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Posted
  • Location: Tidolo, Cremona (Italy)
  • Location: Tidolo, Cremona (Italy)

    Fohn arrived this morning and now it's quite strong!!

    Without commments, as attachments, two images of temperature and wind history..... Sky is completely clear and the colour is a deep blue that I usually find at 2000 mt asl, but I live at 45 m.

    Happy new year :blush:

    post-1649-1167733038_thumb.png

    post-1649-1167733056_thumb.png

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    Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

    superb example of a fohn effect.

    I've only ever experienced one true fohn, last year, one day skiing in wengen.

    temperature went from -4C to +7C in a longer time scale, maybe 3 hours or so.

    The wind was 30-40kt gusting 60kt for about 2 hours.

    the older locals said they had only seen this effect about twice in their life living in the same village.

    John

    thank you for posting this.

    Would it be possible to get a much larger view of the temperature and wind trace please. We could then keep it on our weather file please?

    j

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    Posted
  • Location: Tidolo, Cremona (Italy)
  • Location: Tidolo, Cremona (Italy)
    superb example of a fohn effect.

    I've only ever experienced one true fohn, last year, one day skiing in wengen.

    temperature went from -4C to +7C in a longer time scale, maybe 3 hours or so.

    The wind was 30-40kt gusting 60kt for about 2 hours.

    the older locals said they had only seen this effect about twice in their life living in the same village.

    John

    thank you for posting this.

    Would it be possible to get a much larger view of the temperature and wind trace please. We could then keep it on our weather file please?

    j

    My weather station is not online, these are from a friend of mine living 35 km south east from me... Now I'm going home, I'll try to obtain some larger pictures from my weather station and also a text data, weather is the same in my village.

    I also have a lot of fohn examples from the past, I'll find out some

    Ciao

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    Posted
  • Location: Heswall, Wirral
  • Weather Preferences: Summer: warm, humid, thundery. Winter: mild, stormy, some snow.
  • Location: Heswall, Wirral

    I find fohns fascinating, I experience quite alot myself being in the lee of a mountain/hill range, but I'm sure yours in Italy will be alot stronger due to the size of the mountains (at 2000m there). That graph shows a really strong one there, perhaps 1 and a half hours nearly a 6°C rise?

    The classic fohn effect has blue skies and strong winds, but I have had a foehn where there was light drizzle, the wind wasnt too strong, and the temperature was 18C in February... very balmy, the wind felt very warm though.

    I imagine in a double figure fohn the wind can feel warmer than the air temperature itself.

    What was the wind temperature like in that fohn Stratus?

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    Posted
  • Location: Tidolo, Cremona (Italy)
  • Location: Tidolo, Cremona (Italy)

    Here my weatherstation data as attachment. It's weird the dewpoint "jump" but that is tipical before a strong fohn heating. Yesterday the max temp. was +5,9°

    This is not a record fohn, strong wids are up to 100km/h sometimes and I remember a morning, a lot of years ago, after a early morning with fog, ice and -10°C, a strong fohn arrived at noon and the temperature rised up to +19°C!!!!!

    post-1649-1167744642_thumb.jpg

    post-1649-1167744648_thumb.jpg

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    Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

    tks for that, especially the wind and temp, amazing how identical in time

    John

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    Posted
  • Location: Tidolo, Cremona (Italy)
  • Location: Tidolo, Cremona (Italy)
    I find fohns fascinating, I experience quite alot myself being in the lee of a mountain/hill range, but I'm sure yours in Italy will be alot stronger due to the size of the mountains (at 2000m there). That graph shows a really strong one there, perhaps 1 and a half hours nearly a 6°C rise?

    The classic fohn effect has blue skies and strong winds, but I have had a foehn where there was light drizzle, the wind wasnt too strong, and the temperature was 18C in February... very balmy, the wind felt very warm though.

    I imagine in a double figure fohn the wind can feel warmer than the air temperature itself.

    What was the wind temperature like in that fohn Stratus?

    Here the Parma weather data, very similar to mine, now I'm not at home so I can't check. Also a webcam image. The cloud on the bottom right (the one with the virga inside) is over the Garda lake at 90km north from the webcam location.

    post-1649-1167745390_thumb.jpg

    post-1649-1167745412_thumb.jpg

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    Posted
  • Location: Heswall, Wirral
  • Weather Preferences: Summer: warm, humid, thundery. Winter: mild, stormy, some snow.
  • Location: Heswall, Wirral

    Was that cloud actually more or less the shape of Lake Garda? :blush:

    Yep the stats show that the maximum real feel temperature was 11.7C so it was lower, but I suppose it felt quite warm.

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    Posted
  • Location: Doncaster 50 m asl
  • Location: Doncaster 50 m asl

    Quite a magical effect that a fohn can cause. I heard reports from people in Wengen who remember states of delirium setting in. :unknw: I also understand that suicides increase in an area when a fohn sets up! :lol:

    Many think that it is due to the ionization of air particles. It was even suggested that the reason why a shower wakes you up more is also to do with the movement of air particles due to the water rushing past them.

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    Posted
  • Location: Canmore, Canada [4296ft] & North Kent [350ft]
  • Location: Canmore, Canada [4296ft] & North Kent [350ft]

    Fohn, or as it is called over here, Chinook, can apparantly be the cause of migraines, I have been told. Its amazing to see such a rapid increase in temperature in such a short time. I have seen literally half a foot of snow melt within a day because of this effect

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    Posted
  • Location: Shoeburyness, Essex - 6.2m asl
  • Location: Shoeburyness, Essex - 6.2m asl

    I've been in Calgary when a Chinook has come through, and if memory serves me rightly the temperature rose about 18C in less than a day. It went from mid-winter to a balmy spring day. Very weird to experience.

    What's the record temperature rise with a Chinook , Rich?

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    Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

    hi CC and B

    yes the Chinook is the very best example of a fohn wind. Bigger and better than the Alps, and even more so for the fohn effects we get in the UK. Not surprising really when you look at the topography.

    I'm not sure of the record rise due to a Chinook, but certainly 20C or so in a relatively short time, and yes 6 inches or even a foot of snow can 'disappear' and leave no water either! An indication of just how dry it is. The reason that in Austria and Switzerland, the very first thing to be dug out after a major snowfall are the hydrant pipes.

    There are a number of well documented instances of Alpine villages being struck by fires during fohn winds.

    John

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    Posted
  • Location: Canmore, Canada [4296ft] & North Kent [350ft]
  • Location: Canmore, Canada [4296ft] & North Kent [350ft]

    An Alberta Chinook wind caused a 37.8 degree temp rise in 4 minutes at Pincher Creek

    Pincher Creek, Alberta - Cool can disappear real fast when a Chinook shows up. Named for a First Nation's term for 'snow eater', it's a wind that blowns from the Pacific, gives up its moisture to rise over the Rockies, then packing warm dry air races down the eastern slopes of the mountains, shooting up the temperature on the prairies at an amazingly fast pace. The record is a 37.8 degree rise in 4 minutes on January 6, 1966, at Pincher Creek. A whole region of southern Alberta from Pincher north to the Calgary city limits, markets itself as 'Chinook Country'. Pincher Creek is in ridin', ropin' and ranglin' territory, near the British Columbia and Montana borders. It's known for its heart-tugging Cowboy Poetry Weekend held each June, and because it's the southern end of the the Cowboy Trail, a 640 km ( 400-mile) tourist route that leads past working ranches, small-town rodeos and country fairs. Photo of Kananaskis (Cowboy Trail) Courtesy of Travel Alberta

    Courtesy of canadacool.com

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    Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

    I'll do a short utorial on how it happens when I get the chance.

    Thank you for the original post and other additions to it.

    When I do the item I will use these as illustrations and then have it put into the Guide section.

    cheers

    John

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    Posted
  • Location: Canmore, Canada [4296ft] & North Kent [350ft]
  • Location: Canmore, Canada [4296ft] & North Kent [350ft]

    Also, with regards to world records....

    In popular myth, Chinook is supposed to mean "snow eater", as a strong Chinook can make a foot of snow all but vanish inside of one day. The snow partially melts, and partially evaporates in the dry wind. However, the true origin of the name is that "Chinook Wind" in the local argot of the fur trade era meant that the wind came from the direction of the country of the Chinooks (the lower Columbia River, i.e. from across the Rocky Mountains).

    Chinook winds have been observed to elevate winter temperatures, often from below −20°C (−4°F) to as high as 10°C to 20°C (50°F to 68°F), for a few hours or days, at the end of which, the temperatures plummet to their base levels.

    One of the most dramatic examples of the chinook winds occurred on January 15, 1972, in Loma, Montana. The temperature rose from −47°C (−54°F) to 9°C (49°F); the greatest temperature change ever recorded during a 24-hour period.

    Courtesy of wikipedia

    For more info this is an excellent link... http://en.wikipedia.org/wiki/Chinook_wind

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    Posted
  • Location: Ski Amade / Pongau Region. Somtimes Skipton UK
  • Weather Preferences: Northeasterly Blizzard and sub zero temperatures.
  • Location: Ski Amade / Pongau Region. Somtimes Skipton UK
    hi CC and B

    yes the Chinook is the very best example of a fohn wind. Bigger and better than the Alps, and even more so for the fohn effects we get in the UK. Not surprising really when you look at the topography.

    I'm not sure of the record rise due to a Chinook, but certainly 20C or so in a relatively short time, and yes 6 inches or even a foot of snow can 'disappear' and leave no water either! An indication of just how dry it is. The reason that in Austria and Switzerland, the very first thing to be dug out after a major snowfall are the hydrant pipes.

    There are a number of well documented instances of Alpine villages being struck by fires during fohn winds.

    John

    hi ,

    I spent 18 months out in Alberta and experienced the chinnook on several occasions. As a rule the temperatures do not exceed 7 C, but that feels very warm after a spell of intense cold. They last up to about 72 hours and the most pronounced affects are along the eastern foothills of the Rockies and out to the high plains of Calgary and beyond.The highest temperature recorded are usually in February when winter depressions start to invade higher latitudes. 19C was once recorded in February during a particular mild spell in Calgary. The Bow River melting in 24 hours ! Warm enough to play cricket.

    C

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    Posted
  • Location: Canmore, Canada [4296ft] & North Kent [350ft]
  • Location: Canmore, Canada [4296ft] & North Kent [350ft]

    Interstingly enough a chinook is occuring as we speak with temps getting to 7oC in Calgary today

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    Posted
  • Location: Tidolo, Cremona (Italy)
  • Location: Tidolo, Cremona (Italy)

    The maximum excursion that I remember was from -10° to +19°C in 3 hours and two years ago from 1°C to +29°C; in some places -2° to +31°C in March!!!!!

    Cremona is in the middle of the Po valley and Alps are 50km far from me. In the northern part of the Po valley, near the Alps, in western Lombardy and Piemonte region, sometimes winds are over 110 km/h.

    In 1999-2000 winter season we had 30 days with weak or moderate fohn and 6 with strong one. This year is the first day in this season.

    Ciao

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    Posted
  • Location: Newton Aycliffe, County Durham
  • Location: Newton Aycliffe, County Durham
    hi ,

    I spent 18 months out in Alberta and experienced the chinnook on several occasions. As a rule the temperatures do not exceed 7 C, but that feels very warm after a spell of intense cold. They last up to about 72 hours and the most pronounced affects are along the eastern foothills of the Rockies and out to the high plains of Calgary and beyond.The highest temperature recorded are usually in February when winter depressions start to invade higher latitudes. 19C was once recorded in February during a particular mild spell in Calgary. The Bow River melting in 24 hours ! Warm enough to play cricket.

    C

    "Since it is located at the base the Black Hills and only a few miles from the geographical center of the United States, the climate is highly variable. Spearfish holds the world record for the fastest temperature change. On January 22, 1943, at about 7:30am MST, the temperature in Spearfish, SD was −4 °F (−20 °C). The chinook kicked in, and two minutes later the temperature was 45 °F (7 °C) above zero. The 49-degree rise in two minutes set a world record that still holds. By 9:00am, the temperature had risen to 54 °F (12 °C). Suddenly, the chinook died down and the temperature tumbled back to −4 °F (−20 °C). The 58-degree drop (32 °C) took only 27 minutes"

    I've just ripped that from Wikipaedia, however the Spearfish, South Dakota rise of 27ºC (49ºF) in TWO minutes is officially recognised in the Guiness Book of Records (I remember reading it as a kid)

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    Posted
  • Location: Braintree
  • Location: Braintree

    John

    when you do your tutorial could you include the ones that get formed in the west alps, as i have sat waiting to go hang gliding for days with the wind getting to 60-70km/ph each day from the French Alps and down the Rhone delta, as some times this area gets Fhon's from different directions, and being able to get and idea of how theses work may help ease the boredom :)

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    Posted
  • Location: Heswall, Wirral
  • Weather Preferences: Summer: warm, humid, thundery. Winter: mild, stormy, some snow.
  • Location: Heswall, Wirral

    Funny this thread has been made because we have a fohn in my location today, it is 15C with warm SW'ly breeze :)

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    • 2 weeks later...
    Posted
  • Location: Lecco(Italy) 227m
  • Location: Lecco(Italy) 227m

    I love fohn sometimes..

    yesterday maximum temperature were about 18°C (minimum temperature 1,5°)

    (sono delle parti di Lecco :blush: )

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    Posted
  • Location: Shoeburyness, Essex - 6.2m asl
  • Location: Shoeburyness, Essex - 6.2m asl
    I love fohn sometimes..

    yesterday maximum average temperature were about 18°C (minimum temperature 1,5°)

    Whereabouts are you, Anakin? Can you add your exact location, which I guess is somewhere in Italy? Thanks :blush:

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    Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

    I will eventually publish a bit of a guide to this topic, but it will have to be when I get back from Wengen, skiing maybe!

    again tks for the various inputs.

    mods can you pin it whilst I'm away, or ensure it does not get lost please for me?

    many tks

    John

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