Thursday, March 31, 2016

Cold start to April with occasional bouts of snow

The mild conditions that finished March will unfortunately not be continuing into the start of April as a spell of colder than normal weather pushes into southern Manitoba. A cold front tracking through southern Manitoba today is bringing a northerly flow of colder into the province, along with a coating of snow over western Manitoba (up to 10 cm northwest of Brandon early this morning).  On Friday, a clipper system is forecast to dive across southern Manitoba by the afternoon, bringing occasional snow to the RRV in the afternoon and evening, with a coating to 3 cm possible. This will be followed by a cold Saturday with highs remaining below freezing (normal highs for early April are +5C)  On Saturday night, another fast moving clipper will spread an area of light snow across southern Manitoba, with again, a coating to 3 cm possible Saturday night into Sunday morning. Monday looks quiet and cold before a stronger clipper system threatens rain and wet snow Tuesday into Tuesday night. Below normal temperatures are expected Wednesday and Thursday behind the system before a more general warmup by the end of the week into next weekend. 

Friday, March 25, 2016

The week ahead: Generally mild and pleasant before possible mid week storm system. Long range models indicating unseasonably cold start to April

Weather highlights for upcoming week... (Fri March 25 to Fri April 1st)

Cold night ahead! Clear and cold tonight with lows dropping to -15C in Winnipeg by early Saturday morning.. possibly some -20C readings north of the city.

Nice Saturday.. After a chilly start, ample sunshine will boost temperatures up to 0C by afternoon with light winds in the morning becoming south 20 km/h in the afternoon.

Saturday night into early Sunday.. weak system passing through southern Manitoba may bring a dusting of snow to Winnipeg and the RRV.

Easter Sunday: Nice day. Early flurries giving way to sunshine. Afternoon highs of +5C.

Monday, Tuesday: Dry and mild. Highs of +7 to +10C.

Wednesday Mar 30: Storm system tracking through the Dakotas will bring an area of rain and snow across the Dakotas, possibly spreading into southern Manitoba. At this point, it appears bulk of precip will be over North Dakota, however some models (like the GFS) are bringing more significant precipitation into southern Manitoba, with possible snow accumulations. Will need to watch this system closely and see if models trend further north.

Thursday: Dry and seasonable: Highs near +5C (however, temperatures will be cooler if we get snow from Wednesday system)

Friday April 1: Mother Nature is gearing up for one of her cruel April fools jokes. Clipper system expected to track across southern Manitoba bringing an area of rain and wet snow with it. System will drag a cold front through southern Manitoba by Friday night, ushering in an unseasonably cold outbreak for the first weekend of April. Highs on Saturday and Sunday may only be around the -10C mark, with lows of -15 to -20C possible. (normal highs for early April are near +5C, with lows of -6C)  Below normal temperatures are expected into the first week of April before a moderating trend later in the week.

Wednesday, March 16, 2016

Big melt ends with drenching rains.. colder weather on the way with some snow

Drenching rains this morning caused some street flooding
in Winnipeg, including this stretch of Academy Rd
It's been an exceptionally mild past 5 days over southern Manitoba, with record breaking temperatures soaring into the double digits, even in snow covered Winnipeg.  The mild weather has resulted in a rapid snow melt, with no snow on the ground now throughout the Red River valley including Winnipeg, which had a 30 cm snowpack just a week ago.  The thaw was punctuated by a soaking rain Tuesday through the Red River valley, with 15-20 mm of rain falling in most localities between 6 am and 2 pm. The soaking rain on the still frozen ground caused drainage problems with reports of locally flooded streets in Winnipeg and some overland flooding outside the city.

 The storm system that brought the rain has moved north and weakened while a new storm system takes shape south of Lake Superior. This storm system will spread an area of snow across NW Ontario and northern Minnesota Wednesday, with some of that snow reaching southern Manitoba by the afternoon.

Weather map valid 4 pm Wed March 16 shows band of
wet snow and rain over eastern Manitoba moving west
Usually, weather moves from west to east in our part of the world, but this band of precipitation will be moving into southern Manitoba from the east, as it rotates counterclockwise around the Lake Superior storm system. The band of snow may begin as some rain in the Red River valley in the afternoon but will quickly change to snow as temperatures drop. Snow will continue Wednesday evening with 5 cm possible by Thursday morning. Higher amounts of 10 cm are possible east of Winnipeg closer to the Ontario border, and in fact, snowfall warnings are posted for northern Minnesota and parts of NW Ontario for 10-20 cm of snow Wednesday.  (UPDATE: Snowfall warnings now issued for Sprague and Whiteshell areas for 10-15 cm of snow today) Keep that in mind if you plan on travelling east of Winnipeg Wednesday.   This system will be drawing colder air into southern Manitoba for the latter half of the week into next week with temperatures closer to normal for mid March. High temperatures will be near or slightly above freezing, with lows of minus 5 to minus 10. Certainly nothing abnormally cold for this time of year, but not as mild as the past week or so. 

Saturday, March 05, 2016

Big melt begins

A pattern change to warmer weather is set to begin this weekend, with an extended period of above freezing temperatures likely much of next week across southern Manitoba. The warmer temperatures will start eroding the lingering winter snowpack still intact over much of southern Manitoba, including the Red River valley where current snowdepths range from 25 to 40 cm. However, some places in southern Manitoba have already lost much of their snowpack especially over SW Manitoba along the SK border, and parts of the Pembina river valley around Morden. These places will see the warmest temperatures this weekend, with values likely climbing into the double digits Sunday.  Here in snowcovered Winnipeg and Red River valley, temperatures will not be quite as warm.. with highs Sunday in the 3 to 5C range. Note also that today will be see extensive cloud cover in the RRV as low level moisture gets trapped under a strong inversion (with warm air aloft overriding cold air at the surface) along with brisk southerly winds. Not the most pleasant day even though temperatures will be climbing to near zero today.

Mild temperatures will continue Monday, but a low pressure area tracking though the Dakotas will bring some springtime rain, yes rain, to southern MB Monday afternoon and evening. Slightly cooler weather is on tap Tuesday and Wednesday before temperatures climb above freezing again for the balance of next week.

Thursday, March 03, 2016

Blast from the past: 50th anniversary of the Blizzard of March 4 1966 - one of the worst blizzards on record for Winnipeg and Red River Valley

Portage Ave buses in downtown Winnipeg - Friday March 4 1966
No one was going anywhere on this day (Free Press photo)
The winter of 1965-66 was a cold one in southern Manitoba. January 1966 was tied with January 1883 as the second coldest January on record in Winnipeg, with a bone chilling monthly mean of -26.7C, some 10C below current January normals.  February 1966 saw a brutal cold snap from the 15-20th when temperatures fell to a low of -45.0C in Winnipeg on the 18th, the 2nd coldest temperature ever recorded in the city since 1872. By the end of February, temperatures were finally starting to warm up with the mercury climbing above the freezing mark on Feb 27th for the first time in almost 3 months. Southern Manitobans were eager to see spring weather finally on its way.

But Mother Nature had different plans..

Surface map - midnight March 2 1966
showing low pressure developing
over Colorado
On Wednesday March 2nd, an area of low pressure started to form over Colorado, while a strong upper disturbance was pushing inland from the Pacific. The energy from this impulse would start intensifying this Colorado low and take it northeastward towards the northern US plains. Meanwhile, strong high pressure over Saskatchewan was locking in Arctic air over the Prairies. The battle zone between these two clashing systems was setting up right over the Red River valley and Dakotas.

Surface map - midnight Mar 3 1966
Storm moving over South Dakota
By the morning of the March 3rd, the Colorado low storm system had moved into southeast South Dakota and was moving slowly towards southwest Minnesota. The storm system was getting caught by an intensifying upper low which slowed down the progress of the storm. During this time, winds were increasing over the Red River valley, with Winnipeg reporting north winds of 50 gusting to 70 km/h on the 3rd, along with reduced visibilities of 2-5 km in blowing snow.  Blizzard conditions were widespread over the Dakotas on the 3rd, and would move into Winnipeg shortly after midnight that night.

Friday March 4th 1966 - The Great Blizzard arrives in southern Manitoba

By the time Winnipeggers awoke Friday morning March 4th, blizzard conditions were widespread across the city and throughout the Red River valley. The pressure gradient between the intensifying storm system over southern Minnesota and the high pressure ridge in Saskatchewan was producing incredibly strong northerly winds through the Red River valley, with sustained wind speeds of 70-80 km/h in Winnipeg, gusting as high as 113 km/h (70 mph, 61 knots)   The combination of the severe winds and heavy snowfall from the storm was producing severe blowing and drifting snow with whiteout conditions across the city and valley. Visibility at Winnipeg airport would drop to zero by 4 am Friday, and would stay at zero for 14 consecutive hours into the evening. (Check out this rare CBC video footage showing the whiteout conditions in Winnipeg during the blizzard. Amazing how bad the visibility was even in a built up city.)

March 4 1966 midnight weather map shows storm
over southern Minnesota giving blizzard conditions
over Dakotas moving into southern Manitoba

Storm system at noon Mar 4 1966
giving blizzard conds over RRV.
Storm is at its peak here with
north winds of 80 km/h gusting
over 100 km/h in Winnipeg

Even walking became a challenge in the
deep snow and whiteout conditions
(Portage Ave - Winnipeg)
The slow moving storm system would loop over Minnesota on March 4th, maintaining blizzard conditions over Winnipeg for almost 20 straight hours, and up to 36 hours over portions of the southern Red River valley. The storm dumped 35.6 cm of snow in Winnipeg that day, the second heaviest one day snowfall on record in the city (the greatest one day snowfall of 38.1 cm fell on the exact same date, March 4th, back in 1935)  The heavy snowfall combined with storm force winds led to massive drifts in the city, some as high as rooftops of houses. People who ventured to work or stores in the morning were trapped as roads became impassable.  City buses were shut down by 11 am as streets became blocked with drifts and stranded vehicles. Hundreds of people were stranded downtown at the Bay and Eatons department stores, which became storm shelters for people for the night until they could find a way home.  The city was paralyzed through the weekend into Monday before things could finally get cleared up for the new work week. At least two deaths in the city were blamed on the storm due to heart attacks, and snow removal costs for Winnipeg were upwards of $1 million (1966 dollars), a huge sum back then. Similar scenes were observed throughout the Red River valley and North Dakota, with rural areas immobilized for days by massive drifts left by the blizzard. 30-50 cm of snow fell throughout the Red River valley and southeast Manitoba during the blizzard, with up to 70 cm recorded in Grand Forks from March 2nd to 5th. 50 years later, the Blizzard of 1966 still ranks as one of the most severe blizzards ever to hit Winnipeg and the Red River valley, as well as North Dakota.

Track of 1966 storm shows how system looped over SD and MN
prolonging blizzard over ND and srn MB (from Douglas Ramsey)
Note: A similarly strong blizzard slammed Winnipeg and southern Manitoba on Nov 7-8 1986, dumping 35 cm of snow on the city along with 70-90 km/h winds bringing the city to a standstill. Unlike the 1966 blizzard however, the storm occurred late Friday through Saturday, was well forecast, and did not strand as many people as the 1966 blizzard did.  Also, the blizzard of Apr 4-7 1997 was another severe blizzard to hit the Red River valley. That storm was a longer duration event, lasting 3 full days, and dumping a total of  48 cm of snow on Winnipeg along with blizzard conditions for a full 27 hours. That blizzard eventually led to the disastrous "Flood of the century" that spring over the Red River valley.  

Stranded at Eatons: Hundreds of employees and shoppers had
to spend the night at downtown department stores (Mar 4 1966)
The blizzard left huge drifts across Winnipeg
neighbourhoods, some as high as rooftops
Sidewalks became snow tunnels
due to the massive drifts
Portage Ave after the storm - massive snowbanks made
downtown shopping, and parking, a challenge


Front page of the Winnipeg Free Press - March 4 1966
proclaims "wild blizzard"  as "worst in history"
Front page of the Winnipeg Free Press - March 5 1966
reporting on storm aftermath and cleanup
 Blizzard of 1966 - by the Numbers (Winnipeg)   
  •  Number of consecutive hours with blizzard conditions: 18 (2 am - 9 pm)     
  •  Number of consecutive hours with zero visibility: 14 (4 am - 7 pm)
  •  Wind speeds: North 70-80 km/h sustained, with gusts over 100 km/h
  •  Peak gust: 113 km/h (70 mph, 61 knots)
  •  Snowfall: 35.6 cm (14 inches)
  •  Lowest central pressure of storm: 983 mb on the 3rd, 987 mb on the 4th
  •  Snowdepth: went from 30 cm pre-storm to 66 cm after storm 
  •  Snowdrifts: 1-3 meters
  •  Fatalities: 2 (heart attacks) 
  •  Cost of clean up: $1 million (1966 dollars)
NOTE: Official blizzard conditions are defined as a visibility of 400 meters or less and wind speeds of 40 km/h or more, lasting for at least 4 hours    

March 4 1966 weather column from
Winnipeg Free Press says it all


Grafton: 32" (81 cm)
Devils Lake: 30.5" (77 cm)
Grand Forks: 27.8" (71 cm)
Jamestown: 27" (69 cm)
Bismarck: 22.4" (57 cm)
Langdon: 20" (51 cm)
Fargo: 15.4" (39 cm)

(graphic: NWS Bismarck)

Need more details?  For a detailed historcial account of the blizzard of 1966 and its impacts on North Dakota, northwest Minnesota and southern Manitoba,  consult the book "One to Remember - The Relentless Blizzard of March 1966" by Douglas Ramsey.