Friday, January 29, 2016

Mild end to January.. February to start on a cold note..

Other than a midmonth cold snap, temperatures
have been mainly above normal in January
January is ending on a mild note as another flow of mild Pacific air floods across the Prairies into southern Manitoba. Balmy west winds pushed temperatures up to +3.2C in Winnipeg today, some 14C above normal for late January and just 1.2C off the record high for the date (4.4C in 1992)   Above normal temperatures will continue over the weekend, although they will be cooling off from Friday's values with highs near freezing Saturday and -5 Sunday. The mild end to the month will ensure that January ends up above normal with an average temperature of around -14.5C, or 2C above the normal January mean of -16.4C.  This will be the fifth consecutive month with above normal temperatures in Winnipeg and southern Manitoba, stretching back to last September.

Turning colder for first half of February

Upper pattern for 2nd week of February
suggests below normal temps for MB/Ont
The outlook for February looks colder, at least for the first half of the month as the upper weather pattern changes to allow more prolonged periods of Arctic air into Manitoba. Long range models are indicating that the Arctic vortex over Baffin Island will dig an upper trof across Hudson Bay into eastern North America, while an upper ridge builds over the West Coast. This type of setup usually means a more sustained period of below normal temperatures for southern Manitoba. This will likely mean a colder than normal first half of February.. before hopefully a pattern change to milder weather for the latter half of the month.

850 mb temperature anomalies for 1st and 2nd weeks of February
shows sustained cold pattern coming up (ECMWF EPS guidance)  


A colder than normal February would be at odds with what history suggests February will be like during strong El Nino years (as we have this year)   A composite temperature plot of the past 6 strongest El Ninos since 1950 (image left) shows a tendency of above normal temperatures over the Northern Plains (and southern Prairies)  During the last very strong El Nino in 1997-98, February ended up as the warmest February on record in Winnipeg with a mean monthly temperature of -4.6C, some 9C above normal. The 2nd warmest February in Winnipeg, in 1878, was also during another very strong El Nino year. But there have been some exceptions.The Februarys of 1958 and 1966 were colder than normal in southern Manitoba, especially 1966 which featured a brutal cold snap in mid February that saw temperatures plummet to -45.0C in Winnipeg on the 18th, the second coldest temperature ever recorded here since 1872. But take heart, even in those cold Februarys, temperatures turned milder in the latter part of the month, including a record high of +11.7C in Feb 1958 on the 25th, Winnipeg' all time warmest February temperature. So if we do get that cold weather that is currently being suggested over the next two weeks, there's a good possibility that it won't last the entire month.


  1. Saving grace may be the highly degraded and reduced snowpack over the Prairies and Northern Plains.. allowing for considerable (hopefully) modification of that arctic air and an eventual breakdown of the pattern.

  2. Clipper coming through southern MB on the weekend.. looks like it will bring a swath of 5-10 cm across Winnipeg and RRV, possibly 10-15 cm over Dauphin/Riding Mtn/Interlake regions. Bulk of snow in Winnipeg expected between 3 pm Saturday and 3 pm Sunday.