Ottawa: Will There Be Any -20°C Days This Winter?

[donsutherland1]

In the thread about the AO, a question arose as to whether Ottawa might see no days on which the temperature would fall to -20°C or below. After all, as of December 17, Ottawa's coldest reading had been -17.3°C (12/9).

Since 1950, there have been 12 La Niña cases during which the ENSO Region 3.4 Anomaly was -1 or below in both December and January (a likely outcome this winter). In every case, Ottawa saw the temperature fall to -20°C or below on at least one day in both January and February. As a result, I have a high degree of confidence that Ottawa will see at least one day this winter during which the temperature falls to -20°C or below.

But will Ottawa's snow dearth continue?

In those 12 winters, January and February snowfall came out as follows:

January:

Mean: 52.9 cm

Standard Deviation: 18.2 cm

Median: 49.4 cm

Lowest: 28.4 cm, 1956

Highest: 93.0 cm, 1999

< 30.0 cm: 1 (8%) cases

30.0-49.9 cm: 6 (50%) cases

50.0-69.9 cm: 3 (25%) cases

70 cm or more: 2 (17%) cases

February:

Mean: 59.4 cm

Standard Deviation: 39.0 cm

Median: 46.6 cm

Lowest: 18.2 cm, 1999

Highest: 159.5 cm, 1971

< 30.0 cm: 2 (17%) cases

30.0-49.9 cm: 4 (33%) cases

50.0-69.9 cm: 2 (17%) cases

70 cm or more: 4 (33%) cases

In addition, the following are median snowfall figures for a number of different situations during the aforementioned La Niña situations:

1. Monthly AO of -1 or below

2. Monthly AO of -0.999 to 0

3. Monthly AO > 0

4. During winters when less than 40 cm snow fell in December (To date, Ottawa has seen 21.8 cm of snow in December)

5. All La Niña cases as noted earlier

That data is below:

In short, Ottawa will very likely see more snowfall in both January and February than it has experienced in December. The best chance for a snowy month will probably be February as the jet stream begins to migrate north.

Note: I placed this thread in the weather forecasting discussion section, as I found no subforum that might include the Ottawa area.

[Organizing Low]

thank you so much for this very informative post Don

your ability to research weather stats is incredible!

i figured that a slightly negative AO was probably the best case scenario for snowfall up here with a mod-strong Nina, and your data confrims that.

as for the -20C day, i cant imagine that ottawa could ever go a winter without a -20C reading.....perhaps it has happeend, but to me that seems like a total impossiblity!

[donsutherland1]

thank you so much for this very informative post Don

your ability to research weather stats is incredible!

i figured that a slightly negative AO was probably the best case scenario for snowfall up here with a mod-strong Nina, and your data confrims that.

as for the -20C day, i cant imagine that ottawa could ever go a winter without a -20C reading.....perhaps it has happeend, but to me that seems like a total impossiblity!

Thank you, OL.

Winter 2001-02 came close. Ottawa didn't see a -20°C reading until February 5, 2002.

Hopefully, not too far down the road there will be some notable winter weather in Ontario and Quebec.

[Roger Smith]

I agree, -20 C is like a spring day in Ottawa. Even the winter of 82-83 probably had a couple of nights below -20 C there.

I would imagine there will be a bunch of them by late January or February.

[donsutherland1]

Even the winter of 82-83 probably had a couple of nights below -20 C there.

There were 14 such days in Winter 1982-83.

[Ottawa Blizzard]

Great write up Don! Us Ottawa folks tend to lurk around the upstate New York thread, although we do drop in to the Central thread from time to time!

I think Ottawa's biggest busts were 1931-32, 1932-33 and 2001-2002. The first two were unbelievably mild. Much milder than anything we have had recently. 1933-34 was a legendary winter for cold and snow, which I doubt will ever be beaten.

I'm just hoping that by mid January we see more snow and cold up here. As I mentioned in another thread, 1992-93 was an interesting year. December was actually quite mild, and there was a rainstorm the first week of January. Cold soon settled in with snowstorm after snowstorm pounding the city. That was an El Nino year though and you have to wonder how it was that Ottawa got one of its snowiest ever winters in the midst of an El Nino as usually those result in below normal precip up here. February 1993 was awesome. 34cm on the 13th followed by another major storm on the 22nd!

[snowstormcanuck]

Don't want to hijack an Ottawa thread, but it's been absolutely terrible here in Toronto as well. Last year we just eked out breaking our snow futility record. This year we might smash it.

[donsutherland1]

Snowstormcanuck,

I'll post more details on Toronto this evening. However, I am quite confident that Toronto will not smash its futility record and believe 25 cm or more snowfall for January is likely. The same may hold for February, too.

[Organizing Low]

and there you have it SSC

never bet against Don

[Organizing Low]

Thank you, OL.

Winter 2001-02 came close. Ottawa didn't see a -20°C reading until February 5, 2002.

Hopefully, not too far down the road there will be some notable winter weather in Ontario and Quebec.

i was living in the NYC area between 1999-2007 so i missed those years. i was fortunate to move back just before the winter of 2007-08.....felt like a welcome back present.

[donsutherland1]

As promised, some statistics for January and February during winters when the ENSO Region 3.4 Anomaly was -1 or below in both December and January (a likely outcome this winter).

Apparently, when the ENSO Region 1+2 anomaly was -1 or below (also a likely outcome for at least one of the two upcoming months), Toronto appeared to have somewhat higher snowfall:

- All three January cases saw 30 cm or more snowfall

- 5/6 (83%) February cases saw 25 cm or more snowfall and 3/6 (50%) had 30 cm or more snowfall.

[snowstormcanuck]

As promised, some statistics for January and February during winters when the ENSO Region 3.4 Anomaly was -1 or below in both December and January (a likely outcome this winter).

Apparently, when the ENSO Region 1+2 anomaly was -1 or below (also a likely outcome for at least one of the two upcoming months), Toronto appeared to have somewhat higher snowfall:

- All three January cases saw 30 cm or more snowfall

- 5/6 (83%) February cases saw 25 cm or more snowfall and 3/6 (50%) had 30 cm or more snowfall.

Thanks for the data Don. I posted some numbers in the MW/GL general thread correlating Toronto's (well, I used mby data, but it's close enough) top 10 snowiest months the last 12 years with certain teleconnectors. Here they are again:

MM/YYYY.....SN.........ENSO.........NAO........AO.....PNA

Jan 1999....46.6".....La Nina......0.77.........0.11.....0.16

Feb 2008....35.5".....La Nina......0.73.........0.94.....0.50

Dec 2008....29.6"....La Nina......-0.28........0.65.....-1.41

Dec 2000....24.8"....La Nina......-0.58.......-2.53.....1.23

Jan 2004....23.3"......Neutral......-0.29.......-1.69.....0.41

Jan 2009....22.2"......La Nina.....-0.01........0.80.....0.61

Mar 2008....20.2".....La Nina.......0.08........0.59.....-0.32

Dec 2007...19.8".....La Nina.......0.34.........0.82.....0.14

Jan 2003....17.1".....El Nino.......0.16.........-0.45.....1.29

Dec 2005....16.5"....El Nino.......-0.44........-2.10.....1.38

Obviously, La Nina > El Nino. NAO averages close to neutral, AO neutral or slightly positive (removing those strongly negative outliers), and PNA positive. Snowy months with strongly -AO seemed to be accompanied by a more robust +PNA (in 2/3 occurrences).

[nzucker]

I agree, -20 C is like a spring day in Ottawa. Even the winter of 82-83 probably had a couple of nights below -20 C there.

I would imagine there will be a bunch of them by late January or February.

Ottawa will hit -20C for sure; that's a walk in the park up there...remember, average temperatures are much colder in January and February than December, so it's not too worrying that the barrier hasn't been cracked by Christmas. La Niña winters also tend to have colder airmasses in Canada so I'm convinced we're in for a good arctic outbreak sometime in January. I also think the cities of Ottawa, Toronto and Montreal will also see above-normal snowfall later in the winter as the strong -NAO/-AO block breaks down and we get more SW flow events, cutters, and northern clippers.

[Ottawa Blizzard]

Don, I just wanted to thank you again for this very interesting thread. I am currently in Toronto after having spent Christmas in Kitchener. The difference in snowpack is incredible. Kitchener has about the same amount of snow on the ground as Ottawa, perhaps slightly less, while Toronto has a dusting. The storm next weekend is looking warm (which might be a good thing given I have a five hour drive that weekend!) followed by seasonably cold weather. Here's hoping things crank up by mid January.

[snowstormcanuck]

Don, I just wanted to thank you again for this very interesting thread. I am currently in Toronto after having spent Christmas in Kitchener. The difference in snowpack is incredible. Kitchener has about the same amount of snow on the ground as Ottawa, perhaps slightly less, while Toronto has a dusting. The storm next weekend is looking warm (which might be a good thing given I have a five hour drive that weekend!) followed by seasonably cold weather. Here's hoping things crank up by mid January.

Depends where you are. I still have about 5cm/2" on the ground. Unless that's what you're calling a dusting, lol.

[Ottawa Blizzard]

Depends where you are. I still have about 5cm/2" on the ground. Unless that's what you're calling a dusting, lol.

I'm in northeast Scarborough. Now that you mention it, there's probably a little more than a dusting - maybe 2cm/1 inch. Still, at least it's a white Christmas, which is more than Nova Scotia got!

[Ottawa Blizzard]

I posted a comment in another thread stating that the same weather pattern that could potentially lead to highly populated areas such as the Ohio valley and mid atlantic getting colder winters could also lead to places such as the high arctic and Labrador getting warmer winters. Many scientists are saying that high latitude areas such as Canada will see the greatest amount of warming in the coming years and decades. What if they're right...and what if people like Joe Bastardi are also right when they say that the US and western Europe will be in for colder winters? Everything is relative to what you're used to and to what you experience in your own location. The thing is, this may all be caused by natural factors, not human ones and i think humans often have a macabre fascination with disasters, hence the fear that all these changes could lead to catastrophe.

Sorry about the off-topic, but I though this may be semi-relevant to this thread.

[donsutherland1]

I posted a comment in another thread stating that the same weather pattern that could potentially lead to highly populated areas such as the Ohio valley and mid atlantic getting colder winters could also lead to places such as the high arctic and Labrador getting warmer winters.

The warmth in the high Arctic/Labrador leads to the colder outcomes in the Ohio Valley/Mid-Atlantic. That's a classic outcome of strong blocking.

[snowstormcanuck]

I posted a comment in another thread stating that the same weather pattern that could potentially lead to highly populated areas such as the Ohio valley and mid atlantic getting colder winters could also lead to places such as the high arctic and Labrador getting warmer winters. Many scientists are saying that high latitude areas such as Canada will see the greatest amount of warming in the coming years and decades. What if they're right...and what if people like Joe Bastardi are also right when they say that the US and western Europe will be in for colder winters? Everything is relative to what you're used to and to what you experience in your own location. The thing is, this may all be caused by natural factors, not human ones and i think humans often have a macabre fascination with disasters, hence the fear that all these changes could lead to catastrophe.

Sorry about the off-topic, but I though this may be semi-relevant to this thread.

Well if this is true, then I better expedite my moving plans. Looks like Toronto's in for a long term snow drought.

[Organizing Low]

The warmth in the high Arctic/Labrador leads to the colder outcomes in the Ohio Valley/Mid-Atlantic. That's a classic outcome of strong blocking.

Don i've been following your blocking schemes very closely.

Now I've long since heard that the NAO seems to run in decadal/long cycles.

If you have a moment, could you comment on this?......1) in terms of does the strength of the negative anomaly tend to persist for longer periods within a cycle......esp if its a strong signal like we've been having the past couple seasons. (I'm guessing there probably is not enough data to make a conclusion).....2) do stronger anomalies lead to longer cycles overall .......again im guessing not enough data.

I guess like SSC, I am wondering if I too should make plans to move back to NYC in the nearterm, lol.

I hope you enjoyed the blizzard! How much snow did you get? The pics are fantastic.

It def exceeded the Feb 06 event for which I was present in the strongest banding....but this one was better......so in that regards, I am a bit upset I missed it.

[donsutherland1]

If you have a moment, could you comment on this?......1) in terms of does the strength of the negative anomaly tend to persist for that entire/most of decadal cycle......esp if its a strong signal like we've been having the past couple seasons. (I'm guessing there probably is not enough data to make a conclusion).....2) do stronger anomalies lead to longer cycles.......again im guessing not enough data.

I guess like SSC, I am wondering if I too should make plans to move back to NYC in the nearterm, lol.

OL,

There are longer-term AO and NAO cycles. I'll try to run the data tonight when I get home.

You would always be welcome in NYC with or without abundant snowfall.

I hope you enjoyed the blizzard! How much snow did you get? The pics are fantastic.

It def exceeded the Feb 06 event for which I was present in the strongest banding....but this one was better......so in that regards, I am a bit upset I missed it.

NYC received 20.0". Just outside the city where I live, there was a similar amount of snow, along with some three- to four-foot (0.9-1.2 meter) drifts. During the night, there was also some thunder, though not as much as I heard during the 2006 event. The winds were really noticeable with nearby White Plains having a 67 mph (108 kph) gust at the height of the blizzard. IMO, the combination of heavy snow, high winds, drifting, and thunder made this a more exciting event than the 2006 snowstorm.

[donsutherland1]

With respect to AO cycles, the following graph shows both the annual average and 10-year moving average for the AO:

The 10-year moving average bottomed out in 1966 (-0.423 10-year average) and then peaked in 1995 (+0.253 10-year average). It has generally been falling since that time. When this year's data is in, the 10-year moving average will have fallen further to around -0.125, the lowest figure since 1988 (-0.224 10-year average). In addition, 2010 will finish with an annual average of around -1.025. That would break the record of -0.959 set in 1960. The record high annual average is +1.024, established in 1990.

[donsutherland1]

Some partial verifications:

From Message #1 in this thread:

Since 1950, there have been 12 La Niña cases during which the ENSO Region 3.4 Anomaly was -1 or below in both December and January (a likely outcome this winter). In every case, Ottawa saw the temperature fall to -20°C or below on at least one day in both January and February. As a result, I have a high degree of confidence that Ottawa will see at least one day this winter during which the temperature falls to -20°C or below.

To date, the lowest temperature in Ottawa this month is -25.1°C (-13°F). That almost certainly will not be the coldest reading of the month. A day on which the temperature remains below 0°F is possible.

...In those 12 winters, January and February snowfall came out as follows:

January:

Mean: 52.9 cm

Standard Deviation: 18.2 cm

Median: 49.4 cm

Lowest: 28.4 cm, 1956

Highest: 93.0 cm, 1999

< 30.0 cm: 1 (8%) cases

30.0-49.9 cm: 6 (50%) cases

50.0-69.9 cm: 3 (25%) cases

70 cm or more: 2 (17%) cases

...In short, Ottawa will very likely see more snowfall in both January and February than it has experienced in December. The best chance for a snowy month will probably be February as the jet stream begins to migrate north.

January snowfall (through 1/18) is 29.0 cm in Ottawa. That surpasses the 23.4 cm that accumulated in December. I suspect that this month's snowfall will likely reach or even exceed 40 cm by the end of the month.

In terms of my assessment in Message #9 that "I am quite confident that Toronto will not smash its futility record and believe 25 cm or more snowfall for January is likely..." and in terms of the historic climatology provided for Toronto (Message #11), from which excerpts were:

...some statistics for January and February during winters when the ENSO Region 3.4 Anomaly was -1 or below in both December and January (a likely outcome this winter).

...Apparently, when the ENSO Region 1+2 anomaly was -1 or below (also a likely outcome for at least one of the two upcoming months), Toronto appeared to have somewhat higher snowfall:

- All three January cases saw 30 cm or more snowfall

- 5/6 (83%) February cases saw 25 cm or more snowfall and 3/6 (50%) had 30 cm or more snowfall.

Toronto's snowfall this month (through 1/18) is 36.0 cm. That exceeds December's minimal 10.8 cm and is consistent with all three of the aforementioned January cases.

[Organizing Low]

With respect to AO cycles, the following graph shows both the annual average and 10-year moving average for the AO:

The 10-year moving average bottomed out in 1966 (-0.423 10-year average) and then peaked in 1995 (+0.253 10-year average). It has generally been falling since that time. When this year's data is in, the 10-year moving average will have fallen further to around -0.125, the lowest figure since 1988 (-0.224 10-year average). In addition, 2010 will finish with an annual average of around -1.025. That would break the record of -0.959 set in 1960. The record high annual average is +1.024, established in 1990.

thanks for this Don

sorry i hadnt picked it up when you first posted it.

interesting stuff, ill have to go back and correlate with winters.

[snowstormcanuck]

Toronto's snowfall this month (through 1/18) is 36.0 cm. That exceeds December's minimal 10.8 cm and is consistent with all three of the aforementioned January cases.

Sorry I doubted you Don. Our winter has really picked up since the 6th of January with most parts of the city, aside from Pearson Int'l Airport, either AOA normal. The positive effects of the relaxed/absent blocking have been noticeable.

[Ottawa Blizzard]

Great call Don. Winter has truly arrived in Ottawa. I'm hoping that we at least get 2" out of this system on Friday. It looks to be really cold on Saturday - perhaps we may approach an overnight low of -30C? Given you expect us to surpass 40cm of snow this month I can only guess that you're expecting another 4" snowfall at least after today's event?

[donsutherland1]

Sorry I doubted you Don. Our winter has really picked up since the 6th of January with most parts of the city, aside from Pearson Int'l Airport, either AOA normal. The positive effects of the relaxed/absent blocking have been noticeable.

It's not a problem. The lack of snowfall in December had to be extremely discouraging.

[donsutherland1]

Great call Don. Winter has truly arrived in Ottawa. I'm hoping that we at least get 2" out of this system on Friday. It looks to be really cold on Saturday - perhaps we may approach an overnight low of -30C? Given you expect us to surpass 40cm of snow this month I can only guess that you're expecting another 4" snowfall at least after today's event?

Through 1/18, Ottawa's monthly snowfall was 31.4 cm (it increased another 2.4 cm yesterday). A snowfall next week should probably push Ottawa to or above 40 cm. The GFS and especially the Euro support that idea, though the timing differs somewhat between the two models.

[Ottawa Blizzard]

Through 1/18, Ottawa's monthly snowfall was 31.4 cm (it increased another 2.4 cm yesterday). A snowfall next week should probably push Ottawa to or above 40 cm. The GFS and especially the Euro support that idea, though the timing differs somewhat between the two models.

Is this the January 26th storm? It's looking quite cold right through to early February here, with models seemingly indicating another frigid blast towards the end of the month!

[donsutherland1]

Is this the January 26th storm? It's looking quite cold right through to early February here, with models seemingly indicating another frigid blast towards the end of the month!

Yes, that's the storm.