Today will mark the start of a prolonged spell of unseasonably warm weather for Southern Manitoba. A strong west-to-southwest flow aloft will begin building into the region today, ushering in much milder Pacific air which will help daytime highs climb above the freezing mark. The milder weather will bring unsettled weather with numerous chances for snow or rain along with the risk for freezing rain over the coming 3-5 days.
Today will bring soaring temperatures as gusty southerly winds develop and raise our temperatures from sub-minus 20 values this morning to around -4 or -3°C by the end of the day. While winds will be light early this morning, they will pick up towards midday to 30-40 km/h out of the south as the warm front towards the Red River Valley. As the warmer air advances eastwards, it will produce scattered flurries that will pass through much of the Red River Valley.
Temperatures will remain steady or drop slightly on Thursday night as more warm air surges northeastwards ahead of an incoming low pressure system. Any remaining flurry activity will taper off overnight, but by Thursday morning the potential for precipitation will return.
RDPS Precipitation Type Forecast for Thursday February 18, 2016
Thursday will be a mild but messy day. A low pressure system tracking across the Southern Prairies will spread a wintery mix of precipitation through the region with pretty much anything possible. With a high of just +1°C, much of the day will bring the potential for flurries or ice pellets, with the risk of freezing rain. At this point it doesn’t appear that amount will be too significant for the Red River Valley, but with a significant chance for freezing precipitation, we’ll be keeping close tabs on it.
Winds will be moderate throughout Thursday morning out of the southeast to about 30-40km/h. Temperatures will climb to near the 0°C mark and then remain there through the remainder of Thursday and through Thursday night. The chance for any type of precipitation (flurries, freezing rain, rain showers) will likely continue through Thursday night.
Friday will see even warmer air push into the Red River Valley with a daytime high near +2°C expected. There will continue to be a chance for flurries in the morning transitioning to rain showers. Winds will remain light until later in the day when a weak cold front swings through and ushers in winds near 30km/h out of the west-northwest.
Long Range: Mild Weather Continues
Looking forward, it looks like the warmer temperatures will remain in place for a while yet. This weekend will remain warm with daytime highs near 0°C on Saturday and -5°C on Sunday, with chances for snow on both days.
CPC 6-10 Day Temperature Anomaly Outlook
Further on into next week, temperatures are forecast to continue above seasonal for this time of year as shown above in the CPC’s 6-10 day temperature outlook.
The normal daytime high for Winnipeg is currently -8°C and the normal overnight low is -18°C.
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.
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 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!
Winnipeg will likely see a messy commute on Wednesday morning as a warm front pushes through and brings the potential for some rather intense snow. Behind the front, however, gusty westerly winds will bring very mild weather to the province with temperatures climbing above freezing. This transition will lead into a fairly warm spell that will persist throughout the remainder of the week as multiple disturbances roll through the region.
Snow & Freezing Rain Ahead of Milder Weather
The weather on Wednesday morning will be dominated by a low pressure system and associated warm front that will push through the province Wednesday morning, bringing with it snow, freezing rain and rain to the province. Over western & southwestern Manitoba, precipitation will be a wintery mix of rain, freezing rain and snow. The freezing rain may be fairly intense at times, with total ice accumulations of 2-3mm possible. This will be more than enough to make regional highways treacherous. The freezing rain threat will extend slightly into the southwestern Red River Valley, but will depend significantly on the exact low-level temperature profiles and track of this system. Anyone southwest of Winnipeg in the Red River Valley should stay alert of the potential expansion of freezing rain warnings eastwards.
Wednesday Storm-Total Snowfall Forecast valid at 6PM CST
Freezing Rain Threat for Wednesday January 27, 2016
While light freezing rain is possible throughout the remainder of the Red River Valley, it’s far more likely that the precipitation will fall as snow. To the east of the main band of freezing rain, a swath of fairly intense snow will slump southeastwards overnight and move into the Red River Valley in the morning.
Forecast sounding for Winnipeg early Wednesday morning
This forecast sounding, which shows the forecasted temperature and moisture profile as you move upwards in the atmosphere, is rather telling regarding heavy snowfall:
First is that there is a deep, deep layer of saturation (shown by the red and green lines being close together. Essentially the entire tropopause is forecasted to be saturated with ample synoptic lift moving in. This will provide plenty of moisture for snow generation.
Also revealing is the moist adiabatic profile[1] throughout the mid-to-upper levels of the atmosphere coupled with the cooler advection occurring aloft. This is a fairly traditional profile that often produces widespread embedded convection within the precipitation area.
These two aspects reveal that intense bursts of snow will be likely with this system, resulting in abruptly reduced visibilities and rapid accumulations. The bulk of the snow is expected to fall between 6 and 9AM, with total amounts of 5-10cm possible in Winnipeg and much of the remainder of the Red River Valley. This will likely result in significant delays in the morning commute as drivers battle slippery roads and poor visibility.
The snow will taper off to flurries for the remainder of the morning and then the next phase of the system sets in…
Mild Weather, But Questionably Nice
Behind the warm front, temperatures will continue to climb in Winnipeg to a daytime high of around 2°C as gustier west-northwest to northwest winds move in. The winds will likely climb all the way to around 40-50km/h, making for not exactly pleasant outside weather. As we climb above 0°C, depending on a few different things, the flurries may either stop or transition to some isolated rain showers.
Heading into the evening, the new dominant weather feature will be a very slow-moving cold front gradually slumping southwards through the province. With ample moisture stuck in place and temperatures dropping back below zero, fog and drizzle/freezing drizzle will begin to become a concern. At this point, it looks like the winds will begin to taper off through the evening, becoming relatively light by midnight or so. Once the winds ease, it’s quite likely cloud bases will begin lowering throughout the region with the risk of fog or drizzle developing. The overnight low will sit around -5°C, so if drizzle materializes, it will do so as freezing drizzle.
Thursday will see the Winnipeg and much of the region stuck underneath that pokey front as it begins to stall and push back to the northeast as the next low pressure system begins developing over the western Prairies. Skies will remain mainly cloudy as a slack flow combines with the weak convergence aloft around the front to keep the moisture socked in over the region. With all that low-level moisture stuck in place, the risk for freezing drizzle and/or fog will also continue. Winds will be fairly light and the high will be around -4°C.
The GDPS model shows a mix of rain, snow and freezing rain over Southern Manitoba late Thursady night.
The next weather system will begin moving in on Thursday night, spreading warmer air eastwards. As a result, temperatures will climb to around -2°C by Friday morning alongside some light snow and a threat of another round of freezing rain, this one primarily for the Red River Valley.
Winter Mix for Friday
Friday will be another mild day with temperatures climbing to +1 or +2°C in the warm sector of the second disturbance impacting us this week. Freezing rain or snow will taper off to cloudy conditions with a chance of some drizzle. At this point there’s wide discrepancies in how much precipitation will fall through Thursday night and Friday morning, with everything from a relatively minor event to a chance for another 5-10cm of snow.
Late in the day as temperatures cool slightly, some lighter snow is possible. Temperatures will drop to around -1°C on Friday night.
Normal daytime highs for Winnipeg at this time of year currently sit at -12°C with typical overnight lows near -22°C.
Moist adiabatic is the "temperature path"—how its temperature changes—that an imaginary parcel of air will follow as it moves up and down in the atmosphere if it is saturated. ↩
Warmer weather is on the way for the weekend with temperatures soaring close to the freezing mark, however not before a blustery day that will be rather miserable and may impact transportation throughout the Red River Valley.
Windy Weather Developing
Windy weather is on the way for Winnipeg today courtesy a developing low pressure system pushing eastwards across the Prairies. As this system moves towards Manitoba, a strong pressure gradient will develop over the Red River Valley between the incoming low pressure centre and departing ridge of high pressure. As the gradient strengthens in the afternoon, strong southerly winds will develop throughout the Red River Valley.
Strong winds are expected by Friday evening through Southern Manitoba and the Northern Plains (the highlighted area).
Sustained wind speeds will increase to 40-50 km/h by the early evening. It seems fairly probable given the near-constant light snow and ice crystals that have fallen over the last several days that blowing snow will become a transportation issue for Friday night into Saturday morning. In Winnipeg it shouldn’t be too bad, but in rural areas, particularly along west-east running highways, the potential for near-whiteout conditions exists. Be sure to give yourself extra time and carry a winter survival kit if you will be travelling on area highways.
Warmer Weather Brings Risk for Freezing Rain or Drizzle
Winds will begin tapering off on Saturday morning as the low pressure system arrives, bringing with it a blast of mild Pacific air. Despite the fact that skies will remain cloudy for most of the day, temperatures will soar to a high of -1°C.
Alongside the surge of warm air will come a risk of some freezing rain. An above-freezing level (AFL) will develop overnight, and by morning an area of precipitation is expected to slide through Parkland Manitoba, the Interlake and northern Red River Valley before sliding eastwards into Northern Ontario.
This forecast sounding for Winnipeg from the NAM shows a well-defined AFL with Tw ≥ 0°C.
With sustained warm air advection and a wet-bulb temperature above 0°C in the AFL, the potential for organized freezing rain exists. The highest likelihood lies over the Swan River region and then southeastwards through the Interlake. The risk exists over the Red River Valley, but at this point it doesn’t appear that actual amounts will be particularly high. Nonetheless, it doesn’t take much freezing rain to make things slick, so we’ll monitor things and provide an update if the threat for the Red River Valley increases.
Behind the warm front, freezing drizzle will be possible throughout much of the day with saturated low-levels and the lift associated with the incoming low. Winds will be calm through the afternoon.
Winds will shift to the northwest in the evening as a cold front passes through. Skies will remain fairly cloudy and the threat for freezing drizzle will persist well behind the cold front and through much of the night. Temperatures will drop to around -8°C by Sunday morning.
Sunday will bring weak cold air advection through the day, resulting in temperatures rebounding only slightly if at all through the day. The chance for flurries will redevelop as temperature profiles become too cold for freezing drizzle and more favourable for snow. That said, overall moisture supply will be dwindling, so at this point it appears that there will be just a chance for some flurries.
Sunday night will bring cloudy skies and a low near -10°C.
