Tag: Colorado Low

March to end with a Bang

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This March not only came in like a lion, it will also go out like a lion. A major winter storm will slam the American Red River Valley and parts of south-eastern Manitoba today. Read on for the details.

A Colorado Low will bring heavy snow to parts of southern Manitoba and the northern United States on Monday
A Colorado Low will bring heavy snow to parts of southern Manitoba and the northern United States on Monday

Monday

Monday
-9°C / -15°C
Snow, heavy in some areas. Windy.

A Colorado Low will bring heavy snow and high winds to the Red River Valley and south-eastern Manitoba today. Wind speeds will range from 40-50km/h gusting to 50-70km/h. Some areas may even see winds as high as 60km/h gusting to 80km/h for a period of time. This will produce blizzard conditions in open areas of the Red River Valley and south-eastern Manitoba. The map below illustrates the expected snowfall totals.

Expected storm-total snowfall amounts.
Expected storm-total snowfall amounts.

Travel will become very difficult, if not impossible from points south of Winnipeg and into the American Red River Valley as the day progresses. Highway closures are likely through the day, with some roadways possibly staying closed until Tuesday. Roads that remain open will be in poor shape as well, so those traveling today may need to reconsider their plans.

This storm will wind down on Tuesday as the snow ends and the wind begins to decrease. However, those areas that saw the heaviest snow will have to deal with large snow drifts on Tuesday. Travel will be difficult if not impossible, particularly in the American Red River Valley, on most of Monday and likely into Tuesday as well. Luckily this storm should signal the beginning of the end of the seemingly endless winter we’ve endured.

Tuesday

Tuesday
-8°C / -22°C
Mainly Sunny

Tuesday will be a much calmer day in southern Manitoba. Temperatures will warm into the minus single digits, but a north-west wind will linger as Monday’s storm departs. At least it will be decent shoveling weather…

Wednesday

Wednesday
-4°C / -18°C
Mainly Sunny

Wednesday will see further improvement over Tuesday, as temperatures climb into the low to mid minus single digits. That should be good enough for some light melting of snow off dark surfaces – melting that can’t come soon enough for most people.

Long Range

The long range forecast is looking good for a change. Most models suggest we’ll see near normal weather in the short to medium term, which means high temperatures in the mid positive single digits. That should help to gradually start wearing down our snow pack.

Feeling More Like October

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This week will feel more like October as temperatures return to more normal values.

A Colorado Low Will Pass to our South on Monday

Today

Monday

Mainly Cloudy
9°C / 4°C

Another Colorado Low system has made its way onto the American Plains today and just like the last one, it will mainly miss Southern Manitoba. Border regions may see a bit of rain from this system, but in general it won’t be much of a factor in our weather. It will keep skies on the cloudy side though, with mainly cloudy conditions expected in most of Southern Manitoba through the day.

Tuesday and Wednesday

Tuesday

Mainly Sunny
10°C / 0°C
Wednesday

Mainly cloudy. Chance of Showers.
12°C / 2°C

The Colorado Low will have departed the region by Tuesday, leaving behind sunny skies and seasonal temperatures. The wind will be from the north, but it won’t be terribly strong.

Wednesday may see a bit more rain in Southern Manitoba, as a weak system swings down from the north. Temperatures will be in the
low teens, with more cloud than sun.

Long Range

In the long range models suggest that seasonal to below-seasonal weather will dominate. Based on current forecasts, we’ll likely see some light flurry activity before the month is out, but luckily no major snowstorms are currently in the forecast!

Late-Season Thunderstorm Risk Kicks off Dreary Weekend

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A powerful low-pressure system pushing northwards out of the Dakotas that will bring copious amounts of rainfall to SE Saskatchewan and Western Manitoba will also bring a risk for thunderstorms, perhaps even an isolated severe thunderstorm, this evening in advance of an occluding cold front. This will mark the start of a somewhat dreary weekend for the Red River Valley that will be marked most notably by a wet & windy Saturday and a very cool, albeit sunny, Sunday.

Thunderstorms Possible Today

Friday

19°C / 12°C
Mainly cloudy. Chance of showers with the risk of a thunderstorm late in the day.

We’ll see a mainly cloudy day today with relatively nice temperatures as we sit in the warm sector of the low pressure system pushing into the province. Despite the cloudy weather, we should see temperatures climb to around 19–20°C for a high with south-easterly winds to around 30km/h.

We may see a shower early this morning as the warm front pushes through and brings us into the warmer air, although a majority of the activity will be off to our west. If anything manages to push into Winnipeg, it will be relatively short-lived. After that we’ll see no chance of precipitation until later in the afternoon or the evening as a cold front begins pushing into the Red River Valley from the south.[1]

Event outlook for Friday, October 11th.

Event outlook for Friday, October 11, 2013.

While we sit under cloudy skies, this would be a good time to note that the weather to our west will be decidedly different. Rain will push in early this morning and spread NNE through the day, hitting areas west of the Red River Valley and Lake Manitoba the hardest. In total, anywhere from 35–75mm of rain is expected, with the lesser amounts closer to the Red River Valley and the higher amounts running along the Saskatchewan border then towards Lake Winnipegosis with enhanced precipitation near the Riding Mountains as upslope enhancement in the north-easterly winds amplifies the amount of rain. Environment Canada has rainfall warnings out for many regions in Western Manitoba, and you can check here to see if your region is covered by one and find additional details.

As the cold front approaches the Red River Valley this evening we’ll see considerable destabilization of the mid-levels coupled with an extremely strong 60–70kt 500mb jet beginning to poke it’s nose north of the border. The Red River Valley will lie in a fairly diffluent area aloft with strong convergence along the cold front as it pushes northwards. Limited surface moisture will constrain SBCAPE values to only a mere 400–500J/kg, but the extremely strong dynamics, in particular the strong directional and speed shear, may help promote the growth of strong-to-severe thunderstorms along/just ahead of the cold front.

This all is highly dependant on either enough destabilization occurring or enough convergence occurring along the cold front. At this point, I think that the southern Red River Valley will see the strongest storms with a lesser risk of strong storms further north here in Winnipeg. By the time the front reaches us, it seems like it will be a band showers and/or thunderstorms with less organization than when things initiate in the Dakotas. If any of the storms do become severe, the main threats will be large hail and strong winds. There will be a very small risk of a few weak tornadoes with these storms, but I believe that will be most likely in North Dakota with the odds diminishing fairly rapidly as you push northwards through the Red River Valley.

The showers/thunderstorms will push through overnight as we drop to a low of around 11 or 12°C.

Wet & Windy Saturday

Saturday

↘ 6°C / 2°C
Cloudy with showers. Windy. Temperature dropping through the day.

Saturday in Winnipeg will be marked by wet and windy weather as we move onto the back-side of the Colorado low and see some wrap-around rain and gusty northwesterly winds move in.

The rain will likely be somewhat showery in nature – in that we won’t see solid rain all day long – and there’s some uncertainty on how much we’ll see exactly, but around 5mm seems like a relatively safe bet at this point. If the system is a little faster than forecast we could end up with almost nothing as the rain would fall further north, and if it’s slower than forecast we could see closer to 10mm as we end up under the wrap-around rain for even longer.

The wind will be the main weather story though. Here in Winnipeg we’ll see winds 30–40km/h out of the northwest with gusts up to 60km/h, but it will be a significantly different story for those on the lakes. Winds over the lakes will increase to nearly 50–60km/h on Saturday with gusts as high as 90km/h, which will produce fairly sizeable waves. If you have a home or cottage on the southern or eastern shores of the lakes, you’ll want to make sure you make any preparations you might have to and prepare for some strong wave action and howling winds for Saturday and Saturday night.

With those strong winds will come falling temperatures; here in Winnipeg we’ll likely see temperatures fall to around 5 or 6°C by the end of the day as colder air pushes in on the back-side of the low. Skies will clear and winds will lighten overnight as we drop to around 2°C for our overnight low.

Sunny but Cool Sunday

Sunday

9°C / -2°C
Sunny. Cool.

Sunday will see the return of the sun, but the price we’ll pay is significantly cooler weather than we’ve been having over the past week. Daytime highs on Sunday will top out at only 9 or 10°C and it will be a slow climb to get there. Temperatures will likely drop well below 0°C on Sunday night with a hard frost likely as temperatures dip to around –2°C.

This will also mark the transition into a cooler pattern. Daytime highs will remain around 10°C through much of the week.

  1. It sounds odd, but this system is essentially sideways with the warm front and cold front both moving from south to north.  ↩

Warmer Weekend Ahead With An Uncertain Finish

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Warmer weather will wash across the Red River Valley this weekend as a south-westerly flow brings in mild Pacific air. While the sun won’t be overly present, conditions will be quite pleasant with mild temperatures and light winds. The weekend will finish on an uncertain note as a Colorado Low ejects from the Central Plains with wavering agreement on where it’s heading after that.

500mb Winds for Sunday Morning

500mb winds valid for Sunday morning at 12Z. A complicated set-up will be underway as the polar jet merges with the sub-tropical jet and a shortwave from the northern Prairies merges into a developing Colorado Low.
Friday

Mostly cloudy.
-6°C / -9°C

Skies will be mainly cloudy today as a warm front pushes eastwards towards the Red River Valley. Temperatures will climb up to –7 or –6°C, a welcome break from the cold temperatures we’ve had over the past week. Winds will pick up out of the south-southeast to 30–40km/h this morning with a slight chance of some local blowing snow through the Red River Valley. There will be a very slight chance of a few flakes of snow but there won’t be anything that can be considered significant. Temperatures will drop a few degrees tonight to about –9°C under mainly cloudy skies.

Saturday

Saturday

A mix of sun & cloud.
-4°C / -9°C

Perhaps the nicest day of the weekend will be Saturday as the clouds begin to break up a little and temperatures climb as high as –4 or –3°C. Winds will remain fairly light through the Red River Valley through the day. Not much to say for Saturday night; skies will likely clear in the evening but fairly quickly cloud over again early in the morning on Sunday.

Sunday

Sunday is a very complicated weather day. As it stands right now, we may see absolutely no snow or…quite a bit of snow, including the potential for a blizzard through portions of the Red River Valley. Temperatures should remain close to what they look to be right now with highs near –5°C across much of the Red River Valley. Winds will likely remain relatively light, regardless of the overall pattern, as there will be no significant Arctic high building into the region.

As for the complicating factors…

Sunday

Mostly cloudy. Snow/freezing rain uncertain.
-5°C / -11°C

The general synoptic pattern will be as such: a significant Colorado Low will be ejecting into central Nebraska on Saturday night with a sharp trough digging northeastwards into SE South Dakota while, at the same time, a relatively weak low pressure system slides south-eastwards out of northern Saskatchewan towards central Manitoba. By Sunday morning, the Canadian low and it’s associated jet stream will merge with the Colorado Low with the CO low situated in central Nebraska with a sharp trough extending northwards through extreme western Minnesota then arcing through the Red River Valley northwestwards towards The Pas, MB. It’s always a concerning issue when the troughs end up west of the Red River Valley, as it can often mean a northward progression of the weather into our area.

Models have notorious struggles with complicated setups where two distinct atmospheric streams merge. It’s an incredibly dynamic, sensitive process in which even small changes can dramatically effect the evolution of the entire system, so models can often waver wildly on what the outcome will be from small changes in their initial conditions. That being said, using ensemble forecasts, the track of the low, and it’s associated snow, has been creeping northwestwards; two days ago the entirety of the snow was forecast to push only into Central Minnesota; now it’s forecast to clip southeastern Manitoba, including Sprague and portions of the Whiteshell. Model trends can sometimes be more helpful than the actual model output, and combining the ensemble’s northwards trend with the knowledge that this is definitely a situation where the model may not tilt the 500mb trough enough and then, as a result, not bring the low far enough north or west, I can’t say with any certainty what Sunday will bring.

There’s a distinct chance that the snow will remain entirely on the US side of the border and we’ll be relatively unaffected by this system. Should things develop in such a way that the low digs a little more and the trough tilts a little more, it’s also entirely possible that another 5–15cm of snow, or potentially higher, will fall across the Red River Valley. In addition to the uncertainty with all these elements, should the precipitation push further to the NW into Southern Manitoba, there will be a distinct potential for freezing rain as 850mb wet bulb temperatures sit on the positive side of the 0°C mark.

The reality is that for this type of setup, it’s simply too early to tell what’s going to happen. We’ll most certainly be providing updates in the comments below on the development of this Colorado Low. For now, it’s safe to assume that Sunday will be a warmer day with winds in the 20–30km/h range, but the actual weather conditions may end up being quite poor depending on the evolution of this system.