Tuesday, November 22, 2016

Late start to winter - Winnipeg posts latest date on record for first measurable snow of the season

After a record warm start to November, winter finally returned to southern Manitoba as the first measurable snow of the 2016-17 winter season fell across Winnipeg and southeast Manitoba today. Snow, mixed with ice pellets, began overnight creating a slippery and slow morning commute. About 3-5 cm of snow fell across the city by midday before it turned to a misty drizzle.  The snowfall marked the latest date on record for the first MEASURABLE snowfall of the season ("measurable" snowfall is defined as a snowfall of 0.2 cm or more)  The previous latest date of the first snowfall in Winnipeg was Nov 21 1963, set during the warmest fall on record (sidenote: President Kennedy was assassinated the next day in Dallas). Winnipeg snowfall records date back to 1872 (144 years of data)


Today's snowfall also marked the first time in 225 days that Winnipeg has had measurable snow (last recorded on April 10th when 0.4 cm fell). The 225 days is Winnipeg's 3rd longest snowless streak on record, behind only 1998 (232 days) and 1900 (228 days)  Average snowfree period in Winnipeg is 181 days, which means Winnipeg enjoyed 6 more weeks of snowfree weather this year compared to average.

8 comments:

  1. Hey Rob, storm brewing for early next week? Weather network seems to think so.

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    1. Yeah, long range models are showing another storm system tracking across Minnesota next Monday with snow spreading into southern MB. May be dealing with some mixed precip over SE MB. Still too early to be more specific with snowfall amounts but it's definitely the next system to watch.

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  2. Models continue to struggle in the medium to long range on the storm system expected to impact Dakotas/Minnesota and southern MB/NW Ont early next week. Latest guidance is hinting at a possible double-center storm system, one center over Minnesota and another over the southern plains. The northern center looks to weaken as it moves towards southern MB while the southern system intensifies and tracks towards Lake Superior taking the bulk of weather with it. A scenario like this would mean a less impact storm for southern MB, a bit of snow mixed with rain, while the worst of it slides off to our southeast as the southern low takes over. We'll see if this trend holds on subsequent runs. Note also that temperatures will continue mild, so any precip Mon-Tue will likely be a mixed wet snow-rain event even in Winnipeg/RRV. Still a lot of uncertainty.. we'll continue to keep an eye on it.

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  3. By the way, today marks the 35th straight day above normal in Winnipeg, and with no Arctic air expected here over the next week, this November will easily go down as the warmest November in Winnipeg since records began in 1872. Our monthly average temperature will finish around +2.7C, which blows away the current warmest Nov of 1899 and 1923 at +1.3C. This is a considerable margin to set a new monthly temperature record, and falls over 2 standard deviations above the normal of -4.9C (over 7C above normal!) A historically warm month that we haven't seen in over 140 years of weather records here.

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  4. Models backing away now from that two center solution, and going with a single deeper storm system that will be tracking into North Dakota Monday, then stalling and gradually looping into Minnesota Tuesday. A scenario like this would give bring mainly rain over and east of the RRV, with snow over Westman and interlake areas. Could be seeing fairly strong winds as well with that low deepening into the 970s. We'll see how models handle this over the weekend.. but right now, it's looking more like a rain event for Winnipeg/RRV Monday before gradually transitioning to snow on the backside as the storm pulls away.

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    1. Models still on track with bringing deep 975 mb low over southeast ND Monday morning which then stalls there all day before gradually moving into northern Minnesota and weakening somewhat Tuesday into Wednesday. The storm system will spread a messy mix of rain and wet snow across southern MB tonight as the low pushes into North Dakota, with snow mainly west of the RRV and rain east. Precipitation in Winnipeg and RRV will likely start as wet snow overnight, with a slushy 1-3 cm possible before precip turns to rain early Monday. Changeover to rain will occur sooner east of Winnipeg, and later west if at all. In addition, a band of freezing rain or ice pellets is also possible in the transition zone. In Winnipeg, we could be dealing with a sloppy wet snow for the Monday morning commute but I expect a changeover to rain by mid morning as temps climb. Snow will persist over western MB with 5-10 cm possible over Westman area by late Monday. Additional accumulations likely over Westman Monday night into Tuesday as the storm slowly pushes east (perhaps another 5-10 cm?)

      As the low moves into Minnesota Tuesday, rain or drizzle will change back to snow over much of the RRV and SE MB as colder air wraps into the backside of the system, with some accumulations possible Tuesday into Wednesday as the low slowly tracks east.

      All in all, a messy weather pattern over southern MB to start the work week.

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  5. Rob, it seems that the first outbreak of arctic air could be headed this way in South MB in about 7 to 10 days from now. What are your thoughts on this?

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    1. I've seen rumblings about a big push of Arctic air pushing into western Canada for the first week of December. Looks like it may be a lobe of frigid air from Siberia that pinches off and crosses the Arctic into western North America, bringing the first big cold outbreak of the season. The core of the coldest air appears that it will be centered mainly over western Canada (Yukon, BC, Alberta) although we will likely trend to below normal temps as well. Keep in mind that by Dec 10th, our normal highs are around -8C and lows near -18C.. so any change to even normal temperatures will feel like a shock to the system. This November has been so exceptionally mild, we've forgotten what it's supposed to be like here in December.

      Now, I don't know if this will be a transitory cold snap, or a whole scale pattern change to cold weather the rest of the winter. But signs are pointing to an end to the exceptionally mild pattern we've been experiencing for about 6 straight weeks now.

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