Category: Forecasts

The Heat is On

Brad Leave a comment

The hottest weather of the year will give way to a return to unsettled conditions with multiple low pressure systems tracking through the province over the next week.

Temperatures will soar over the next few days as very warm air moves into the region alongside increasing dew points, resulting in some blisteringly hot weather. The decidedly summer-like weather will be short-lived, though, as a system moving through on Saturday puts southern Manitoba back into an unsettled pattern with multiple follow-up low pressure systems expected over the coming week.

Dew point values are forecast to climb over 20°C today (shown in orange colours).
Dew point values are forecast to climb over 20°C today (shown in orange colors).

Start the Warm-Up

Friday
28°C / 19°C
Hot and increasingly muggy. Slight chance of a shower or thunderstorm.

Today will mark the start of a significant warm-up. Southerly winds at 20-30km/h will help our dew point rise through the day to around 20°C, making it feel fairly muggy outside by the end of the day. The temperature will climb to around 28°C, which will feel more like 35 or 36 with the humidity factored in.

There will be a very slight chance of a shower midday or early in the afternoon. The evening looks quite nice at this point, and then Winnipeg & the Red River Valley will see a chance of a thunderstorm overnight. The low will be around 19 or 20°C.

AWM thunderstorm outlook for July 4th into the 5th, 2014. Full discussion is available in the comments.
AWM thunderstorm outlook for July 4th into the 5th, 2014.

UPDATE: A discussion on today/tonight’s thunderstorm potential is available below in the comments.

Saturday: Sweltering Heat and Severe Storms

Saturday
32°C / 18°C
Hot and muggy. Slight risk of severe thunderstorms.

Make sure your A/C is in tip-top shape, because Saturday is going to be a scorcher. Even warmer air will push into the region on Friday night, making high temperatures on Saturday soar all the way into the low 30’s. Here in Winnipeg, the daytime high should sit somewhere close to 32°C. When combined with the humidity, it will feel more like 40 or 41 outside, easily making it the warmest day of the year so far. Winds will be fairly light out of the south shifting to westerly at around 20km/h.

AWM thunderstorm outlook for July 5th into the 6th, 2014. Full discussion is available in the comments.
AWM thunderstorm outlook for July 5th into the 6th, 2014.

UPDATE: A discussion on today/tonight’s thunderstorm potential is available below in the comments.

All that heat and humidity does mean there will be a risk for severe thunderstorms. At this point it there’s still a fair amount of uncertainty as to whether or not storms will develop or not, so we’re going to wait until tomorrow to do a detailed thunderstorm outlook. In general, most storm parameters look quite favourable, but a strong capping inversion will be in place in the low-levels. Two potential triggers will need to be watched:

  1. A weak cold front slumping southwards through the day – I don’t think this is very likely to trigger much.
  2. A shortwave and associated jet maximum moving along the international border overnight.

If any thunderstorms develop, they will likely be severe. The main threats will be torrential rain[1], large hail and strong winds. Right now it seems most likely that thunderstorms will hold off until overnight, but we’ll take a closer look later today and add a thunderstorm outlook to this post.

Sunday Showers?

Sunday
26°C / 15°C
Chance of showers or thunderstorms.

Sunday will be a generally unsettled day with a risk of showers or thunderstorms as a cold front pushes across the province. Winds will pick up out of the west to around 40-50km/h as we head to a high of around 26°C. Severe weather is not expected right now, but the showers or thunderstorms moving through the region could be heavy/strong.

Winds will stay strong through the night as temperatures dip to the mid-teens.

Unsettled Week Ahead

There will be plenty of chances for showers or thunderstorms in the coming week. Right now it looks like the best chances are Monday, Tuesday night, then Friday. Highs will likely be in the mid-20’s with lows in the mid-teens and the humidity will remain at more comfortable levels.

  1. Yes, especially because we need more rain.  ↩

A Chance to Dry Out

Brad Leave a comment

A ridge of high pressure building into the province will offer several days of dry weather.

A break from the wet weather is finally here thanks to a ridge of high pressure that is building into the province. In a pleasant change of events, that will allow this forecast to be a whole bunch shorter than many of late.

Wednesday
22°C / 10°C
A few clouds

Thursday
25°C / 12°C
Mainly sunny

Friday
26°C / 18°C
Cloudy periods

The dry weather can’t come soon enough as the flooding situation continues to worsen over the southwestern corner of the province. Fortunately, conditions will be near-perfect over the next several days.

Today will bring a few clouds and a high in the low 20’s as the ridge begins pushing into Manitoba. Winds will be quite light today out of the northwest at around 15km/h. The temperature will drop to around 10°C under clear skies tonight.

Thursday will be a much more summer-like day with sunny skies and a high near 25°C. Winds will be light out of the southwest at only around 15km/h. Clear skies again tomorrow night as we head towards a low of 12°C.

Summer continues its return on Friday as temperatures climb a degree or two higher than Thursday. We’ll see a few cloudy periods as a warm front pushes towards the province. The temperature will fall to around 17 or 18°C on Friday night with a few clouds.

Blistering Weekend Ahead

Looking ahead to the weekend, there is only one word to describe it: hot. A very hot and humid air mass will build into southeastern Saskatchewan on Friday and then spread eastwards into Manitoba on Saturday. High temperatures will be in the lower 30’s on Saturday while dew point values climb into the 21-24°C range. The heat and humidity will combine to likely produce humidex values over 40 on Saturday. Needless to say, that is swelteringly hot and will firmly remind people that we are, in fact, in the middle of summer.

Sunday will continue to be hot until a cold front sweeps through in the afternoon. Temperatures will climb into the upper 20’s or just break 30°C which will feel more like the upper 30’s thanks to the humid air still present in the region. Slightly cooler and drier air will move in for Sunday night and next week as the winds shift westerly behind the cold front.

Any storm potential for the weekend is still unclear. To some degree severe storms are always possible when such hot and humid air pushes into our region, but at this point there simply isn’t a clear indicator as to whether anything will develop. We’ll have more on it later in the week.

Enjoy some dry weather and, finally, a real taste of summer!

Another Couple Days of Rain Before the Sun Comes Out

Brad Leave a comment

We’ll have to endure another couple days of miserable, cool, and rainy weather before conditions finally turn more summer-like again.

”
Periods of rain will continue in southern Manitoba on Monday

Monday

Monday
19°C / 10°C
Periods of Rain

Today will be another nasty day in southern Manitoba. The large low pressure system that has been affecting us since Saturday will continue to produce rain today. The intensity of the rain will not be as high as what we saw on the weekend, but many areas could see an additional 5-10mm through the day, with locally higher amounts. It will remain windy as well, with a west to north-west wind at 30km/h gusting to 50km/h.

Tuesday

Tuesday
17°C / 7°C
Chance of Showers

Showery and cool weather will just keep coming on Tuesday. Luckily, it appears significant accumulating rain should be over by this point, with just the odd light shower remaining. However, temperatures will be well below seasonal and it will be windy again. Overall, another nasty day.

Wednesday

Wednesday
23°C / 11°C
Mainly Sunny

It looks like we’ll finally see a break in the weather on Wednesday, as high pressure moves in and skies clear out. Temperatures should be in the low twenties under sunny skies and light winds. It will be a nice day, even if it is still a bit below seasonal for this time of year.

Long Range

Fortunately, given the weather of late, the long range forecast is looking encouraging. Models suggest that we’ll see a warming trend late this week into the weekend. At least for the time being there is no indication of another cool-down in the forecast.

It’s Going to Be Wet Somewhere

Brad Leave a comment

A muggy and increasingly unstable air mass will bring heavy showers and thunderstorms to Southern Manitoba this weekend; the “where” is nigh-impossible to predict.

The last few days has seen increasingly warm and humid air building into the Southern Prairies and today will mark the transition in Southern Manitoba into the new air mass. Unfortunately, the large-scale weather pattern will be very slow-moving and result in several days of showers which, thanks to the ample humidity, will certainly be very heavy at time.

The GDPS is forecasting over 100mm of rain through Manitoba with the upcoming system. We probably won't see that much. Probably.
The GDPS is forecasting over 100mm of rain through Manitoba with the upcoming system. We probably won’t see that much. Probably.

Due to the disorganized nature of the showers, it’s impossible to say where exactly is going to see the most rain; that will only become clear as events unfold and each successive round of showers develops. Overall rainfall totals will fall into a huge range; some places may see only 5-10mm or less by the end of the weekend, while others may see anywhere from 50-100mm…or more?

We’ll go day by day and outline the most likely scenarios and what you can generally expect. Due to the high water levels through much of Southern Manitoba, we’ll be a little generous with our “slight risk severe” area due to sensitivity to rainfall (especially large quantities in short duration). We’ll make a small note on our convective outlooks to highlight this as well.

Friday: Heavy Rain in SW Manitoba

Friday
26°C / 18°C
Mixed skies. Thunderstorms likely in the afternoon and overnight. Muggy.

Today’s main threat area will be southwest Manitoba where a combination of the remnants of thunderstorm activity from overnight will be moving through this morning and more thunderstorm activity will develop this afternoon and spread eastwards.

This morning will bring two possible areas of showers, the first over southwestern Manitoba as the remnants of the overnight storms in Saskatchewan lift north-northeastwards and the second being a slight chance of some shower or thundershower activity in the Red River Valley.

Skies will be mixed through the day as we head to a high of around 26°C as southerly winds bring in significantly more humid air; dew point values will climb above 20°C through the afternoon, making it feel positively muggy out there.

Thunderstorm outlook for June 27 & 28, 2014 for 1PM CDT through 7AM CDT.
Thunderstorm outlook for June 27 & 28, 2014 for 1PM CDT through 7AM CDT.

Thunderstorms will redevelop this afternoon over SW Manitoba and spread eastwards through the evening. The main threat from the thunderstorms today will be heavy rain thanks to elevated precipitable water values and likely slow storm motion. Back-building thunderstorms are entirely possible too, which would result in very local areas seeing torrential rains and flash flooding. Marginally severe hail is possible, but the threat would likely be limited to the earlier storms in the day. Other than that, little severe weather is expected. There is a slight chance of funnel clouds over SW portions of the province thanks to relatively high vorticity values ejecting from the base of the incoming upper-level trough and somewhat favourable low-level winds, but conditions don’t look favourable for the development of tornadoes.

The thunderstorm activity will expand into heavy shower activity as well overnight as things push eastwards and northwards. Rainfall totals will be highly variable, with some places seeing nothing and others seeing potentially more than 50mm. The heavy rain concern will shift into the Red River Valley for the overnight period. The low will be around 18°C.

Saturday: Wet Weather

Friday
25°C / 18°C
Cloudy with showers or thunderstorms, heavy at times.

Saturday looks to be the wettest day as a low pressure system lifts northwards out of North Dakota into Southern Manitoba, spreading showers throughout much of the southern portions of the province.

The break between tonight’s convection and Saturday’s weather will be short lived as showers — perhaps with some embedded thunderstorms — lift northwards out of the Dakotas into Southern Manitoba. The showers or thunderstorms will be heavy at times and will likely not taper off until closer to the evening. Rainfall totals will wind up somewhere between 10mm and 50mm, highly variable across the region.

The clouds will begin to scatter out overnight, although complete clearing isn’t likely until Sunday. The low will be near 18°C.

Sunday: A Reprieve

Friday
25°C / 14°C
We’ll see the sun!

Sunday will provide a reprieve from the drenching of the first half of the weekend. The rain activity will remain further north through the northern Interlake and regions adjacent, while further south we see the sun finally make an appearance. Things look dry through the day, although cloud and showers may push through Southern Manitoba through the night as a trough rotates through the region on the back-side of the main low pressure centre.

Winds will be breezy out of the west or southwest on Sunday at around 30-40km/h with gusts to 50-60km/h on top of that. The high will be near 25°C and the overnight low near 14°C.

Cooler Weather Returns for Next Week

Temperatures will return to slightly below normal as cooler air begins to filter southwards on the back-side of the low. Daytime highs will generally be in the low-to-mid 20’s with little chance of rain through the first half of the week.