Alberta Clipper To Bring Snow and Extreme Cold

Brad Leave a comment

Conditions will change dramatically this weekend with no thanks to an Alberta clipper system that will spread snow into Southern Manitoba tonight and usher in extremely cold Arctic air1 to the region on it’s back side. Before that system arrives tonight, however, we’ll get to enjoy a beautiful day with temperatures climbing towards the 0°C mark!

Friday

-2°C / -18°C
Mostly cloudy and warm. Chance of an afternoon flurry. Snow beginning overnight.
Saturday

⇒ -18°C / -32°C
Snow. Windy with blowing snow. Cold.
Sunday

-26°C / -33°C
Mainly sunny. Very cold.

Today will be an exceedingly pleasant day for what has been a markedly cold December. Thanks to a flow of mild Pacific air brought in by westerly winds ahead of the Alberta clipper, we’ll see our temperature climb to around –3 or –2°C today with relatively light winds. Skies will likely remain mostly cloudy through much of the day with the cloud cover being bolstered by the warm temperatures over the snow and a weaker leading impulse tracking through the Interlake. We may see a few breaks in the cloud here or there, particularly through the mid-to-late afternoon period. Unfortunately, that’s where the good news ends. An Alberta clipper is on the way, and it’s a doozy.

Total new snowfall by Saturday evening. Anywhere from 5 to 15cm can be expected along the main frontal zone.
Total new snowfall by Saturday evening. Anywhere from 5 to 15cm can be expected along the main frontal zone.

The system will begin spreading snow into the Red River Valley overnight along a line cutting across the northern Red River Valley. The heaviest band of snow will set up along the main frontal zone aloft which will be aligned roughly from Dauphin to Winnipeg and ESE into the Whiteshell. Underneath the heaviest band of snow around 5-10cm of snow can be expected by Saturday morning with amounts tapering to just 2-3cm near the US border. In addition to the snow, a cold front will begin to slump southwards late overnight which will usher in much cooler air. We’ll see temperatures drop to around –18°C with winds shifting out of the north.

Saturday

Saturday will be…miserable. Our temperature will remain steady near around –18°C as cold air continues to infiltrate into Southern Manitoba. Snow will persist through much of the day — although it will likely lighten to just a few flurries by the late afternoon — with another 2–5cm expected to fall across the Red River Valley which will bring storm-total snowfall amounts to around 5cm in areas on the fringes of the system track and anywhere from around 7–15cm under the heaviest band of snow. The winds will become more of an issue on Saturday as they increase out of north to 30–40km/h with gusts as high as 60km/h. These winds, aided by the fresh snowfall, will create areas of poor visibility in blowing snow, especially on any west-east running highways.

Please note: Driving conditions will likely be extremely poor on Saturday morning. In addition to the blowing snow, roads will likely be extremely slippery; the warm temperatures on Friday will likely produce moisture on road surfaces which will rapidly freeze overnight. On Saturday morning, roads will likely be icy with fresh snow on top and blowing snow on top of that. If you need to travel, carry a winter survival kit and give yourself lots of time to reach your destination.

The system will move out on Saturday night bringing clearing skies and extremely cold temperatures as an Arctic airmass settles over the region. Our overnight low will bottom out at about –32°C with fairly light winds.

Sunday

Sunday will be a mainly sunny but very cold day. The temperature will only recover to the low minus 20’s. Winds will remain light — little consolation given the temperatures, though. It’ll drop to around –33°C on Sunday night under clear skies.

When Will It End?

The latest NAEFS 8-14 day temperature outlook is calling for below-normal temperatures for Manitoba.
The latest NAEFS 8–14 day temperature outlook is calling for below-normal temperatures for Manitoba.

Unfortunately, all signs point to the cold weather sticking around for at least the next 4–7 days, if not longer. The NAEFS guidance shows below-normal temperatures expected in the 8–14 day range while all the shorter-range models show cold weather through the next week. The GFS is hinting at a system that might push through late next week that would bring slightly milder temperatures, but it would be short-lived and doesn’t look indicative of a pattern change.

It looks like we’ll definitely be closing out December 2013 as one of the Top 5 coldest Decembers on record in Winnipeg with little reprieve on the horizon. So go enjoy the last nice day of 2013 and then get your long johns ready, plug in the car, get a warm drink, fill up the hot water bottle, renew your CAA membership and whatever else you need to do to prepare for another prolonged bout of extreme cold.

  1. I’m doing my best to not use the phrase “bitterly cold” in today’s blog.  ↩

Santa Delivers A Break From the Deep Freeze

Brad Leave a comment

Merry Christmas!

All of us here at A Weather Moment would like to take just a moment to wish you and your families a very Merry Christmas! It’s been a wonderful year here at A Weather Moment and I want to thank you for dropping by — whether this is the first time you’ve ever been to the site or come here regularly — to see what we have to say about the weather. I hope that you find (or continue to find!) what we do here of value and continue to stop by for your weather forecasts, summaries and news!

Holiday Forecast

At the risk of sounding like a broken record that simply utters the phrase “deep freeze” over and over again, I’m glad to let everyone know that we all get perhaps the most wonderful Christmas gift that could be given to us this year: a break from the deep freeze. The next few days will bring temperatures near-then-surpassing our normal temperatures for this year as warmer air floods eastwards across the Prairies.

Christmas Day

-15°C / -25°C
Mixed skies with a chance of afternoon flurries.
Boxing Day

-11°C / ⇒ -10°C
Cloudy periods with seasonal temperatures. Chance of flurries in the morning.
Friday

-4°C / -17°C
Mixed skies and warm. Slight chance of light, isolated flurries.

We’ll see mixed skies today with a daytime high of around –15°C and a chance of some afternoon flurry activity as a weak upper disturbance makes it’s way over our area. No significant accumulations are expected. Winds will be a fairly steady 20km/h or so out of the northwest. We’ll continue to see mixed skies through the overnight period as the temperature drops to around –25°C.

Tomorrow will bring cloudy periods with fairly seasonal temperatures as the mercury climbs to around –11°C. A few flurries are possible in the morning as a weak upper-level warm front pushes eastwards over the Red River Valley. Winds will be fairly light out of the south at only around 15–20km/h. Overcast conditions are expected on Thursday night as a warm front pushes eastwards through the region. Little-to-no precipitation is expected with it as it manages to keep our temperature steady near around –10°C.

Friday will again bring mixed skies, although we do have a chance at becoming mainly sunny for a decent amount of time sometime between the late morning and mid-afternoon period. There’s a slight chance of an isolated flurry or two, but nothing worth going into any detail about. The temperature will climb to a balmy –4°C or so thanks to westerly winds bringing in much milder air.

GDPS precipitation accumluations from Friday evening to Saturday evening show a swath of 10-20cm of snow just north of Winnipeg.
GDPS precipitation accumluations from Friday evening to Saturday evening show a swath of 10–20cm of snow just north of Winnipeg.

Snow will push in overnight as a powerful Alberta Clipper moves into the region. It’s still too early to make any precise predictions, but it appears that the track of the system will bring the heaviest band of snow through the Southern Interlake region with anywhere from 10–20cm of new snow on the ground by the end of Saturday. Amounts drop off to 2–5cm in the Southern Red River Valley. Here in Winnipeg it could end up being a major snowfall; cold air has a tendency to be a bit of a bigger bully than the models let it be and shift storm tracks further south. It wouldn’t take too much shifting for that 10–20cm band to move right over Winnipeg. It’s all too early to tell specifics at the moment, though; it’s fairly likely we’ll see accumulating snow Friday night/Saturday morning, the only question is will it be a little or a lot? We’ll have more details on the system in Friday’s post once things have a chance to develop more.

The Weekend

Things go downhill from there, unfortunately. Another shot of bitterly cold Arctic air[1] will push into the Prairies which will push our daytime highs back into the –20’s and overnight lows to near or below –30°C. Unfortunately, it also looks like it’s going to stick around until at least the middle of next week, if not longer.

So enjoy your Christmas present of a pretty nice 3 days and get out there while you can! From all of us here at A Weather Moment, we wish you and your families a very Merry Christmas and all the best in the coming year!

  1. Have we used this phrase enough to be able to ™ it yet?  ↩

Mild, Snowy Christmas Eve Gives Way to Another Cold Snap

Brad Leave a comment

This week will see cold weather continue — not exactly the Christmas present that many were hoping for.

The Wind Will Pick Up on Monday Night

The Wind Will Pick Up on Monday Night

Monday

Monday

Sunny
-23°C / -25°C

After a frigid morning, temperatures won’t recover a whole lot today, but at least it will be sunny! Afternoon temperatures will be in the low to mid minus twenties, with increasing winds. Wind speeds during the morning and afternoon won’t be particularly high, but winds will increase through the evening and into the overnight period. Some blowing and drifting snow is likely in open areas on Monday night as winds increase to 30-40km/h gusting to 50-60km/h out of the south. To add insult to injury, snow is expected on Monday night into Tuesday. The snow will begin in Western Manitoba on Monday night, and push into the rest of Southern Manitoba by Tuesday morning.

Christmas Eve

Tuesday

Mainly cloudy. Snow.
-12°C / -20°C

Tuesday will be warmer than Monday as those stiff southerly winds overnight bring in some milder air, but this reprieve from the cold will be accompanied by snow. A total of 4-8cm of snow is expected in Southern Manitoba by the time the snow ends on Tuesday afternoon. Temperatures on Tuesday morning will be in the minus twenties, but by afternoon we should climb into the minus single digits over Western Manitoba and the mid minus teens over Eastern Manitoba. The Red River Valley will likely remain stuck in a southerly flow through the day, causing temperatures to remain a bit below -10C.

Christmas Day

Wednesday

Mainly cloudy. Chance of flurries.
-18°C / -28°C

Another cold front will pass through Southern Manitoba on Christmas morning, allowing cold weather to return for the big day. The wind will also pick up behind this front, generating chilly wind chill values. High temperatures for Christmas will be in the upper minus teens, with a chance of flurries through the day.

Long Range

The long range forecast looks cold, cold, cold. We may see one warmer day towards the end of the week, but other than that there is no moderation in the forecast.

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Elsewhere in Weather News: December 21st, 2013

Matthieu Leave a comment

Southern Ontario, Midsection of US Anticipate Ice Storm

A major ice storm has been taking shape as of Friday night across parts of Oklahoma and Texas and will continue to push northeast. A potent cold front with Arctic air filtering in behind it is clashing with gulf moisture moving north and thereby creating prime conditions for ice accumulation from Oklahoma all the way to southern Ontario. Dangerous travel conditions are expected as there could be significant ice accumulation due prolonged periods of freezing rain through this weekend. With this comes the possibility of downed power lines so residents have been made aware to prepare for power outages across southern Ontario. So overall, not ideal conditions for holiday travel this weekend as all kinds of precipitation will be falling across the eastern half of the US and southern Ontario.


Freezing rain sounding from Oklahoma on Friday evening. Note the shallow freezing layer near the surface where the arrow is. (Souce: Twisterdata)
Freezing rain sounding from Oklahoma on Friday evening. Note the shallow freezing layer near the surface where the arrow is. (Souce: Twisterdata)

Freezing rain forms when there is a deep layer of warm air that is above freezing aloft. As the ice crystals fall and meet the warm layer, they melt and become raindrops while falling towards the ground. A shallow layer of cold air just above the surface of the earth must also be present for freezing rain to form. Supercooled water droplets – drops of liquid water that exist in below freezing air, will be in place and won’t have enough time to freeze into ice pellets, thus will freeze (as ice) on contact as they hit the ground.

In addition to this, a severe weather outbreak is expected in Dixie Alley of the US today. The outbreak is associated with the same system as the cold front slices through the warm, moist air mass in place. A moderate risk has been issued by the Storm Prediction Center as well as a 15% hatched area for tornadoes in Mississippi and northern Louisiana. Chances of tornadoes are quite high, the only possible limiting factor is that CAPE will be fairly low (only around 500-1000J/kg) but this will still be sufficient for supercells which will quickly evolve into a quasi-linear convective system – a line of severe thunderstorms that can have bowing segments. SPC gives fairly strong wording for today in Dixie Alley saying that “there is potential for several tornadoes – some of which should be strong”.

By Monday night the system will have moved off the US East Coast but will still be a weather-maker for Atlantic Canada.