunday

Mainly Sunny
27°C / 15°C

Sunday should be mainly precipitation free in Southern Manitoba, except for perhaps a stray shower or thundershower. Temperatures are expected to be in the mid or upper twenties with light winds and mainly sunny skies.

Long Range

As we move into next week the heat is expected to crank up once again. Temperatures in the upper twenties or near thirty degrees are expected on most days. Models hint at the potential for storms later in the week, but it is too early to discuss that any further.

Beautiful Weather Ahead; Summary of 2013 So Far

We’ll see a beautiful second half to the week as an upper ridge continues to dominate the Eastern Prairies bringing more heat and humidity to Southern Manitoba with daytime highs climbing to (or just over) 30°C.

Wednesday

31°C / 19°C
Mainly sunny.
Thursday

30°C / 18°C
Mainly Sunny. Becoming humid.
Friday

30°C / 18°C
Mix of sun and clouds. Humid. Risk of showers or thunderstorms.

The next couple days will bring mainly sunny skies with highs just over 30°C. Winds will remain fairly light and comfortable dew points will make for perfect summer weather. By Thursday afternoon, dew points will begin to climb ahead of an approaching trough line making things start to feel a little sticky.

On Friday, we’ll see continued hot weather however the upper ridge will have moved off and we’ll see a trough line pushing across Southern Manitoba. Depending on how things develop on Thursday night in Saskatchewan, we may see a few dying showers or thundershowers on Friday morning, but the main threat for any storm activity should hold off until the afternoon. Moisture pooling along the trough will push the dew points towards 20°C, making it feel very humid and closer to 37 or 38°C than the high of 30°C. There’s a decent chance we’ll see some thunderstorms on Friday afternoon develop along the trough line, a few of which may be able to become severe. MLCAPE values from 800–1000J/kg are fairly low, however SBCAPE values look to sit between 1500–2000J/kg; if a storm is able to get organized enough to really tap the surface moisture the main threats would likely be heavy rain given the ample moisture available coupled with fairly weak bulk shear and slow storm motion. We’ll have a more comprehensive look at the severe weather threat for Friday in the next blog post. Enjoy that summer weather!

A Look at 2013 So Far

We’ve made it half-way through 2013! This year has started in sharp contrast to last year where unprecedented heat swept over North America very early in the year, leading to a record-breaking start to spring and summer that fast-tracked 2012 to one of the top–5 hottest years ever for Winnipeg. 2013 has seen a painfully slow start to the summer weather as the icy grip of winter hung on for an inordinately long time leading to one of the latest snow melt dates ever record in the Red River Valley.

2013 Monthly Temperatures

Monthly average temperatures from the Winnipeg Richardson International Airport for 2013. The dashed line represents the 1981–2010 average.

Looking at monthly average temperatures, perhaps most interesting is how “normal” this year actually has been. January and February ended up almost perfectly seasonal, as have May and June. March and April, however, clearly show the impact of the prolonged cold and snow pack. April finished with a monthly average temperature of –2.1°C which was 6.6°C below normal and a whopping 7.9°C below 2012.

Jan Feb Mar Apr May Jun
2012 –10.8 –9.8 2.2 5.8 12.2 17.7
2013 –16.7 –14.0 –8.0 –2.1 11.1 17.5
Average –16.4 –13.5 –5.8 4.5 11.4 16.9
Table of average monthly temperatures from the Winnipeg Richardson International Airport for 2013. Temperatures are in °C. Average is for the period 1981-2010.

Looking at the year-to-date average temperature, things look about as we would expect. We started off near-seasonal with things falling a little below-normal through our cold spell in the spring which has been maintained as we’ve seen temperatures climbing back to seasonal with no above-seasonal weather. We’re a good deal cooler so far than last year, but that’s expected given the start we had in 2012.

2013 YTD Average Temperature

Year-to-date average temperatures from the Winnipeg Richardson International Airport for 2013. The dashed line represents the 1981–2010 average.

Despite the spring that would never end, this year is shaping up to be surprisingly seasonal! The 30°C weather recently is certainly helping me forget the snow that stuck around for so long…

Jan Feb Mar Apr May Jun
2012 –10.8 –10.3 –6.1 –3.2 –0.1 2.9
2013 –16.7 –15.3 –12.9 –10.2 –5.9 –2.0
Average –16.4 –14.9 –11.9 –7.8 –4.0 –0.5
Table of year-to-date average temperatures from the Winnipeg Richardson International Airport for 2013. Temperatures are in °C. Average is for the period 1981-2010.

Precipitation so far this year at the airport has been near-normal and slightly less than last year. I’d just like to make a comment that this spring/summer, especially over the past month, has been extremely wet of portions of the Red River Valley. This season has had an abnormally high number of slow-moving thunderstorms that has locally produced huge amounts of rainfall. Even here in Winnipeg, once some stations from other areas of the city are included, amounts of precipitation so far this year has varied by almost 8 inches!

2013 YTD Precipitation for Winnipeg

Table of year-to-date precipitation from the Winnipeg Richardson International Airport & Rob’s Obs unofficial observing site in Charleswood for 2013. Average is for the period 1981–2010.

The observations from Rob’s Obs include two significant precipitation events that only part of the city saw: the first is a back building thunderstorm that brought over 75mm of rain to the southwest portion of the city as well as multiple showers that passed over western portions of the city last week that gave another 20mm of rain to that area. As can easily be seen, while the airport is sitting at near-normal amounts of precipitation, some areas of the city are approaching twice the normal yearly amount. For some other areas in Manitoba, such as areas near Reston, MB, they’ve already received an entire year’s worth of rain over the past month, and that’s on top of the precipitation that’s fallen earlier this year. It’s been very wet in general over Southern Manitoba so far this year. Here’s the year-to-date precipitation values:

Jan Feb Mar Apr May Jun
2012 12.0 16.5 63.0 102.0 200.0 262.0
2013 30.0 38.0 57.0 90.5 159.5 222.3
2013
Rob’s Obs
3.0 8.6 24.8 66.9 185.6 441.6
Average 19.1 33.6 59.0 89.1 149.0 237.8
Year-to-date precipitaiton from the Winnipeg Richardson International Airport & a Charleswood observation site for 2013. Precipitation amounts are in mm. The dashed line represents the 1981-2010 average.

It will be interesting to see how the remainder of the year plays out. While 2012 started off very warm, we actually had below-normal temperatures in the second half of the year that brought us closer to seasonal – although it was still an exceptionally warm year – than it originally seemed that we would. We’ve had a cold start to the year, but we seem to finally be getting into the swing of summer and plenty of hot weather seems to be in the future as long-range models continue to support/sustain a large ridge over the Rockies.