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.

Hot Start to July

We will have a hot end to the Canada Day long weekend and a hot start to the month of July.

Pleasant Conditions are Expected on Canada Day Across the Eastern Prairies

Canada Day Monday

Monday

Mainly Sunny
28°C / 12°C

Temperatures on Monday will be in the upper twenties in Southern Manitoba. Skies will be mainly sunny and winds will be light, making it a perfect Canada Day!

Tuesday

Tuesday

Mix of Sun and Cloud. Chance of showers and risk of a thundershower
30°C / 16°C

Tuesday should see temperatures climb up around the 30C mark in most of Southern Manitoba. We may see some pop up showers or thundershowers as the atmosphere will be a bit less stable than it was on the weekend. Wind speeds will remain light, so conditions will generally be very nice.

Wednesday

Wednesday

Mainly Sunny. Slight chance of a shower or thundershower.
31°C / 17°C

Wednesday will again be a hot day in Southern Manitoba. Temperatures will once again be around the 30C mark. There may also be a few pop up showers or thundershowers again on Wednesday, but they are expected to be even more isolated than on Tuesday. The wind will be breezy from the south or south-west, providing a bit of relief from the hot weather.

Long Range

The long range forecast shows hot weather continuing in Southern Manitoba through the foreseeable future. Models suggest that we will stay above normal for much of the next 10-16 days. The accuracy of these forecasts past the 7 to 10 day range can be quite bad in many cases, but the overall trend appears to indicate a hot first half of July. Typically these hot patterns don’t like to break down very quickly at this time of year, so I wouldn’t be at all surprised if we saw generally hot weather last through much of July.

Thunderstorm Threat Ramps Up Over Southern Manitoba

A broad shift in the jet stream is set to bring an influx of moisture from the Gulf of Mexico northwards into Southern Manitoba while a southwesterly flow aloft sets up bringing multiple upper-level disturbances & instability over the region. The increased moisture, combined with the relatively unchanging southwesterly flow will set us up for multiple days with a significant thunderstorm risk over the southern portion of the province.

Wednesday

Wednesday

26°C / 15°C
Afternoon clouds; chance of showers/thunderstorms.

Today’s weather will be dominated by an approaching warm front from Saskatchewan. We’ll might see few showers exiting the Red River Valley this morning – left over from some weak nocturnal convection – with plenty of sun through the morning. The sun will heat things up fairly quickly and there’s a chance we’ll see some showers or thunderstorms develop early-to-mid afternoon as we warm up. Any storms that develop today will not likely become severe; a majority of the shear will be isolated in the upper levels and the complete lack of low-level shear may even be substantial enough to inhibit storm development. We’ll drop to an overnight low of around 15°C as we head into a busy end of the week.

Thursday

Thursday

25°C / 16°C
More cloud than sun; getting humid. Showers or thunderstorms likely.

Thursday presents Southern Manitoba with plenty of heat and rising humidity as the day progresses. We’ll see a high of nearly 26°C while the dew point climbs into the high teens through much of the Red River Valley by the end of the afternoon. Whether or not that humidity will make it up to Winnipeg will depend on how soon the winds turn from northeasterly to southeasterly; the sooner they do, the more humid we’ll get. The building heat and humidity will create a fairly potent setup for severe storms, however.

image-1

Severe thunderstorm outlook issued on Wednesday, June 19 @ 6:30AM CDT

By late afternoon CAPE values are expected to climb to 2500–3000J/kg near the international border thanks – in no small part – to the climbing dew points. LI values are forecast to drop to the –8 to –10°C range, indicative of the steep lapse rates aloft and the potent storm potential. Good wind shear will be in place with southeasterly surface winds veering to a strong westerly wind at 500mb. In addition, a shortwave is forecast to eject into Central North Dakota by mid-afternoon and push northeastwards into the RRV by evening, bringing with it enhanced destabilization and lift. One big question mark remains, though. While we have plenty of moisture, instability, shear, and a trigger, the cap may be make or break storms for the day, or rather, the lack of a cap may.

Models are having a hard time determining just how warm it will be in the mid-levels of the atmosphere; some want to establish a cap that will inhibit convection until later in the day, but others keep the environment uncapped which will result in the maintenance of an MCS coming out of Saskatchewan on Thursday morning. In that case, we’d see showers and thunderstorms build into the Red River Valley in the morning and persisting through much of the day. Conditions still look somewhat favourable for the development of isolated strong to severe storms in this scenario, despite the ongoing showers and thunderstorms. If the cap does develop though, the MCS will likely die out to our west and a significant threat for severe thunderstorms would mount in the Southern Red River Valley.

It’s still too early to be too certain on the threat for Thursday as models are still working to resolve the interaction with various shortwaves and the main upper low anchored over the American mountain northwest. For now I’ve extended a slight risk through Southern Manitoba along the International border.

Friday

Friday

26°C / 13°C
Mix of sun and cloud; humid.

Friday will end up a fairly hot day with temperatures climbing into the mid-to-upper 20’s with dew points rising to nearly 20°C. The humidity will make it feel closer to the low-to-mid 30’s, so it definitely looks to be one of the first really hot days of the year. Conditions should hold out through most of the day before thunderstorms develop in North Dakota and begin pushing northwards. It’s still too early to tell their exact path which will be heavily dependant on where exactly upper-level features lie. They may end up moving into SW Manitoba, the RRV or the Whiteshell through Friday night.

We’ll have a busy few days ahead so expect plenty of updates in the comments below! Briefly looking ahead to the weekend, Saturday and Sunday both look showery over much of Southern Manitoba with a risk of thundershowers. There will be some breaks here and there, but we’ll take a closer look at that on Friday.

Mainly Seasonal With A Chance of 30°C

We’ll see fairly typical weather for this time of year across Winnipeg and the Red River Valley with a big exception being tomorrow: with southerly winds and a big upper ridge moving across the region, there’s a good chance we’ll see temperatures in the upper 20’s, perhaps even breaking 30°C on Saturday afternoon.

500mb Wind Speed

500mb wind speed from the GEM-REG for midday today depicting the upper ridge that is moving into the province.

We’ll see plenty of sunshine today as the aforementioned upper ridge begins working it’s way into our region. Temperatures will be able to climb up much higher than yesterday, where a cool air mass combined with clouds limited our temperatures. We’ll see a high near 25°C today, although it will be a bit of a climb as we dig out of a rather chilly morning.

On Saturday, the upper ridge will move across the province, bringing with it 850mb temperatures in the 17-18°C range. Winds will be out of the south, not the southwest, so we won’t see any significant downslope effect to help our temperatures out. As a result, we’ll see widespread highs near 28°C with a few locales getting as high as 29 or 30°C by the late afternoon.

A powerful cold front will dive southwards through the Red River Valley on Saturday evening which will usher cool Arctic air in from the north. 850mb temperatures will plummet to nearly 0°C for Sunday which will hold our daytime high to the mid-teens, most likely below the seasonal normal high of 18°C, under cloudy skies.

Cooler air will continue to push southwards into the beginning of next week, with 850mb temperatures dropping below 0°C on Monday and remaining over the region for much of the week. This will likely result in daytime highs in the mid-teens and overnight lows in the low single-digits for much of the week under more cloud than sun and a chance of showers on and off through the week.