A Smoky Transition Back to Summer Heat

Brad Leave a comment

Today will be a bit of a mixed bag here in Winnipeg as a dying cold front completes its slump into Southern Manitoba bringing a chance of showers alongside another batch of forest fire smoke gradually working into the Red River Valley. Fortunately, winds will become more southwesterly as the week progresses, pushing the smoke to our north and bringing back hot summer weather to the area.

Today will start off with a slight chance of showers or thunderstorms until around midday after which the clouds will start pushing off to our southeast and see increasingly smoky skies build in. Temperatures will only climb to around 21°C today and then dip down to the low teens tonight.

NOAA 1hr. Vertical Smoke Forecast valid July 08, 2015 7PM EDT
The “total smoke” product from NOAA is forecasting a thick layer of smoke across Southern Manitoba by this evening.

Thursday and Friday will herald the return of summer. Winds will shift more westerly to southerly and begin tapping into warmer air to our south. There should be a deep enough layer of southerly winds to push the smoke north of Winnipeg through the day. Temperatures will be soaring into the upper 20’s on both days under mainly sunny skies.

The biggest difference between Thursday and Friday will be the humidity; while dew points in the mid-teens on Thursday will make it feel slightly humid, it’s expected that dew points will climb up to the 20°C – or even a bit higher – for Friday, making it feel downright tropical out there.

Overnight lows on Thursday & Friday will be in the upper teens.

Unsettled Weekend?

Weather models are pointing towards a potentially unsettled weekend as a large upper-level low lifts northwards into Alberta with a deep trough extending southeastwards across the Prairies.

GDPS 24hr. QPF valid 00Z July 13, 2015
Total precipitation forecast from Saturday evening to Sunday evening from the GPDS.

It’s not worth getting caught up in details at this point when dealing with a large, highly convective system such as this. The main thing to take away is that with a large low lifting into Alberta, it’s likely our weekend will continue humid, warm and potentially bring some wet weather.

Mainly Sunny with a Good Chance of Smoke

Scott Leave a comment
Several forest fires have produced widespread smoke over Southern Saskatchewan & Manitoba .
Several forest fires (circled in red) have contributed to the widespread smoke over our region the past week.

This week will see relatively benign weather, but unfortunately also the continuation of forest fire smoke over southern Manitoba. A persistent west to north-west flow aloft will continue to transport smoke from northern Saskatchewan into southern Manitoba.

Monday

Today will see cool conditions in southern Manitoba as a chilly air mass surges down from the arctic. High temperatures are only expected to be in the mid teens, but skies will be mainly sunny. Surface winds will be breezy from the north.

Tuesday

Tuesday will see somewhat warmer conditions from Monday as some warmer air begins to return from the south-west. High temperatures should reach the low to mid twenties under mainly sunny skies. The only unknown in Tuesday’s forecast is how extensive forest fire smoke will be over the region. Should smoke be quite extensive, temperatures will likely stay closer to 20C, whereas less smoky skies will promote temperatures in the mid twenties. Our forecast is a compromise position between these two possibilities.

Wednesday

Temperatures are expected to remain near to slightly below seasonal for Wednesday, with highs in the low to mid twenties. There is a decent chance of showers or thunderstorms during the day as some mid-level instability develops in the atmosphere. Severe storms are not expected, but do not be surprised to hear some thunder!

North Dakota Sees First Significant Tornado Day this Year

Matthieu Leave a comment

Last Saturday, on June 27th, North Dakota saw its first tornado outbreak of the year where 19 twisters touched down across the state.

[map autofit=”1″ disable_scrollwheel=”1″] [pin tooltip=”Roseisle”]Roseisle, Manitoba[/pin] [pin tooltip=”Pisek”]Pisek, North Dakota[/pin] [pin tooltip=”EF-2 occurred just west of here”]Holmes, North Dakota[/pin] [/map]

A surface trough moving across the region associated with an upper level wave was the focus for severe weather across the region last Saturday. Plenty of instability was in place – MLCAPEs in the order of over 2000J/kg and sufficient shear (around 40 knots) was enough to support supercells in the region under the northwest flow. The first supercell in the region fired on the Manitoba side of the border and brought very large hail the size of tennis balls and strong winds to Roseisle and surrounding communities, such as Miami, MB. As the supercell drifted towards the south southeast it crossed the border into North Dakota near Walhalla, and held together quite well. A damage survey conducted by NWS Grand Forks it was found that several weak tornadoes were spawned out this supercell before it encountered a cluster of thunderstorms and weakened. Later on in the day several other tornadic supercells fired along the surface trough to the south of the initial supercell that was in northern North Dakota and produced more tornadoes.

After conducting a damage survey of the area, NWS Grand Forks concluded that 19 tornadoes touched down on June 27th, 2015. (Source: NWS Grand Forks)
After conducting a damage survey of the area, NWS Grand Forks concluded that 19 tornadoes touched down on June 27th, 2015. (Source: NWS Grand Forks)

After it was all said and done, it was concluded that the strongest tornado of all, a cone tornado, was one that touched down near Grand Forks and was of EF-2 strength (winds between 177km/h and 217km/h). The other tornadoes reported were mostly of rope type and weaker; of EF-0 to EF-1 strength. Thankfully the NWS Grand Forks was quick on the warnings and did a good job alerting the public of a nearby tornado – no injuries or deaths were reported with any of the 19 tornadoes.

One of the rope tornadoes in ND observed near Pisek. (Source: Matt D)
One of the rope tornadoes in ND observed near Pisek. (Source: Matt D)

In other weather news this week, the west Pacific has been quite active typhoon-wise as three tropical storms are currently active, and of those one is expected to strengthen significantly by the beginning of next week, possibly to super typhoon status.

Summer Warmth and Smoke Lead into an Unsettled End to the Weekend

Brad 1 Comment

Widespread smoke will remain in place today as a northwesterly flow gradually lightens and leaves the smoke to languish across Southern Manitoba. A low pressure system tracking into the northern Prairies tonight will bring a southerly flow at all levels to Southern Manitoba which will help clear skies out as well as lead towards an unsettled end to the weekend.

Today will bring partly cloudy skies which will seem a whole lot cloudier thanks to the widespread smoke that remains entrenched over Southern Manitoba today. That smoke will keep our temperatures slightly cooler than they would be under clear skies, leaving us with a high temperature later today of 26°C. Winds will remain fairly light through the day. The humidity will be more comfortable than yesterday’s dew points of 20°C; dew point values are expected to sit in the low- to mid-teens this afternoon.

Winds will begin picking up out of the south overnight which should help begin clearing the smoke out of our area. Our temperature will dip down to around 17°C.

Saturday will bring the humidity back to Southern Manitoba alongside gusty southerly winds to 30–40km/h. It will be quite a warm day with temperatures soaring into the upper–20’s or even hitting the 30°C mark while dew point values climb back towards the 20°C mark as the southerlies bring in more humid air from the Northern Plains.

GDPS 12hr. QPF valid Sunday morning.
The GDPS continues to forecast a swath of nocturnal convection occurring on Saturday night.

Saturday night will see thunderstorms initiate over Western Manitoba then slowly push southeastwards. There will likely be a chance for some severe thunderstorm activity over Parkland Manitoba; we’ll take a closer look and issue a convective outlook if warranted tomorrow. These showers and thunderstorms will slowly stall out towards the Red River Valley near morning and then sit over the region for much of Sunday. Temperatures will climb to a very humid 23°C or so on Sunday before the cold front finishes pushing through.

Behind the cold front, cooler and less humid air will begin working back into Manitoba. Sunday night will see the coolest overnight low in a while as it dips towards the low teens. With that cooler, drier air will come a northwesterly flow which will likely mean a return to smokier conditions.