Friday, December 25, 2015

Deepest Christmas snowcover in Winnipeg in 15 years

41 cm of snow over the past week has resulted in the deepest snow cover at Christmas in Winnipeg in 15 years.  As of this morning, the airport was showing a snowdepth of 21 cm, the deepest snowpack at Christmas since a 30 cm reading on Dec 25 2000. At my site in Charleswood, I recorded a snow depth of 30 cm this morning.. the deepest snowdepth on Christmas since Dec 25 2000 (31 cm).        
  
Christmas day snow on ground stats (Winnipeg since 1955)

Least snow on ground....... TR (1997) *
Most snow on ground......... 80 cm (1955)
Average snow on ground.... 16 cm 

Click on "1997" for CBC video of Winnipeg's snowfree Christmas that year. Prior to 1955, there have been at least 3 Christmases noted with no snow on the ground in Winnipeg: 1939, 1913, and 1877.

* NOTE: Official "snow on ground" readings for the airport started in the fall of 1955, and continued until 2002. Thereafter, snow on ground measurements at the airport have been taken by an automated sonic snow sensor at the XWG autostation which uses sound waves to estimate snow depth.  This automated method is not as reliable as human read measurements due to sampling errors caused by drifting, which human based measurements could take into account. Since 2004, manual snow depth readings have been taken at the Charleswood 2 climate site (my backyard) as a secondary source of snow depth measurements in Winnipeg. Note however, that snow depth readings at this residential site are generally higher than readings at the airport, which is more exposed and more prone to blowing and drifting.   

Christmas day snowdepth in Winnipeg since 2000

(Rob's Obs readings)  ........ Airport

2015 ......... 30 cm .............. 21 cm
2014 .........  5 cm   .............   1 cm
2013 ......... 21 cm .............. 10 cm
2012 ......... 24 cm .............. 18 cm
2011 .........   2 cm  ..............  1 cm
2010 ......... 23 cm ................ M
2009 ......... 10 cm ................ 4 cm
2008 ......... 24 cm ............... 14 cm
2007 ......... 28 cm ............... 15 cm
2006 ......... 11 cm ...............  7 cm
2005 ......... 14 cm ................ M
2004 ........... 8 cm ................ 4 cm
2003 ........... 4 cm ................ M
2002 .......... 11 cm ............... 12 cm
2001 .......... 12 cm ............... 12 cm
2000 .......... 31 cm ............... 30 cm

Prior to 1955, there have been 3 Christmases documented in Winnipeg with no snow on the ground, although these are not part of the official climate record. They were 1939, 1913 and 1877. (Click here for a Winnipeg Tribune article on the rare "green" Christmas in 1939 in Winnipeg that year.) There was also reference made that in Dec 1834, the first snow of the season in Winnipeg fell on Dec 28th.. so it's possible Dec 1834 was also a brown Christmas (but then, we don't know what they considered the first significant snow back in 1834)

Scenes from Christmas day 1939 in Winnipeg

The following photos graced the front page of the Dec 26th 1939 edition of the Winnipeg Tribune. The photos show Winnipeggers taking advantage of a rare snowfree Christmas day that year with activities like lawn bowling at Assiniboine Bowling Club (left) and golf at the St Charles golf course (right). Dec 1939 was the 3rd mildest December on record in Winnipeg, and included the warmest December temperature ever recorded in Winnipeg with a high of 11.7C on Dec 6th.


Lawn Bowling in Winnipeg Christmas Day 1939
Golfing on Christmas Day 1939

 


Monday, December 21, 2015

Another round of snow moving into southern Manitoba Tuesday afternoon/evening.. 5-15 cm likely

Grey area highlights regions most likely
to see 5-15 cm snow Tuesday aftn/night
After a tame start to winter with little in the way of snow, Mother Nature is making up for it this week as yet another storm system brings another round of snow to southern Manitoba Tuesday. This will be the third significant snowfall of the past week in Winnipeg, after last Wednesday's 20 cm dump and Saturday's 5 cm snowburst. For tomorrow, a storm system pushing in from Washington state will track east into North Dakota, spreading snow along the US border by the lunch hour. As the system tracks east, snow will spread into the Red River valley and southeast Manitoba through the afternoon, reaching Winnipeg by mid to late afternoon just in time for the late afternoon rush hour. Snow will increase in intensity through the evening, with a period of heavy snow possible giving snowfall rates of 2-3 cm/hr at times. This will have serious impacts on the afternoon/evening rush hour if the band of heavy snow moves in by 4 pm. Total snowfall from this system is expected to be in the 7-10 cm range for most of the Red River valley including Winnipeg, but amounts of 10-15 cm are possible where the heavier snow band lingers a bit longer. Snow will taper off overnight Tuesday and should be done by the Wednesday morning commute. Luckily winds will not be that strong with this system and temperatures will be mild around -5C which should help with snow clearing operations Tuesday night.  Even so, expect a slower commute Wednesday morning as the city digs out from yet another snowfall.  

Tuesday, December 15, 2015

Snowfall warning issued for WInnipeg/RRV.. 10-20 cm of snow possible Wednesday

A snowfall warning has been issued for Winnipeg and the Red River Valley for Wednesday as a storm system from Colorado moves into Minnesota. Snow from this system will spread into southern Manitoba after midnight and become heavier towards morning.  Snow is expected to move into Winnipeg around 3 am overnight, and become heavier by 6 am or so with 2-5 cm of new snow by the morning rush hour.  Plan to allow extra time to get to work or school tomorrow morning as the commute will be slow due to snow covered roads and slippery conditions. A period of moderate to heavy snow is expected through the morning with snowfall rates of 1-2 cm/hr at times giving another 5-10 cm by midday before snow eases off in the afternoon and evening with another 5 cm or so. This will make for a very slow commute for the drive home (unless everyone leaves earlier because of the storm) All in all, 12-20 cm is possible for Winnipeg by Wednesday night. Occasional light snow will continue Wednesday night into Thursday morning with another couple cm possible. Winds will also pick up later Wednesday into Wednesday night so drifting and some blowing snow will become an issue although bulk of snow will be over by then.

Models coming in line that heaviest swath of snow tomorrow will set up somewhere from the Pilot Mound-Altona area north through Winnipeg into southern Lake Winnipeg region. 10-20 cm possible within this swath. 10 cm outside this main area. Dry slot will give lesser amounts to our southeast and has pushed the heavier band further west.. which is why initial forecast of heavier amounts southeast of Winnipeg has changed. That's what the latest guidance is saying.. now let's see how it all pans out. Got my snow ruler ready!

STORM UPDATE

A snowy commute home for Winnipeg drivers as a band of
heavy snow crosses the city in time for "rush" hour
(photo credit: Winnipeg Free Press)
Light snow started up in Winnipeg around 2 am and by 8 am, I measured 2.4 cm at my site in Charleswood. Snow started to pick up in intensity through the morning with another 4 cm by noon. Snow continued steady but fairly light through the afternoon, before a heavier snowband pushed through the city from 3-5 pm dumping 5 cm of snow in 2 hours at my site. I recorded a storm total of 14 cm by 5 pm, and 15.5 cm by 6:30 pm. Winds were generally light through much of the event, although they started to pick up late in the afternoon into the evening out of the northwest causing some blowing and drifting snow. General snowfall amounts of 10-15 cm were common through the Red River valley and SE Manitoba up to the evening. Snow continued Wednesday night with another 5 cm by Thursday morning. Storm total at my site was 20.5 cm.  

Sunday, December 13, 2015

Storm system to bring snow to Red River valley and SE Manitoba Wednesday.. colder temperatures to follow

Probability of at least 5 cm of snow
within 24 hrs by Wednesday evening
(WPC graphic)
Mild weather continues over southern Manitoba with extensive cloud, patchy fog and occasional freezing drizzle. This stagnant weather pattern is expected to persist for the next couple of days before a more significant storm tracking through Minnesota Wednesday impacts southern Manitoba with snow and increasing winds. There remains some uncertainty with the track of this storm, which will influence snowfall amounts over southern Manitoba. At this point, models are indicating the heaviest snow with this system will fall mainly in eastern North Dakota and northern Minnesota, with lesser amounts over southern Manitoba. Even so, southeast Manitoba and the Red River valley should see some snow with this system, with 5-10 cm possible for most areas. Should the system track a bit further west, snowfall amounts will likely be higher across southern Manitoba. Note also that the system will be bringing increasing north winds Wednesday, which would lead to blowing and drifting snow issues especially over the Red River valley.  Stay tuned for future updates on this developing system.

Average temperatures in Winnipeg over
past 90 days shows persistent warmth
A change to colder weather will follow in the wake of this system for the end of the week into the weekend, with temperatures falling to more seasonable levels for mid December. Keep in mind, normal highs are now -10C in southern Manitoba with lows of -20C.. temperatures we have yet to see so far this season.  The coldest temperature since Nov 1st in Winnipeg has been only -17.5C on Nov 26th,  and we've only dropped below the -15C mark on only 2 occasions so far this season. Truly remarkable given that normal lows are now -20C. Temperatures have been so consistently above normal over southern Manitoba over the past 2 months that dropping to near normal temperatures would seem like a bitter cold snap. Thanks to the strongest El Nino since 1997, Arctic air intrusions have been blocked from surging southward, allowing a persistent flow of mild Pacific air to prevail over the Prairies and much of north America.  In the past 8 weeks, Winnipeg has seen only 5 days below normal, with none since Nov 27th. So a change to even normal temperatures will seem cold. However, indications are the cold weather will not be that intense or prolonged, with above normal temperatures expected to return by next week. This is consistent with a strong El Nino winter, where cold air intrusions are less frequent and shorter in duration.        

            

Sunday, December 06, 2015

December warm spell continues - but trend to colder weather and snow by end of week

It was another balmy day across southern Manitoba Sunday, with temperatures once again well above normal for December.  Snowfree areas and localities in downslope regions were the warmest again as temperatures soared into the double digits yet again, including 11C in Winkler, 10C in Morden and 11C in Wawanesa. In these areas, daytime highs have been above freezing for a full week now, including 2 or 3 days in the double digits.  

Winnipeg didn't fare quite as warm Sunday with southerly winds off a lingering but diminishing snowpack over the northern and eastern Red River valley keeping temperatures in the low single digits (high of +3C) Nonetheless, considering normal highs are now -7C and lows near -18C, few people will complain about temperatures some 10-15C above normal (except cold weather and snow lovers)   But if you're looking forward to colder weather or snow, there's some good news in the forecast. Models are indicating an end to the current December warm spell later this week, with a return to more seasonal temperatures by the weekend. Before that, a weak system tracking across southern MB Tuesday may bring some mixed precipitation (including a threat of freezing rain) Tuesday.  A stronger system will impact southern MB by Thursday with some snow possible which will herald the arrival of colder air later Thursday and Friday into the weekend. There is a possibility of more snow on the weekend, but models are less certain about the timing and amounts.. so that will need to be monitored. In any case, enjoy the balmy weather while you can.. colder weather and snow is on the way for the end of the week.

Dec 4 2015 - Morden soars to record 14.2C. Warmest December day since 1969

Morden resident cuts his lawn on Dec 4 2015
as temperatures soar to 14.2C (from CBC)
One of the more remarkable milestones of this current December warm spell was registered in Morden, MB on Friday Dec 4th when the mercury soared to an astonishing 14.2C, making it not only the warmest spot in Manitoba that day, but in all of Canada.  Having a place in Manitoba get national hot spot honours in December is exceedingly rare, as the balmy west coast, Maritimes or southern Ontario are typically the warmest areas of Canada in winter. The 14.2C reading was a record high for Morden for Dec 4th, beating the previous record high of 12.2C in 1916. It was also Morden's 3rd warmest temperature ever recorded in December, surpassed only by a 14.4C reading on Dec 1 1969, and their all time December high of 17.8C on Dec 6 1939 (yes, 17.8C!).  The 1939 record was established during a historic warm spell that brought the warmest temperatures ever recorded in southern Manitoba in December, including Winnipeg's all time December high of 11.7C on Dec 6th (the only time Winnipeg has observed a temperature of 10C or more in December). That year went on to see a green Christmas across much of southern Manitoba, including Winnipeg.

Max temperatures across southern MB - Dec 4 2015
Warmest readings in snowfree and downslope areas
So how did Morden get so warm on Friday?  Two main reasons: no snow on the ground and warming downslope winds off the Pembina escarpment.  A look at the max temperature map on Dec 4th shows the warmest readings that day were observed over southwest Manitoba (where there was no snow cover), especially in areas with warming south-southwest downslope winds off higher terrain.This included areas east of Riding Mountain (Dauphin, McCreary), north of the Turtle Mountains (Boissevain, Deloraine) and east of the Pembina escarpment (Morden, Miami) Downslope winds off higher terrain can add 2-7C (and sometimes more) to downwind localities compared to areas outside the downslope zone.

 

Relief map of Pembina valley (left) shows Pembina escarpment running just west of Morden, dividing higher terrain to the west and the lower flat plains of the Red River valley to the east. South to southwest downslope winds blowing off the higher terrain can result in warmer temperatures immediately to the east of the escarpment (like a mini-chinook)  Image on the right is a visible satellite image taken Dec 4th at 2:45 pm showing snowcover over southern MB. There was a distinct line from Portage La Prairie through Carman to Emerson, separating snow-covered areas to the east and bare ground to the south and west. Temperatures were some 5-10C cooler over the snow-covered areas, with highs of +2-4C, including a windy +2.3C in Winnipeg (surface plots on image are in degrees F. Morden is shown as 57F (14C) at this time)  The high resolution image below shows the snowcover in greater detail. Note the distinct snow line running through Carman to northeast of Emerson. Note also deeper snowpack (brighter white area) still evident west and northwest of Winnipeg.


High resolution MODIS satellite image showing snowcover
over Red River valley on Dec 4 2015

Synoptic set up - Dec 4 2015

Sfc map - 6 am Dec 4 2015
925 mb - 6 am Dec 4 2015
On the morning of Dec 4th, southern Manitoba was is a southerly flow of very mild air between a surface ridge south of Lake Michigan, and a trough over western Saskatchewan.

Of note is how warm the air was just above the surface that day. Air temperatures up to +14C were observed over the Morden area at 925 mb, or about 700 metres above ground.  This is exceptionally warm air for December, and was helped northward by a strong south-southwest wind of 50+ knots (90+ km/h) at this 925 mb level. These warm values would eventually cool off to +8C by mid afternoon, but it showed the potential for temperatures over 10C in snowfree areas that day. Morden got the greatest benefit of this warm air aloft, helped by sunshine, snowfree ground, and downslope winds. It should be noted that on this day, the downslope winds did not reach much further east of Morden, and in fact, nearby Winkler, just east of Morden, only got up to 9.5C that day as their winds were more southeast through the day tapping cooler air off the snowcovered Red River valley.

 A look at Morden's hourly temperature chart for Dec 4th shows that temperatures rose from +5C at 9 am to +10C by 11am, and 12.7C by noon. It would climb to a maximum of 14.2C shortly after 2 pm, before downslope winds from a 200 degree direction shifted to the southeast (160 degrees) tapping cooler air over the snow-cooled Red River valley. Temperatures dropped quickly to 8C by 3 pm and +5C by 4 pm.


Road trip to Morden  

Snowcover becomes meager
east of Carman
It's not very often that a place in Manitoba experiences 14C in December, so I decided to take a drive to Morden that day to witness such a rare event. Considering it was just an hour away from Winnipeg made it that much more amazing to experience. I left Winnipeg shortly before 1 pm heading off on Highway 3 through Sanford to Carman. There was a brisk southerly wind gusting to 60 km/h, keeping temperatures in the +2 to +3C range almost all the way to Carman. As I got closer to Carman, the meager snowpack started to diminish and the temperature rose to +6C in Carman.

Snowcover disappears south
of Carman
Green fields north of Morden
Dec 4 2015

As I turned south on Hwy 3 heading to Morden, the snowpack disappeared completely just south of Carman and from there on, there wasn't a hint of snow anywhere, with the landscape resembling something from October or April.  The temperature rose to 10C by the Hwy 23 intersection and 11C by the turnoff to Morden.

Hwy 3 to Morden - Dec 4 2015
Once I headed west to Morden, the outdoor temperature on my car thermometer climbed 1C per kilometre as I headed into the downslope region, reaching 14C by the time I got into Morden. My car thermometer would peak at 15C at 2:15 pm. Getting out in Morden, it felt like April.. no snow on the ground, a balmy breeze under clear blue skies, and temperatures in the teens. It was quite the difference from chilly snowcovered Winnipeg just an hour away! By 3 pm, the temperature had dipped to 11C as winds shifted into the southeast and by 3:30, it was down to 7C as I headed back to Winnipeg. It was a quick visit, but certainly a novelty to experience springlike warmth just an hour outside of Winnipeg!  If you're looking for a balmy getaway near Winnipeg, keep an eye on those downslope winds!


Downtown Morden - Dec 4 2015

Car thermometer registers
15C in Morden - Dec 4 2015

Dec 4 2015 in Morden - or is it April?


Wednesday, December 02, 2015

Mild November caps off 4th warmest fall on record at Winnipeg

Mild weather continued through much of November across southern MB, with mean monthly temperatures almost 4C above normal for November. In Winnipeg, November finished with an average monthly temperature of -1.0C or 3.9C above normal. This ties Nov 1928 as Winnipeg's 20 mildest November since 1872. Temperatures were especially mild over the first 3 weeks of the month before the first snowfall of the season on the 18-19th. Up until then, temperatures were above normal every day ending a streak of 25 straight days above normal since Oct 26th.     
  


Temperature anomaly map (left) for November 2015 shows core of abnormal warmth centered over northern Minnesota and southern MB in November. Only 4 days of the month were below normal in Winnipeg (right)  

The mild November helped cap off the 4th mildest fall in Winnipeg since 1872, tying the falls of 2009 and 1953 at 7.3C, or 3C above normal.







90 day graph of temperatures (right) in Winnipeg over the Sep-Nov period 2015. All 3 months were above normal, with only 19 days below normal over the 3 month period. 

Outlook for December: 


6-10 day CPC outlook
3-4 week outlook to Dec 25th

Milder than normal weather is expected to continue through at least the first half of December, thanks to a very strong El Nino this year. The next week looks especially mild, with an extended flow of Pacific air that will keep temperatures about 10-15C above normal into next week. Temperatures will be at or above the freezing mark over much of southern Manitoba over the next few days, especially in snowfree areas such as the Pembina valley (Morden, Winkler), SW Manitoba (Melita), downslope areas east of the Riding Mtns  (Dauphin, McCreary) and forested areas (Whiteshell)  In these areas temperatures may reach +5 to +10 C by the weekend.  Long range models are hinting at colder weather (near normal) arriving the weekend of Dec 12-13th, but it's too early to say if that's a trend to colder weather for the second half of December, or a passing cold snap. Past El Nino years suggest that cold snaps are usually short lived and not as intense as the upper pattern rebounds to bring a return of milder Pacific air over the country.  In fact, when looking at past strong El Nino years, there's a very high probability that December will end up warmer than normal in southern MB (as well as much of the northern and eastern US). The image below is a composite of average December temperature anomalies of 6 strong El Nino years since 1950 (1997, 1991, 1982, 1972, 1965, 1957)  Of these years, only one December was colder than normal in the Prairies (1972)  The top 2 warmest Decembers on record in Winnipeg occurred during strong El Nino events (1877 and 1997)  

Composite image of December temperature anomalies
based on 6 strong El Ninos since 1950

Saturday, November 21, 2015

The week ahead..

A general look at the weather this week..

Sunday Nov 22nd: Hi: +1C. 
Some snow then turning milder. 
System tracking through central MB will spread an area of snow across the Interlake and eastern Manitoba. Bulk of snow will be mainly north and east of Winnipeg where 2-5 cm is possible, but Winnipeg will likely see a period of snow between 9 am and 3 pm, with a dusting to 2 cm possible. Once the snow ends, winds will shift into the west and draw in milder air sending temperatures up to the 0 or +1C mark by late afternoon.

Monday Nov 23rd: Hi: +2C 
Fair and mild. 

Tuesday Nov 24: Hi: +1C 
Fair and mild.

Wednesday Nov 25th: Hi: -2C in the morning falling to -8C by evening.
Turning windy and colder with snow.
A potent storm system emerging from the west coast will track across Montana and into the Dakotas bringing a widespread area of snow across southern Manitoba. Current indications are for 2-5 cm of snow for Winnipeg during the day. Increasing north winds and colder temperatures will likely produce areas of blowing and drifting snow especially in the afternoon and evening. 

Thursday Nov 26th: Clearing and colder: Hi -10C. 
Generally fair but cold. Temperatures dipping to -20C Thursday night.

Friday Nov 27th: Hi: -7C 
Nicer afternoon after a cold start to the day with temperatures at or below -20C.

Saturday Nov 28th:  Hi: -4C 
Milder with a chance of flurries. 

Sunday Nov 29th: Hi -5C 
Grey Cup day: Fair and seasonably cold.
At this early point, it looks like conditions should be fair and seasonably cold for the Grey Cup with average temperatures for late November and no precipitation expected. Models are not showing any major storm systems over the Grey Cup weekend, with a warming trend expected for the first week of December.  Things could change, but at this point, weather conditions look favourable for the Grey Cup game.

Tuesday, November 17, 2015

Major storm system to bring first wintery blast of season across southern and central MB Wednesday night into Thursday...

A pair of strong storm systems over North America will converge into a major storm system over the Manitoba/Ontario border late Wednesday, bringing the first onslaught of wintery weather to much of southern Manitoba Wednesday night into Thursday.  This will be the first real taste of winter for many in southern Manitoba after what has been an exceptionally mild fall to this point with little in the way of snow or cold weather.  Wednesday will start off cloudy and mild with periods of rain developing in the afternoon ahead of the converging storm systems. Things start to get interesting later Wednesday afternoon into Wednesday evening as the two storm systems begin to converge over NW Ontario producing an increasing NW flow of colder air across southern Manitoba. Rain will change to snow Wednesday evening as temperatures drop below the freezing mark, and continue through Wednesday night into Thursday morning. Strong northwest winds of 50-60 km/h with gusts of 70-90 km/h will produce locally poor visibilities in snow and blowing snow with local power outages possible due to the combination of ice buildup and strong winds. Snowfall amounts for Winnipeg and the RRV are expected to the in the 5 cm range with the bulk of snow falling across central and northern Manitoba, including the interlake and Whiteshell regions where locally heavier bands of lake effect snow are possible. As a result, expect a slower commute Thursday morning as drivers deal with the first snowfall of the season along with subfreezing temperatures and strong winds.

Sunday, November 15, 2015

Very mild start to November as extended autumn continues.. but change to colder weather on the way this week

It was another glorious fall-like weekend across southern MB with sunny skies and temperatures in the double digits. Sunday's high of 13.1C in Winnipeg was almost 15C above normal for Nov 15th, and was our 21st straight day above normal (since Oct 26th). The weather was par for the course in what has been an exceptionally mild start to November across much of central and eastern North America, especially over the upper US midwest and central Canada, including southern MB. In Winnipeg, the average temperature over the first half of November has been +3.3C, which is almost 6C above normal for the Nov 1-15 period.  Every day this month has been above normal so far and the coldest temperature this month has been only -6.4C, even though normal lows are now close to -10C. The downside of the mild weather has been frequent cloud cover, with only 4 days of sunshine through the first 12 days of the month. Snow however has been virtually absent in Winnipeg, with only a couple days with some light flurry activity. As of mid November, the grass is still green in the city thanks to a lack of deep freezes so far.



Figure 1 (left): Mean temperature and anomaly from normal (C) showing core of exceptional warmth this November over upper midwest  
Figure 2: (right) Winnipeg mean daily temperature past 30 days (Oct 16 - Nov 15) showing persistence of above normal temperatures over past 4 weeks


As mild as it's been, it may be surprising to learn that Winnipeg has had even milder starts to November in previous years. At 3.3C, the first half of November this year will rank only as the 8th mildest start to November since 1872. The warmest start to November (as defined by the mean daily temperature from Nov 1-15) was in 1981 and 1931, with an average temperature of +4.9C over the first half of the month.  Nov 1981 saw 10 days reach +10C or more in the first half with a peak of 18.2C on Nov 4th.  This year, Winnipeg has recorded only 4 days in November of +10C or more. This shows that our warmth this year has been mainly due to exceptionally mild nights, rather than mild days. Frequent cloud cover and lack of cold air intrusions has resulted in a persistence of mild nights with temperatures well above normal minimums for November. The top 10 warmest first halfs of November in Winnipeg since 1872 are:


So what does the rest of November look like? Well, mild weather is expected to continue the first half of this week, then a pattern change around mid week as a strong storm system brings a substantial cool down later this week with temperatures likely falling below normal for the first time this month. We may even see our first shot of accumulating snowfall here in the city Wednesday night into Thursday. Colder than normal temperatures will dominate through next weekend before a moderating trend next week.

Multi-model ensemble shows big temperature dip coming to
Winnipeg by Thu Nov 19th (850 mb temps top)
The transition to colder weather will likely be accompanied by
our first snowfall Wed night into Thursday  (precip amts bottom)

Friday, October 30, 2015

A mild October.. will mild pattern continue through November?

October 2015 was another mild month over the Prairies with temperatures averaging some 2-3C above normal over western and central Canada. In Winnipeg, the month finished with an average temperature of +7.1c, or 2.1C above the normal October average of +5.0C (30 year average). The mild weather comes on the heels of a warm September that finished 3C above normal, and was Winnipeg's 6th warmest September since 1872. The combined Sep-Oct average temperature of 11.5C made it Winnipeg's 9th warmest such period since 1872. (30 year average is +8.9C)


Map of temperature anomalies (left) showing widespread warmth in October over western North America. 30 day temperature graph for Winnipeg (right) showing dominance of above normal temperatures during October.  

Weather outlook for November 2015

According to NOAA, the mild weather pattern is expected to continue through much of November across the Prairies, with generally above normal temperatures over the next 2-4 weeks. (see maps below)  This doesn't mean warm weather every day, but generally a greater frequency of above normal temperatures during the next month.





CPC temperature outlooks maps for early and late November
 (8-14 day outlook left, and 3-4 week outlook right) 



The mild pattern appears to be in response to a very strong El Nino that has developed over the Pacific this year, and is currently on track to be one of the strongest El Nino episodes recorded since reliable records began in 1950. As of October, the 3 month averaged El Nino index was at +1.5 and expected to climb to +2 or higher by December, the strongest El Nino since 1997, regarded as the strongest El Nino event since 1950.  

Backgrounder: 2015 El Nino 

 Top: Graph of Oceanic Nino Index since 1950 showing strongest ENSO events
Lower: Graph of this year's El Nino ocean temperature anomalies expected to peak by December 

Note that Winnipeg had its second warmest winter on record in 1997-98, thanks to the unusually strong El Nino that year. That winter saw very little snow through December, with only a trace of snow on the ground in Winnipeg on Christmas day. The winter finished with an average temperature of -8.2C, a whopping 6C above normal, and the second warmest winter on record in Winnipeg, second only to that of the incredibly mild winter of 1877-78 (another very strong El Nino year)



NOAA winter outlook for Dec 2015-Feb 2016 showing greater odds
for drier and warmer than normal winter over Prairies


Will El Nino bring mild weather for Grey Cup? (Nov 29 2015 in Winnipeg)    

Grey Cup organizers and football fans are hoping that the mild weather pattern so far this autumn will continue through November, or at least through Nov 29th when the 103rd annual Grey Cup is scheduled at Winnipeg's Investors Group Field. Normal highs in Winnipeg by the end of November are around -6C, with lows of -14C. Temperatures on Nov 29th however have ranged from a high of +6C to a low of -33C (based on Winnipeg airport data since 1938). Last year, Winnipeg saw a high of -8.7C on Nov 29th with a low of -19.6C, and a game time temperature of -16C with strong northerly winds of 40 km/h giving windchills of -28 to -30. Officials are hoping for much milder conditions this year as footballs fans gather for the annual football finale. Given previous El Nino patterns, there are better odds this year that temperatures will be warmer than normal in Winnipeg for the end of November. Crunching some numbers from similar El Nino patterns in the past shows about a 55% chance of above normal temperatures for late November this year (highs > -4C), a 25% chance of below normal temperatures (highs < -7C) and a 20% chance of near normal temperatures (-4 to -7C)

So it appears that milder than normal conditions are favoured for the Grey Cup this year. If so, it would be the third consecutive time that Winnipeg has hosted the Grey Cup with mild weather (along with 2006 and 1998). But as any sports fan will tell you, underdogs can always win a game. So although mild weather is the odds on favourite this year, it only takes one storm system to bring in an untimely shot of snow and cold weather to southern Manitoba at the end of November, even during an El Nino year. This year's strong El Nino would lower the odds of that happening, but you can't rule it out completely. So let's hope the mightly forces of the El Nino Zephyrs from the west prove too strong for the punishing attack of the Arctic Express from the north. Go team El Nino!!



EXTREMES FOR NOV 29 USING PRE-AIRPORT CITY DATA BACK TO 1872

RECORD HIGH: +  7.2C (1932)
RECORD LOW:  -36.7C (1875)


PREVIOUS GREY CUP WEATHER IN WINNIPEG:
NOV 19 2006 ........Clear. High + 1.5C, low -9.2C.   Kickoff temp: -3C
NOV 22 1998 ....... Sunny. High + 9.7C, low: 0.6C.  Kickoff temp: +5C. Record mild day!
NOV 24 1991 ....... Sunny. High - 15.6C, low: -21.9C. Kickoff temp: -16C

WEATHER FACTORS THIS YEAR:
- Very strong El Nino pattern favours milder than normal conditions for late November
- 55% chance of highs > -4C on game day, 25% chance of highs < -7C


Sunday, October 11, 2015

Powerful winds expected overnight through Monday morning.. gusts of 100 km/h or more expected.

After an unseasonably warm and pleasant Thanksgiving weekend, the weather will be taking a dramatic turn tonight into Monday as a pair of cold fronts push across southern Manitoba. The first cold front is pushing through this evening and will shift balmy south breezes into the west with temperatures falling into the teens. A few showers and isolated thunderstorms are possible along this front with westerly wind gusts of 60 km/h possible. The second cold front will be pushing through the RRV early Monday morning, ushering in powerful NW winds and much cooler temperatures in the single digits.. a dramatic difference from Sunday's almost summerlike weather. The big story Monday however will be the winds.. with sustained north to NW winds of 60-70 km/h gusting to 100 km/h or more at times. This can lead to roof and tree damage as well as local power outages.  The strongest winds are expected between 4 am and noon in Winnipeg and the RRV, before the winds start diminishing somewhat in the afternoon (but still strong into the early evening)        

Note that a rare STORM force wind warning has been issued for Lake Manitoba and the south basin of Lake Winnipeg for Monday morning. Storm force wind warnings are issued for winds of 48 knots (90 km/h) or greater on the lakes. These warnings are seldom issued and are used only for the strongest windstorms on the lakes. As a result, mariners and cottage owners need to be prepared for very strong north to northwest winds off the south end of the lakes gusting to 100 km/h or more overnight through Monday morning, with major crashing waves causing local shoreline erosion. This is NOT a time to be on the water, so stay onshore Monday until winds subside.

So batten down the hatches.. a major change in the weather is on the way!  

POST SUMMARY..

Strongest wind gusts reported Oct 12 2015 
(EC and MB ag-wx stations) 

Starbuck .............. 104 km/h
Gretna ..................100 km/h
Victoria Beach ....... 96 km/h
Emerson ................ 96 km/h
Elm Creek ............. 96 km/h
Altona ..................  95 km/h
Winnipeg .............. 94 km/h
Treherne ............... 94 km/h
Morris ................... 86 km/h
Gimli ..................... 86 km/h


Tuesday, October 06, 2015

Some rain on the way Wednesday, then clearing skies with a warm Thanksgiving weekend ahead

A quick moving low pressure system will cross southern Manitoba Wednesday bringing an area of rain into the Red River valley by mid to late afternoon into the evening. The bulk of the rain is expected between 4 pm and midnight in Winnipeg and the RRV with general amounts of 5-10 mm expected. Amounts up to 15 mm are possible in some areas where embedded convection will generate locally heavier showers at times. Rain will move out of southern Manitoba overnight Wednesday with clearing skies expected Thursday as a ridge of high pressure builds in from the west. That ridge will cross southern Manitoba Friday bringing sunny skies and seasonable temperatures in the mid teens.

The outlook for Thanksgiving weekend looks fantastic with well above normal temperatures expected. As the ridge moves east of Manitoba, a southwest flow of unseasonably warm air will spread across all of the Prairies Saturday and Sunday, sending temperatures soaring into the 20s along with plenty of sunshine. Temperatures in Winnipeg could be approaching record highs by Sunday (current record high for Sunday Oct 11th is 26.1C on Oct 11 1942) A cold front is forecast to push through southern MB Sunday evening with a chance of showers, followed by  somewhat cooler conditions for holiday Monday (but still above normal with highs of 16-18C) All in all, looks like a great holiday weekend to enjoy fall weather at its finest!   

Friday, October 02, 2015

September 2015 Highlights


See Winnipeg weather for additional details on September 2015 weather.

Tuesday, September 29, 2015

New weather station online!



After 14 years of trusty weather data with an original Davis Vantage Pro weather station, I've finally upgraded to a new Vantage Pro 2 unit.  The new station is equipped with a 24 hr fan aspirated temperature shield which should result in even more accurate temperature readings than before (which were already pretty good).  Wind data will also return, although the anemometer is currently mounted on a 10 foot pole in my backyard surrounded by forest on the north and east sides. As a result, wind speeds and direction will not be ideal, but it's better than nothing. Eventually, I hope to move the anemometer to rooftop level to get more accurate wind readings. The new station will also give UV readings as my old unit did. All the data is uploaded onto my Rob's Obs website and updated every 5 minutes.  Data is also uploaded every 10 minutes to Weather Underground (ID = IMBWINNI3) 

Hopefully, this station gives me just as many years of trusty, reliable and accurate weather data as my original Davis station did.

Thursday, September 24, 2015

Rainfall across southern MB overnight


Graphic showing rainfall reports from area of convection last night that tracked across ND/MB border. Bulk of rain fell in northern ND just south of international border where 50-100 mm (2-4") was reported. Generally 15-30 mm fell across far southern MB, with the highest amounts of 20-30 mm in the Pembina valley. Most of the rain fell south of Winnipeg with just a trace to 1 mm reported in the city.

Tuesday, August 04, 2015

Weather station issues

After 14 years of reliable service, It looks like my trusty Davis Vantage Pro weather station is starting to show its age. I'm experiencing more frequent data transmission problems which means current weather data is not getting uploaded to my website. The issue appears to be a failure with the super-capacitor in the sensor suite (ISS) which helps to power the unit when the solar panel is not operating (nighttime, cloudy skies, weak sun)  As a result, I only get data during bright sunlight hours wen the solar panel is providing power to the unit.  This ISS super-capacitor needs to be replaced (which is a bit of work) or I just might bite the bullet and upgrade to a new weather station altogether (after 14 years, it may be time)  In the meantime, I will try to keep the station running on backup batteries until I figure out what to do with it. If anyone has experience or advice on repairing the super-capacitor on the Davis Vantage Pro ISS, let me know.        

Monday, May 04, 2015

Blog on haitus for awhile

Folks..

I'm not finding the time to update this blog as frequently as I have in the past, so I'm just going to suspend the blog for awhile until I can find more free time to devote to it. I may post some entries from time to time, but they won't be on a regular basis. I thank everyone for their loyal following and participation, and I hope to return to more frequent updates in the fall. Until then, you can follow some excellent weather blogs at A Weather Moment or Winnipeg Weather for current local weather information and updates. 

Rob     

Tuesday, April 14, 2015

Warm and windy Wednesday.. Burn ban in effect

A low pressure system tracking into southern Saskatchewan will bring a strengthening southerly wind across southern MB Wednesday , especially through Winnipeg and the Red River valley.  Southerly winds will increase to 40 or 50 km/h by mid morning with gusts to 70 or possibly 80 km/h by midday into the afternoon. The windy conditions will be accompanied by warm temperatures in the low 20s, and very low humidities of 15 to 20% leading to dangerous fire weather conditions.  Local grass or brush fires are possible, and a burning ban is in effect for much of southern and eastern MB. The strong winds may also lead to areas of blowing dust as dry topsoil gets blown around by the gusty winds.  Once winter snow cover is gone, April becomes a prime month for grass fires and blowing dust in the Prairies as strong gusty winds can combine with dry surface conditions to help promote fires and drifting topsoil. Increasing dewpoints, surface moisture, rainfall, and leaf/crop green-up in May and June help to reduce the threat of grass fires and blowing dust as the growing season progresses. However, grass fires can also flare up in the fall.. particularly in October at the end of the growing season and before the first snows of winter.

Thursday, April 02, 2015

Chilly start to April


Woodlands radar at 11:50 am shows
squall line of heavy snow heading
towards Winnipeg from the northwest 
Winnipeg about half an hour later. Visibility
dropped to near zero in heavy snow for about
30 minutes leaving about 2 cm of fresh snow
(photo from @kirastorm)
After a springlike first day of April that saw temperatures climb to 16C in Winnipeg, the weather turned decidedly winterlike today across southern MB as a sharp cold front sliced across the region this morning, ushering in a strong push of Arctic air today. The front was accompanied by periods of snow, including a band that tracked across the city over the lunch hour producing near whiteout conditions in heavy snow, as well as gusty north winds and temperatures near-5C. The band gave a quick coating of about 2-3 cm of snow that whitened the bare landscape. Skies cleared by late afternoon, but that will allow temperatures to drop to well below normal values tonight as an Arctic ridge of high pressure builds southward. Overnight lows of -14C are forecast for Winnipeg, some 10C below normal for early April. (it's been worse though.. record low for April 3rd is a frigid -27.8C in 1932)  Unfortunately, it looks like we'll be locked in a cold pattern into early next week before we start seeing some moderation towards normal values later in the week. That will mean daytime highs struggling to get above freezing or the low single digits over the next few days, with lows in the -10C range. Luckily, no major snowfall is expected during this cold snap, with only some minor dustings expected from time to time as weak systems pass through. Look at the bright side.. this time last year, we still had 40+ cm of snow on the ground, and we wouldn't see bare ground until April 20th!

Sunday, March 22, 2015

Some wintery weather for the first week of spring..

After a spring like end to winter this year, old man winter will be making a return visit this week as a series of weather systems track across the southern Prairies and northern Plains states. The first system tonight is fairly weak, and is bringing some snow to southern Saskatchewan as of this (Sunday) evening. This area of snow will track across southwest Manitoba and the Riding Mtns tonight into the Red River valley overnight into Monday morning. Generally 2-4 cm of snow is possible with this disturbance, with a coating of 1-2 cm possible for Winnipeg overnight into Monday morning. Not a lot of snow.. but our first taste of the white stuff in over two weeks for the Monday morning commute.. so be prepared for it (roads in the city should just be wet rather than snow covered, but there could be some slippery sections, especially outside the city) 

Forecast probabilities of snowfall 10+ cm
Tuesday into Wednesday Mar 24-25th

Things get more interesting Tuesday into Wednesday as a stronger storm system tracks across Montana into North Dakota. This system is forecast to spread an area of heavier snow over southern Saskatchewan Tuesday which will be spreading into SW Manitoba, western Parklands and Interlake areas by Tuesday afternoon/evening. Temperatures will be warmer (above freezing) over Winnipeg and the RRV as well as SE Manitoba, so precipitation will likely begin as rainshowers later Tuesday before changing over to snow Tuesday night into Wednesday.  Snow is expected to continue much of Wednesday before tapering off Wednesday night. Snowfall amounts with this system will vary widely across southern MB, but at this time it appears the bulk of snow will be over the Riding Mtns and Interlake areas (possibly 10-20 cm) with lesser amounts over the RRV and SE MB (5-10 cm?). However, changes in the storm path and intensity could result in heavier amounts elsewhere. Stay tuned on this developing storm system as it brings a potentially significant snowfall over portions of southern Manitoba by mid week.

This photo montage from @JoshWright nicely chronicles
progression of snowcover in Winnipeg area over
the past couple of weeks


Storm snowfall update: (as of 9 am March 25th) 

Winnipeg ................ 5 cm
Portage La Prairie .... 5-10 cm
Brandon .................. 6 cm
Steinbach ................ 5 cm

Dauphin .............  15-25 cm
Rossburn ............. 20 cm
McCReary ........... 18 cm
Hodgson .............. 18 cm
Gilbert Plains ........ 15 cm
Neepawa ............. 15 cm
Roblin .................. 14 cm
Rivers ................... 10 cm
Miami ..................... 6 cm
Pinawa .................... 5 cm
Morris .................... 2 cm