Weekend to Bring A Break From The Heat

Slightly cooler weather will move in this weekend behind a low pressure system forecast to move through tonight and tomorrow. In addition to the cooler temperatures, this system will bring a chance of rain and thunderstorms to the Red River Valley.

Tonight & Tomorrow

Friday

27°C / 18°C
Increasingly cloudy; risk of a thunderstorm late in the afternoon into the evening. Humid.

We’ll see gradually increasing cloud today as the surface trough associated with a low pressure system pushing into the northern Interlake approaches. There may be some ongoing thunderstorm activity along the trough this morning as it pushes through SW Manitoba and that threat will move eastwards into the Red River Valley by the late afternoon or early evening. A southerly wind ahead of the trough coupled with a capping inversion will draw moisture northwards once again and trap it near the surface, making for another hot, sticky day here in Winnipeg. Our high temperature will only climb to around 27 or 28°C, though, thanks to the increasing cloudiness through the day. That hot, humid weather will bring the threat for thunderstorms – potentially severe – late in the afternoon into the evening hours. At this point, it seems like somewhere between 8PM and 11PM seems like the most likely time for seeing any potential storm activity. After that we’ll see our temperature drop to around 18°C under a partly cloudy sky.

Saturday

25°C / 12°C
Becoming cloudy, good chance of showers or thundershowers. Humid again.

Saturday will be another humid day as we remain in the moist air mass ahead of the cold front. We’ll see a fairly good chance of showers or thundershowers beginning later in the morning and through the afternoon. Skies will start off as a mix of sun and cloud but should become fairly cloudy in the afternoon as things become more unstable with the approaching cold front. We’ll see a high of around 25°C which will mark the last day in our hot, muggy air mass. The threat for showers or thunderstorms will persist until the cold front passes.

500mb Winds for Saturday Afternoon

500mb winds forecast by the NAM show an intense upper-level low pushing into Southern Manitoba which may be the catalyst for showers and thunderstorms on Saturday afternoon and evening.

The cold front will push through overnight, bringing northwesterly winds that will clear out much of the moisture and drop us to a comparatively cool 12°C for an overnight low with clearing skies.

Sunday & Holiday Monday

Sunday

23°C / 8°C
Sunny. Cooler and much less humid.
Monday

25°C / 13°C
Sunny and warm.

Sunday and Labour Day Monday look absolutely beautiful. Sunday will be slightly cool with a high of only around 23°C and lead into a chilly night with a low dropping into the single digits bottoming out around 8°C. The heat starts to return on Monday with sunny skies continuing as we climb to a mild 25°C.

The Trend Next Week

Looking further into the week, it looks fairly nice overall as the upper ridge begins rebounding back northwards into the Prairies. Highs will push back into the upper 20’s with humidity staying fairly low until late in the week. Things look fairly dry through the first half of the week, with a few weak disturbances bringing the threat for isolated-to-scattered thunderstorms late in the week. For the most part, though, it looks to be a beautiful, warm week. Summer may be late, but it doesn’t look like it’s going anywhere soon!

Hot Weather Continues

The hot weather in place over the Red River Valley will stick around through the rest of the week, although a few more weak disturbances will bring in a little more cloud alongside the risk of a few showers or thunderstorms.

Wednesday

31°C / 18°C
A mix of sun and cloud. Humid.
Thursday

28°C / 18°C
A mix of sun and cloud. Humid. Slight chance a shower or thunderstorm.
Friday

27°C / 17°C
Mainly sunny. Chance showers or thunderstorms Friday night.

Today

We’ll see another hot and humid day today as temperatures climb into the low 30’s again with dew points hovering around 19–20°C. No precipitation is expected although we’ll see a mix of sun and cloud associated with a weak frontal system that wills be in the area.

Thursday

Tomorrow will be an interesting day; at this point it looks like we’ll see a fair amount of cloud in the morning before clearing out for the afternoon as an area of showers and thunderstorms moves across North Dakota and perhaps portions of the southern Red River Valley. Should this system push further north, there would be a slight chance of showers in the morning here in Winnipeg, but at this point I think that we’ll stay dry. Things will be pleasant in the afternoon as we climb to a high around 28°C before a weak upper-level cold front pushes into the Red River Valley. As it sweeps through in the evening, there will be a chance of some showers or thunderstorms pushing into the Red River Valley alongside it. Most regions in the RRV will see a chance of a shower or thunderstorm in the evening and overnight hours. Things will move out overnight as we drop to a low around 18°C.

Friday

Friday will be a beautiful day with mainly sunny skies and a high around 27°C. The humidity will drop off through the day as we heat up and are able to mix some of the remaining moisture near the surface out. There’s little threat of precipitation until the evening and overnight hours as low-pressure system pushes into Southern Manitoba, where thunderstorms will be possible with this system along a trough that will push through the Red River Valley. Depending on how things set up, there may be a slight risk of a severe thunderstorm with this system, so we’ll be sure to keep an eye on how things are setting up.

The Long Weekend

A preliminary look ahead through the long weekend looks beautiful. Skies should clear on Saturday morning and after that, it looks like nothing but sun, sun and more sun all the way through Monday. Highs look to be in the mid-to-upper 20’s, generally between 25–28°C with overnight lows dipping down to around the 12–13°C mark thanks to significantly less humidity in the air mass behind Friday night’s low pressure system.

Heat Continues

After a sweltering weekend, the heat will persist into this week with temperatures remaining well above seasonal values.

A Large Upper High Centred Over the United States will Continue to Bring Hot Weather to Southern Manitoba This Week

Monday

Monday

Increasing Cloudiness in the Morning
30°C / 17°C

Today will see increasing cloudiness in the morning with the approach of a strong upper level jet stream. Clouds will be mainly mid and upper level in nature, but will help to hold down temperatures somewhat. There will be a slight risk of thunderstorms in Western Manitoba during the evening and early overnight period, with isolated severe cells being possible. This risk will result from a weather system pushing in from Saskatchewan.

Tuesday

Tuesday

Mainly Sunny
32°C / 19°C

Tuesday will be a Mainly Sunny day in Southern Manitoba. Temperatures will climb up into the low thirties with light winds. No significant weather is expected.

Wednesday

Wednesday

Mainly Sunny
32°C / 20°C

Wednesday looks to be quite similar to Tuesday. Temperatures are expected to once again climb up over 30C with skies being mainly sunny. The wind might be a bit stronger, but that probably won’t be a bad thing given hot hot it will be.

Long Range

In the long range it appears we’ll stick with the heat for some time yet. Models really show no significant cool downs in the foreseeable future.

Elsewhere in Weather News: August 24th, 2013

California Wildfires Threaten National Park

A small wildfire started about a week ago in the back country trails of the California forests near Yosemite National Park has now turned into a raging wildfire. The wildfire which was initially located outside park boundaries has recently encroached on the national park territory. Covering about 425 square kilometers, the fire is only 2% contained bringing concern to many residents in the area who are under voluntary evacuations. Twelve buildings have been damaged or destroyed by fire already and another 4,500 around Yosemite are at risk. In all, 7,000 firefighters were brought in to battle the wildfire.

Wildfire smoke

Visible satellite shows extensive amount of smoke in eastern California. Smoke outlined in orange, red the location of the Yosemite fire. (Source: CoD satellite)

Very dry heat has been in place over the region for the last week priming the conditions for wildfires. Relative humidity values are expected to remain in the single digits, combined with temperatures in the mid to high twenties, no relief will be provided to the firemen battling the blaze. Drought has persisted since the beginning of summer for much of California and as of Friday 98% of the state is experiencing drought, with the severity ranging from moderately dry to extreme. Due to the dry conditions, 15-20 large wildfires are currently burning in California.

Usually, the wildfire risk peaks in late September in California as the Santa Ana winds come into play. Santa Ana winds are severe winds that are funneled through the mountains. As these winds are funneled through and descend in height (moving towards the coast) they are heated by natural processes, namely, adiabatic heating, causing for extremely hot and dry weather. These easily spread wildfires by blowing embers towards flammable vegetation.