Monday, December 29, 2008

Alberta clipper threatens snow for New Year's Eve/Day

Another Alberta clipper system is forecast to spread an area of snow across southern Manitoba Wednesday evening reaching Winnipeg sometime Wednesday night, just as we usher in the new year.  The snow is expected to continue into Thursday morning before tapering off by afternoon.  Early snowfall projections with this system are in the 5-10 cm range. Note that the system will also be accompanied by brisk southeast winds ahead of it Wednesday evening, and gusty northwesterly winds behind it on Thursday, so blowing and drifting snow may be a problem in addition to the snowfall.       

Thursday, December 25, 2008

Some snow on the way as cold snap eases..

The cold weather of the past 2 weeks will finally be loosening its grip over southern MB over the next few days with temperatures rising to normal values for late December. The milder temperatures will be ushered in with occasional snow bearing systems moving across the southern Prairies, both tomorrow (Friday) and Sunday. Friday's system will be a developing low across the Dakotas that will spread snow into southern MB Friday into Friday night. Amounts with this system look to be around 5 cm for most localities in southern MB, possibly up to 10 cm in some localities. Brisk northerly winds behind the system may produce areas of blowing and drifting snow Friday night. An Alberta clipper will threaten another 5-10 cm of snow to southern MB late Sunday into Monday morning.

Season's Greeting from Rob's Obs

Carol of the Bells - Computer Controlled Christmas Lights from Richard Holdman on Vimeo.

Tuesday, December 23, 2008

College of DuPage server problems

Links through College of DuPage are currently unavailable due to server problems. They hope to have it up and running soon. Until then, access to warnings and some satellite photos on my website will not be working properly. EC warnings can be found through the Weatheroffice website.

Friday, December 19, 2008

Snowfall warning issued for areas near the US border - Winter Storm Warnings south of the border

A storm system moving across the Northern Plain states is spreading an area of snow through North Dakota  and southwest MB today. This area of snow will slowly move eastward tonight and persist through Saturday and Saturday night over North Dakota and southern MB. A snowfall warning has been issued for areas along the US border from Killarney through Emerson to Steinbach and Vita for up to 15 cm of snow by Saturday evening. Here in Winnipeg, we will still see snow out of this system tonight and Saturday, with amounts up to 10 cm expected by Saturday evening.   

Once again, conditions are expected to be worse south of the border. Like last weekend, this will mean difficult travel conditions if you're heading into North Dakota or northern Minnesota, although this event should not be as severe as last weekend's blizzard in those areas.   Nevertheless, winter storm warnings have been issued for North Dakota and northern Minnesota for snowfalls of 15 to 25 cm tonight through Saturday along with gusty winds and blowing snow through Saturday night.  People planning to travel to the States this weekend should be prepared for poor driving conditions and allow extra time to reach their destination.  

Wednesday, December 17, 2008

A respite from wind chill

The cold is here to stay for awhile, but at least the wind is nice and light today which will make those -20ish temperatures more bearable. In fact, with bright sunshine and afternoon highs near -21C, it won't feel too bad at all out there today. For tonight, a weak system from Alberta will cross southern MB bringing some light snow to the area, with a dusting to 2 cm possible in most localities including Winnipeg. Behind the system, northerly winds of 20 km/h will develop for Thursday, with temperatures in the mid minus 20s producing windchills in the minus 35 to minus 38 range (still shy of -40 warning level) Winds should drop off again Friday so windchills warnings may not be necessary for the rest of the week over much of southern MB. On Saturday, a storm system over the central Plains will bring an area of snow over the Dakotas into southern MB. Like last weekend's storm, the bulk of the snowfall with this next storm system is expected to remain south of the border, however it's possible parts of southern MB could see 5-10 cm on Saturday. Unfortunately, gusty northerly winds are forecast behind this system for Sunday with temperatures in the mid minus 20s and windchills likely in the -40 to -45 warning range again. Below normal temperatures are expected to continue through the first part of next week, with models hinting at some moderation by Christmas.

Note that Winnipeg has had a daily maximum temperature below -20C since Sunday Dec 14th. With forecast highs below -20C for the next 5 days, it's possible we may go 10 straight days before we crack the -20C mark again. This would be the longest such streak for a December in recent memory. (longest -20C streak for a December in Winnipeg was 15 straight days from Dec 11-25 1879, during Winnipeg's coldest December on record)

Monday, December 15, 2008

There's cold..then there's real COLD!

Yes it's cold here.. but we're not the only ones suffering through frigid temperatures. The cold weather has flooded much of western Canada and the northern States with well below normal temperatures. Even the balmy west coast is shivering through subfreezing temperatures, with Vancouver expected to remain below freezing for the next week. And if you really want to see cold.. check out Siberia. Verkoyansk was a brutal -56C this morning (actual air temperature, not windchill) with plenty of -50C readings across Siberia. Makes that -30C feel downright balmy, eh? Finally, it's always an interesting read to see what real cold weather is like. Check out this interesting article, Life at Minus 80, about the day Snag, Yukon hit -62C (-81F) on February 3rd, 1947.. North America's coldest temperature on record. Don't you feel warmer now?

Wind chill.. Get used to that term..

OK, OK.. so we're all complaining about the cold. And it looks like we'll be stuck with it for awhile (possibly through the end of December) so we might as well get used to it (or leave if you're lucky enough) The main issue over the next week or two will be the wind.. which will determine whether or not windchill warnings are required. Environment Canada issues windchill warnings when the windchill is forecast to reach or exceed -40 for at least 3 hours, with a windspeed of at least 11 km/h. This week, with high temperatures around -25C, and low temperatures in the -30 to -35C range, it won't take much wind to reach those windchill warning levels. At -30, you need a windspeed of only 11 km/h to produce a windchill of -40. At -25C, you need a sustained wind of at least 33 km/h to produce a windchill of -40. These values look likely tonight into Tuesday, but winds may be light enough by Wednesday so that windchill may not be an issue (though it will still be cold) Wind speeds may pick up again in the 15-25 km/h range for the end of the week.

Remember that windchill is not an actual temperature, but rather a measure of the cooling rate of the atmosphere based on the temperature and windspeed. Your body loses heat more quickly when a wind is present.. the faster the wind, the more rapidly you lose heat. For more details on this windchill issue, read my entry from last winter explaining the windchill factor.

Sunday, December 14, 2008

Southern MB dodges blizzard.. but not bitter cold

A strong winter storm system passing through the northern Plains has spared much of southern MB from significant snow or blizzard conditions, but not from bitter cold temperatures and extreme windchills. The storm, centered over southern Minnesota this morning, has brought snow and blizzard conditions to much of North and South Dakota overnight which will continue into today. Areas of southern MB near the ND/MN border from Emerson to Sprague will still see some snow with this system today (perhaps 2-4 cm), with locally poor visibilties in blowing and drifting snow especially in the southern Red River valley, but blizzard conditions are expected to remain south of the border.

The main story over the next few days will be the bitter cold, with strong winds today producing extreme windchills of -40 to -45. At these values, frostbite is possible within 10 minutes. Winds will ease somewhat Monday and Tuesday, but with bitter cold temperatures continuing (-25 to -35C), wind chills will be an issue through much of the week.

Friday, December 12, 2008

Major winter storm to affect southern Prairies/northern Plains this weekend..

A strong storm system pushing into southern BC today will cross into Montana Saturday before merging with a central Plains storm system Saturday night. This Alberta clipper/Colorado low hybrid storm will then push up through Minnesota on Sunday bringing strong northerly winds, snow and blowing snow, and bitterly cold temperatures to the Dakotas and parts of southern MB, especially Saturday night into Sunday. The result will be a major winter storm for the northern Plains and much of the southern Prairies along the US border, with blizzard conditions possible in many areas including the Red River valley. A winter storm watch has been issued for the Red River valley in MB with blizzard watches across all of North Dakota and NW Minnesota. For North Dakota information on this storm, consult their winter storm page.

Models continue to show Winnipeg will on the northern edge of the heaviest snow from this system with the bulk of the snow (15-25 cm or more) falling through the Dakotas and northern Minnesota into NW Ontario. Remember though, with storms like this, it's not the total amount of snow that's the problem.. it's the wind in combination with falling snow that creates the problems with blowing and drifting. So it's important not to focus solely on the snow amounts with this system (although that will certainly be a factor), but rather the winds, poor visibilities and extreme windchills.

Winds will be increasing by Saturday evening across southern MB with snow and strong winds continuing Saturday night through Sunday. As a result, there will be extensive blowing and drifting snow Sunday especially through the Red River valley and open areas along the US border with blizzard conditions possible. The Hwy 75 corridor will likely be very bad especially from south of Winnipeg down to Emerson where blizzard conditions are possible Sunday. Travel into the States this weekend is not advised due to this dangerous storm which will likely be shutting down highways across the Dakotas, and possibly parts of southern MB as well. Add to that bone-chilling wind chills of -40 or lower, and you have yourselves a serious winter storm. Get ready folks, this will make for an interesting end to the weekend..

Wednesday, December 10, 2008

Major Arctic blast moving in Sunday....

Another Alberta clipper gave us more snow today with 5-6 cm reported across much of Winnipeg and southern MB. But Mother Nature is saving her worst for the weekend, as a bitterly cold Arctic blast will be moving in by Sunday on the heels of another snow bearing system. This system will be moving into Montana on Saturday then into the Dakotas on Sunday spreading another area of snow across southern MB over the weekend. Another 5-10 cm of fresh snow is expected Saturday into Sunday with this system, on top of the 10 cm that has fallen this week. The problem will be Sunday afternoon and evening behind this sytem as increasing northerly winds gusting to 60 or 70 km/h drives in bitterly cold Arctic air producing poor visilities in blowing and drifting snow. In fact, blizzard conditions are possible over southern MB Sunday afternoon through Sunday night especially over the Red River valley. In addition, temperatures will be plunging into the minus 25 to minus 30 range, with wind chills in the minus 40s. All in all..a nasty end to the weekend with a very cold start to the week ahead.

Monday, December 08, 2008

Cold.. and staying cold..

The weather looks cold for the next couple of weeks at least as a large Arctic airmass spreads over the Prairies. For this week, the cold weather will be briefly moderated somewhat by occasional weak Alberta clipper systems tracking across the southern Prairies from the west. Across southern MB, one of these clipper systems is forecast to track through on Wednesday followed by another one on Friday. Each of these systems will spread cloud and some snow to southern MB bringing about 2-5 cm with each system. Still, these minor amounts in combination with the cold temperatures will make for icy road conditions through the upcoming week. Behind these systems will be a reinforcement of Arctic air into southern MB, especially over the weekend into next week with daily highs in the minus 20s and lows in the minus 30s.

Thursday, December 04, 2008

You think it's cold now.. wait til next week!

Get the cold weather gear and block heater ready.. the coldest weather of the season so far is poised to spread over the Prairies next week with temperatures likely in the minus 20s and minus 30s. We'll get a sneak preview of this cold airmass over the weekend as an Arctic high drops in from the north, giving us highs only in the minus 15 range and lows near minus 25 Saturday night. On Sunday into Sunday night, an Alberta clipper is forecast to spread cloud and snow across southern MB with 2-5 cm possible. In behind this clipper will be a major push of Arctic air as a massive Yukon ridge drives very cold air across the Prairies. This cold air will spread into southern MB on Monday with gusty northerly winds, and temperatures around minus 20, giving windchills of minus 30 to minus 35. Very cold conditions are expected the rest of the week as the Arctic airmass builds in..possibly modified briefly midweek as a weak clipper system scoots by. Look for daily highs next week in the minus 18 to minus 23 range, and lows in the minus 28 to minus 33 range.

Tuesday, December 02, 2008

EC releases winter outlook for 2008/09

EC has issued its winter outlook for the upcoming 3 month period of December through February. The outlook, produced from a consensus of 4 climate models ingesting 3 weeks of current weather conditions and extrapolating into the future, indicates warmer than normal conditions this winter over the East Coast (mainly Newfoundland and Nova Scotia) while colder than normal conditions are forecast from northern Quebec through Hudson Bay and northern MB into NWT and the Yukon. Over southern MB, there are equal chances of a "normal" or below normal winter with a lower probability of a mild winter. Across the rest of the country, model consensus does not point to any specific outcome, with generally equal chances of above, near or below normal conditions (i.e. a non-forecast)

EC's 3 month outlook is available on EC's Weatheroffice website at this site. NOTE: For monthly and seasonal outlooks, I highly recommend you look at the probabilistic outlook map rather than the deterministic outlook map. The deterministic maps do not accurately reflect the true output of the climate models, which is better reflected by the more informative probabilistic maps. The probabilistic maps more accurately indicate where the climate models are showing the best agreement for above or below normal conditions occurring, and where there is the most disagreement. This measure of uncertainty is not indicated on the deterministic maps which make them subject to greater misinterpretation.

Monday, December 01, 2008

Alberta clipper system approaching MB

A strong Alberta clipper system is moving across northern SK today ushering in a gusty southwest flow of very mild Pacific air over southern AB and southern SK. Temperatures have soared into the mid teens over southern AB with several record highs established for December 1st.  This warm airmass will be moving towards southern MB over the next 24 hours, but the bulk of the mild air will be bypassing to the south of Winnipeg into the Dakotas overnight. Even so, gusty south winds tonight of 40-60 km/h will bring rising temperatures overnight to the Red River valley, with temperatures expected to climb towards the freezing mark by daybreak. In fact, there's a chance we may get above zero (+1 to +3C) for a brief period early Tuesday morning as our winds shift into the west and tap some of the retreating mild airmass over southern SK. Regardless, the mild temperatures will be short lived as strong northwest winds develop behind the clipper system Tuesday, and bring increasingly colder air through the day. So watch for temperatures to fall Tuesday, especially in the afternoon and evening as those northwest winds pick up. 

As for precipitation with this system,  it looks like Winnipeg may get a period of snow tonight with a risk of freezing rain or ice pellets overnight as the warm front approaches. The bulk of the snow should remain north of Winnipeg through the Interlake and central MB, but we could see a couple of cm tonight. If any freezing precipitation develops, the best chance will be between 10 pm and 4 am, but amounts should be light. Nonetheless, road conditions could be on the slick side Tuesday morning as this system moves through with some mixed precipitation and near freezing temperatures. Look for windy and colder conditions by Tuesday afternoon with occasional flurries giving a dusting to 2 cm over Winnipeg and the Red River valley.                   


November 2008 Highlights

November 2008 finished milder than normal in Winnipeg and Southern MB, the 4th month in a row with above normal temperatures. Precipitation for the month was also above normal, but that was largely due to a storm system on the 6-7th that brought large amounts of rain, freezing rain, ice pellets and snow to the Red River valley. The last 3 weeks of the month were quiet and inactive, with little in the way of significant precipitation or large temperature swings. As a result, the month seemed to delay winter after a somewhat early start.

Overall, the month finished over a degree above normal with a mean temperature of -4.2C at the airport (-3.2C at my site) vs a long term November average of -5.3C. The month began on a very mild note, with a record high of 18.8C on the 3rd.. the warmest November day in Winnipeg since Nov 5th 1975 when we hit 23.9C (all time November high). The mild start and snowfree ground had golfers enjoying some late season golf through Nov 4th, with no hint of winter like weather. That would change soon enough however as a storm system tracking through from the Dakotas on Nov 6th-7th brought a messy mix of rain, freezing rain, ice pellets and snow to the Red River valley. The storm brought some 40-70 mm of rain and ice pellets to the southern Red River valley bringing high water levels to the Red River on the heels of a wetter than normal fall. By the morning of the 7th, Winnipeg and much of the western Red River valley had been transformed into a winter wonderland, with about 5-8 cm of snow falling in Winnipeg and heavier amounts of 15-25 cm west of the city from Pilot Mound through Portage. Snow has remained on the ground since with a month end snowcover of 5 cm in Winnipeg. Areas further south and east of Winnipeg however saw much less snow with this storm system, and enjoyed snowfree grounds through the end of the month.

After the 7th, the weather turned quiet and uneventful with some minor snowfalls now and then but little in the way of high impact weather. A mid month cold snap brought the month's coldest temperature of -19C on the 21st but that was followed by mild and dry conditions to end the month. The month finished with about 15 cm of snow at my site, slightly less than an average November monthly snowfall of 21 cm.

Overall, an early tease of winter, but a mild and quiet month overall.