Tag: Above-Normal Temperatures

Summer Arrives!

Brad Leave a comment

Southern Manitoba is set to bathe in summer-time warmth as temperatures soar well above normal.

A broad upper-level trough developing over the Rocky Mountains will combine with a strengthened sub-tropical ridge over the southeastern United States to produce a southerly flow that will bring substantially warmer air to our region. As well as the warmer temperatures, humidity will become more noticeable heading into the weekend as higher dew point temperatures are advected northwards into the region. With the warmer weather will also come the potential for some shower or thunderstorm activity across much of Southern Manitoba.

Friday
25°C / 16°C
Mainly sunny. A little breezy.

Saturday
30°C / 17°C
Cloudy periods with a slight chance of showers or thundershowers. Windy and warm.

Sunday
24°C / 14°C
Chance of a morning shower or thunderstorm.

Friday

Today will be a very pleasant day. Under a mainly sunny sky, the temperature will climb to near 25°C as a southerly wind at 20-30km/h provides just enough of a breeze to keep things comfortable. The humidity will be more prominent than it’s been so far this year, but it will still be quite comfortable with dew point values climbing to around 15°C.

Heading into the night, temperatures will drop to about 16°C with variable cloudiness through the overnight hours with a slight chance of some shower .

Saturday

Tomorrow will start with a fair amount of mid-level instability riding ahead a warm front pushing eastwards. This will present itself with a slight risk for showers or thunderstorms through the early morning. Afterwards, we’ll see cloudy periods with fairly windy conditions with a southerly wind at around 30-40km/h. Very warm air will work in aloft, driving our daytime high up to 29 or 30°C. In addition to the warmer air, the southerly winds will also advect more humid air northward with the dew point climbing towards 17 or 18°C which will start to make it feel a little sticky outside.

Temperatures of 30°C or greater (dark green) are expected across much of Manitoba on Saturday.
Temperatures of 30°C or greater (dark green) are expected across much of Manitoba on Saturday.

As everything heats up, there will be a potential for thunderstorms, but there will be little in the way of a threat for severe storms. If we quickly look at the ingredients required for thunderstorms:

  • Moisture: Dew points will climb into the mid-to-upper teens, through a suitably deep layer, and be supportive of storm generation. The dew points are on the low side for the atmospheric thermal profile which will result in relatively high-based storms.
  • Instability: Deep instability will be present. Mid-levels are fairly unstable, and low-levels will destabilize fairly dramatically by mid-afternoon thanks to intense surface heating driving temperatures towards 30°C.
  • Shear: This is where things fall apart. While the low-level winds will provide favourable inflow into the storm bases, winds will be very slack through the mid-levels. This will dramatically impact the ability for storms to organize and will limit their potential growth.
  • Trigger: Triggers for storm generation look fairly weak. The synoptic triggers look to remain outside our region; the warm front will be in Central Manitoba, the cold front will be hanging back through Central Saskatchewan and the main warm sector trough also will trail back into southeastern Saskatchewan. The intense surface heating will likely produce many mesoscale triggers, especially along significant terrain such as the western escarpment of the Red River Valley and the Riding Mountains.

As a result, we’ll see the potential through much of Southern Manitoba for thunderstorms, however they’ll likely be short-lived, high based storms whose main threat will be strong winds or large hail.

It’s likely that rain with embedded thunderstorms will develop in North Dakota on Saturday night and lift northeastwards into Southern Manitoba, bringing the risk of rain and thunderstorms to somewhere in Southern Manitoba through the overnight period into Sunday morning. The areas that will see the risk will depend highly on exactly where the precipitation develops in North Dakota.

Temperatures will remain quite mild Saturday night with the overnight low bottoming out at only around 17°C.

Sunday

Sunday will be the most organized day for precipitation of the weekend. The system bringing the warmer air to the province will push off to the East through the day, dragging a cold front across the province. Widespread showers and thundershowers will be associated with the cold front as it pushes eastwards, and as a result showery weather is likely. It’s a little early for too much detail, but it seems like the chance for precipitation will start around mid-to-late morning and taper off by late afternoon.

The temperature will climb to around 23 or 24°C before the cold front swings through. Things will clear up by Sunday evening and we’ll see a beautiful night with a low near 14°C.

UPDATE: An updated look at Sunday’s weather is available in the comments section below.

Next Week

Next week looks to continue the warmth with highs in the mid-20’s, but by mid-week it looks like unsettled weather will return to Southern Manitoba and bring multiple days with chances for showers or thunderstorms. It seems like we’ll lock into seasonal to above seasonal temperatures, so get out and enjoy the summer weather that we’ve all waited so long to see!

Summer Weather on the Way

Brad Leave a comment

After another stretch of below-normal temperatures, some truly summer-like weather is finally on the way.

Winnipeg will be under the influence of a ridge of high pressure that will keep us dry through the remainder of the week. A developing flow from the Gulf of Mexico looks poised to set up Southern Mantioba for a quick shift into summer-like weather for the end of the week.

Wednesday
15°C / 6°C
Mixed skies with a clearing trend.

Thursday
23°C / 12°C
Mainly sunny.

Friday
26°C / 14°C
Mainly sunny.

Today will bring mixed skies to Winnipeg and the Red River Valley as the system cloud associated with the low that moved through on Monday and Tuesday begins exiting the province. Cloud will likely persist through the afternoon as some fair weather cumulus develop as we warm up to our high near 15°C. Skies will clear tonight as the temperature drops. The temperature will drop to around 6°C tonight.

Tomorrow will bring mainly sunny skies, relatively light winds and a high temperature returning to a seasonal to slightly above seasonal 22 or 23°C. Things will be calm and mainly clear Thursday night with temperatures dropping to near 12°C.

Friday will mark the shift towards decidedly more summer-like weather. Under mainly sunny skies, warmer air pushing into the region will push our daytime high towards around 26°C. In addition to the warmer weather, we should also see the first days of the year that could potentially be considered “humid.” For a quick summary of the relationship between dew point and how humid it feels, and why relative humidity is a poor choice, check out the brief primer at the bottom of this post.

There’s uncertainty in exactly how humid it will get here in Southern Manitoba. Some weather models, such as the Canadian GDPS[1] are pushing dew point values as high as 20°C in the Red River Valley, but values that high are likely overdone thanks to the delayed start to the growing season due to the abnormally cold spring. It’s likely we see dew points climb into the mid-teens at least, though, so it’s fairly safe to expect that we’ll be seeing our first real shot of summer heading into the weekend.

Unsettled Weekend

There’s still a lot of uncertainty associated with the large amplitude upper-level pattern that’s expected to develop this weekend, so in general vagueries…

As the NAM shows, a broad flow from the Gulf of Mexico all the way to Southern Manitoba will be established by Saturday morning.
As the NAM shows, a broad flow from the Gulf of Mexico all the way to Southern Manitoba will be established by Saturday morning.

It’s going to be quite warm on Saturday. Daytime highs in the upper 20’s seem quite likely as well as dew points climbing into the mid-to-upper teens, although as mentioned above, there’s some uncertainty to exactly how high the dew points will get. Sunday will also be warm with highs in the mid-20’s.

Thunderstorms, potentially severe, will be possible both days, although exactly when and where is far too uncertain at the moment. It seems entirely possible that the thunderstorm activity will be constrained to the evening/overnight periods when elevated thunderstorms can develop, although late afternoon severe storms cannot be ruled out at this point. For both days the best chance for thunderstorms appears to be over Parkland Manitoba, SW Manitoba and into SE Saskatchewan and Montana/North Dakota. Here in the Red River Valley, nocturnal elevated activity looks like the most plausible scenario.

We’ll be taking a closer look at the thunderstorm and severe weather potential in Friday’s post. Until then, enjoy the imminent summer weather!

A Quick Lesson on Dew Points

Perhaps the most convenient way to quantify how humid it is outside is to look at the dew point temperature. The dew point is the temperature where water evaporates into the air at the same rate that it condenses out of the air; to put that in simpler terms, if the air comes in contact with something cooler than the dew point, water will condense out of it. Think of it as the temperature your cold glass of your favorite hot weather beverage needs to be to “sweat”.

The higher the dew point temperature is, the more water is in the air. This is an important distinction from relative humidity. Air has a quirky trait that allows it to hold more water the warmer it is. This means that air at -5°C cannot hold as much water as air at 25°C. This makes relative humidity ambiguous since it is a measure of how much water is in the air versus how much water the air can hold, or “how full the glass is.”

So a relative humdity of 100% at -5°C has less water in the air than a day where the temperature is 10°C with a relative humidity of 35% because the dew point in the first case is -5°C, while in the second case, despite the relative humidity of only 35%, the dew point is around -4.8°C.

As the dew point climbs, your perception of it being humid increases as well. In general, once the dew point rises to around 15 or 16°C, you’ll begin to notice that it feels humid. By 18 or 19°C it can begin to be uncomfortable. By the time the dew point climbs into the low-to-mid 20’s, as long as there’s sunshine, it can be extremely sticky feeling outside. Dew points in excess of 25°C are dangerous and can pose extreme health risks.

  1. Global Deterministic Prediction System  ↩

Incoming Mild Air Brings Unsettled Weather

Brad Leave a comment

A textbook frontal passage is in store for the Red River Valley over the next few days as an incoming warm front brings a chance of flurries and another mild day before the cold front slumps through the region at week’s end, bringing another windy chance for snow.

Wednesday
-10°C / ⇑ -3°C
Cloudy, light flurries starting midday.

Thursday
+4°C / -7°C
Warm with mixed skies. Windy with flurries overnight.

Friday
-6°C / -20°C
Chance of early morning flurries, otherwise mainly sunny.

We’re off to a cold start this morning, but temperatures will soar today as a strong warm front pushes across the Red River Valley. Southerly winds will pick up through the day to around 30-40km/h by mid-afternoon. There will be a chance of flurries beginning midday and lasting through the early evening. No significant accumulations are expected and thanks the warming temperatures and recent melting, blowing snow should be minimal. Temperatures will climb to around -10°C by evening but continue rising through the overnight period to nearly -2°C by Thursday morning.

Mild air is set to push into Southern Manitoba again on Thursday.
Mild air is set to push into Southern Manitoba again on Thursday.

Thursday will be another beautiful day very reminiscent of Monday this week. Winnipeg will see relatively light winds and mixed skies as the temperature climbs all the way to 4°C. Similar to Monday, there will probably be significant variation across the city with some places climbing several degrees higher to 7-8°C.

Things will take a less pleasant turn on Thursday night when a cold front slices through Southern Manitoba. Gusty winds out of the northwest to 40km/h will accompany some flurry activity that will spread into the Red River Valley from north to south through the mid-to-late evening hours. The wind and any straggling flurries should taper off early Friday morning.

Friday sees an Arctic ridge of high pressure building into Manitoba bringing cooler temperatures with it. In Winnipeg, temperatures will be some 10°C cooler than Thursday with a daytime high only near -7 or -6°C under mainly sunny skies.. Winds will remain light and the temperature will drop close to -20°C on Friday night.

Cool Weekend Ahead

Temperatures will remain well below normal through the weekend in the Red River Valley. Saturday’s high looks to be near -15°C under mainly sunny skies while Sunday sees the coldest axis of air shifting off to the east, allowing temperatures to climb to the low minus single digits with a few cloudy periods.

In the southwest corner of the province, flurries will be possible numerous times over the next 5 days as the main frontal zone sets up across the region and weak disturbances ripple along it.

Unsettled Pattern Continues

Brad Leave a comment

Residents in the Red River Valley have barely had time to get the shovels out after Wednesday’s snowfall and Thursday’s blowing snow/blizzard, but more snow and wind is on the way as another system tracks through today. The unsettled weather will continue through the weekend with a brief improvement on Saturday followed by more unsettled weather on Sunday.

Friday
-8°C / -10°C
Increasing cloud in the afternoon then snow. 4-8cm accumulation.

Saturday
-7°C / -9°C
A mix of sun and cloud. Blowing snow in the morning. Chance of flurries.

Sunday
-5°C / -20°C
Light snow developing through the day.

Another Shot of Snow Tonight

More snow is on the way later today through tonight as another low pressure system dives southeastwards through the province. Before that, though, we’ll see mainly sunny skies with relatively light winds out of the south at only around 20-30km/h by the afternoon. The temperature should climb up to around -8°C in Winnipeg while areas closer to the U.S. border may see the temperature get as high as -5°C or so.

Expected storm-total snowfall amounts by Saturday morning.
Expected storm-total snowfall amounts by Saturday morning.

Cloud and snow will stream in fairly quickly from the northwest later this afternoon as the low pressure system begins slumping southwards through the Interlake. The heaviest snowfall will fall before midnight with lighter flurries persisting thereafter into the early morning. The snow will taper off by tomorrow morning with totals generally between 4-8cm through Winnipeg & most of the Red River Valley.

Blizzard conditions may develop in the southwestern Red River Valley thanks to the funnelling effect of the western escarpment.

Winds won’t be as strong as Wednesday through the snowfall event – around 30km/h gusting to 50 or so in Winnipeg and the eastern Red River Valley and a little bit stronger in the western Red River Valley at around 40 gusting 60km/h. There will be some blowing snow through the overnight period, but I don’t think we’ll see anything as extensive as on Wednesday night into Thursday. The one caveat may be the southwestern Red River Valley[1] where blizzard conditions may develop thanks to a funnelling effect of the western escarpment. Winds may climb up to 50 gusting 70km/h which should be enough to produce a widespread white-out. The strong winds will move in overnight and taper off midday tomorrow.

Nice Start to Weekend, Snowy End

Skies will clear out early Saturday morning with any blowing snow hanging on a little longer until the winds die down. Otherwise we’ll see mixed skies with a high near -7°C with fairly light winds. There will be a slight chance of a flurry or two, but no accumulations are expected.

We’ll drop to an overnight low of just -9°C[2] as more cloud cover begins working it’s way in ahead of another disturbance on it’s way. There will be a continued chance for some isolated flurries overnight.

Sunday will be a mainly cloudy day with snow developing through the afternoon. We’ll climb up to a high of around -5°C. The snow will taper off through the evening on Sunday with some breezy northerly winds producing some blowing snow through the Red River Valley. At this point it doesn’t look too bad, fortunately. Skies will clear Sunday night and we’ll drop to an overnight low of around -20°C.

We’ll continue on an unsettled track through next week as very cold Arctic air begins pushing it’s way back into the region. It seems like we’ll be seeing overnight lows near -30 to -35°C in the latter half of the week, so enjoy the upcoming mild weather!

  1. Areas near Carman, Altona, Winkler, Morden, and Emerson are most likely.  ↩
  2. An overnight low that’s warmer than our normal daytime high for January 17th!  ↩