Weather

Wing_Z

Wing_Z

Charter Member 2011
...has been talked about recently.
This one just jumped out at me when switching to tower view at Frankfurt.
Hope it clears up for Christmas...

c17-2.jpg
 
Now that sir is fog! :icon_lol:

I hate instrument flying, but it is a challenge and when real world weather presents it in the sim, I take the challenge. In real life, I would never, ever take an airplane up in muck like that. Heck, the whole reason I like to fly is to see Earth from a better perspective.

Caz
 
It was an IFR flight, with RW (stock) weather updated every 15 minutes, as discussed in another thread.
Approaching EDDF it started turning to custard.
I was pleased that the weather transition was relatively smooth.
The landing was AP automatic, visibility what you see above.
On taxiing in, it started to snow!

Normally it's no fun to fly in fog, true, but when it catches you out, and you make it down in one piece, you feel like a hero...:)
 
Cazzie said:
Now that sir is fog! :icon_lol:


Caz
Click to expand...

No Sir

This is Fog or what FS9 will do when you encounter Real Fog or 0.00 sm of Visibility.

FS9 does not handle 0.00 sm of visibilty correctly and what happens is a white out of...

Well you can see in the Screen shots. :icon_lol:

It makes landing interesting to say the least. Its easier and harder than landing in 0.01 sm of Visibility.
 
Well...be fair.
In 0 nm visibility, you would not be able to see your hand in front of your face! ;)
 
What Dave is seeing is not zero vis, but a situation in FS that if the dewpoint is higher than the temperature, which is impossible in the real world, is reported, the textures in FS go all white. That is why his plane and building textures are all white.
 
JSkorna said:
What Dave is seeing is not zero vis, but a situation in FS that if the dewpoint is higher than the temperature, which is impossible in the real world, is reported, the textures in FS go all white. That is why his plane and building textures are all white.
Click to expand...

Might be true but in Weather Set it was reading 0.00 sm Visibility and every time it has read 0.00 vis thats what it generates.

Still it is a flaw in the sim.
 
JSkorna said:
What Dave is seeing is not zero vis, but a situation in FS that if the dewpoint is higher than the temperature, which is impossible in the real world, is reported, the textures in FS go all white. That is why his plane and building textures are all white.
Click to expand...

Actually a case for supersaturated air does exist although not normally as a warm-air, steady state condition.

http://journals.pepublishing.com/content/p0h8123p68322372/
http://mozaic.aero.obs-mip.fr/web/features/publications/2003-15.html

The immediate result of an aircraft flying thru it (in the UPPER atmosphere) is the formation of one type of contrail.

We have gathered in situ tropical humidity observations from several field experiments. These measurements included accurate water vapor sensors mounted on the NASA ER-2 as well as balloon-borne instruments. The humidity observations provide a few examples of supersaturated air near the tropopause (as predicted by our model); however, further observations of water vapor and wave motions near the tropical tropopause are required to clarify the cloud formation and dehydration processed.
http://geo.arc.nasa.gov/sgp/modelling_aug01/model3.html

At lower altitudes another effect can be seen in those spectacular "shockwave" pics of Tomcats, etc breaking through a 'wall' of mist. At the point where the compression wave forms, the air temperature and density change rapidly, resulting in supersaturation and then precipitation of water vapour as it cools.

I guess the way to visualize this in Dave's case (and mine at the same time) is to think of the FS engine reading this oversaturation (from confused or incorrect temp./dewpoints) and, realizing it should be trying to produce a true "Zero visibility", forms an 'internal cloud'. Without the capability of totally blanking the display it stops sending pixel/colour data and you get the 'whiteout'. Regardless of how/why, it's a real pain to try and fly in :isadizzy:

For other low visibility situations (<1sm vis) the FS engine actually does produce pretty realistic effects as seen in the C-117 pics.

Rob
 
Rob,

Now show me a METAR where the dewpoint is higher than the temperature.
 
Where did you find the absolute zero visibility, and, out of curiosity, how can I reproduce the whiteout? :jump:

The worst visibility I've found to date in FS was on a pacific island in full summer... there was to make Englishmen go green with envy for the fog on that island... and there wasn't an ILS available either on that runway... in the end, it was a bug of IVAO's weather, as all the other weather engines did not give anything like that result, as it's natural (in the tropical pacific, in summer, I dare you find a place where there's fog, much less one that gave you less than a 5 meters visibility like that that would have paralyzed any airport in spite of any kind of ILS ever invented), but never had any whiteouts in FS ever. :ernae:
 
The worst visibility I have encountered was on a 75 mile Alaskan bush flight in Brian Gladden's PA-22 Super Pacer. Using FSMetars to pull down real time weather, the beginning of the flight saw heavy clouds...which made flying in the high mountains a bit tricky. The last 1/3rd of the flight, the cloud layer lowered and a heavy ground fog developed. As I got within 15 miles of my destination, visibility was down to 300 feet. I could not see a darn thing....and I could not try to drop lower in an effort to find cleaner air as the terrain screen on my GPS showed that I was still in some pretty peaky terrain. I could not find the small airstrip for nothing...took 6 go arounds before I finally got a break in the ground fog and could see the strip...barely. Landed a bit hot and a bit hard....but I landed.

OBIO
 
It's an error in the METAR and ASv6.5 has an internal check to adjust the dewpoint if this happens, so the textures don't white out in FS!
 
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