Snow to Start the Week

A Colorado Low system will bring the potential for snow over parts of the Red River Valley and South-Eastern Manitoba on Monday and Monday night. This will not be a particularly potent Colorado Low, but it could cause problems nonetheless.

The Colorado Low (red L) at 6pm on Monday

The Colorado Low (red L) and its predicted track – Image valid on Monday, February 20, 2012 at 6pm

On Monday the Colorado Low system will be slowly moving north from the Central United States. The main low pressure centre will be located near the Nebraska/Kansas border around the noon hour and stall out over that region for the rest of the day. Meanwhile a secondary low pressure centre will be developing over Southern Manitoba or Northern North Dakota. This secondary low pressure centre will proceed to absorb the more Southern low centre on Monday night, creating one low near the Lake of the Woods by early Tuesday morning. Snow will begin in Southern Manitoba on Monday afternoon and the heaviest bands will exit the region on Monday night. Some light wrap-around snow may linger into Tuesday.

GEM-Regional's QPF outlook

Forecast snowfall accumulations by the GEM-Regional model. For simplicity assume the numbers along the side correspond to snowfall amounts in centimetres

All that information is nice, but that main question for most people is “how much snow will we get”. This is where things get tricky. Some models (such as the GEM-Regional above) are suggesting that South-Eastern Manitoba, including Steinbach, Sprague, and the Whiteshell will get upwards of 10cm of snow. This same model is predicting somewhere around 5 to 10cm for Winnipeg. As you can see in the graphic above, there will be a sharp cut-off in snowfall amounts to our west. This means that areas such as Portage, Morden and Carman will probably see no more than 2cm, if that. The fact that there will be a sharp cut-off in snowfall accumulations makes predicting amounts for given cities very difficult. If the cut-off line moves a little bit further west, then Steinbach and Winnipeg may see 10cm of snow. However, if the cut-off line moves a little further east, then Winnipeg may see very little if any snow, while Steinbach and the Eastern Red River Valley only get a few centimetres. Other models have completely different ideas for snowfall amounts with this system, so don’t assume that the GEM-Regional is correct (in fact we never assume that models are correct!).

Now that I’ve given you the background information on this snowfall event, I will provide my personal predictions. As I have alluded to above, there is still lots of uncertainty in snowfall predictions and as such the below forecasts are simply my best “guesses” given the information available.

  • Winnipeg: 2 to 4cm
  • Steinbach: 4 to 8cm
  • Portage: 0-2cm
  • Morden: 1-3cm
  • Whiteshell: 5 to 10cm, locally higher amounts near the Ontario border

Once we get through Monday, the weather will turn nice again. Tuesday and Wednesday will be warm with highs just below the zero mark in most parts of Southern Manitoba. Another low pressure system will be passing through our neck of the woods later in the week…but we’ll have more details on that later. Models are hinting at colder weather (i.e. below normal weather) for next weekend. Winter may not be done with us yet!

Elsewhere in Weather News

Giovanna – The Aftermath

Since reported last week, Giovanna, a cyclone in the western Indian Ocean with category 4 intensity at its peak, reached the central coast of Madagascar and caused considerable damage. The dangerous cyclone left 15 people dead and about 40,000 people homeless, most of them on the eastern coast where the cyclone made landfall and brought with it a significant storm surge and intense rainfall. Thankfully the capital city of Antananarivo (population 1.4 million) managed to avoid the center of the cyclone but the city still experienced widespread blackouts.

The track of Cyclone Giovanna

Super cyclone Giovanna’s complete track, added with its forecast track where it will eventually dissipate. (Source: HEWS)

Had the cyclone’s track had been slightly shifted to the north by about 40km, the damage would certainly have been greater in the capital. At its peak (over the western Indian Ocean before making landfall) the storm reached an astonishing 1,000 kilometres in diameter with sustained wind speeds estimated at about 230km/h.

Since heading back out into the Indian Ocean (Mozambique Channel), Giovanna’s track was more favourable to those in the region as it had taken a southerly track then turned easterly, not only avoiding a second landfall in Madagascar, but also completely avoiding Mozambique –the country that was ravaged by disastrous floods this year.

Elsewhere in the world, weather has been relatively quiet compared the last couple weeks. Some other weather news that could possibly make headlines this week is: another winter storm arriving in the UK this past Sunday, strong thunderstorms affecting the southern United States this past weekend, flooding in Peru and Brazil’s recent heat wave.

A Beautiful Weekend Ahead

Our left-over moisture will slowly clear out today and tonight ushering in a beautiful weekend with plenty of sunshine and warm temperatures. With Winnipeg’s average daytime high sitting at around -8°C right now, we can expect to see tempeatures nearly 10°C above normal by the end of the weekend!

Sunny Skies

Many areas in Southern Manitoba that are typically covered in snow at this time of year are completely bare. PHOTO BY ERIN GARDIN.

We’ll see a mix of sun and cloud here in Winnipeg today, with the ever-present chance of a few snowflakes, but any snow that does develop will be less significant than the few light flurries we saw yesterday in the city. The daytime high today will be cooler than yesterday, around -4°C, as a trough of cool air aloft swings over Southern Manitoba. The snow much of the Red River Valley recieved between 2 and 5cm of on Wednesday as a shortwave embedded in an upper trough swung across the province will not be sticking around for very long. An upper ridge has begun to build into the Prairies and will continue it’s trek into Southern Manitoba over the next two days. Here in Winnipeg, we’ll see winds switch around to southerly overnight tonight, which will usher in milder air and push our temperatures up for the weekend.

Upper Ridging

GEM-REG 500mb Winds valid 12Z Friday Feb. 17 (6AM CST)

We’ll see temperatures soar this weekend with a light south-southwest flow and mild air pushing in aloft. 850mb temperatures are expected to increase to slightly above 0°C by Sunday night, which will ensure that through the weekend we have daytime highs of 0°C – 3°C in Winnipeg.

Temperatures are expected to reach as high as +2°C this weekend; that’s 10°C above normal for Winnipeg at this time of year.

Any areas that manage to return to snow-free quickly will be able to add a couple degrees to those temperatures. Overnight lows will still be cool, with temperatures dropping down to around -11°C tonight and tomorrow night.

By Sunday, a low-pressure system will begin ambling it’s way out of Alberta into Saskatchewan. This will increase the southerly upper-level flow and provide the needed kick to really push those 850mb temperatures up. With the dramatically warmer 850mb temperatures in place, our overnight low on Sunday night will essentially be just a degree or two cooler whatever the daytime high makes it to.

The low will then track eastwards across Manitoba Monday into Tuesday. Models disagree significantly on what will happen happen for Winnipeg, with some giving us 5 to 10cm of snow and others keeping the precipitation 250 miles away from us. We’ll certainly keep our eyes on this system as it develops!

Weather? What Weather?

Our exceptionally unexceptional February continues with very little in the way of weather. After a mild, but dull, day today we’ll be back to sunshine and seasonal to slightly above seasonal temperatures.

Precipitation Outlook

12hr. QPF from the GEM-REG, valid at 06Z Thursday February 16 (1AM Local Time)

A very weak upper trough is moving over the region today, bringing with it cloud and a slight chance of flurries. The risk is greatest in areas south of the Trans-Canada Highway, from The Brandon/Pilot Mound regions eastwards into the Whiteshell. SLRs are expected to climb up to 15:1 to 20:1 range, so some areas closer to the US Border or into the Whiteshell may see as much as 2cm of snow. It’s unlikely that Winnipeg will see even 1cm of snow today.

The rest of the week will be sunny with daytime highs near -3°C and overnight lows near -10°C. There’s a slight chance of some snow on the latter half of the weekend, but we’ll leave that for discussing on Friday.

Updates to the Mobile Site

Some of you may be familiar with the U of M Weather Central: Mobile site that I maintain. Well, (in a Professor Farnsworth voice)…

Good news, everybody!

I’m working on updating the site as we speak. It’s no small task, as it’s a pretty comprehensive site, but I’m working on making it better than ever! A task which doesn’t seem too difficult, given I made the old one (which serves its purpose adequately) while learning how to code. Anyways, here are my goals for the redesign:

  • Utilize the latest mobile technologies to provide a modern, compelling experience that is well-supported across the mobile space (iOS, Android, Windows Phone 7).
  • Improve the page layout and design to visually group information better and to provide quick access to all available information.
  • Utilize responsive design so that the page layout will optimize itself for phones, iPads, or desktop computers!
  • Fix long-standing bugs from the old code (incorrect forecast icons, among others).
  • Enhance existing features. One example is that the site now uses the sunrise and subset times of a city to calculate when to change from daytime to nighttime imagery.
  • Broaden Canada-wide support.
  • New features! Mobile model viewer! Mobile satellite Viewer! Mobile RADAR viewer! And more!

These are the main goals. The biggest hurdle is moving everything from a pure PHP solution to a tightly integrated jQuery/PHP solution. I plan on developing what will essentially be APIs to retrieve the data and provide a JSON-encoded response. What does that mean? The site will be fast, versatile, and standards-compliant. I also plan on making the .PHP files public so that people can easily access select Environment Canada data in a practical, modern way.

I think this new site will be really great and hands down the number-one way to get weather data on the go (and hopefully it’ll be good enough you’ll use it at home too!).

Pleasant Weather This Week

A fairly calm and uneventful week is in store weatherwise. Temperatures this week will be much warmer than the values experienced late last week.

NAM temperature forecast for Tuesday, February 14, 2012

NAM temperature forecast for the Prairies – valid Tuesday, February 14, 2012

Weather conditions for the first half of this week will be pleasant. High temperatures on Monday and Tuesday will generally remain in the -2 to -6C range in Southern Manitoba with light wind speeds. However, those parts of Southern Manitoba that are mostly snow-free will see temperatures around zero during this time period. The stronger February sun will heat these darker, snow-free areas more easily than white snow-covered regions resulting in warmer temperatures. Regions west of the Red River Valley and south of the Trans-Canada highway are the most snow-free parts of Manitoba and therefore will be noticeably warmer than areas around Winnipeg (that have more snow cover). By Wednesday it appears that all of Southern Manitoba will get up close to the 0C mark as a light southerly flow brings in some warmer air.

The weather outlook for the end of the week is just a little bit cooler from that of the beginning of the week. Temperatures on Thursday and Friday look to remain around or slightly warmer than seasonal values (normal high is -9C). Models are currently showing the potential for some light flurries on Friday into Saturday, but other than that it doesn’t look like we have any chance of seeing snow this week.

Seven weeks of winter down, six to go.

Elsewhere in Weather News

Super Cyclone Giovanna Threatens Madagascar

A very strong and dangerous cyclone named Giovanna has spun up in the western Indian Ocean this past Friday.

Super cyclone Giovanna marches towards Madagascar on IR satellite, with its predicted path. (Source: Sat24)

Super cyclone Giovanna marches towards Madagascar on IR satellite, with its predicted path. (Source: Sat24)

Giovanna is currently categorized as a category three cyclone (wind speeds of 160km/h) and is forecast to sustain its wind speed as it barrels towards the island of Madagascar. The combination of low wind shear and relatively warm waters of the western Indian Ocean is what has contributed to the rapid intensification of Giovanna. With the storm moving slowly towards the southwest, the landfall will take place on the Tuesday the 13th, bringing with it: torrential rains, a high storm surge and powerful sustained winds. The areas taking a direct hit with this cyclone will have a shot at receiving 250mm of rainfall (more than half of what Winnipeg receives yearly), wave heights reaching 24 feet and not to mention the sustained winds of about 190km/h. The storm may slowly intensify into category four, depending on whether or not an eyewall replacement cycle will occur before Giovanna makes landfall. This occurs when the cyclone’s thunderstorm bands circling around the eyewall use up some of the eyewall’s moisture and subsequently collapses the eyewall. Eventually, a new eyewall forms, strengthening the cyclone further and the cycle restarts.

Models predicting rain rates of above 45mm/h (red) as Giovanna approaches Madagascar (Source: Sat24)

Models predicting rain rates of above 45mm/h (red) as Giovanna approaches Madagascar (Source: Sat24)

The remnants of Giovanna will emerge into the Mozambique Channel and may re-intensify into a tropical storm. Unfortunately, this would bring heavy rains to Mozambique again, as they have already been plagued with torrential rains this season, more notably cyclone Funso (blogged about three weeks ago) which dumped significant rainfall on Mozambique’s coast not too long ago.

Elsewhere in Weather News has been provided by Matt