Tag: Rain

Mild Friday Leads to Cooler Weekend

Brad Leave a comment

The mild weather will continue today with daytime highs of +1 or +2°C today as yet more warm air washes over Southern Manitoba. The system responsible for this mild spell will be making its way across the region today and after it brings some mixed precipitation, it will push eastwards into Ontario, taking the warmth with it. Northerly winds will develop tonight and begin to usher in cooler, more seasonal temperatures.

Today will bring some more organized precipitation across the Red River Valley as the main disturbance that’s been responsible for the warmth this week moves across the region. With temperatures so close to the freezing mark, what type of precipitation will be falling is a bit of a difficult question to answer. Looking at the Red River Valley as a whole, we can say that there will be mixed precipitation, however for any one location may see just rain, just snow, or both. Even if snow falls, with the above-0°C temperatures, it won’t be able to accumulate much. By the time the precipitation tapers off, just 1-2 mm of rain or cm of snow will have fallen.

With light winds and above-zero temperatures, it also is possible that drizzle or fog patches are an issue throughout much of the day.

As the system moves into Ontario later today, northerly winds will begin developing over Southern Manitoba and draw in cooler air from the north. Drizzle or freezing drizzle will be possible through the early evening hours, but that risk should dissipate heading into the overnight period. Temperatures will dip to about -6°C with gusty northerly winds up to 30 km/h.

GDPS 850mb Temperature Forecast
The GDPS shows the gradual return of colder air via 850mb temperatures.

Saturday will bring mixed skies and diminishing winds as the Red River Valley sees a weak ridge of high pressure begin to build in. There’s a bit of uncertainty to exactly how much cloud will clear out of the region; it will likely trend towards cloudier, but we should see a few sunny breaks through the day. Temperatures will recover just slightly from the overnight low to a high of -5°C. The colder weather will continue pushing southwards with gradual clearing through the evening & overnight that will allow temperatures to dip to an overnight low near -17°C.

Sunday will bring partly cloudy skies to Winnipeg, but the southern Red River Valley will likely see cloudier skies as a weak low pressure moves through North Dakota. This system will produce some light snow for areas further south, but in Winnipeg there will just be a chance of flurries. Temperatures will be slightly cooler than seasonal with a high of -12°C. Skies should clear on Sunday night as temperatures head to a low near -16°C.

Long Range: Not Cold For Long

This cool-down will be brief; by Monday daytime high temperatures approaching the freezing mark will return to the Red River Valley.

Temperatures will be variable next week with warm days giving way to 1-2 days of seasonal temperatures before warmer weather returns again. No significant precipitation events are expected through next week.

Winnipeg’s seasonal daytime high is currently -7°C while the seasonal overnight low is -18°C.

Mild Weekend Then Into A Colder Stretch

Brad Leave a comment

A low pressure system crossing the Prairies will bring another wave of unseasonably mild air into Southern Manitoba and help temperatures climb above 0°C for the second time this week. Heading into the latter half of the weekend, unsettled weather will develop over Southern Manitoba bringing flurries as cooler air begins gradually slumping southwards out of the Arctic and across the Prairies.

Today will be a much nicer day for Winnipeg than it appeared like it would be earlier this week, all thanks to a more northern track for today’s low pressure system crossing the province. As a result of this trajectory, Winnipeg will still see the warmth we expected before, but much less of the precipitation, which will now mainly fall through Central Manitoba and the Interlake before heading off into Ontario.

For the city, today will start off with a chance of…well, just about anything—snow, freezing rain, or showers—as a warm front pushes through and brings our temperatures above zero. As the warm front pushes off to the east relatively early in the day, we’ll be left with skies on the cloudier side and temperatures in the +1-2°C range. Windswe will start out of the south at around 30-40km/h before shifting to westerly behind the warm front at similar speeds. The chance for showers will redevelop mid-day and through the afternoon as a little bit of cooling aloft moves across the region. Expect temperatures to drop to around -2°C tonight with a few clear breaks developing.

RDPS 12hr. QPF Forecast for Friday January 29, 2016
This RDPS forecast showing accumulated precipitation through Friday shows how most of the precipitation is expected to our north and east

Saturday will bring more warm weather cloudier skies once again, although a few sunny breaks are certainly possible and the southwestern Red River Valley may actually end up seeing a fair amount of sunshine. Temperatures will climb to around +1°C with lighter winds than Friday.

A cold front will begin slumping southwards through the region on Saturday night. This will bring cooler temperatures and send our overnight low down to around -11 or -12°C under cloudy skies. Alongside the cooling will be a chance of some light flurry activity.

Sunday will be a cooler day with a high in the near -6°C or so. Under mainly cloudy skies, Winnipeg will see a slight chance for flurries throughout the day thanks to favourable temperatures throughout the lower atmosphere. This cooler weather will mark the leading edge of a return to seasonal and below-seasonal temperatures for a short while.

Long Range: Colder, But For How Long?

Looking forward into next week, it looks like cooler weather will return to the Prairies as the conditions that have supplied the warmer weather to the region over the past week collapse southwards and allow cooler Arctic air to slump southwards.

GEPS Maximum Temperature Forecast valid February 1-6, 2016
GEPS maximum temperature forecasts valid for the February 1-6, 2016 time period

The GEPS[1] is showing a transition into slightly below normal conditions next week. This image shows the maximum temperature expected in each 6-hour time period from Monday through Saturday. Ensemble forecast systems produce numerous forecasts, and then statistical analysis can be done on the output to (in theory) produce more accurate forecasts, especially in the long range. In the image above, the easiest way to understand it is that the value along the line is a fairly reasonable "most likely" temperature, while the red shading on either line represents the certainty; if there’s little shading extending from the line that means there is high confidence in the values; if there’s a lot of shading extending above and below the line, it means that there’s more uncertainty associated with the forecast at that time.

The GEPS shows fairly reasonable confidence that daytime highs will be dropping into the -15 to -20°C range early next week, a fair amount below the seasonal highs of -11°C for this time of year. With daytime highs in that range, it’s likely overnight lows will dip into the mid-minus 20’s. Heading toward the end of the week, though, there begins to be a lot more uncertainty on the weather pattern, so we’ll just have to wait and see for when the warm-up returns!

  1. Global Ensemble Prediction System  ↩

Winter Arrives

Brad Leave a comment

Environment Canada made headlines with the special weather statement for Winnipeg issued Monday with a referential start: winter is coming. And how.

Today will mark the beginning of a harsh slide into winter after a essentially a month of temperatures well above seasonal for this time of year. The change in the pattern will be brought courtesy a rather peculiar weather setup that will see a relatively weak Colorado Low moving north through Minnesota into Northwestern Ontario merge together with an Alberta Clipper quickly moving eastwards across the Prairies. Each system is moderately potent in their own right, but when combined, they will form a new storm system that will rapidly intensify, driving strong northwesterly winds through the province alongside the first significant snowfall for many regions of Southern Manitoba.

Today will start deceptively. Relatively light winds and temperatures climbing towards 5 or 6°C will give a false sense of security betrayed only by the increasing cloud cover that will build in through mid-day into the afternoon. Some light rain will develop over the Red River Valley this afternoon, which will mark the end of our above-seasonal temperature streak and usher in winter. As the rain moves into the region, winds will pick up out of the northwest to around 50km/h sustained with gusts as high as 70–80km/h. The rain will switch over to snow sometime in the evening and likely begin piling up fairly quickly as the strong winds rapidly cool the ground and other surfaces.

The strong winds and snow will persist through tonight as temperatures dip down towards –3°C or so as colder air begins filtering into the region. With snow piling up and such strong winds in place over the Red River Valley, it’s quite likely that driving conditions become quite poor as roads freeze, become ice covered, and see reduced visibility in blowing snow.

AWM Snowfall Forecast issued November 18, 2015
AWM Snowfall Outlook issued November 18, 2015

Thursday will continue to bring light snow and strong winds to the region as temperatures remain around –4°C or so. The winds will be a bit lighter than at their peak, but will likely remain near the 40 gusting 60km/h mark through much of the day before beginning to taper off in the evening. Overnight, other than some lake-effect snow streaming southeastwards off of Lake Winnipeg, there’s likely to be just a few flurries lingering in the region. Temperatures will dip down to –6°C for the overnight low.

In general, around 5–10cm of snow is likely to fall with this system through southeastern Manitoba, the Red River Valley and northwestwards into Parkland Manitoba. Exact amounts will depend on the timing of the change-over from rain to snow and how quickly the snow begins accumulating instead of melting on the ground.

Friday will be a mainly cloudy day with just a very slight chance of light, scattered flurries. Temperatures will recover only a degree or two from the overnight low with highs around –4°C. There may be a few clear breaks through the Red River Valley on Friday night, but overall there will still be a fair amount of cloud as temperatures head towards an overnight low near –10 or –11°C.

Colder Weather Continues Through The Weekend

The cooler weather, which while a significant drop from what we’ve been experiencing is, in actuality, just a couple degrees below seasonal values for this time of year, will persist through the weekend.

NAEFS 8-14 Day Temperature Anomaly Outlook valid for November 25 to December 2, issued 12Z November 17, 2015
The NAEFS is showing a trend towards seasonal temperatures for the remainder of November.

Daytime highs around –5 or –6°C will be in place over Winnipeg & the Red River Valley this weekend, with a chance of some more flurries on Saturday improving to sunnier fare on Sunday. Overnight lows will be in the low minus single digits. So, while it may be a huge change from the weather we’ve been having, we’ll be shifting to more seasonal weather for the end of November.

Dreary Start to the Week

Scott Leave a comment

This week will start out on the dreary side as a series of low pressure systems bring rain to southern Manitoba. Some parts of southern Manitoba may even see a bit of snow by midweek.

A low pressure system will bring light rain to parts of southern Manitoba on Monday
A low pressure system will bring light rain to parts of southern Manitoba on Monday

Monday

Today will feature mainly cloudy skies and light rain showers as a low pressure system passes through southern Manitoba. Rainfall amounts in the Winnipeg region are expected to be under 2 mm, but areas further north may see slightly higher amounts. Winds will be light and temperatures will be relatively mild (near 10C), so conditions will generally be comfortable outside of the rain showers.

Tuesday

More rain appears to be on tap for Tuesday as we come under the influence of another low pressure system pushing up from the south. Like Monday, accumulations are expected to be small, with amounts of only around 2 mm expected. It will be windier and cooler than Monday though, with temperatures in the mid single digits and breezy north-east winds.

Wednesday

Wednesday will see the continuation of Tuesday’s system with more rain likely in store. Accumulations will probably range from 2-4mm in the Red River Valley. There is a chance of snow in the higher terrain of western Manitoba, but it is too early to say how much could fall. Temperatures will be in the low to mid single digits with a breezy north-west wind.

Long Range

The long range forecast continues to strongly hint at above-normal weather for the first half of November. The combination of a positive Arctic Oscillation and the increasing influence of El Nino will allow Pacific air to continue moving across the Prairies while preventing significant Arctic air masses from surging southward. That isn’t to say we won’t get cold weather this November, but it certainly seems most likely that warmer conditions will dominate. Given that the normal high for this time of year is only 3C, “warm weather” will be a relative term from this point forward.