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Weather Appreciation

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Re: Weather Appreciation

Postby Glacier » Sep 26th, 2012, 1:27 pm

There is zero credibility behind the Farmer's Almanac weather predictions other than they do what you or I could easily by looked at seasonal averages. The only reason people think they get their numbers right is because they make vague predictions based on these past averages, and wouldn't you know it, they are right once in a while - sort of.

"The ability to predict events that far in advance is zero," says Knight. "There's no proven skill, there's no technique that's agreed upon in science to be able to do that."

[...]

Knight points out that the Farmers' Almanac words its predictions imprecisely, making it difficult to assess their accuracy.

"They say from November 5 thru 10, for that whole period: sunny/cool. If one day is sunny and cool, does that count? Does every day have to be sunny and cool? If you held them to every single word for the entire area and every word for the entire period, then I say they might not even be right one third of the time. In fact, they might be right 10 percent of the time." Acknowledges Knight, "I don't think they're holding themselves to that degree of accuracy, and I don't think other people are either."

Perhaps the strongest long-term predictor when it comes to weather is climate history, the way the weather "normally" behaves in a given region. But awareness of the past record, Knight points out, requires little to no scientific skill.

"I could say things like October 8 to 15 in this area: generally dry, very cool weather expected; first frost and freezes in the valleys. And I would be right probably eight out of 10 years," says Knight. "I could say February 12 to 19: heavy snow along parts of the eastern seaboard. I'm going to be right seven out of 10 years. There is some relative frequency to these things, but to say that this is of great scientific accuracy would be a real misnomer."


http://www.rps.psu.edu/probing/almanac.html
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Re: Weather Appreciation

Postby noneofyourbiz3 » Sep 26th, 2012, 4:10 pm

What does it say about todays skies? Good lord from 730am onward I watched the sky created behind planes. Im convinced today skies have been geo engineered.
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Re: Weather Appreciation

Postby Glacier » Oct 1st, 2012, 2:40 pm

Driest August and September on record in Vancouver, Victoria, Nanaimo, and Fort St John (to name a few).

Image
Vancouver experienced the driest August and September in 116 years, according to Environment Canada.

Records at YVR go back to 1937, but records at the Steveston station date back to 1896.

For the period August 1 – September 30, only 8mm of rain was recorded, beating the previous record of 9mm.

The normal rainfall over the two month period is 90mm.

“We had a very persistent range of high pressure that is going to bounce back,” says David Jones, Meteorologist at Environment Canada.

Jones says it will be windy tonight in the Lower Mainland, before another high pressure ridge returns, bringing us sunshine and dry weather for the next 10 days.

“It’s absolutely stunning weather,” says Jones.

http://www.globaltvbc.com/driest+august ... story.html


By comparison, this was the 5th driest Aug-Sept in Vernon with only 20 mm of precipitation falling.

And from Fort St John...

Image

Unofficially, 1.8 millimetres of rain last Friday was just enough to prevent last month from being the driest September on record in this area. That leaves the total for the month, at 2.6 millimetres, just ahead of the 2.5 low end record set in 1975.

However, there's little doubt the local airport weather station did set a new record low for the last three months of summer - July, August and September. The weather bureau total for that period is now at 47.7 millimetres, and the previous record low was 55.9, set in 1945.

Not only is the 2012 total a new record, it is also only a quarter of the norm for that three month period.


Vancouver Island was even drier with Victoria only receiving 0.4 mm in September and 3.8 mm since July.
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Re: Weather Appreciation

Postby Glacier » Oct 4th, 2012, 4:39 pm

September was extremely dry from one extreme end of the province to the other. Here are a few examples:

Esquimalt = 0.4 mm!
Peachland = 1.0 mm!
Victoria, Summerland, Fort Nelson - 1.2mm!
...
Fort St John =2.6 mm
Salmon Arm =2.8 mm
Kelowna = 2.9 mm
... And the list goes on.


The normal for Kelowna in September is 34 mm, which is less than most of the province typically receives, but there were barely any places that recorded even this amount. Pretty the only places in BC that got any rain to speak of last month were the usual suspects (Prince Rupert, Kitimat, and the like).
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Re: Weather Appreciation

Postby Queen K » Oct 4th, 2012, 8:30 pm

I'd appreciate a bit of a warm up tomorrow. Thanks in advance.
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Re: Weather Appreciation

Postby Glacier » Oct 12th, 2012, 1:19 pm

How the temperature changes as you head up the Fraser...

TemperatureFraserRiver.png
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Re: Weather Appreciation

Postby zzontar » Oct 13th, 2012, 7:46 am

Glace, I've always wondered how much lighter the lake is now that the water level has dropped a couple of feet... just in case you're bored and love calculations. :lol:
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Re: Weather Appreciation

Postby zzontar » Oct 13th, 2012, 7:46 am

Glace, I've always wondered how much lighter the lake is now that the water level has dropped a couple of feet... just in case you're bored and love calculations. :lol:
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Re: Weather Appreciation

Postby zzontar » Oct 13th, 2012, 7:46 am

Oops, triple post.... ???
Last edited by zzontar on Oct 13th, 2012, 10:25 am, edited 3 times in total.
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Re: Weather Appreciation

Postby Cumungala » Oct 13th, 2012, 6:34 pm

Nowhere in Kelowna has ever recorded snow in September. The chance of Kelowna getting snow in October is unlikely but it does happen. Using the Downtown Kelowna weather stations (The original Kelowna weather station, Kelowna Bowes Street and Kelowna PC Burnett) with continuous data between 1899 and 1999 I found out that Downtown Kelowna has had 15 years where there was snow in October. Over 100 years this equals out to about once every 7 years. The earliest in the year that Kelowna has ever had snow was October 9, 1958 where 15.7cm fell! October 1958 was also the snowiest October on record, and it all fell in just one day. The last time Downtown had snow in October was October 29, 1993 where 3cm fell. Most of the time the snow only falls on one day, but 1919, 1932, 1971 and 1984 all had multiple October days where snow fell.

The Kelowna Airport on the other hand, which collected data between 1968 and 2005, recorded snow in October 12 times. During the same period, the downtown station at the time (PC Burnett) only recorded it 4 times. The last time the Airport recorded it was October 17, 1996 where only a trace fell.
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Re: Weather Appreciation

Postby Glacier » Oct 15th, 2012, 5:09 pm

Update from the graph above to show the entire Fraser system (elevations in parentheses)...

Fraser.png
Last edited by Glacier on Oct 16th, 2012, 10:09 pm, edited 3 times in total.
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Re: Weather Appreciation

Postby Cumungala » Oct 15th, 2012, 11:19 pm

November is obviously a lot more likely to see snow than October in Kelowna. This time I counted years when November didn't get snow for the downtown Kelowna stations (original Kelowna station, Bowes and PC Burnett. There have been only 15 years between 1899 and 1999 where there was no snow in November. Two more years have happened since then with 2002 and 2009 not seeing a single snow flake in the entire month of November. On the other hand, the record for snow in November is 1996 where 52.8cm fell.

The chances of seeing snow in December in Kelowna is pretty much a certainty, seeing that only one year in history has never recorded snow in December. That year was 1900, which strangely was the year after records began for Kelowna. It was definitely a green Christmas that year!! The all time December snow record for Kelowna was 1917 where 128.5cm fell during the entire month. This is more than we usually get for the whole winter. The chances of a White Christmas for areas near the lake in Kelowna is about 50-60%, and areas away from the lake its about 75%.

The chance of snow in January is certain for Kelowna. There has never been a year without snow in January here, but a few years came close. 1992 only recorded 0.5cm for the whole month. The all time January snow record is 71.5cm from 1982.

February has only had 3 years without snow in Kelowna: 1915, 1931 and 1934. The all time snow record for February is 67.2 cm from 1937.

The chances of snow in March are likely but not certain for Kelowna. There were 23 years between 1899 and 1999 WITHOUT snow in March and there have been 2 more years since 1999 with the latest being 2006. The all time March snow record for Kelowna is 65.4cm from 1904.

The chances of snow in April in Kelowna are unlikely but possible. There were 23 years WITH snow in April between 1899 and 1999, and 3 years since. The latest was 2009. The all time record for April is 7.4cm from 1953. The latest in the year that downtown Kelowna has ever recorded snow was April 26, 1955 where only a trace fell.

There has never been snow recorded in the month of May at any of the Downtown stations between 1899 and 1999. It could very well have happened at the airport or other stations away from the lake though, but it would have probably been only a trace amount with probably a single occurance.

The earliest Kelowna has ever recorded snow was October 9th and the latest is April 26. This means that Downtown Kelowna's snow range is 199 days or 200 days if its a leap year. Kelowna's no-snow range is 166 days. This means that even though Kelowna is such a mild place, we can still theoretically receive snow on any given day for 55% of the year. And that's just Downtown Kelowna.
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Re: Weather Appreciation

Postby Glacier » Oct 16th, 2012, 1:27 pm

Well there are some facts I didn't know. October is the driest month of the year in the South Okanagan, but even they have experienced some precipitation over the past few days (precipitation in mm)....

oct2012.jpg


Back to the graphs above. In practice, dropping 100m in elevation increases the temperature by 0.65 degrees. In this way, the following graphs show what the temperature would BE at each place in question if we dug a trench down to sea level. Notice how things are much more closely bunched together!

It looks like rivers that head west of the Fraser have very cold winters (Chilcotin, Nechako), and rivers heading east of the Fraser have more mild winters (Quesnel, South Thompson, Nicola). This probably has to do with how dry the climates are. As you head west towards the Coast Mountains there is a rain shadow, but as you head east, you end up in the wet Cariboo/Columbia/Monashee Mountains. Head far enough west in the Nechako, you get some moderating effect of the Pacific.

FraserElevationAdjustedSummer.png
July Temperature


FraserElevationAdjustedWinter.png
January Temperature
Last edited by Glacier on Oct 16th, 2012, 10:40 pm, edited 2 times in total.
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Re: Weather Appreciation

Postby zzontar » Oct 16th, 2012, 9:48 pm

Okay, I got bored and tried my own calculations and figured that if the lake drops a couple of feet, it loses close to 214 million metric tonnes of water! :200:
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Re: Weather Appreciation

Postby Glacier » Oct 16th, 2012, 10:02 pm

Which density were you using? You have to figure out the temperature gradient of the water before vs the temperature after. Sure, you could just assume a density of 1.0000, but then you're accuracy would suffer.

What, no comments on the sweet graphs above?
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