A Danish Astronaut Captures Rare Blue Flashes ↦

Eric Berger, writing for Ars Technica:

Scientists don’t know much about the mysterious, powerful electric discharges that sometimes occur in the upper levels of the atmosphere in conjunction with thunderstorms. The first photograph of the phenomenon—which can occur as high as about 90km above the surface of the Earth and are known variously as sprites, pixies, elves, or jets—was only taken from Earth in 1989.

Fortunately for scientists interested in these storms, the International Space Station offers an excellent vantage point at an altitude of about 400km. So Danish researchers devised a “Thor experiment”—named after the hammer-wielding Norse god—to study the phenomenon. As part of the experiment, an astronaut on board the station would image thunderstorms under certain conditions, and these observations would be correlated with data collected by satellites and ground-based radar and lightning detection systems.

It has been interesting seeing more and more proper research going into these upward-directed electric discharges from thunderstorms. I recall just in the early 2000’s stories about pilots who had seen these phenomenon but didn’t share their experiences because they felt people may not believe them.

Now we know not only that these blue flashes exist, among other upper-atmosphere related phenomenon, but also that thunderstorms may have a role in troposphere-stratosphere gas exchange.

Interesting stuff. Follow through the link for more photos; the published paper with findings is available here.1

  1. Chanrion, O., T. Neubert, A. Mogensen, Y. Yair, M. Stendel, R. Singh, and D. Siingh (2017), Profuse activity of blue electrical discharges at the tops of thunderstorms, Geophys. Res. Lett., 44, 496–503, doi:10.1002/2016GL071311. 

Seasonably Cool & Unsettled

Temperatures will be seasonably cool in the Red River Valley through the remainder of the week with the chance of showers returning to the region.

Today will be fairly pleasant, all things considered, with a fair amount of sunshine until cloud cover moves in through the mid- to late afternoon ahead of a low pressure system lifting northeastwards out of the Northern Plains. Temperatures will climb to around 20°C this afternoon.

Tonight will bring showers and/or thunderstorms to Southern Manitoba, however the exact distribution of the precipitation remains a little uncertain. Two features will support rainfall: the main upper low which will track through WestMan & the Interlake and a secondary shortwave that will lift through North Dakota. What begins as a large line of rain will likely focus towards these two features overnight. This means that here in the Red River Valley, amounts will likely be less, or even non-existent, compared to areas to the west/north or south/east. The primary chance for rain will occur between around 9PM to 4AM. In heavier showers, 15-25mm of rain could be seen, while many places will likely see 5-10mm. Again, here in the Valley, we may escape with little precipitation, depending on how things develop. Expect a low near 12°C.

A complex low pressure system will bring precipitation to much of Southern Manitoba on Thursday night.
A complex low pressure system will bring precipitation to much of Southern Manitoba on Thursday night.

Thursday will bring mixed skies with a high once again near 20°C. The day will be otherwise fairly unremarkable. Expect more cloud and a low near 11°C. All in all a pleasant first day of school!

Friday will see another disturbance move across Southern Manitoba, bringing another chance for some scattered showers under mainly cloudy skies. Sunshine should start poking out through the afternoon as skies become more mixed behind the disturbance. Expect a high near 18°C. Skies will clear overnight as temperatures dip to around 9°C. Some lake-effect showers are possible overnight in the lee of both Lake Manitoba and Lake Winnipeg as cool northwest winds roll over the warm lake surface.

Long Range

The weekend is looking fairly dry with variable cloudiness and daytime highs in the upper teens or low twenties. Sunday will likely be windy out of the south. Overnight lows will continue near 10°C.

Winnipeg’s seasonal daytime high is currently 20°C while the seasonal overnight low is 8°C.

Weather Turns Unsettled For Labour Day Weekend

After a warm but windy day in Winnipeg & the Red River Valley today, the weather will turn unsettled for the weekend as multiple low pressure systems move through the province.

Today will be a warm and windy day over the Red River Valley. Temperatures will climb to a high near 27 or 28°C while strong southerly winds develop over the region ahead of a strengthening low pressure system in Saskatchewan. Winds near 30 km/h this morning will strengthen to 40 gusting 60 km/h by midday. That should be as strong as they get, however there is a slight chance that winds may reach as strong as 50 gusting 70 km/h.1 We should see plenty of sunshine, although by the second half of the afternoon some cloud cover will begin working into the region.

Tonight will be mild with plenty of cloud cover and windy conditions continuing. Winnipeg will see a chance of showers or thunderstorms overnight as the first weak impulse of many moves through. Expect a low near 18°C.

A cold front will push eastwards across the Red River Valley on Saturday.
A cold front will push eastwards across the Red River Valley on Saturday.

Saturday will bring fairly cloudy skies, albeit with a few sunny breaks likely in the morning, and a chance of showers or thunderstorms as a cold front pushes into the Red River Valley, slowing down and stalling out through the day. Winds will start out around 30 gusting 50 km/h and then taper off as the front moves into the valley. Temperatures will reach a high near 26 or 27°C.

Any shower or thunderstorm activity will slowly move towards the southeast through the evening, however may only barely make it east of the Red River Valley by morning.

Sunday brings with it some uncertainty, but will likely be a wet day. For the first time in quite a while, we’ll be dealing with a Colorado Low moving through North Dakota and into northwestern Ontario. This system will push the front that passes through on Saturday back to the northwest, developing an area of rain that stretches from South Dakota all the way through Manitoba. How far west the rain will push remains an uncertainty; many models suggest the rain pushing northwest of Winnipeg with anywhere from 20-40 mm likely2 while others keep the entire area of rainfall just to the southeast of Winnipeg.

The GDPS, one of many solutions for Sunday, paints over 50mm of rain through the Red River Valley between Sunday morning and Monday morning.
The GDPS, one of many solutions for Sunday, paints over 50mm of rain through the Red River Valley between Sunday morning and Monday morning.

In either of those outcomes, it’s still quite likely that areas to the south of Winnipeg, particularly in the southern Red River Valley3 will see accumulating rain along with breezy winds out of the northeast.

Temperatures will be cooler on Sunday with a high near 22°C. The rain should taper off by Monday morning with temperatures dipping to a low near 12°C.

Extended Forecast: Labour Day Monday

Monday will be a fairly cloudy day with cool conditions left in the wake of the Colorado Low. Winds will be breezy out of the north as temperatures climb to a high near 19°C. There will likely be a continued chance of showers, but nothing to the extent of what will be seen in places on Sunday. Monday night looks to bring another chance for showers or thunderstorms ahead of yet another disturbance moving into the region.

Winnipeg’s seasonal daytime high is currently 21°C while the seasonal overnight low is 9°C.

  1. Yesterday, numerous places in western North Dakota as well as Estevan, SK saw winds as high as 50G70 km/h. 
  2. Although higher amounts may be seen on a more localized basis. 
  3. Sorry, Letellier. 

Mixed Bag Ahead For The Weekend

Seasonal to slightly above-seasonal temperatures are on the way to Winnipeg this weekend alongside a couple chances for rain as a couple low pressure systems move through the province.

Today will be a relatively pleasant day in Winnipeg as sunny skies give way to some afternoon cloudiness as temperatures climb to around 25°C. Winds will be out of there south at 15-20 km/h. Expect a low near 13°C tonight with increasing cloudiness near morning.

A low pressure system will move but on Saturday, bringing fairly cloudy conditions and a chance of showers. Temperatures will reach a high near 23°C with winds out of the south at 20 km/h. Depending on the strength of this system, a few thundershowers may be possible, but no severe weather is expected at this time.

A low pressure system will bring warmer weather to Winnipeg on Sunday
A low pressure system will bring warmer weather to Winnipeg on Sunday

Sunday will be a much warmer day as a low pressure system tracking across the central Prairies draws air up from the south. Daytime highs will reach around 28°C work winds continuing out of the south at around 20-30 km/h. Skies will be partly cloudy, but the cloud cover will thicken up heading into the evening hours as a trough extending southwards from the low pressure system approaches. This feature will bring a chance for showers or thunderstorms Sunday evening into the overnight. Temperatures will remain miles on Sunday night with the temperature hovering near 20°C until late overnight when a cold front moves through and stops the temperature towards the mid-teens.

Update: Severe Thunderstorms Possible on Sunday

The threat for severe thunderstorms will return to Winnipeg, the Red River Valley, the Interlake and points eastwards as a warm and relatively humid air mass building in over the region clashes with a cold front pushing eastwards across the province later today.

AWM Day 1 Convective Outlook – August 28, 2016
AWM Day 1 Convective Outlook – August 28, 2016

Today’s thunderstorms are expected to develop along a cold front pushing into the Interlake & Red River Valley late this afternoon, likely around 6-7 PM. These thunderstorms will likely grow fairly quickly a complex of severe thunderstorms that will move east-southeastwards with new storms developing as they build southwards down the cold front. These thunderstorms will be capable of all modes of severe weather: torrential downpours causing flash flooding, large & damaging hail, wind gusts exceeding 100 km/h, and tornadoes. It will be prudent to monitor Environment Canada for any watches or warnings that may be issued later today.

MoistureInstability: Ample instability is expected to develop ahead of the cold front with MLCAPE values approaching 4000 J/kg. This will be capped by roughly 30-50J, but is expected to erode through the mid-to-late afternoon. The cap brings the only uncertainty to today: will it break and produce surface based thunderstorms with a tornado threat, or will it prevail and shift the convection to an elevated mode that will favour large hail and strong winds?

Shear: With a potent upper low entering northern Manitoba and dynamic cold front moving through the region, 40-55 *kt* of bulk shear produced with looping hodographs.

Trigger: The cold front combined with forcing from the escarpment should be enough to initiate convection today.

The thunderstorms will progress across the region through the overnight hours.

Winnipeg’s seasonal daytime high is currently 23°C while the seasonal overnight low is 10°C.