Thursday, January 30, 2014

Cold but stable pattern into first part of February

Some good news and bad news on the weather front. The bad news is that the below normal temperature pattern of the past two months is expected to continue into February with no signs of any major pattern change towards milder weather in the foreseeable future. The good news is that the volatile pattern of frequent clipper systems and snowfall across southern MB over the past two weeks will be ending for the next little while, as a drier more stable pattern takes hold across the Prairies with generally high pressure systems dominating. This will be welcome news to snow weary Manitobans who have had to endure frequent rounds of nuisance snowfalls over the latter half of January, along with strong winds, blowing and drifting snow, and wild temperature swings. This will also be welcome news to overworked road crews who have had a tough time keeping area roads and highways cleared.  The frequent bouts of bad winter weather has led to numerous accidents over southern MB, with MPI reporting well above normal accident claims for both December and January. The upcoming stable pattern should help bring accident claims down over the next little while. (as long as motorists drive safely and for the conditions!)

As for January 2014, it will end up with a mean temperature of around -20C in Winnipeg.. about 3.5C below normal for January (1981-2010 average of -16.4C), the coldest January in Winnipeg in 10 years (January 2004 average -21.7C)   As cold as January seemed this year, it won't even rank in the top 40 coldest Januarys in the city since records began in 1873, showing how cold Januarys can get in southern MB, and also how spoiled we've become with the warmer winters of the past decade.  The normal for January in Winnipeg is now -16.4C (1981-2010 average), some 3C warmer than 30 years ago.  However, if we look at the combined period of December-January, then the average temperature of -20.5C this winter in Winnipeg makes it the coldest Dec-Jan period since 1949-50 (average of -21.2C) and the second coldest in the past 120 years.  So if you're feeling that it's been awhile since you've experienced a winter this cold through the end of January, you know why.

Top 15 coldest December-January periods in Winnipeg (since 1872)

1.    -23.2C   1886-87
2.    -22.4C   1884-85
3.    -22.2C   1887-88
4.    -22.0C   1882-83, 1879-80, 1876-77
7.    -21.6C   1872-73
8.    -21.5C   1893-94, 1874-75
10.  -21.4C   1883-84
11.  -21.3C   1880-81
12.  -21.2C   1949-50  (coldest of the 20th century)
13.  -21.0C   1892-93
14.  -20.5C   2013-14
15.  -20.4C   1906-07   

As for what is in store for February, cold weather will likely continue much of the month based on past climate trends. Of the 25 Januarys in Winnipeg with a mean temperature of -20 to -22C, 76% were followed by colder than normal Februarys, while only 16% were warmer than normal. 8% were near normal. Note however that the most recent cold January, January 2004, was followed by a milder than normal February, so there is some hope that February can turn around, although admittedly the odds are against us. We can only hope Mother Nature takes some pity on us for her harsh start to winter this year.  

Link: How cold has this January been in the US?  (from Chris Burt, WeatherUnderground)


  1. Rob, I've heard the term OMEGA block used before. What exactly is an OMEGA block?? Is that the pattern that we are currently in, or expected to be in for the beginning of the month.

  2. Anonymous.. An "omega" block refers to a type of weather pattern in the upper atmosphere (commonly defined by the jet stream) that resembles the Greek letter omega, that is, a large hump in the middle bounded by two dips on either end. This pattern is usually very stable (aka "blocking" pattern), often lasting for many days or even several weeks and results in a prolonged stretch of dry warm weather under the middle "hump" (or ridge), while cool unsettled weather persists in the dips (or troughs) on either side. So if you like dry warm weather, the omega block can mean good news if you're under the ridge portion of the block, but bads news if you're stuck in the troughs on either side.

    Over the past couple of weeks, we've had an omega block over the Yukon and Alaska giving them unseasonably warm dry weather, while we've had persistently cold weather downstream under the upper trough on the eastern flank of the omega block.

  3. To give you an idea how exceptionally warm it's been in Alaska under that upper block, consider that on Monday Jan 27th, Nome AK hit a high of 51F (+10.6C), which was not only its warmest temperature ever recorded in January, but also warmest for Nov, Dec, Feb and March! 51F is their normal high in early June! Putting that into perspective, it would be like Winnipeg hitting 24C in January. Incredible.

  4. Wow can you say boring for the next couple of weeks? Below normal and no snow. A break from shoveling at least! But after that I might be ready for another storm, even if it is snow!

  5. That January stat may come as a surprise to people (not even top 40 coldest) but if we look at the combined period of Dec-Jan, then it becomes the coldest start to winter (Dec-Jan) in Winnipeg since 1949-50, or 64 years ago. I think that's what people are feeling.. not necessarily how cold January was, but how long and cold this winter has been. In that regard, yes.. it's been 64 years since we've seen a winter as cold as this one has been through the end of January.

  6. Looks like a stratospheric warming will be occuring over Greenland in about 10 days which could lead to a blocking pattern and a -NAO later in February. Not good news for us, not at all. Hard to imagine this but it sure is starting to look like we are in for repeat of 2013 as far as March and April are concerned. Yikes.

  7. On the bright side January did warm up alittle from December. A good start yes?

  8. Rob, what are the chances of a repeat of March and April 2013 this year?

  9. Anonymous.. My gut feeling is that March and April will likely continue to be below normal, although I don't think April will be as bad as last year. Still, if you look at years like 1950, 1979, and 1996 which have good correlation with this winter, spring was very late with below normal Aprils, and all were followed by major floods on the Red that spring. I sure hope it doesn't pan out like that this year and Mother Nature gives us a break, but at this point, it's not looking promising for an early spring.

  10. Rob,
    On Cbc news last night they said little or no snow on Thursday and weather network is calling for 5cm. What do you think?

  11. Todd.. We have a frontal trof dropping in from the north with a westerly flow ahead of it… not really the best set up for a good snow for us. Models are showing a dusting to 2 cm Thursday afternoon into Thursday night. 5 cm seems a bit on the high side given current guidance.

  12. Well, there is some good news on the weather front. There continues to be some indications of warmer weather for the 2nd half of the month however with good news there is also bad news and that is the cold may likely return at month's end in response to the stratosphere warming event that will take place over the pole in a week from now. But any warmer weather we can get, we'll take it.

  13. Hey Rob,

    It's getting kind of boring outside with no snow in over a week. Do you see any on the horizon? Perhaps a significant snowfall?


  14. Rob Will this polar warming event have the potential to match 1989

  15. Jeff..

    Staying pretty quiet with no major systems in the foreseeable future.. for the next week anyways. Might see weak systems by the end of next week.. but right now, nothing to indicate a major dump on the way. That could change, but at this point, looks quiet.. which is fine by me. Can use the break after that awful January.

  16. >> Anonymous said... Rob Will this polar warming event have the potential to match 2009?

    I assume you're talking about the advertised "stratospheric warming" signal that some have alluded to later this month, which is supposed to bring in another prolonged cold spell over central and eastern Canada. I have no idea how strong it is or if it will develop.. so I can't speculate on comparisons with other years.

  17. Snow depth by year. Massive difference. Could be a late spring. :-)


  18. Hi Rob,

    I see WN & EC are calling for snow next Wed. Any chance it is more than 5 cm?


  19. >> Anonymous said... Hi Rob, I see WN & EC are calling for snow next Wed. Any chance it is more than 5 cm?

    Anonymous.. Still early, but yes, Wednesday's system does look like it has the potential to bring more than 5 cm to Winnipeg and southern MB. In fact, European model is calling for at least 10 cm for Winnipeg based on last night's model run, while other models are a little more conservative in the 2-5 cm range, although they do hint at heavier snowfall with the system somewhere in southern MB. We may also see a dusting to a couple of cm of light snow on Tuesday. But Wednesday's system is the one to watch.. could be our first significant snowfall since our last clipper back on January 25th (a nice 2.5 week break without snow)

  20. @Dingod
    Corrections made to "2014"see NOHRSC Regional Snow Analysis Upper Midwest
    An assimilation was performed 2/5/2013 over the Western part of the United States and Canada to adjust the modeled snow water equivalent. Throughout much of the area up to 1 inch of water needed to be removed from the snowpack except for the Sierra Nevadas, Cascades, and Mogollon Rim in Arizona where up to 1.5 inches of water was added to the snowpack. New observations over Canada helped to validate current snow conditions and required large amounts of water, up to 8 inches, to be removed. The large snow pack that had covered the Western United States a few weeks ago is now starting to break up and is beginning to concentrate at higher elevations. Airborne Snow Surveys are scheduled for parts of the Missouri River Basin and as data becomes available it will be assimilated into the model. More snow is expected over the area starting Thursday and continuing into the weekend.

    NOHRSC Airborne Snow Survey Program
    The Airborne program has no scheduled flights in this region for the week of February 04, 2013.

  21. Suprisingly, the warmest day in december is 10.7 on thee sixth in 1939, and the warmest day in February is the exact same on the 25, back in 1958!

  22. Welcome back windchill warnings. Oh how, I've missed you for the past 2 weeks.....NOT!!

  23. Quick moving weak system forecast to bring a dusting to 2 cm of snow to Winnipeg/southern MB Tuesday before a second stronger clipper system tracks through North Dakota Wednesday, bringing more significant snowfall across southern MB later Wednesday through Wed night into early Thursday. Amounts for Winnipeg vary from a couple cm from GPDS model to a good 8-10 cm from GFS. GFS is strongest of the 3 main long range models, so we'll see if it trends to a weaker system, or other models buy on to the GFS solution. In any case, looks like some accumulating snow on the way for mid week.

    After that, some good news with a nice warming trend by the 17th (early next week) with temperatures climbing towards the freezing mark.. and possibly above.

  24. Although the temperatures have tended to be in the -20s instead of the -30s in Jan/Feb, the persistent wind is making this winter feel like one of those "coldest ever" years. Also, the lack of a break - a few days of milder weather.