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.

Elsewhere in Weather News: July 6th, 2013

Tropical Storm Erick

On Friday a tropical storm – tropical storm Erick, formed off Mexico’s coast, over the Pacific Ocean. Erick has been hugging Mexico’s west but staying over the Pacific. Since it has been staying over warm sea surface temperatures (SST) of about 28-29°C, Erick has had the chance to strengthen and is expected to become a hurricane. It currently has sustained winds around the 80km/h mark. But because of its proximity to land, SSTs gradually decreasing as you head north and a bit shear present, Erick is only expected to intensify into a category one hurricane this weekend. Mexico’s west coast is not in the clear though, cities and resorts such as Manzanillo, Tecomán and Puerto Vallarta are expected to receive heavy, possibly flooding rains from Erick’s outer bands. A hurricane watch has been issued for the region because of Erick.

Erick

IR picture of tropical storm Erick on Saturday morning. (Source: CIMSS)

After a few days of being close to the coast Erick is expected to take a left turn into the wide open Pacific Ocean and will succumb to its death as SSTs are much cooler and shear will tear the storm apart.

More Flooding in China

In other weather news, China has yet again faced severe flooding because of torrential rains that inundated eastern China and southwestern China. In the southwest it was not uncommon to see 24 hour rainfall accumulations of 200mm from the monsoonal rains. In the east, Shenyang was the hardest hit city where streets were flooded out and houses inundated. The flooding is blamed for 39 deaths this past week in China.

A few sunny days this weekend should let things dry out before the chance of rain will increase again early next week in Shenyang.

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.