I understood that these effects are caused by the freezing of water vapor and are mostly likely to happen FAR below 0° C. So I considered this visual evidence of bitter cold even before your concluding sentence.
Saadsays
I looked up the weather up there out of curiosity…. -8???
I like winter but damn…
It’s 63 here down in Jawja. I wish we actually had a winter here.
Duncsays
I looked up the weather up there out of curiosity…. -8???
Pretty cold, but not that extreme…
It’s 63 here down in Jawja. I wish we actually had a winter here.
Oh shit, you’re using Fahrenheit… OK, -8 F really is cold.
Bruce Fuentessays
We hit a low of about -10F (-23C) last night. Still below 0F. -1F (-18C) currently. Time to go out and move some snow.
Bruce Fuentessays
BTW, I am about 200 miles(320KM) NW of PZ, just east of Duluth, MN.
-8 is getting there. Once has to pull a car battery because the seatbelt dangling kept the door open and drained the battery. It was -17 during the day in the Twin Cities.
blfsays
It’s about 9 here in the evening, expecting to drop down to about 7 during the night. ℃, that is. Will probably have carry a sweater if I go out for dinner.
unclefrogysays
well that is why I do not live in the north or the mountains! that is colder than my freezer gets.
It does get chilly here down in L.A. and people do complain of cold but damn.
having never seen anything like that I thought it was an artifact of the camera you, say that that is an effect of freezing water vapor?
what I notice about the seasonal change mostly is the changing color of the light do to the angle of the sun.
uncle frogy
jack16says
A trickle charger is handy for cold-weather starting.
jack16
Rob Grigjanissays
unclefrogy @12: Yeah, it’s about light refracting through hexagonal ice crystals. There’s a wide range of incident angles which result in a roughly 22 degree deflection*, which is why (with crystals randomly oriented about their central axis) you see a halo at 22 degrees away from the sun. The sun dogs (bright patches either side of the sun) are a result of plate-like crystals being largely horizontally oriented (vertical central axis).
I am deeply impressed to see people posting high-level technical explanations of sun dogs. I’ve had a brief look into them for my academic work, and more-or-less ran away due to the ridiculously complex scattering that results. From ice! A crystal formed from a three-atom molecule!
methuseussays
I miss northern winters. It’s currently 85 here today. Later in the week it’ll be down to around freezing at night, but still 55-60 during the day. People still pull out parkas anytime the temp gets down below 60, though. I still sometimes wear shorts.
gijoelsays
I’m currently in Brisbane where it’s 34c (93f). Also the sky is white due to the large amount of bushfire ash in the air. I’d kill any deity of your choice to stop this awful weather.
I’d kill any deity of your choice to stop this awful weather.
The only problem is that they’re all Level 25 and have 400 hp.
Badlandsays
@gijoel
Try being in Perth for the next five days. It’s going to be nasty.
gijoelsays
@19 Yeah, > 40C. That’s pretty bad.
birgerjohanssonsays
Rob Grigjanis @ 14, Hj Hornbeck @ 15
-Something even more mysterious are the vertical columns of light you sometimes see rising up from light sources on cold winter nights. Random light scattering should result in halos or rings.
It is as if the ice crystals magically “know” the vertical axis and deflect light by 90 degrees.
Since the crystals are so small they basically hover in the air, there is no aerodynamic force resulting from falling vertically and affecting their spatial orientation.
Sound waves are refracted sideways by the temperature inversions near the ground in winter, but temperature inversions cannot affect the orientation of ice crystals. So what is happening?
Rob Grigjanissays
birgerjohansson @21: The plate-like crystals I mentioned in #14 are oriented roughly horizontally as they slowly descend. The light you see doesn’t come from directly above the source. It is reflected from the bottoms of crystals between, and above, you and the source. So the column is an optical illusion.
gijoelsays
@19 The heat I could tolerate but the smoke in the air really aggravates my asthma.
Gorgeous!
I understood that these effects are caused by the freezing of water vapor and are mostly likely to happen FAR below 0° C. So I considered this visual evidence of bitter cold even before your concluding sentence.
I looked up the weather up there out of curiosity…. -8???
I like winter but damn…
It’s 63 here down in Jawja. I wish we actually had a winter here.
Pretty cold, but not that extreme…
Oh shit, you’re using Fahrenheit… OK, -8 F really is cold.
We hit a low of about -10F (-23C) last night. Still below 0F. -1F (-18C) currently. Time to go out and move some snow.
BTW, I am about 200 miles(320KM) NW of PZ, just east of Duluth, MN.
Sun dogs. Some details here.
That’s called a sundog where I live.
(jinx!)
Make that NE Of PZ. Why is there no edit capability?
-8 is getting there. Once has to pull a car battery because the seatbelt dangling kept the door open and drained the battery. It was -17 during the day in the Twin Cities.
It’s about 9 here in the evening, expecting to drop down to about 7 during the night. ℃, that is. Will probably have carry a sweater if I go out for dinner.
well that is why I do not live in the north or the mountains! that is colder than my freezer gets.
It does get chilly here down in L.A. and people do complain of cold but damn.
having never seen anything like that I thought it was an artifact of the camera you, say that that is an effect of freezing water vapor?
what I notice about the seasonal change mostly is the changing color of the light do to the angle of the sun.
uncle frogy
A trickle charger is handy for cold-weather starting.
jack16
unclefrogy @12: Yeah, it’s about light refracting through hexagonal ice crystals. There’s a wide range of incident angles which result in a roughly 22 degree deflection*, which is why (with crystals randomly oriented about their central axis) you see a halo at 22 degrees away from the sun. The sun dogs (bright patches either side of the sun) are a result of plate-like crystals being largely horizontally oriented (vertical central axis).
*See interactive ray diagram here.
I am deeply impressed to see people posting high-level technical explanations of sun dogs. I’ve had a brief look into them for my academic work, and more-or-less ran away due to the ridiculously complex scattering that results. From ice! A crystal formed from a three-atom molecule!
I miss northern winters. It’s currently 85 here today. Later in the week it’ll be down to around freezing at night, but still 55-60 during the day. People still pull out parkas anytime the temp gets down below 60, though. I still sometimes wear shorts.
I’m currently in Brisbane where it’s 34c (93f). Also the sky is white due to the large amount of bushfire ash in the air. I’d kill any deity of your choice to stop this awful weather.
The only problem is that they’re all Level 25 and have 400 hp.
@gijoel
Try being in Perth for the next five days. It’s going to be nasty.
@19 Yeah, > 40C. That’s pretty bad.
Rob Grigjanis @ 14, Hj Hornbeck @ 15
-Something even more mysterious are the vertical columns of light you sometimes see rising up from light sources on cold winter nights. Random light scattering should result in halos or rings.
It is as if the ice crystals magically “know” the vertical axis and deflect light by 90 degrees.
Since the crystals are so small they basically hover in the air, there is no aerodynamic force resulting from falling vertically and affecting their spatial orientation.
Sound waves are refracted sideways by the temperature inversions near the ground in winter, but temperature inversions cannot affect the orientation of ice crystals. So what is happening?
birgerjohansson @21: The plate-like crystals I mentioned in #14 are oriented roughly horizontally as they slowly descend. The light you see doesn’t come from directly above the source. It is reflected from the bottoms of crystals between, and above, you and the source. So the column is an optical illusion.
@19 The heat I could tolerate but the smoke in the air really aggravates my asthma.