Dog Days of Summer

The weather has been very warm so far this July and there is no sign of this pattern changing any time soon. The dog days of summer are in full swing.

A surface high pressure system will help keep the weather warm and calm through Monday and Tuesday

A surface high pressure system will help keep the weather warm and calm through Monday and Tuesday

Temperatures on Monday will remain warm, but will be fairly comfortable. High temperatures in Southern Manitoba will generally be in the upper twenties with low humidity. Tuesday should be a bit warmer than Monday, with highs near thirty degrees, but once again humidity levels will remain relatively low. By Wednesday the humidity will rise ahead of an approaching trough of low pressure. At this time it appears that there may be a risk of severe storms on Wednesday afternoon and evening in the Red River Valley and South-Eastern Manitoba as this trough runs into a hot and humid airmass. However, the timing of the front is still a bit uncertain, and the speed at which is moves will determine which areas are at risk for storms on Wedensday.

At this point you can probably predict what next weekend has in store…yes you guessed it, more hot weather. It looks like we may be lucky enough to get one cooler day on Thursday, with high temperatures close to normal (i.e. in the mid twenties) before we heat up again for the last weekend of July.

Elsewhere in Weather News: July 21st, 2012

On Saturday July 14th, an unusually strong tornado struck the northern half of Poland leaving a large path of destruction in its wake, in the region of Pomerania. The twister, at times measuring one kilometer in width, tore up trees, disintegrated houses within seconds, and downed power lines for several kilometers. The village of Wycinki and surrounding forest, Bory Tucholskie National Park, were hit the hardest: upwards of 500 hectares of forest were completely flattened by the tornado; over 100 homes were destroyed; and trains had to reroute because of fallen debris on the tracks.

Dramatic video of the tornado scraping by a house and the aftermath. (Source: Youtube/profoundtransformati)

The tornado was estimated to be of EF-2 strength with winds churning at around 200km/h. One fatality in the village of Wycinki was reported when a man tried to take cover in his cottage and was struck by the walls collapsing on him. There were also an additional 10 injuries reported due to the tornado.

Poland tornado

The tornado from a different angle in Sztum. (Source: Associated Press)

Severe weather in Poland appears to be occurring more frequently these past years. This year alone, Poland has seen its fair share of severe weather spanning from large hail events to flash flooding. Tornadoes are not a common occurrence in Poland but they have happened before. The following lists a few significant outbreaks recorded in the past:

  • The Lublin, Poland tornado of 1931 which killed six people and is thought to have been an EF-5 tornado (however that ranking has not been proven).
  • The May 1958 2-day tornado outbreak in Poland which caused three deaths and over 100 injuries.

  • The August 2008 outbreak where multiple tornadoes including 5 EF-3 and 1 EF-4 were spawned killing three people in south-central Poland.

2008 Poland tornado

Picture of the devastation caused by the August 2008 tornado outbreak in Poland. (Source: Wikimedia)

Warm Weather Continues; Little Rain in Sight

Upper-level flow for this evening

Upper-level flow forecast for this evening over Central North America from the GEM-GLB. Of note is the shortwave pushing out of Alberta. This feature will flatten the upper ridge over Southern Manitoba and bring some unsettled weather to SW MB on Sunday.

Rainfall will continue to be spotty and elusive over the Red River Valley as warm temperatures persist and and upper-level ridging maintains it’s hold over the Eastern Prairies. While numerous systems trek through Alberta and Saskatchewan into Northern Manitoba over the next few days, mainly sunny skies are in store for us as we head into the weekend with daytime highs generally around 28°C across much of the Red River Valley. Humidity levels will be lower today and through the weekend than they were on Thursday, however overnight lows will still remain relatively warm in the high teens.

On Sunday, a low pressure system will move eastwards out of Saskatchewan through the Interlake region. Models are suggesting that a band of nocturnal thunderstorms will push into Southern Manitoba on Saturday night and push eastwards before dying around mid-morning. It’s far too early to know where these storms will actually occur, so we’ll be sure to provide updates in the comments. After that band of thunderstorms falls apart, the rest of Sunday actually looks quite nice with clearing skies in the RRV and a high near 30°C.

Next week looks to start off quite pleasant with little chance of precipitation in the RRV until mid-week.

Hot to Really Hot Weather on the Way

Southern Manitoba will quickly heat up to be extremely hot for the later half of this week, while any rain/thunderstorms will remain fairly elusive through the Red River Valley.

You might need one of these on Thursday...

You might need one of these on Thursday.

A strong thermal ridge will start pushing it’s way into Manitoba toady with 850mb temperatures of 22-24°C. This will really crank up the heat over the Red River Valley. Today will be our coolest day over the next few days, with temperatures “only” climbing to 27°C with light winds from the north. There will be some clouds around today and a very slight chance of a shower or two late this afternoon as the warm front starts pushing into Southern Manitoba. Winds will shift to the south overnight tonight, with a low around 18°C.

The southerly wind should help clear the air of any haze and smoke that’s remaining in the Red River Valley, which will allow the full power of the sun to help cook the atmosphere on Thursday. 850mb temperatures will climb towards the mid-20’s, which will help surface temperatures easily climb into the mid-30’s. Two uncertainties exist to the daytime high:

  1. Moisture. The higher the dewpoint is, the more energy it takes to heat it up. That makes it harder to reach really high temperatures when the dewpoints are high than when the air is dryer. For Thursday, the NAM currently predicts dewpoints to be right around 20°C, the GFS pumps dewpoints up to nearly 25°C, and the GEM has them right around 22°C.
  2. Wind direction. Winds will be southerly to start the day, however a weak trough pushing across the RRV should start to shift the winds to southwesterly. When a southwesterly wind is in place over the RRV, it helps to increase daytime highs by a few degress as the wind downslopes over the western escarpment and heats up a little bit. The air often drys out a bit in this process as well, which aids in helping the temperatures increase a bit.

Should the moisture end up being on the lower side and we do get a southwest wind in place over the the RRV, temperatures could potentially shatter our previous hottest day of the year. Models indicate temperatures of 37-40°C are possible over the southern RRV, while temperatures of 34-37°C can be expected over the northern RRV. I’d be very hesitant to say we’re going to hit 40°C in Manitoba on Thursday, especially with dewpoints in the 20’s. It will certainly be an extremely hot day, and when the temperature and the dewpoint are taken into consideration, widespread humidex values of 40-45 will be seen across Southern Manitoba with the potential for isolated spots to see even higher values. Either way, it’s almost certain we’ll see temperatures at least in the low-to-mid 30’s over the RRV, with humidity making it feel much closer to the low 40’s.

Things will cool off a bit on Friday as some less-warm air filters in aloft. 850mb temperatures are expected to drop to a more modest 15-20*deg;C, which will cap daytime highs to “only” 30 or 31°C. Dewpoints should also be a good 3-5°C lower, making it a slightly more comfortable day.

There’s a slight chance of a shower or thundershower on Thursday evening over the more northern portions of the Red River Valley, although any activity will likely stay in the Interlake region. Our chances for showery weather increase into the weekend as cooler air beings to inflitrate it’s way in aloft while down here at the surface we remain near the nose of a thermal ridge. Highs will remain in the high 20’s through the weekend.