Unsettled & Cooler…Again

Another disturbance tracking across the Prairies will bring more wet weather to Winnipeg and keep temperatures cooler than seasonal for late June.

Today will start off with a line of showers and/or thunderstorms moving eastwards through the Red River Valley as a cold front pushes eastwards across the region. General rainfall amounts within the Red River Valley from this system will be around the 5-10 mm mark, although locally higher amounts are possible in thunderstorms. That said, it’s likely that the eastern Red River Valley sees higher amounts while the western Red River Valley trends towards lower amounts. Depending on exactly how things have evolved overnight, though, there may be sizeable gaps in the line of precipitation resulting in some areas seeing no rain at all.

The wet and stormy weather will clear out of the valley midday, and Winnipeg will be left with gradually clearing skies into the evening. Temperatures will climb to high near 22°C this afternoon with winds picking up out of the northwest to 20-30 km/h behind the cold frontal passage.

Winnipeg will be on the western edge of tomorrow’s rain, with much of it falling to the east and north of the Red River Valley.

Winnipeg should see fairly clear skies tonight with light winds as temperatures dip to a low near 13°C.

Thursday will likely begin with some sunshine, but quickly cloud up in the morning as another low pressure system begins moving into the area. Any wet weather should hold off until mid-to-late afternoon; heading towards evening it looks likely that another batch of scattered showers or thunderstorms will develop. With the wet weather holding off until later in the day, it will actually be relatively pleasant despite the cloudy skies with temperatures climbing to a high near 22°C and light winds.

Scattered showers will likely continue across the Red River Valley on Thursday night, supported by a cold low stalled over the region. Temperatures will head to a low near 14°C.

A deep upper trough with cold low embedded will be in place over Manitoba on Friday.

Friday will bring mainly cloudy skies and scattered showers or thundershowers to Winnipeg and the Red River Valley. Temperatures will be cooler as a cold low stalls over the region; daytime highs throughout the Red River Valley will be just 19-20°C. Winds will be light out of the north at 10-20 km/h.

Long Range

Canada’s 150th anniversary celebrations are looking okay at this point; cloudy skies in the morning should gradually clear through the day, although we may see a few light showers through the first half of the day. Temperatures will climb to a high near 21-22°C with winds out of the north at 10-20 km/h. For the evening celebrations, skies should be mixed or partly cloudy with temperatures somewhere in the 15-20°C range.

Sunday will be a pleasant day with partly cloudy skies and a high near 23°C. Heading into next week it looks like we’ll finally snap out of this cool spell and see some seasonal to above-seasonal temperatures build in for the week!

Winnipeg’s seasonal daytime high is currently 25°C while the seasonal overnight low is 12°C.

Seasonal Temperatures Build Back, But Quick Return to Unsettled Conditions

In what is quickly becoming the summer that just can’t quite get going, seasonal warmth will be ushered out of the region by unsettled conditions nearly as quickly as it arrives as another large low pressure system moves into the Prairies.

Winnipeg will see a return to more seasonal temperatures today as the weather system that had brought the cooler temperatures moves off to the east. Today will be perhaps the most pleasant of the next few as sunny skies will combine with light winds and a high near 22°C. Expect temperatures to dip down to around 10°C tonight with some cloud cover moving into the region near morning.

Tomorrow will bring slightly warmer temperatures alongside breezy southeasterly winds that pick up to around 30 gusting 50 km/h. The increasing warmth and wind is thanks to a trough of low pressure pushing eastwards across the Prairies associated with an upper low moving out of Alberta. Winnipeg will see a daytime high climb towards 24°C with mixed to cloudy skies for much of the day, although it’s likely that we’ll see a few sunny breaks in the afternoon. Temperatures will dip to a low near 15°C on Tuesday night under cloudy skies with an increasing chance of rain towards morning.

A band of showers and thunderstorms will push across southwestern Manitoba towards the Red River Valley early Wednesady morning
A band of showers and thunderstorms will push across southwestern Manitoba towards the Red River Valley early Wednesady morning

Wednesday will bring the low pressure system through Manitoba, spreading showers and/or thunderstorms throughout the region, primarily through the morning hours. After that Winnipeg will be left with cloudy skies and a slight chance of showers. Temperatures will reach a high near 19°C with cloudy skies continuing on Wednesday night as the low drops to around 14°C.

Long Range

The unsettled weather continues for the second half of the work week. Slightly cooler-than-seasonal temperatures will beg in place right through the weekend with highs generally in the low 20’s and overnight lows near 10-12°C.

It won’t be soaking wet, but Winnipeg will see a chance of showers late Thursday, much of Friday, and on Canada Day Saturday as well. None of these days look like particularly large soakings or anything of that sort, just generally unsettled conditions.

Winnipeg’s seasonal daytime high is currently 25°C while the seasonal overnight low is 12°C.

Environment Canada To Close Kelowna Upper Air Station ↦

CBC reports on ECCC’s upcoming closure of the Kelowna upper-air station:

ECCC is shutting down the Upper Air station at the end of June because, with the parking lot expansion, it will no longer be safe for technicians to launch weather balloons from outside the station.

A spokesperson says the agency knew in October 2015 that UBC Okanagan was planning to expand its parking lot but it only found out a week ago the project was going ahead.

Upper-air stations, of which there are 31 across Canada, are locations where a compact set of instrumentation is attached to a large balloon and launched into the atmosphere. The instrumentation measures temperature, dew point1, wind direction and speed, and pressure. These measurements are combined to create a graph called a sounding and gives weather forecasters an understanding of how the atmosphere changes in the vertical.

These measurements are also crucial in supplying accurate data for weather models to ingest and use for their forecast production.

An example of a sounding graph created from data obtained by a morning launch from the upper air site in Stony Plain, AB.

The loss of the Kelowna sounding site will have a direct impact on the ability to forecast weather in the region, as well as likely contributing to a small degradation in the quality of weather models.

There is a quote in the CBC article that should be pointed out as wrong:

The data collected at the Kelowna Upper Air Station is not essential for local weather forecasting, according to ECCC, but the station is an important source of information for weather models.

In the world of weather forecasting, real data is the single most valuable resource. Forecasters have more weather models spitting out forecasts than they can reasonably assess2 but models can only be so accurate. Real data, while significantly less in quantity, is the real deal and crucial for many forms of weather forecasting. The soundings generated from these upper air sites are actively used by meteorologists to help them forecast weather such as: thunderstorms and thunderstorm severity, freezing rain, snowfall intensity, blizzards3, and drizzle/freezing drizzle.

The measurements taken by upper air stations provide crucial information used meteorologists for improving the accuracy of severe summer weather forecasting.

Here at A Weather Moment, we’ll use whatever real soundings we determine could be representative of what the weather here will be like4 before resorting to using model-generated soundings. They are a very important piece in the puzzle of weather forecasting.

Lastly, I think one of the questions that needs to be raised is what value ECCC assigns to upper air data. The CBC article states that they’ve known of the plans for 2 years already, but in the meantime have developed no plan for what to do about it. It seems like that would be ample time to create a plan for relocation in case it was needed, but the article paints a picture that shows an unprepared organization that has to close the site while they figure out what to do. The situation as presented seems to suggest that ECCC has devalued upper air data, which would be of deep concern to me.

Over the past winter, I decided to keep an eye on how well the models handled the forecast of major storm systems at two points:

  1. Before they make landfall and are contained entirely in the Pacific with no upper-air stations able to launch balloons to sample them.
  2. Once they make landfall and are sampled by upper air sites.

I was interested in the results as the general trend in the modelling community has been to rely more and more on remote sensing; data that is generated not by being directly measured, but derived by running direct measurements through mathematical equations to calculate them. This is used often with satellite data. The idea is attractive: we have satellites that are looking at everywhere, so we could get these values everywhere instead of just where we have upper air stations. It seems perfect.

Unfortunately, the reality is that for many of the elements important for weather forecasting, the accuracy of remote sensing is simply not good enough yet. In The academic community, there has been a search for a replacement for sending up balloons for several years now that has led them through technologies such as LIDARS and WV-DIAL, but the accuracy has yet to reach a point where they can be relied on as replacements.

Technician Afeworki Mekonnen about to launch a weather balloon from the Upper Air weather station in Kelowna, B.C. Credit: CBC News/Afeworki Mekonnen

In my qualitative assessment of model performance over the winter, I found that before these storm systems reached land, model forecasts were highly variable and there tended to be little agreement between different models. Once they reached the west coast, however, and began being sampled by actual upper air stations, the models quickly trended towards similar solutions, with greater consistency in the forecast from run to run. Given the wide variety of storms that I kept track of through the winter that spanned a wide range of intensities and speeds, I don’t think that the improvement in forecast skill is simply a correlation. I’m willing to say that upper air stations make forecasts better, both those generated by weather models and those improved on by meteorologists.

But it doesn’t end there. Also mentioned on Saturday via Twitter:

I can only hope that the short-term closure at Iqaluit is not a further indication on a devaluation of upper air data. The quality of remotely-sensed data will continue to gradually improve, but it still can’t match the quality provided by balloon launches at upper air stations. If Canada is serious about improving the quality of the weather forecasts it offers Canadians, it needs to be serious about improving the density of its upper air stations across the country.

  1. The dew point is a measure of how much water the air contains. 
  2. Off the top of my head: RDPS, GDPS, REPS, GEPS, NAM, 3km NAM, RAP, HRRR, HRRRX, GFS, ECMWF, CFS, ECMWF… 
  3. Both of the heavy snow and wind variety as well as the more common “clear sky” blizzards produced by strong winds in much of the eastern Arctic and portions of the eastern Prairies. Clear sky blizzards are fairly common in the Red River Valley. 
  4. The closest upper air stations to Winnipeg are in International Falls (MN), Bismarck (ND), and The Pas (MB). 

Missing: Summer

Decidedly un-summer-like weather lies ahead for Winnipeg as an outbreak of cooler air from the north entrenches the Red River Valley in below-seasonal temperatures under cloudy skies.

Daytime highs will be nearly 10°C below seasonal for late June today and tomorrow as Winnipeg sits under the influence of a large cold trough slowly rotating across Manitoba.

Today, Winnipeg will see highs struggle to reach just 14°C with breezy northwesterly winds at 30 gusting 50 km/h. The cool and windy weather will be accompanied by cloudy skies, making for a bit of a lousy end to the work week. While no significant rain is expected, there’s a small chance of some scattered light showers through the day.

Temperatures will dip down to a low near 9°C tonight with winds continuing at 20-30 km/h. A more organized band of showers will slump southwards into the Red River Valley early- to mid-evening and then persist for much of the night. Amounts will be relatively light, however, with just 2-5mm expected in the valley.1

2-5mm of rain is expected in the Red River Valley on Friday night into Saturday morning.
Saturday will bring more cloudy skies as the showers taper off in the morning. There may be another light sprinkle or two through the day afterwards, but it should remain fairly dry. Temperatures won’t improve much compared to Friday; highs are only expected to reach around 16°C with winds strengthening back to 30 gusting 50 km/h. Skies will being to clear late Saturday into Saturday night as temperatures head to a low near 8°C.

Sunday will bring some sunshine back to Winnipeg, particularly in the morning. For the afternoon, we expect more cloud to build back into the region with a chance of some afternoon/early evening showers. Temperatures will be warmer with highs reaching about 20°C and the winds will be lighter, at around 20 km/h. Expect clear skies on Sunday night with a low near 10°C.

Long Range

More seasonal warmth returns for Monday & Tuesday, but then it appears things turn unsettled again mid-week and then below-normal temperatures spread southwards again for the end of the week.

Winnipeg’s seasonal daytime high is currently 24°C while the seasonal overnight low is 12°C.

  1. Higher amounts closer to 10mm will be possible if any locally heavier showers develop.