February ends on mild quiet note.. Winter of 2011-12 4th warmest on record in Winnipeg. First winter in 70 years without a -30C reading.

90 day temperature graph for Winnipeg showing temperature anomalies from Dec 1st to Feb 28th. Only 18 days this winter have been below normal.

February 2012 will end on a mild and quiet note in southern MB, with highs this afternoon just slightly below freezing under partly sunny skies. February will finish with an average temperature near -10C in Winnipeg, about 3.5C above normal. Together with a very mild December and January, the winter of 2011-12 will go into the record books as the 4th mildest winter in Winnipeg since records began 140 years ago in 1872. (Note: "Winter" is defined as the 3 month period of Dec, Jan and Feb) This winter will finish with an average temperature of -9.7C, almost 6C above normal and just 0.2C below the third warmest winter of 1986-87 (-9.5C) February also marks the 8th consecutive month that has averaged above normal in Winnipeg, extending a streak that began last July.

Note also that Winnipeg has yet to hit the -30C mark this winter, with the lowest temperature so far of -28.9C (recorded on Jan 18th and Feb 10th). If the -30C mark isn't reached this month, it would be the first winter in over 70 years and only the second time in Winnipeg's history that the city has failed to drop to -30C or lower during the winter. The only other winter with a non -30C temperature between November and March was the winter of 1930-31, with an extreme minimum temperature of -29.4C on Feb 9th.

Top 5 warmest winters in Winnipeg (since 1872)

1. 1877-78 ............. -7.2C
2. 1997-98 ............. -8.2C
3. 1986-87 ............. -9.5C
4. 2011-12 ............. -9.7C
5. 1930-31 ............ -10.1C

Normal winter average .... -15.3C (1971-2000 normal)

Major winter storm to hit south of the border over Dakotas/Minnesota.. blizzard conditions possible late Tuesday into Wednesday

A powerful winter storm system is forecast to track across South Dakota into southern Minnesota Tuesday into Wednesday, bringing widespread heavy snow and blizzard conditions to portions of the eastern Dakotas and Minnesota. The worst conditions are expected near and south of the Fargo area, where snowfall totals of 30 cm or more are expected along with strong winds and blizzard conditions, especially Tuesday night into Wednesday. Travel will become severely impacted in this area with highway closures possible, including the I-94 corridor between Bismarck and Minneapolis. The storm is expected to affect much of northern and and central Minnesota as well, including through the Minneapolis area where a wintery mix of snow, freezing rain and ice pellets is likely. People planning on travelling to or through the Dakotas or Minnesota tonight or Wednesday should be prepared to alter travel plans as this major winter storm moves in.

The storm is not expected to impact southern Manitoba, although some snow from the system will spread up to the international border where a few cm are possible.

Storm system threatens snow for Sunday

A storm system is expected to cross North Dakota Sunday bringing a widespread area of snow across the southern Prairies and northern Plain states. Current indications are that the heaviest snow with this system will affect areas mainly near and south of the international border Sunday, although snow is expected across much of southern Manitoba as well. Early snowfall estimates point to about 5 cm along the TransCanada corridor (including Winnipeg) with 10 cm closer to the US border and 10-20 cm south of the border. If the storm tracks further north, these amounts will increase northward. This system is still 3 days away, so there continues to be some uncertainty on its exact track and associated snowfall, but it certainly bears watching, especially if you're considering travel Sunday across southern MB or the northern US states. Stay tuned.

UPDATE: Sat Feb 25th: Winter storm warnings are now in effect for northern ND and MN, and southern SK up to the Manitoba borders. Looks like worst of storm will be tracking from central Alberta through southern Saskatchewan into North Dakota where snowfalls of 10-20 cm are forecast, with southern MB on the northern edge of the heaviest snow (up to 10 cm possible near the US border - see accompanying map showing 24 hr snowfall amounts between noon today and noon Sunday). Note that over southern SK today, strong easterly winds and snow will combine to produce possible blizzard conditions at times today, including over the TransCanada from the AB border to Regina area. If you have travel plans out west today or south tomorrow, be prepared for poor highway conditions and possible road closures.

Snowfall totals from Sunday across southern MB..

Winkler ............ 16 cm
Belmont ........... 13 cm
Miami .............. 12 cm
Altona .............. 10-15 cm
St Labre .......... 10 cm /SE of Steinbach/
Steinbach ......... 5 cm
Winnipeg .......... 4 cm
Oakbank ........... 2 cm

Feb 20-21st snowfall

Radar image showing 24 hour accumulation estimates up to 8 am Feb 21st based on radar returns. Note sharp western edge of snow shield bissecting Winnipeg.

Yesterday's storm system brought the most significant snowfall of the winter to areas east of the Red River valley overnight into Tuesday morning. Snowfall amounts of 10-20 cm were widespread east of Winnipeg, including 13 cm in Oakbank, 14 cm in Landmark, 15 cm in Beausejour, and 15-20 cm over Steinbach, Pinawa, Falcon Lake and Sprague. In Winnipeg, there was a sharp gradient in snowfall accumulations across the city, ranging from 3 cm in the west end up to 9 cm in the southeast (St Vital area). For further details on this event, see Weather Moment storm summary as well as North Dakota/Minnesota snowfall summary.

System to bring snow over RRV, southeast MB and neighbouring US, NW Ontario Monday into Monday night

A storm system developing over the US plains will bring an area of snow over the eastern Dakotas and NW Minnesota Monday, which will spread into southeast MB Monday afternoon into Monday night. Snow may be heavy at times especially south of the US border and east of the RRV where amounts of 10 cm or more are possible. In fact, the US National Weather Service in Grand Forks has issued a winter weather advisory for areas south and east of Grand Forks into NW Minnesota where 3 to 5 inches of snow is forecast (8 to 13 cm). UPDATE: Winter weather advisory has been expanded northwest to include Grand Forks and areas up to the Canadian border.

(Map showing 24hr snowfall amounts from RGEM between 6 am Monday and 6 am Tuesday. Dark green area is 10-15 cm over Lake of the Woods with sharply lower amounts west of the RRV. Light green line is 2.5 cm. Model output from 00z Feb 20 RGEM run)

In southern MB, there will be a sharp western edge to this area of snow, with little or no snow falling west of the RRV. In Winnipeg, snow is expected to begin late in the afternoon, with 2-5 cm possible through Monday night. Depending on where this western edge sets up, Winnipeg may get brushed with just a dusting of snow (more likely), or heavier amounts of 5-10 cm (less likely). Fortunately, winds with this system will be light and temperatures will be near the freezing mark so snow will be wet (even possibly beginning as rain at first) with little in the way of blowing or drifting. However, the snow may be heavy at times, especially south and east of Winnipeg with visibilities reduced to 500 metres or less. This will create locally poor travelling conditions and slick road conditions at times over the southern RRV and SE MB by Monday evening including Hwys 1, 59 and 75 south and east of Winnipeg.. an issue for residents heading back from the US or NW Ontario from the long holiday weekend.

Milder week ahead.. and staying dry..

Milder weather will be returning to southern MB this week as the Arctic airmass of the past few days moves east. Temperatures will rebound to the minus 5 range today into Monday and Tuesday before rising towards the freezing mark by midweek. The main story will be the continued dryness with little or no precipitation expected the rest of the week as storm systems pass by well to the south or north of southern MB. Snowfall has been scarce this winter over the RRV, with no measurable snow so far this month and well below normal amounts over the winter. Snowfall in Winnipeg through Feb 11th this winter has totalled 48 cm, compared to a long term average of 75 cm by this time (64% of normal). Last year, we had already received 115 cm by early February leading up to a major spring flooding situation. (see photo above comparing a stretch of Saskatchewan Ave between this year and last year. Photo credit George Morrison)

Warmer winters - the new "normal" ?

This past January was Winnipeg's 3rd warmest January on record, with a monthly average of -10.8C, 7C above the "normal" January average of -17.8C. It was also Winnipeg's 7th consecutive month above normal. But what is "normal" exactly and how is it defined? In the case of monthly average temperatures (the average of all the daily highs and lows during the month), "normal" is based on a 30 year average of monthly temperatures at that site, and are updated every decade. This is the standard definition of normal as defined by the World Meteorological Organization (WMO) and is the standard used around the world.

The table below lists the 30 year normals for Winnipeg over the past century for each winter month, as well as the winter season overall (defined as Dec-Feb period) The latest 30 year normals (defined by the 1981-2010 values in red) shows a significant warming trend over the past set of 30 year normals (defined by the 1971-2000 period in blue) This is because the updated normals now include some exceptionally warm winters from the 2000s, and have lost some cold winters from the 1970s. For example, the new "normal" for January will now be -16.4C, a full 1.4C warmer than the -17.8C average we've been using over the past decade. (Note: Environment Canada is still not officially using the updated 1981-2010 normals since they have a backlog of quality control to do on climate data. Until that is done, they will still use the 1971-2000 normals.) Looking further back, the new January average of -16.4C is almost 3C higher than the normal January value of -19.3C in the 1951-80 period. In other words, a normal January in the 50s, 60s and 70s would be considered 3C below normal now! Winters were definitely colder 30 years ago!

30 year winter normals - Winnipeg

30 yr period....... DEC ....... JAN ...... FEB.........WINTER (DJF)

1981-2010 ....... -13.5C .... -16.4C .... -13.5C ...... -14.5C
1971-2000 ....... -14.4C .... -17.8C .... -13.6C ...... -15.3C
1961-1990 ........ -14.7C .... -18.4C .... -15.2C ..... -16.1C
1951-1980 ........ -14.0C .... -19.3C .... -15.6C ..... -16.3C
1941-1970 ........ -13.7C .... -18.3C .... -15.8C ..... -15.9C
1931-1960 ........ -13.2C ..... -17.7C ..... -15.5C ..... -15.5C
1921-1950 ........ -13.6C ..... -17.5C ..... -15.4C ..... -15.5C
1911-1940 ........ -13.3C ..... -18.3C ..... -15.4C ..... -15.7C
1901-1930 ........ -13.7C ..... -18.2C ..... -15.6C ..... -15.8C
1891-1920 ........ -13.8C ..... -18.8C ..... -17.2C ..... -16.6C
1881-1910 ........ -14.6C ..... -20.1C ..... -18.4C ..... -17.7C
1873-1900 ....... -15.4C ..... -21.1C ...... -18.7C ..... -18.4C

Note also that the new 1981-2010 normal for December is almost 1C warmer than the 1971-2000 normals (again due to some very mild Decembers in the 2000s). On the other hand, February has remain relatively unchanged (-13.5C vs -13.6C) Put them all together, and "normal" winters in Winnipeg now average -14.5C, the mildest they've ever been since record-keeping began in the 1870s. (and +0.8C higher than the 1971-2000 winter normal)

The table also shows that winters in the 1920s, 30s and 40s were milder than the 50s, 60s and 70s. So this does show some sort of natural climate variability over the course of a century. However, the table also clearly shows that the past decade has seen some exceptionally mild winter weather that has made winters in Winnipeg the warmest in modern history. Will the trend to warmer winters continue through the 2010s, or will natural climate variability bring some colder winters back in our future? Let us know what you think in the latest Rob's Obs poll..

We interrupt this mild winter for a brief cold snap..

The above normal temperatures so far this month will give way to a couple of days of bitterly cold weather as a sharp cold front crosses southern MB early Thursday. Northerly winds of 30 to 50 km/h will usher in much colder air from northern MB Thursday, with 8 am temperatures around -10C falling to -22C by 6 pm along with windchills of -35 (see forecast temperature graph) Temperatures will continue to fall Thursday night reaching -30C by Friday morning, along with windchills near -40. Friday will be bright and sunny but very cold, with highs only in the minus 20s . Fortunately winds should be light Friday as high pressure builds over the region. The cold snap is expected to be short lived however as moderating temperatures move in over the weekend into next week.

Super Sunday sets new record highs over southern Manitoba

It's Super Sunday today as the Giants take on the Patriots in the 46th Super Bowl in Indianapolis.. but the phrase could just as easily have described the weather in southern Manitoba today as sunny springlike conditions prevailed across the southern Prairies. In Winnipeg, temperatures soared to a daytime high of +6.8C, 17C above normal and just 0.4C off the day's record high of +7.2C set in 1963. Temperatures of +7 to +10C were recorded over the snowfree western RRV including Carman and Morden. At least 3 record highs were set in southern MB today including Melita (6.3C), Pilot Mound (+8.8C) and Fisher Branch (+5.6C) The mild weather will be short lived however as a cold front crosses southern MB overnight, ushering in more seasonable temperatures for Monday and Tuesday.

Another foggy night tonight.. staying mild through the weekend..

Mild temperatures, melting snow, light winds, and clear skies have combined to produce widespread dense fog the past two nights in Winnipeg and the Red River valley, and similar conditions are expected again tonight. Areas of dense fog are expected to redevelop after sunset, with locally near zero visibility at times tonight into Friday morning. Increasing cloud cover tonight may make the fog less widespread than the past two nights, but areas of fog are still expected. The fog has made for some poor travelling conditions, but has also created some dazzling wintery landscapes as trees become coated in a beautiful white layer of hoarfrost (see photo) Milder than normal weather is forecast through the weekend over southern MB before more normal temperatures move in next week.