Snowy Wednesday morning commute.. then a mild slushy afternoon..

Weather map valid 6 am Wed morning shows area
of snow over RRV (blue) with freezing rain (red)
over southwest Manitoba (RGEM model)

A quick moving storm system over northern Alberta will be dropping southeast into southern Manitoba overnight, bringing a wintery mix of precipitation to the area. Snow will be spreading into the Parklands and northern Interlake regions after midnight reaching Winnipeg and the Red River valley by 5 am Wednesday morning. Snow will likely be heavy at times through the morning rush hour in Winnipeg with 5 to 10 cm possible between 6 am and noon. That will have a significant impact on the morning commute due to snow covered roads and poor visibility so plan on taking extra time getting to work or school Wednesday morning.  Further west, snow will likely mix with or change to freezing rain over southwest Manitoba where freezing rain warnings are in effect.

Meteogram for Winnipeg from ECMWF model shows
heavy burst of snow through Wed am rush hour

For Winnipeg, snow will taper off by noon before things will get a lot slushier in the afternoon as our winds shift into the west tapping milder air from Saskatchewan. This will send temperatures above freezing in the Red River valley including Winnipeg with afternoon highs near +2C expected. That will mean a lot of slush and melting snow on the roads into the evening rush hour, so make sure you have plenty of washer fluid if you're out driving Wednesday.    

Staying cold into next week.. then a warming trend

Southern MB will be locked into a cold weather pattern for the next little while until a moderating trend begins next week.  Temperatures this week will continue below normal (normal highs -13C, lows -23C) with a reinforcing shot of Arctic air this weekend when temperatures will struggle in the mid minus 20s, and lows in the minus 30s. This will be the longest stretch of below normal temperatures in southern MB since at least August. Long range guidance is hinting of a moderating trend by the middle of next week, with temperatures hopefully rising into the minus single digits by the end of the week.

Mild start to January.. but colder weather on the way by next weekend

2016 is off to a mild start over southern Manitoba with temperatures above normal along with mainly sunny conditions. (Normal highs right now are -13C with lows of -23C) The mild and tranquil weather pattern is expected to continue much of this week, before a change to significantly colder weather (as in plug-in-your-car cold) moves in later in the week through next weekend.

Winnipeg forecast shows change to much colder weather by next weekend

850 mb temperature plot valid next Monday Jan 11th
from ECMWF shows large Arctic outbreak over Prairies

Temperatures this week will be mainly in the minus single digits with no significant precipitation expected through Thursday. On Friday, a storm system passing through the Dakotas will spread an area of snow across southern Manitoba, with a general 2-5 cm possible. Winds will shift into the north behind this system, heralding the arrival of much colder air for the weekend into early next week. Look for daytime temperatures in the minus 20s and nighttime lows in the minus 30s as the coldest airmass of the season pushes into the Prairies.



So once that cold air gets here, how long will it last?  The coldest core of the airmass looks like it will be coming through Sunday through Tuesday before a slight moderation next week. After that, it's tough to say how January will end up, however given past previous strong El Nino episodes, the odds favour a milder than normal January over southern MB.  Of the past 6 strong El Ninos since 1950, five Januarys were milder than normal here, including during the record strong El Ninos of 1997-98 and 1982-83.  (see composite map below)  Note that cooler than normal weather is more likely over the southern US due to a strong southern jet stream bringing more frequent storm systems and precipitation from California through Texas to the US southeast.  

JANUARY TEMPERATURE ANOMALIES DURING STRONG EL NINOS

Composite map showing average temperature anomalies in January
based on average of past 6 strong El Ninos since 1950

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 

* NOTE: Official "snow on ground" readings for Winnipeg 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 can 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 (by about 30%), owing to the fact that the airport site is more exposed and more prone to blowing, drifting and compacting of the snow pack. 

Prior to 1955, there have been at least 3 Christmases noted with no snow on the ground in Winnipeg: 1939, 1913, and 1877 (based on anecdotal and newspaper reports) Coincidentally, the 4 years with green Christmases in Winnipeg were also the top 4 warmest Decembers on record.

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. Coincidentally these are 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 that 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 are from Christmas Day in 1939 in and around Winnipeg. The photos show Winnipeggers taking advantage of a rare snowfree Christmas day that year with activities like lawn bowling at Assiniboine Bowling Club (bottom left) and golf at the St Charles golf course (bottom right). Dec 1939 was the 3rd mildest December on record in Winnipeg, and included the warmest December temperature ever recorded in the city with a high of 11.7C on Dec 6th.

Winnipeggers pose on a rare snowfree golf course on
Christmas Day 1939 

Lawn Bowling in Winnipeg Christmas Day 1939

Golfing on Christmas Day 1939

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.