Fairly Normal Start to the Week

This week will start out with fairly normal conditions for early June with a chance for rain, and moderate temperatures.

Monday will be a nice day in southern Manitoba
Monday will be a nice day in southern Manitoba

Monday

Monday
22°C / 13°C
Mainly sunny

Today may start out with a bit of rain in the morning as a piece of upper-level energy swings through but skies should quickly clear, making for a pleasant day. Any rain that does fall in the morning will be light, so it won’t be a big deal. By the afternoon we should see mainly sunny skies with temperatures in the low twenties and light winds.

Tuesday

Tuesday
23°C / 10°C
Chance of showers or thundershowers

Tuesday will see the chance for showers and thundershowers in the Red River Valley and south-eastern Manitoba ahead of an approaching trough. Any thundershowers that develop will present the risk of small hail and gusty winds. For those areas that miss out on the showers and thundershowers, it will be a nice day with temperatures in the low twenties and a breezy south-west wind.

Wednesday

Wednesday
19°C / 5°C
Mix of sun and cloud

A cold front will blow through southern Manitoba early Wednesday morning, setting us up for a slightly cooler day. Highs on Wednesday will be in the upper teens in most areas (perhaps a few readings in the low twenties), with skies being a mix of sun and cloud by the afternoon. The wind will be breezy and from the north.

Long Range

The long range forecast suggests we’ll continue to see normalish weather for the foreseeable future. That means high temperatures in the low to mid twenties and the frequent chance for rain or thunderstorms (albeit generally of the non-severe variety).

Elsewhere in Weather News: June 7th, 2014

Large Hailstorm causes Millions in Damages

This past week featured severe thunderstorms that tore through the Nebraska countryside producing extremely large hail in the region. Conditions were primed for a severe weather outbreak this past Tuesday; moisture streamed up from the Gulf of Mexico, a strong jet streak was in place overhead and the environment was relatively uncapped. Convective Available Potential Energy (CAPE) was quite high that day which was a significant contributor to the large hail sizes observed. Generally the higher the CAPE, the faster the updraft velocity which means that the updraft can support larger hailstones. Supercell thunderstorms were triggered Tuesday afternoon and persisted through the evening, trailing along the warm front that bisected the region.

In total over 200 hail reports were submitted on Tuesday and of these 38 were considered large hail reports (hail of 5cm in diameter or larger). The most damage caused that day appeared to come out of the town of Blair, Nebraska where hail caused major damage. Windows were blown out and car windshields smashed by the baseball size hail that fell – damage totaled in the hundreds of millions. Other storms along the warm front, the weather feature that triggered the severe weather, moved into the Omaha area not only bringing hail, but also torrential downpours. 13.5mm of rain was recorded in 3 minutes at the Omaha airport!

Hail damage in Hoover, NE shows the strength of baseball size hail, completely shredding the siding and breaking the windows. (Source: Kevin Krohn)
Hail damage in Hoover, NE shows the strength of baseball size hail, completely shredding the siding and breaking the windows. (Source: Kevin Krohn)

There is a possibility for more severe storms this weekend in Texas and New Mexico, but the parameters are not as as favourable for severe weather as seen this past Tuesday in Nebraska. Models show the active pattern continuing in the US Plains into next week, and rightfully so as severe weather season nears its peak.

A Fairly Pleasant Weekend

Although temperatures will be a little below normal for foreseeable future, a fairly pleasant few days are on tap for Winnipeg. A ridge of high pressure over the central Prairies will work at clearing out the clouds giving us plenty of sun for Friday and Saturday while winds slowly diminish. A low passing through on Sunday will mark the return of potentially rainy weather.

Friday
19°C / 7°C
Sunny with afternoon clouds. Breezy.

Saturday
18°C / 7°C
Mainly sunny.

Sunday
18°C / 8°C
Cloudy periods with a chance of showers.

Significantly cooler air than seen over the past week is working its way across the Prairies into Southern Manitoba, dropping daytime highs from the the mid-to-high 20s to the high teens. Temperatures will remain roughly 5°C below normal for the next week as a much cooler pattern locks in; daytime highs aren’t expected to reach over 20°C until late into next week.

Today will bring some late morning/afternoon cloud with a breezy west-to-northwesterly wind at around 20-30km/h. Temperatures will reach around 18°C. Expect clearing skies tonight and a low of around 7°C.

Tomorrow will be very similar to today except with a little less cloud and lighter winds. High near 18°C once again and a low near 7°C again.

Showery Sunday?

A weak low pressure system is forecast across Southern Manitoba on Sunday, bringing a renewed chance of showery weather. At this point, it looks like little in the way of particularly active weather will occur; even a rumble of thunder looks out of the question.

Probability matched mean precipitation from the SREF model for Sunday morning.
Probability matched mean precipitation from the SREF model for Sunday morning.

In general, the system is expected to spread some light shower activity from west to east across Southern Manitoba through the morning hours, persisting into the afternoon. Overall amounts look to be low; in the image above, I’ve used a probability matched mean ensemble[1] which can better capture higher amounts embedded within the mean precipitation field, and it still only shows around 2-4mm for most areas.

There are some hints the system may pick up strength and produce 5-10mm over the woods from Pinawa down to Sprague, but it’s still a little too far out to say much reliably.

Sunday won’t be all showers and cloud, though with a good chance of a few sunny breaks through the day. Highs will be near 18°C once again with an overnight low around 8°C.

Heading into next week it looks as if the cooler temperatures will continue with a couple more chances for precipitation through the first half of the week.


  1. For those who are curious, this takes the ensemble mean value, but matches the rain rate distribution in the ensemble mean field to the complete ensemble. Can help prevent “smearing” of the precipitation field.  ↩

Sunshine Gives Way to Unsettled Weather

The beautiful summer weather will stick around for one more day before a large upper trough pushing across the Prairies spreads showers and generally unsettled weather into Southern Manitoba.

Forecast precipitation for Wednesday night from the RDPS.
Forecast precipitation for Wednesday night from the RDPS.

Today will be an almost ideal summer day across much of the Red River Valley. Sunny skies will gradually see increasing cloudiness through the afternoon hours, however before things cloud up temperatures will climb all the way up to around 27 or 28°C while light winds begin picking up in the afternoon to 20-30km/h.

Wednesday
27°C / 14°C
Increasing cloudiness in the afternoon.

The story will be a little different over southwest Manitoba today, where an incoming surface trough will combine with warm weather and moderate instability to produce mid-to-late afternoon thunderstorms. Around 1250J/kg of CAPE will combine with 25kt of bulk shear and a 25-30kt LLJ to support upscale growth from a few isolated thunderstorms to an eastward moving line by the evening. This line will weaken fairly quickly as it moves into the Red River Valley thanks to the loss of daytime heating and the storms moving away from their main support.

The overall threat of severe weather in southwest Manitoba is marginal. The main risks will be large hail, but that seems like a fairly off chance at best. A rogue wind gust can’t be ruled out either, but again, I don’t have particularly high expectations for severe weather. Were I the SPC, it would be a “See Text” sort of day.

This line will bring a chance of showers or thunderstorms to Winnipeg and the Red River Vally through the overnight hours. No severe weather is expected. Temperatures will drop down to around 15°C or so.

Thursday & Friday

Thursday
25°C / 10°C
Cloudy periods; slight chance of showers.
Friday
21°C / 8°C
A mix of sun and cloud.

Tomorrow will bring cloudy periods with a slight chance of showers through the day. The precipitation risk will increase towards evening as a second impulse digs the upper trough into Manitoba, leaving us with a chance of showers on Thursday night.

Cooler air will also start filtering in. Thursday’s high of 25°C will be replaced by cooler weather for the remainder of the week and weekend. The temperature will drop to around 10°C on Thursday night.

Things should push off to the east on Friday morning leaving behind some sunny skies, but skies look to become mixed midday. There may be a chance of seeing some rain on Friday afternoon, but guidance is very mixed right now as to whether or not a band of rain will push northeastwards out of North Dakota. At this point it seems more likely that things will stay dry than not. We’ll see highs across the Red River Valley top out around the 21°C mark. The overnight low on Friday night will drop into the high single digits.

The Weekend

The weekend across the Red River Valley is looking fairly nice, albeit a little cool. Saturday will see afternoon cloudiness bring a slight chance of late-day showers. Sunday looks fairly sunny, although cloud will likely increase in the evening ahead of another system forecast to push through the region on Monday. Highs will sit near the 20°C mark with overnight lows in the mid-to-high single digits.