Tag: fog

Mild Friday Leads to Cooler Weekend

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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.

Temperature Roller Coaster Ahead

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Temperatures will be taking a ride on a roller coaster this week as abnormally warm weather briefly gives way to a more seasonal cold snap and then soars back to well above-normal conditions. By the latter half of the week, above-0°C daytime highs may even be possible.

A mild air mass over the Red River Valley will bring a typical "warmer than it ought to be this time of year" mix of conditions to the region. It will be mainly cloudy today with a chance of flurries throughout much of the day, although if any snow does materialize, it should be light. Throughout the morning hours, though, fog patches and the risk of freezing drizzle will be the more prominent weather. The temperature should climb to around -1°C for a daytime high with light winds.

RDPS Forecast 2m Temperatures valid 21Z Monday February 15, 2016
The RDPS is forecasting temperatures just below freezing across Southern Manitoba today.

Light northerly winds will develop this evening, ushering in cooler air. As the cloud cover gradually scatters out, temperatures will drop to an overnight low near -18°C. The light northerly winds will continue through Tuesday courtesy of an Arctic ridge building into the region. Temperatures will rebound to a high of about -13°C under partly cloudy skies, and then drop into the minus twenties for an overnight low near -22°C.

Tuesday night will be the coldest night for a while as a significant pattern change begins on Wednesday which will result in a more persistent flow of Pacific air across the Prairies. The result will be a second half of the week that brings daytime highs well above normal. For Wednesday, a warm front will push across the Red River Valley, bringing southerly winds of 20-30 km/h and temperatures climbing to about -7°C. The warm weather will continue to push in on Wednesday night with temperatures climbing a couple degrees more. With that warmer weather moving in, there will also be a chance of some flurries, but no significant accumulations are expected.

Long Range: Warm!

The second half of the week will be mild, albeit cloudy, as significantly warmer air moves in from the west.

GDPS Forecast 850mb Temperature Anomalies valid 12Z Friday February 19, 2016
The GDPS is forecasting 850mb temperatures to be around 20°C above normal on Friday.

This surge of warm air is well represented by the forecast 850mb temperatures heading into Friday. As shown above, a surge of warm air around 20°C above normal is forecast to move into the region. The temperatures at this level don’t correspond 1:1 with surface temperatures, so don’t expect it to be 20°C above normal (which would be a high of +12°C) on Friday. Rather, what we’ll see is temperatures getting about as warm as they’re allowed to get with the established snowpack we have, and they likely won’t budge too much once they get there, at least until the warm air leaves.

Temperatures will likely climb to +1 or +2°C on Thursday with a chance of some light snow. Once we reach that high temperature, temperatures will likely remain there until a weak cold front moves through on Friday night. It looks a bit uncertain at this point, but there will be the chance for precipitation throughout both Thursday and Friday.

Heading into the weekend, it will be cooler but still above normal with daytime highs in the minus mid-single digits. There will be the occasional chance for some flurry activity.

The normal daytime high for Winnipeg is currently -8°C and the normal overnight low is -18°C.

Seasonal Temperatures & Dreary Weather Rounds Out The Week

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The remainder of the work week will bring fairly seasonal temperatures to Winnipeg as the weather slowly improves. For the weekend, however, another blast of well above-seasonal temperatures is on the way!

Today will see a continuation of yesterday’s fog and drizzle patches through the morning hours, but it should dissipate with conditions improving by late morning as a weak cold front passes through the region. Behind that, we’ll be left with mainly cloudy conditions and light winds as the temperature climbs to around 3°C. The cloud cover will stick around overnight as we head to a low near –1°C.

Thursday will see a chance of flurries in Winnipeg & the Red River Valley as a weak shortwave drifts over the region in the northwest flow aloft. Northwesterly winds to around 20km/h will accompany a very close to seasonal high of 1°C. If we do see snow, it won’t accumulate to much, if anything at all.

12hr. Cumulative QPF valid 00Z Friday November 13, 2015
Flurries are possible through the day on Thursday while a much larger system passes through Ontario. Accumulations are expected to be light.

After the shortwave passes through on Thursday, skies will begin to clear, although with so much low-level moisture in the region, exact timing will be tricky. Skies will likely clear out at some point Thursday evening/overnight, however the cloud might persist into Friday morning before clearing. This timing will affect our overnight low forecast; if things clear out earlier, then we should see a low near –5°C or so, while if the cloud sticks around through the night, the low will be closer to –1 or –2° C.

Regardless of how Friday starts, we’ll be heading towards a mainly sunny high of 3 or 4 °C. Friday’s overnight low will sit near 0 to +1°C as much warmer air begins building in for the weekend.

More Warm Weather This Weekend And Beyond

Heading into the weekend, temperatures will soar again as the large-scale northwesterly flow that was in place shifts to be a more zonal, westerly flow, replacing cooler air with more mild, Pacific-sourced weather.

NAEFS 8-14 Day Temperature Anomaly Outlook valid November 17 to November 24, issued 12Z November 9, 2015
The NAEFS continues to forecast above-normal temperatures for Manitoba in the 8-14 day time range.

Generally speaking, daytime highs should climb into the upper single digits for both Saturday and Sunday which, while not sounding particularly warm, will be anywhere from 7–10°C above normal for this time of year.

Another low pressure system will work its way into southern Manitoba early next week, and while most of the precipitation looks like it will remain well north of the Red River Valley, the pattern does look like we may once again see the return of low cloud, drizzle and fog. It’s too early to tell, but just in case, you’d better get out there and enjoy the sun this weekend before it gets covered up again!

Spring Storm Marks A Return to Form

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A storm system pushing through Southern Manitoba tonight will bring snow, rain and everything in between to Southern Manitoba tonight, marking a significant shift in the upper-level flow that will bring seasonal to above seasonal temperatures through the weekend and into next week.

Friday
7°C / +2°C
Increasing cloud. Rain beginning this evening. 10-15mm.

Saturday
10°C / 0°C
Clearing in the afternoon; chance of showers.

Sunday
11°C / 0°C
Mainly sunny. Chance of showers overnight.

First Significant Rain of the Year

Today will be a pleasant day; high temperatures will sit around 6 or 7°C this afternoon with mainly sunny skies giving way to increasing cloudiness this evening. Winds will begin to pick up this afternoon to around 30km/h. The big story, though, is the low pressure system that will track through tonight.

A major low pressure system will begin pushing into Southern Manitoba tonight. This system, marking the transition into a warmer weather pattern, will spread significant rain and snow through the province during the overnight hours. Things will start off in the afternoon through the Parkland region with snow spreading eastwards from Saskatchewan. As the system pushes towards the Interlake and Red River Valley, precipitation will extend southwards, primarily as rain and then push eastwards through the remainder of the night. Winds will also be fairly strong, with sustained winds around 30-40km/h and gusts up to 60km/h.

Multiple precipitation types will be coming into play again with this system. The primary rain-snow line, at this point, looks like it will sit 50-100km north of the Trans-Canada highway. This line is not set in stone, however, and will likely meander north and south as temperature profiles change and precipitation intensifies and subsides. Areas near the rain-snow line may see precipitation flip from one to the other multiple times. With this low pressure system freezing rain is not expected, but ice pellets or a rain/snow mix are entirely possible.

Expected precipitation types for tonight's storm system.
Expected precipitation types for tonight’s storm system.

Precipitation, while relatively short-lived, will be fairly intense with this system. The heaviest axis of precipitation looks to extend from Parkland Manitoba, through the southern Interlake and northern Red River Valley and then through SE Manitoba into NW Ontario. For those on the snow side of the rain/snow line in Parkland Manitoba (including Dauphin), snowfall amounts will peak at around 10-20cm with amounts tapering off towards the northern Interlake and the rain/snow line. For the areas that will see rain, amounts will be split into three main groups:

Location Rainfall Amount
Extreme SW Manitoba (Melita) <= 5mm
SW Manitoba & Southern RRV 5-10mm
Winnipeg/Northern RRV & SE Manitoba 10-15mm

Saturday will start off mainly cloudy with mist and fog scattered through the Red River Valley. There will be a slight chance of showers, particularly through the northern half of the valley through Winnipeg and into the Southern Interlake. For any activity that does occur, however, amounts will be fairly minimal. Winds will be relatively light and skies will begin to clear for a sunnier afternoon. The temperature will top out around 10°C.

Saturday night will see temperatures dip to around 0°C with light winds. It’s likely that the substantial precipitation coupled with rapid snow melt and calm winds will produce fairly extensive fog through the Red River Valley. Fog is notoriously difficult to predict, so we’ll keep tabs on things into the evening hours and try to give as much heads up one way or another as to what to expect. Just be aware that for travel overnight Saturday into Sunday, fog may play into the picture.

Warmer Weather Arrives

We’ll start pushing into the significantly warmer weather on Sunday as another low pressure system approaches, bringing with it another pulse of warm air. Temperatures in Winnipeg will climb to around 11°C on Sunday with light winds under mainly sunny skies[1]. Temperatures on Sunday night will drop to around 0°C once again, but we do have an ever so slight chance of seeing some showers overnight as a disturbance tracks along the U.S. border.

Daytime highs should sit near to just above normal through much of next week, generally in the 10-15°C range. No threats for precipitation are expected until the second half of the week.

  1. If we end up with fog on Saturday night, we’ll see a cloudier Sunday morning, however skies should clear by late morning for a sunny afternoon.  ↩