Stormy Night Ahead; Cooler Weekend

Another 30°C+ day will give way to stormier weather tonight as a cold front pushes across Southern Manitoba. We’ll see a slightly cooler weekend than the weather of late as we remain in the cooler air behind this system.

Precipitable Water for Friday Night

Precipitable water from the GEM-REG as the cold front pushes into the RRV tonight. Elevated values of 40-50mm through the RRV indicate the potential for stronger storms with locally heavy rainfall.

We’ll see temperatures climb into the low 30’s across Southern Manitoba again today as we remain under the influence of a pool of warm air entrenched over the Eastern Prairies. After some of this morning’s debris cloud from last night’s nocturnal convection clears out, here in Winnipeg we’ll climb to a high near 31 or 32°C, while areas to our south could reach as high as 33°C today.

Things will change promptly this evening as a cold front pushes across the province. Showers and thunderstorms will develop along the front in the early to mid-evening and continue to grow in coverage as the night progresses. This line of showers and thunderstorms will move through the Red River Valley overnight, bringing 5-15mm of rain to the region, the potential for some areas to see a bit over 1” total accumulation, and hopefully a good light show. These storms are not expected to be severe, and could potentially be one of the last night-time light shows we’ll get in 2012.

Tomorrow we’ll see a daytime high only around 24°C with a southwesterly wind at 20-30km/h. Sunday will reach about 25°C with lighter winds. Skies should be mostly sunny both days, with just an occasional cloudy patch here and there.

Temperatures are expected to climb back towards the 30°C mark through the first half of next week.

Hot, Sunny Weather This Week

Winnipeg and the Red River Valley will be basking in hot, sunny weather this week as an upper ridge pushes it’s way across the Prairies. We’ll see a chance of thunderstorms on Thursday evening as a disturbance rolls through the RRV, but quickly return to sunny, warmer-than-seasonal weather.

850mb Temperatures this evening from the GEM-REG

850mb temperatures for this evening from the GEM-REG model. Warm air is building into S. MB bringing daytime highs near 30°C.

A broad southerly flow ahead of an incoming upper ridge has pumped temperatures up over Southern Manitoba back to the 30°C mark. 850mb temperatures will climb up to nearly 20°C today, which will allow our daytime high to soar towards 31 or 32°C. The warm air in place over us will also result in a dramatically warmer overnight low; while the past couple nights have dropped into the low-to-mid teens, we’ll see the mercury barely dip below 20°C tonight.

The normal daytime high for late August in Winnipeg is about 24°C. The normal overnight low is about 11°C.

Thursday will be another warm day, however an incoming shortwave will slide along the International Border through the day, bringing some showers on Thursday morning to SW MB and the risk of an isolated thunderstorm to the Red River Valley, from the Winnipeg area all the way south to Fargo. If storms develop, they’ll develop late in the afternoon along a weak trough line that’s expected to develop in response to the upper feature. Ultimately, I think that most of the storms will remain south of the border with only a very slight chance of anything popping up on the Manitoba side of the RRV. Scott’s Southern Manitoba Mesonet will be a great way to track the trough through the afternoon to see if the threat for storms has passed by you. Despite the heat that will be present with daytime highs near 30°C, dynamics look fairly weak and I do not expect that any storms that may develop will become severe.

We’ll see temperatures dip to around 15°C on Thursday night. On Friday, we’ll see plenty of sun and daytime highs continuing to be near 30°C.

For the weekend, it looks like a cold front will sweep into the province on Saturday, bringing with it some showers and cooler weather; daytime highs look to be in the low-20’s for Saturday. Temperatures look to rebound quickly on Sunday, though, with highs pushing back to the high-20’s. So despite our rather cool start to the month, we may yet come out with our 14th consecutive month of above-normal temperatures in Winnipeg. 5 days out of the next 7 are forecast to have daytime highs at least 3°C above normal, and overnight lows look to remain above normal as well.

Hot Weather Returns

After a period of cool weather over the last while, warmer conditions are set to return.

30C temperatures are expected on Tuesday in Southern Manitoba

The NAM model is predicting that Southern Manitoba will see temperatures of 30C or higher on Tuesday

A ridge of high pressure will build over the Prairies this week, allowing for some of the warmest weather we’ve seen this August to develop. Monday will be a pleasant day, with high temperatures in the mid to upper twenties. By Tuesday many areas should see their first 30C readings this month, as warmer air pushes in from the west.

The ridge will begin to break down on Wednesday and Thursday as a series of impulses move in from the Pacific. These impulses with have one or more low pressure systems associated with them, causing some unsettled weather to start developing over the Prairies later this week. It looks like an easterly flow will develop over Southern Manitoba on Wednesday out ahead of an approaching low. Depending on how the frontal features setup on Wednesday we may or may not see another 30C day. At this point it looks most likely that Wednesday will have temperatures in the upper twenties, rather than thirty, but there is the potential for warmer weather. On Thursday we may see our first risk of thunderstorms in a while as a strong southerly flow draws up more humid air from the south ahead of an approaching low pressure system.

As we move toward the weekend weather models show a series of fairly strong low pressure systems moving through our region. Should these systems develop more or less as predicted it would likely mean a rainy and cool last weekend of August.

Elsewhere in Weather News: August 18th, 2012

A Look Worldwide into July, 2012

As reported on Friday, Winnipeg is shaping up to be one of the hottest years since record-keeping began 139 years ago, with July closing out as the 5th hottest month on record for the city. Wondering how the rest of the world faired this past month?

Interestingly, most of the Northern Hemisphere has also experienced extreme temperature anomalies this year. According to the National Climactic Data Center (NCDC), the Northern Hemisphere land surface temperatures this July were 1.19°C above the average, making July 2012 the warmest July in the Northern Hemisphere ever. This year has experienced no shortage of record breaking temps in the Northern Hemisphere – it is now the fourth month in a row that surface land temperature records in this hemisphere have been broken. Canada and the United States have contributed greatly to the record-shattering numbers these past four months but the heat wasn’t confined to North America. South-Eastern Europe has seen conditions almost identical to ours this summer – very dry with record-setting warmth; while Serbia and Bulgaria have been impacted with severe drought this growing season, resulting in severe crop losses. Bulgaria has lost around 10% of its wheat crops due to the sizzling heat, and their maize crops have decimated to the point whereby getting half their average crop will have to suffice. The only countries in the world to have shown significant temperatures below normal this July were Australia, Argentina and parts of the Antarctic.

Temperature anomalies July 2012

July temperature anomalies and circled, areas talked about in EIWN. (Source: NASA Earth Observatory)

Precipitation anomalies July 2012

Precipitation anomalies for July 2012 and circled in red is where severe drought is occurring in South-Eastern Europe. (Source: NCDC)

Arctic Melting

In some areas of the Arctic, July temperatures have exceeded 6°C above average. Arctic ice is continuing to melt at a disturbing rate. The expanse of the Arctic sea’s ice coverage is now at its lowest ever at this time of the year, having dropped even further than measurements from the record-setting year, 2007. In July, almost all of Greenland’s entire ice sheet experienced melting – a “rare event” as described by the National Snow & Ice Data Center (NSIDC). To put things into perspective, sea ice used to reach seven million square kilometers in the 1990s at their minimum, while it has only surpassed five million square kilometers once in the past six years (showing a 29% decrease of minimum sea ice extent in the last few decades). This has lead scientists, like Walt Meier, a scientist at NSIDC, to believe that sea ice could potentially be eliminated by the year 2030 if melting continues at this pace. If this does happen, the ice melt could trigger a domino effect: raising ocean levels, releasing methane from frozen soils, and so on.

Sea ice extent graph

Sea ice extent by year. (Source: NSIDC)