Frigid finish for February.. coldest winter in Winnipeg in at least 35 years

Simulation of general upper air pattern this winter
showing lobes from the "polar vortex" (outlined)
pushing south into central North America this year
(image credit: earth.nullschool.net)

Another spell of frigid weather is in store for southern MB this week as the relentless winter of 2013-14 refuses to ease its grip across central and eastern North America. Temperatures this week will be running some 15-20C below normal for the end of February, when highs around -6C in Winnipeg are more usual at this time of year. The coldest weather is expected later this week as a surge of bitterly cold Arctic air plunges in from the north, producing daytime temperatures in the minus 20s and nighttime lows in the minus 30s, temperatures more typical of a cold snap in mid January than late February. No way to sugarcoat it folks.. it's just miserably cold and will stay that way all week.  (We're not alone in our winter misery. Check out article on winter misery index to put this year's harsh winter into historical perspective even in the US)

90 day temperature anomalies across the US (deg F)
showing core of abnormally cold temperatures during winter of 2013-14
over central North America

This latest cold snap will ensure that February finishes well below normal in Winnipeg, the third straight month with well below normal temperatures here. February is on pace to finish with an average temperature close to -20C, some 6.5C below normal for February (normal monthly mean of -13.5C in Winnipeg based on 1981-2010 average) This would make this the coldest February in Winnipeg since 1979 which had a mean temperature of -22.0C.  The next coldest most recent February was in 2003 with a mean temperature of -19.4C.

This frigid February will also cap off what will end up as the coldest winter in Winnipeg in at least 35 years. The overall average winter temperature since December 1st will end up around -20C, the coldest winter here since the winter of 1978-79 which had an average temperature of -20.8C.  That winter was the 10th coldest winter on record in Winnipeg going back to 1872.  The coldest winter on record here was 1874-75 with a mean temperature of -23.0C.  (Average winter temperature in Winnipeg is -14.5C, based on 1981-2010 normals.)

90 day temperature anomalies for
Winnipeg Dec 2013-Feb 2014
Mild days have been rare

TOP 15 COLDEST WINTERS IN WINNIPEG  (since 1872*) 

1.      1874-75 ......... -23.0C
2.      1886-87 ......... -22.9C
3.      1883-84 ......... -22.3C
3T.    1884-85 ......... -22.3C
5.      1882-83 ......... -21.7C
6.      1892-93 ......... -21.5C
6T.    1935-36 ......... -21.5C
8.      1887-88 ......... -21.3C
9.      1879-80 ......... -21.0C
10.    1978-79 ......... -20.8C
11.    2013-14 ......... -20.3C   (updated)
12.    1916-17 ......... -20.2C
13.    1889-90 ......... -20.1C
14.    1872-73 ......... -19.8C
14T.  1875-76 ......... -19.8C
14T.  1949-50 ......... -19.8C


"normal" winter average  ........................  -14.5C (based on 1981-2010 normals)

*NOTE: Winnipeg records from Winnipeg airport (1938-current) and St John's College (1872-1938)

Any hope for a turnaround in March? 

Understandably, winter weary Winnipeggers are eager for a change from the below normal weather pattern of the past 3 months. Unfortunately, current forecasts and past history suggest that March will likely remain colder than normal. Of the top 15 coldest winters listed above,  *ALL* were followed by colder than normal Marches (based on a normal temperature of -5.8C for March, 1981-2010 average) The average March temperature following those 15 top cold winters was -12.2C, or over 6C below normal. The warmest March in the group was 1917 at -6.7C, while the coldest was in 1883 at -15.2C.  

It's easy to understand why March would continue below normal following a very cold winter.  A long cold winter will ensure a deep and persistent snowpack well into March, making it difficult for warm air to surface. Solar energy will either be reflected back into space by the snowcover, or be used to help melt the snowpack instead of warming the air. So a lot of energy is lost due to snowcover. Only when snowcover is gone can more persistent warmth become established. But getting rid of snowcover will take time.. unless there's a major shift in the overall pattern to bring persistently warm weather and some rainfall to accelerate snowcover loss. Such a shift is possible, but history suggests that it's not likely to happen. As a result, be prepared for another colder than normal month in March. That doesn't mean every day will be below normal..  we'll have some mild days in there as well. But overall, colder than normal weather will likely predominate during the month.  Note that days are getting longer and the sun is getting stronger in March, so at least the cold won't feel as intense as the middle of winter. Still, the sooner we get back to "normal" weather, the better.