Tag: Below-Normal Temperatures

A Glancing Blow

Brad Leave a comment

A Colorado low responsible for a tragic severe weather outbreak yesterday across the the Southern United States, and Arkansas in particular, has spread rain northwards into Southern Manitoba this morning. A decent soaking is in store today and then see a cooler, unsettled week ahead as the Colorado Low persists through much of central North America.

Monday
8°C / 0°C
Periods of rain ending by the evening. 10-15mm. Breezy.

Tuesday
10°C / 0°C
A few clouds.

Wednesday
7°C / 0°C
Showers likely.

Late last week it looked as if we were set to get as much as 25-30mm in a widespread swath through much of Southern Manitoba, however we pointed out the complexities of the setup and how minor changes in the positioning of features could cause big changes in how much precipitation is produced.

It turns out the models did fairly well with the overall picture. Thanks to a little more tilt to the upper trough and the upper low being captured a little sooner than originally forecast, the system as a whole won’t push as far northwards as it looked last week and as a result we’ll see a little less rain than it looked like then.

We’re still in for a decent soaking today, though. Periods of rain will persist through the late afternoon or early evening, and in general much of Southern Manitoba will see 10-20mm of rain. Areas further north, towards the Interlake and much of Parkland Manitoba will see in the 5-10mm range, but it does appear that, for the most part, anywhere along and south of the Trans-Canada corridor in SW Manitoba and the Red River Valley will see between 10 and 20mm with the higher amounts closer to the U.S. border. The temperature will sit around 8°C today with breezy winds out of the east at 30km/h with gusts to around 50km/h.

Total rainfall expected today across Southern Mantioba.
Total rainfall expected today across Southern Mantioba.

Near the border there’s a slight chance of accumulations creeping up towards 25mm (1”) or so, but that will depend on fairly heavy rain and some lingering rainfall a bit longer than it seems like it’s likely too. The rain will taper off by this evening and we’ll see gradual clearing through the evening. The temperature will drop to around 0°C.

Another Short-Lived Break

Tuesday looks to be a cool but pleasant day with a high temperature of around 10°C and mostly sunny skies. Temperatures will drop to around 0°C once again on Tuesday night with increasing cloudiness.

Wednesday brings back the showery weather as another shot of rainfall pushes into Southern Manitoba from east to west on the back-side of the Colorado Low. Accumulations don’t look significant at this point, perhaps 3-5mm on the high end, but it does seem like it will be a cool, dreary day with a high of only around 7°C. The showers should taper off by the evening as we drop to the freezing mark yet again, this time under cloudy skies.

Where’s Summer?

Unfortunately, not here. Below-normal temperatures are once again forecast for the 7-14 day outlook, meaning we’ll likely see high temperatures only in the high single digits or low teens for the next week or two.

But it’s gotta warm up eventually, right? Right? Here’s hoping for a big turnaround in May.

Spring is in Sight

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The GFS depicts an upper-level ridge building into our region early next week.
The GFS depicts an upper-level ridge building into our region early next week.

Winter-weary Winnipeggers can take solace in the fact that an end to the never-ending winter is in sight. There is increasing confidence that a large upper-level ridge will build into the Central U.S. and Southern Prairies early next week and finally bring some seasonal to slightly above seasonal temperatures to the region. First, though, we’ll have to make it through the rest of the week.

A Cold End to the Week

Cold temperatures will continue to persist through the remainder of the week with well below seasonal highs and lows expected. These cold temperatures are being caused by a large stationary trough of cold air over Hudson Bay that has locked the eastern Prairies into a northwesterly flow that has allowed cold Arctic air to spill southwards, dashing the warm-weather hopes of battered and beleaguered Manitobans.

Wednesday
-2°C / -17°C
A few clouds.

Thursday
0°C / -10°C
Partly cloudy. Slight chance of flurries.

Friday
5°C / 1°C
Late day cloudiness; warming up.

Tonight will be the coldest night for the remainder of the week in the Red River Valley thanks to another push of cold air on the back side of a low pressure system passing to our south. There will be a strong chance of another swath of record low temperatures broken – similar to Monday night – as overnight lows dip some 15-20°C below normal.

Thursday brings a similar high to today, around -2°C, however temperatures just off the ground will be a little bit cooler. This combination will result in stronger low-level instability and we could potentially see a few light flurries develop through the Red River Vally similar to what was seen on Monday afternoon. Overall the risk is very slight, though. Temperatures will drop to a more mild -10°C Thursday night as warmer air begins pushing eastwards.

Friday will be the warmest day so far this week. Temperatures look to climb above the freezing mark towards +4 or +5°C with only a bit of cloudiness to contend with. Winds will be a little breezy out of the southeast to around 20-30km/h, but overall it will be quite a pleasant day with plenty of sunshine. Some cloud will begin streaming in late in the day ahead of the next system pushing towards the region. The cloudier skies will help keep our overnight low fairly warm, with a chance we won’t even drop below 0°C. We may have to contend with some unpleasant weather through the overnight hours, though…

Big Shift on the Weekend

Precipitation amounts forecast on Friday night by the GDPS.
Precipitation amounts forecast on Friday night by the GDPS.

Models are all hinting towards some precipitation on Friday night into Saturday morning as a low pressure system lifts northeastwards through the Prairies. It’s still far too early to speak towards the system in much detail at all, other than saying the bulk of it looks to happen during the overnight period. Some models, such as the pictured output from the GDPS[1] really wind the system up and produce significant quantities of rain or snow while others lift the system much further north with little precipitation development. We’ll have more details on precipitation type and how much of what to expect later on in the week.

The bigger news is that this system marks a significant pattern shift as the upper level ridge we mentioned at the beginning of the article begins developing and pushing eastwards. As it does so, warmer air looks set to flood the Prairies, quickly launching our temperatures back towards seasonal to above-seasonal. Sunday will have temperatures close to normal[2] and we might see it get as warm as the low-to-mid teens on Monday, if we can manage to work past our snow cover.

Multiple days of near-to-just-above freezing temperatures coupled with the strong April sun should do quick work to melt the remaining snowpack across much of the Red River Valley. Melt will be minimal until the weekend, but even one or two days with temperatures in the 5-10°C range will do quick work with much of the remaining snow. Once we can eliminate the snow pack, extremely abnormal cold will be much harder to come by and it will be much easier to see seasonal temperatures.

  1. Global Deterministic Prediction System – Canada’s long-term forecast model.  ↩
  2. Seasonal temperatures for Winnipeg currently are around 11°C for a daytime high and 0°C for an overnight low.  ↩

Remember Winter?

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Expected precipitation types on Saturday.
Expected precipitation types on Saturday.

Supplications for summer will be silenced as the stage is set for a sloppy spring storm that will supply snow to Southern Manitoba. Two disturbances will impact the region – one this morning and the other tonight through Saturday – and bring decidedly messy spring-time weather to the region followed by a surprisingly cold air mass for mid-April. Get those snow shovels out and read on to find out what to expect in your area.

Disturbance #1

The leading disturbance moving through the province this morning is by far the weaker of the two and will move through quite quickly. Disorganized showers or flurries are possible across the region through the morning hours, then we’ll see the clouds begin to clear out giving some sun for the afternoon. We’ll reach a high of only around +4°C today with light northeasterly winds.

Friday
4°C / -3°C
Cloudy periods. Slight chance of morning flurries or showers.
Saturday
1°C / -8°C
Snow. 5-10cm.
Sunday
-2°C / -14°C
Mainly sunny.

Disturbance #2

Our reprieve from the snow threat will be short-lived, however, as another system pushes into Southern Manitoba tonight. Cloud will stream into the Red River Valley this evening ahead of the main precipitation associated with this low, which will not push into the RRV until the second half of the overnight period. Temperatures will drop to only around -3 or -4°C overnight.

As the precipitation shield undergoes rapid expansion early in the evening, snow, heavy at times, will fall along and south of the Trans-Canada Highway in southwestern Manitoba through a good portion of the night which will result in some of the highest accumulations for this storm. By the time all is said and done, 10-20cm of snow is possible over southwest Manitoba.

Further east in the Red River Valley, snow will push in much later in the overnight period, first spreading into the Morden/Winkler region and then pushing northeastwards. Snow will reach Winnipeg by early Saturday morning. The heaviest snow will fall in the southern portion of the RRV with enhanced amounts possible in the southwest corner near the escarpment where upslope winds will help enhance snowfall.

The main snowfall event for the Red River Valley will occur through the day on Saturday. Weak warm advection aloft will do little to help temperatures at the surface which will be stuck out of the north feeding cooler, dryer air into this system. Coupled with the snow, temperatures through the valley won’t climb much more than a degree or two above zero. It will likely be warm enough at the surface (and aloft) to melt some of the snow that falls. This will reduce snowfall amounts a bit, but given the intensity of the precipitation expected, snow accumulation should overpower the melting factor fairly quickly.

Total snowfall expected Friday night through Saturday. Amounts may be lower depending on how much melts.
Total snowfall expected Friday night through Saturday. Amounts may be lower depending on how much melts.

In general, most areas seem to be set to see around 5-10cm of snow, perhaps a little less if there’s more melting. With temperatures near zero, it will be a somewhat wet, heavy, sloppy snow that will likely make driving very unpleasant and slippery. The snow should taper off on Saturday evening as the system pushes off to the east. Skies will clear in advance of an Arctic ridge pushing into the Prairies and we’ll drop to an overnight low near -8 or -9°C.

Cooler Weather Ahead

Behind this system, very cool arctic air will push into the Prairies. Sunday will be mainly sunny with some afternoon cloud but the temperature will top out more than 10°C below normal at only around -2°C.

The start of next week continues the sunny trend, although Monday will be nearly 20°C below normal with a high of only -8°C. More seasonal air looks to build back in midweek.

Hope on the Horizon

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Bad news first: temperatures will remain below through to the end of the week. Good news: we’re on a gradual warming trend with some signals beginning to show that we may switch into a milder regime next week. Before that, though, we’ll see a slight chance for some flurries and some gradually warming weather.

RDPS output depicting expected precipitation amounts through the day today.
RDPS output depicting expected precipitation amounts through the day today.

Today will bring mainly cloudy skies with a high near -5°C. There will be a very slight chance for some flurry activity, although it will be far more likely closer to the U.S. border. A intensifying low pressure system in South Dakota will generate a band of snow through northern North Dakota running parallel to the border. While a few cm of snow are expected in North Dakota, just 1 or 2cm at most will likely fall on the Manitoba side of the border.

The very slight chance for flurries will continue through the overnight period as the temperature drops to around -15°C with skies clearing later in the night.

Wednesday
-5°C / -15°C
Cloudy. Slight chance of flurries.

Thursday
-8°C / -19°C
Mainly sunny.

Friday
-5°C / -14°C
Sunny.

After that, things look pretty calm as a ridge of high pressure dominates the weather story. Thursday and Friday will both be sunny days with relatively light winds. Temperatures will slowly inch higher, reaching around -8°C tomorrow and back to near -5°C on Friday.

Warmer Weather Next Week?

While it does look like we’ll see normal weather next week, we will likely still remain below normal, which will be around 3-4°C for daytime highs. At this point, it looks like we’ll climb towards 0°C for a high on Sunday, then plunge back into winter for Monday with highs back towards -10°C, then rebound back to nearly 0°C for the remainder of the week. It’s still a long ways out, so things could easily change between now and then, though.

With how things have been this year, I’ll take “below normal” as long as we can get this snow melting.