Snowy Friday Brings Return to Warmer Weather

A low pressure system moving through Manitoba today will bring a fresh batch of snow alongside some gusty southerly winds to Winnipeg and lead a transition back to a stretch of above-normal temperatures that will set up through the weekend and persist into next week.

Snow will be in place throughout the Red River Valley this morning and most places will see about 2-5cm of accumulation before it moves off to our east for the afternoon. In its wake, temperatures will rise under cloudy skies to our daytime high near -2°C.

Through the morning, winds will be out of the south-to-southeast at 20-30km/h, but will taper off as the snow pushes off to the east.

The big question for the remainder of the weekend is exactly how warm it’s going to get. And, unfortunately for some, I’m leaning on the pessimistic side.[1]

GDPS Forecast 850mb Temperature Anomaly
GDPS forecast 850mb temperature anomaly valid Sunday morning

Heading into the weekend, significantly milder air will be pulled eastwards across the Prairies, but the big question is how warm will it get? This isn’t quite so easy to answer for a variety of reasons, but one of the biggest being the snowpack in place over the region.

The GDPS is forecast temperatures at 850mb, approximately 1.5 km above the ground, to climb to nearly 20°C above normal for this time of year. Typically temperatures at 850mb can be used as guidance for daytime highs and overnight lows, however that relationship can be complicated in the winter time. As warm air moves in, the snow at the surface cools it and helps develop an inversion.[2] Inversions work to isolate the surface from the warmer air moving in, and can result in very warm air aloft not making it down to the surface.

Forecast Sounding for Winnipeg valid Sunday morning
Forecast Sounding for Winnipeg valid Sunday morning

This is a forecast sounding, which shows the forecast of temperatures (red) with height (up is higher) for a specific location. The inversion is fairly clear and is depicted by the area near the bottom where the red line moves to the right instead of the left. This will likely result in our temperatures being lower than some automated forecasts may suggest.

The overall weather pattern through the weekend will be a steady flow of warm air aloft interacting with a dynamic surface pattern. Saturday will start with cooler temperatures near -11°C and mainly cloudy skies trapped underneath a ridge of high pressure that will slide off to our southeast. It will likely be a cloudy day as low-level cloud is reinforced by cool outflow from the high pressure system trapped beneath the inversion of the warmer air aloft.

As a low pressure system begins tracking eastwards across the Prairies, it will help moderate winds develop over the Red River Valley. By mid-to-late afternoon on Saturday, winds will strengthen to 30-40 km/h out of the south as the temperature rises to -1°C. The winds will strengthen slightly for Saturday night to 40 gusting 60 km/h. These stronger winds will persist much of the night under cloudy skies and help the temperature remain steady near 0°C.[3]

Sunday will see the winds drop off in the morning and the Red River Valley move solidly into the warm air. While skies will likely start cloudy, some sun should begin poking out for the afternoon as the winds pick up a southwesterly component and start mixing some drier air into the valley. Daytime highs look to climb to the 4°C mark with overnight lows dipping to just -1°C under partly cloudy skies.

Long Range: Continuing Warm

There’s no question about it: the warm weather will be the dominant weather story for the coming 10-14 days.

NAEFS 8-14 Day Temperature Anomaly Forecast — Valid March 11-18, 2016
NAEFS 8-14 Day Temperature Anomaly Forecast — Valid March 11-18, 2016

El Niño is back with a vengeance as above normal temperatures are expected to sweep across much of southern Canada and the United States. It’s hard to say exactly how warm it will get, but for Winnipeg it seems quite likely that daytime highs above 0°C will become quite commonplace over the coming weeks.

Precipitation outlooks are for near-normal amounts, so the odd disturbance giving us a couple cm of snow or a few mm of rain should be expected. Get ready for sloppy roads, warm sun, and suspension-shattering potholes.

Winnipeg’s seasonal daytime high is currently -4°C while the seasonal overnight low is -14°C.

  1. Which I’m relieved to say is still above normal for this time of year!  ↩
  2. An inversion is when temperatures behave abnormally with height in the atmosphere, rising with height rather than falling.  ↩
  3. There’s a slight chance with some of the stronger winds that the could be some bursts of warmer air through the night that could see temperatures climb to +2 to +3°C.  ↩

Temperatures Creep Back Towards Seasonal

Benign weather is in store this week for Winnipeg with temperatures gradually returning towards seasonal values. The weather will become more active heading towards the weekend as warmer weather begins pushing eastwards across the Prairies and returns above-seasonal temperatures to the region.

Today will be a pleasant day with mixed skies courtesy a weak system passing through southwestern Manitoba. Winds will be fairly light at just 10-20 km/h. The daytime high will climb to about -8C then drop to -19C tonight as skies clear. As a note, it will likely be considerably cloudier in the SW RRV and through southwest Manitoba as a thicker layer of cloud remains in the region.

Thursday will bring sunny skies, light winds, and a high near -9C. On Thursday night, some cloud will begin moving into the Red River Valley ahead of an incoming low pressure system, resulting in slightly milder overnight lows. Temperatures are expected to dip down to about -15C.

GDPS 12hr. Precipitation Totals valid 00Z Saturday March 5, 2016
The GDPS is showing light snow for Friday in the Red River Valley.

On Friday, a low pressure system sliding along the international border will spread an area of light snow from Saskatchewan east-southeastwards through SW Manitoba and the Red River Valley. It currently looks like snow will push into the Red River Valley in the morning and taper off by evening, with 2-4cm of new snow possible.

Temperatures will return to seasonal values on Friday with a daytime high near -5°C. Skies will clear through Friday night as temperatures head to a low near -12°C.

Long Range: Mild Weather Returns

A strong signal of a return to milder weather is showing up once again for much of Eastern North America

A major pattern shift will allow unseasonably warm air to spread back across much of the continent beginning this weekend and persisting through next week, driven by a collapse of the major west coast upper ridge that’s been in place for the past few weeks and the development of a zonal upper-level flow across much of the continent.

This flow will favour warm temperatures with daytime highs likely at or above 0°C here in Winnipeg for much of next week. These flows do typically bring more numerous disturbances through, so while temperatures will be mild, there’s a good chance that we’ll see more chances for rain or snow as well.

Winnipeg’s seasonal daytime high is currently -5°C while the seasonal overnight low is -15°C.

Seasonal Weather Leads To Blustery End of Week

Winnipeg will see near-seasonal temperatures over the coming days with some light flurry activity mixed in before a big warm-up moves in for the weekend. The transition to warmer weather won’t be particularly graceful, however, as a howling southerly wind develops on Friday, making for a rather unpleasant shift.

The weather in Winnipeg through today and tomorrow will be dominated by the gradual arrival of a weak Arctic high that will slowly build southeastwards out of the Northwest Territories across Saskatchewan and Manitoba. Weak is the key descriptor of this ridge; it will bring with it little in the way of cold air nor will it be able to muster up much clearing either.

That said, today’s weather will be relatively pleasant, all things considered. Skies will be mainly cloudy through the day with some occasional light flurry activity. Temperatures will climb a little bit from where we start off to about -10°C with fairly light winds throughout the day. Tonight will continue to bring mainly cloudy skies—although a few clear breaks are possible—and temperatures dipping down to about -18 or -19°C. If more clearing develops than is expected at this point, the overnight lows could dip closer to about -23°C.

Tomorrow will bring very gradual clearing to Winnipeg with the morning likely starting off fairly cloudy and slowly becoming mixed to mainly clear throughout the day as the Arctic ridge slides into the Red River Valley. With the arrival of that system, the daytime high tomorrow will be cooler at around -15°C with a light northerly wind. There’s a slight chance of some flurries through the early morning, but for the most part no precipitation is expected on Thursday. Expect a low on Thursday night near -21°C under partly cloudy to mixed skies.

Friday will be…unpleasant. As many who have lived in Winnipeg for a while know, whenever a big warm-up is on the way there is often "the day" before the warm weather arrives; a day where it’s rarely as nice as it sounds like it’s going to be and those famous southerly winter winds make an appearance. Friday will be that day.

As the Arctic ridge pushes past and moves to our southeast, it is quickly replaced by a strengthening low pressure system moving across the Prairies. As the low moves into eastern Saskatchewan and begins spreading warmer air aloft over Southern Manitoba, its relatively close proximity to the Arctic ridge will result in a tight pressure gradient over the Red River Valley, oriented very favourably for the development of strong southerly winds. While starting the day off light, the winds through the Red River Valley will increase to around 30 gusting 50 km/h by noon, and then further strengthen to 40-50km/h gusting to 70km/h by the evening hours.

GDPS MSLP & Surface Wind Forecast for Friday
The GDPS shows the strong southerly winds (emphasized in yellow) expected over the Red River Valley on Saturday.

Temperatures will gradually climb to around -12 or -11°C by late in the afternoon—although it will feel closer to -25 throughout much of the day due to the wind chill. Temperatures will continue to rise overnight as the warmer air finally begins working its way into the valley; by Saturday morning the temperature is expected to climb to about -8°C in Winnipeg.

With strong warm air advection aloft and the surface flow dominated but the outflow from an Arctic ridge, it’s likely that Friday will be fairly cloudy as stratus streams northwards out of the ridge.

Warm Weekend Ahead

This weekend looks beautiful with temperatures well above seasonal expected throughout the Red River Valley. In Winnipeg, the temperature is expected to climb all the way to around the freezing mark under mainly cloudy skies. Sunday looks fairly nice, perhaps evening bringing some sun to the region, with daytime high closer to the -5°C mark.

Temperatures are expected to return to seasonal values for the start of next week.

Big Warm-Up to Start the New Year

While the cold snap that settled into Winnipeg for Boxing Day was incredibly short-lived with temperatures returning to seasonal values just 3 days later, that didn’t stop many from wondering where the nice weather went. Good news for those that didn’t want to even deal with a few days of (relatively easy-going) Winnipeg winter: a big warm-up is on the way for the start of 2016.

The weather today and tomorrow will be defined by the passage of a slow-moving upper-level low pressure system that is tracking through North Dakota. This system will spread plenty of cloud across Southern Manitoba, some will be higher-level cloud, while there will also be low-level cloud that will have fog patches along its edges and some light flurry activity under it. The sun may make a few appearances through the day, but overall it will be mainly cloudy.

Temperatures will be fairly similar both today and tomorrow with daytime highs of -9 and -8°C and overnight lows both nights around the -12 or -13°C mark.

Thursday will bring a bit more sun than Wednesday and less chance of any flurry activity.

Forecast 850mb temperatures for Thursday afternoon from the RDPS
The 850mb temperature forecast from the RDPS clearly shows the surge of warm air pushing into the Prairies on beginning Thursday.

By Friday, the warm air begins surging over the province. The set-up for this delivery of warmth is a rather odd one; over the past couple days, an upper-level ridge has been building northwards over the B.C. coast, pushing warm air into Alaska and the Yukon. This upper-level ridge is forecast to spill eastwards over the Rocky Mountains and then build into the Central Prairies. This will release the built up warmth over the western Arctic and allow it to spill southeastwards across the Prairies. It’s certainly a rarity that Winnipeg sees warm advection in a northwest flow, especially in January of all months. The leading edge of the warm air should help temperatures climb to around -5 or -4°C with a bit of a westerly to northwesterly breeze. Skies should be fairly clear for the most part. Expect temperatures to dip down to the low minus-teens again on Friday night.

Long Range

Warm weather should persist through the weekend. A brief shot of cooler air on Sunday night could result in a few flurries on Sunday morning, but no significant snowfall is expected. Daytime highs through the weekend will likely sit near -3°C, although if everything were to happen perfectly, then a high near 0°C could be possible. Saturday looks mainly sunny at this point, while a bit more cloud is in store for Saturday night and Sunday.

Monday still looks quite mild with daytime highs close to the freezing mark, but then more seasonal air works its way back into the region mid-week.

Seasonal daytime highs for Winnipeg at this time of year are near -13°C. Seasonal overnight lows are near -23°C.