Tag: Freezing Rain

Unsettled Weather Ahead

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A warm but unsettled few days are ahead as mild Pacific air surges across Southern Manitoba.

850mb Temperatures valid this evening

850mb temperatures from the NAM valid for early this evening.

Snow will taper off early this morning with a lingering chance of a stray flurry or two sticking around through much of the day across the northern half of the Red River Valley. Southerly winds will pick up through the day to 30-40*km/h as the warm front alluded to in Wednesday’s post pushes into the Valley. Temperatures will warm up quickly as the front passes with temperatures climbing to around -4 or -3°C, a few degrees warmer than the seasonal normal of about -6°C. Temperatures will remain steady through the night as that south wind continues to keep us in the warm air.

Another disturbance will pass through the northern Red River Valley tonight, however there’s some uncertainty to the areas that precipitation will fall. It currently looks like most, or all, of the precipitation will fall north of Winnipeg, focused in the Interlake region. There’s a slight chance that it will fall a bit further south, clipping Winnipeg and other areas in the northern half of the Red River Valley. If any areas in the Red River Valley are affected by this disturbance, they’ll almost certainly have to deal with freezing rain as there will a massive AFL (Above Freezing Level) just off the surface where temperatures will be nearly +10. With precipitation falling through it, the AFL will cool to 2-3°C, which is still more than warm enough to melt any snow that will be falling into it. Potentail freezing rain accumulations will be light but not insignificant at 1-2mm. Just to reiterate, the risk area for freezing rain will likely be confined to the northern half of the Red River Vally.

In addition to the weather from this disturbance, there will be the potential for freezing drizzle through the entire RRV as warm, moist air overruns our cold snowpack.

Saturday and Sunday will be cloudy days with beautifully warm temperatures for this time of the year. Daytime highs will sit right around 0°C. There will be a slight chance of non-accumulating flurries Saturday night into Sunday, otherwise no significant weather is expected. As winds lighten up, there will be the potential for fog patches through the valley in the overnight hours.

A storm system looks to move into the area on Monday morning, bringing rain or snow in the morning and snow in the afternoon. There’s still uncertainty in the track of the system and how much of the precipitation will impact the Red River Valley, so we’ll be sure to provide an update or two in the comments below through the weekend. The one thing that is certain is that this system will mark a return to more seasonal temperatures as cooler air sweeps over Southern Manitoba in it’s wake.

A Mixed Bag On The Way

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Today will bring warm temperatures along with a bit of light rain or snow as a Pacific system tracks through the Interlake towards Hudson Bay. Temperatures will climb above 0°C today before they gradually cool down by the end of the week to more seasonal values.

Probability of Snowfall >= 2cm

Probability of 12 hour snowfall accumulation exceeding 2cm, valid overnight Wednesday into Thursday morning.

A low pressure system tracking across the extreme Southern Prairies will arc northwards through Southern Manitoba today, lifting northwards through the Interlake region then exiting towards Hudson Bay. This system will intensify as it pushes into Manitoba and precipitation should blossom as it approaches the RRV. Two challenges exist with this system:

  1. When exactly will the precipitation develop/intensify?
  2. How far north with the system be?
  3. What will the phase of the precipitation be, snow or rain?

We’ll likely see some precipitation early this afternoon in the form of snow as the warm front pushes through the RRV. The Western RRV has a risk of some freezing rain if temperatures can stay below 0°C for long enough with this batch of precipitation. Any freezing rain that does develop will be short-lived, though. The snow will likely stop for the short period we’re in the warm sector of this system, but will return by late-afternoon/early evening with some rain or wet snow as the cold front passes through the area. The precipitation will end later in the evening. Snowfall accumulations today should be quite low in the RRV given the warm temperatures, however areas further east in the Whiteshell have a decent chance of getting around 2cm.

Temperatures should reach the 3-4°C range through most areas south of the Trans-Canada Highway today and drop only a little below 0°C overnight.

For Thursday, temperatures will reach close to 0°C as an elongated trough moves across the RRV, bringing with it a slight chance of flurries. It should pass by lunch, after which the NW winds will bring in cooler air and drop the temperature slowly through the afternoon.

The rest of the week will be relatively quiet, with temperatures gradually returning to more seasonal values (daytime highs moving from the low minus single digits to the high minus teens). The next chance for significant weather looks to be early next week.

Since it will likely be quiet on the weekend, I plan on having a bit of a special post on Friday! We’ll look at how warm this winter has actually been, and I’ll be unveiling a great new tool (barring no more problems…) that I’m really excited to let everybody get their hands on!

Chance of Freezing Rain Over The Red River Valley

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A large upper trough swinging across the Prairies is supporting two low pressure systems, one in central Saskatchewan and one in the Northern Plains of the United States, that will move across Manitoba overnight and tomorrow morning, bringing with them snow and the risk of freezing rain.

Dec. 31 Prog

For southern Manitoba, the main concern will be the precipitation generated along the apex of the frontal wave as it occludes southeastwards from the northern low in Central Manitoba to Minnesota. The warm front will align somewhere near a line from Winnipeg to Sprague, and slowly shift south/southeast through the day. Areas near the International Border have the greatest risk of freezing rain, due to the higher intensity of the precipitation expected there. The risk diminishes as you head north towards Winnipeg. I agree with the latest Environment Canada forecast that calls for ice pellets in Winnipeg; the warmest air should stay south of the city and we will likely have enough cold air entrenched to freeze any rain that comes out of an above-freezing layer. I can’t exclude the chance of a brief period or two of freezing rain, especially late overnight and early tomorrow morning. As this system develops, snow will become the predominant weather type, and much of the RRV can expect between 2-4 cm of the white stuff, while a few localities may get up to a couple inches.

I think it’s likely areas south of Morris will see some duration of freezing rain before sitching over to snow. The good news is that this doesn’t have the makings for a large-scale freezing-rain event, so there shouldn’t be any concern of widespread highway closures. Given that some roads are already very slippery, however, drivers should take caution when travelling overnight or tomorrow as fresh snow may be hiding a layer of ice underneath. Always drive with care when freezing rain and snow occur.

This system should clear out tomorrow afternoon, bringing in strong northwesterly winds behind it gusting up to 70 km/h. Fortunately, the arctic cold front is well to our north, so while chilly, we likely won’t even seen our temperature drop to even -15 to -20°C for overnight lows before the next swell of warm air pushes across the Prairies, bringing us continued pleasant winter weather with daytime highs in the -5 to 0°C range! The strong winds will move in tomorrow evening and last through much of the day on Sunday before tapering off, bringing us wind chill values as low as -25 in Winnipeg.

So hang in there, a couple chilly days and we’ll be back to pleasant temperatures with a fresh coat of snow! Happy New Year!

Miserable Weather on Tap

Brad Leave a comment

Don’t let the bits of sun and relatively warm temperatures fool you; tonight is going to be downright awful.

A complex double-barreled low pressure system (a term used when two separate lows are moving together as one entity) is moving out of Saskatchewan and Montana into Southern Manitoba this morning.  This system has brought a mix of precipitation into Southern Manitoba this morning, including freezing rain over western areas and heavy snow in the Interlake.  Numerous warnings have been issued across the region for weather happening now or expected to happen this evening.

The risk of freezing rain will persist through much of Southern Manitoba for an hour or two longer before temperatures will be warm enough that any precipitation will simply fall as rain.  Even though little precipitation has fallen over the Red River Valley this morning, Manitoba Highways is reporting that many sections of Highway 75 and Highway 1 heading west of Winnipeg are partly iced cover due to the slight melt and re-freeze yesterday afternoon.  As temperatures will just barely get over 0°C today, there may be portions of highways that are still quite slippery throughout the day.

Tonight
Perhaps the biggest impact from this storm will occur tonight over the Red River Valley.  As the low passes to the east, cold air will plummet down the backside of the system through the RRV.

 
24hr Accumulated QPF valid 12Z Saturday March 12, from the 00Z run of the GEM-LAM REG Model 

As the system passes, an intense band of wrap-around precipitation will move into the RRV, bringing heavy snow to Winnipeg by 6 or 7PM tonight.  Along with this heavy snow, this system will bring significant winds as well.


Surface Winds valid 06Z Saturday March 12, from the 06Z run of the GEM-LAM REG Model 

Sustained winds of 50-60 km/h with gusts potentially as high as 90 km/h will blast cold air into the RRV, which will plummet the temperature from 0°C or +1°C down to approximately -14°C or -15°C over the span of a few hours.  This will rapidly freeze any standing water which will very likely create extremely slick roads tonight.  And last but not least, these winds, combined with the heavy snow, will very likely produce blizzard conditions through a good portion of the night.

The weather conditions will deteriorate extremely quickly this evening to become a significant winter storm.  Anyone who has plans to travel in the Red River Valley tonight should keep updated on warnings, forecasts (or for a smartphone), the RADAR, and highway conditions to be able to make safe, educated travel plans.  Good satellite imagery to track this system can be found here at the U of M.