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Damian Clark

ATIS

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When receiving ATIS in FS2002, they have been consistently reporting-" Temerature 15C Dew Point 15C".If I'm not mistaken- (from my limited weather study, I'm not a real pilot) that would mean where Temp and Dew Point collide..condensation will form as clouds or if on the ground as fog.Even though I'll get an ATIS of 10-15 miles visibility.Am I right or wrong...I think back to the Kennedy Accident where many VFR real life pilots reported that they would have thought twice about launching when the ATIS at the Cape on that evening had Temp and Dew point within a few degrees of each other suggesting the liklihood of fog compounded with night flight over water (a bad recipe for VFR from what I hear but what do i know not having been up there).Thanks,Greg

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Hi Greg,I've noticed this problem too in FS2002. Everytime I don't use FSMeteo (which is da bomb!) or Real World Weather (which is crap any way), the temperature and dewpoint are always the same. I believe you are right on about the formula for fog to occur, (though I'm not a meteorologist, I only took an intro class to it a couple years ago.) I think this is just another example of FS's horrible wx engine. Whenever I start a default flight, the altimeter is always 2992 and the temp/dewpoint is always the same. You'd think by now, they'd atleast give you random weather to start up in, then you could tweak it to what you want, but this is just another case of FS2002 slacking off in the wx dept. Hopefully it will be fixed in FS2004 and perhaps we won't need programs' like FSMeteo or Activesky (don't get me wrong, I don't fly without FSMeteo now.) But to solve your problem, get FSMeteo and you should get proper weather effects, so if the two are the same, you will have fog. I believe FlyII and X-Plane also show wx data and effects way better than FS2002's wx engine. Hope this helps.MaulWho Wants To Fly The Big Jets In & Out Of Chicago O'Hare...I DO! :-wave

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It may only be a bug in the ATIS report feature because so far, in the internals of FS2002, there is a DEW Temp that is variable in both time and distance.Hope this helps!

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Just because temp and dew point are the same (100% relative humidity), it does not mean there will be clouds or fog...only a likelyhood of them forming. There needs to be other factors for clouds and fog to form (condensation nuclei, lifting force, cooling of the air, etc.). You could have >10 SM visibility even with 100% humidity.However, you can always go in and change the dew point in FS. However, as I never fly without FSMeteo, I don't know if it is bugged.

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Hi,Yep doesn't always indicate visibile moisture when temp and dewpoint are the same.Technically, Dew Point is the temperature at which the air becomes "saturated" or 100% humidity. FURTHER cooling of the air is now required for clouds and fog to form. This isn't an exact science either. Temps are reported in whole digits only so 1/1 could actually mean 1.9 and 1.0, still not the same. And as Ken stated you also need condensation nuclei (small particles in the air that moisture can adhere to such as dust, smog chemicals, etc..).One good way to tell if a low temp/dewpoint spread is going to yield clouds or fog is by the baro pressure.Higher pressure generally means lower visibilities, partly due to the fact that air is stable and won't be moving around as much, collecting smog, dust, dirt, etc. easily.Lower pressure generally means higher visibilities, likewise inversely, due partly to the fact that the air is more unstable and moving around, cleansing it so-to-speak.The Dew Point setting in FS does work, btw!-Damian[table border=0" cellspacing="30" cellpadding="0][tr][td align = "left"]Damian ClarkHiFi Simulation SoftwareDeveloper of ActiveSkyThe next-generation weather environment simulation for FS2002!http://hifi.avsim.net/activesky[/td][td]http://hifi.avsim.net/activesky/images/wxresmallbanner.jpg][/td][/tr][/table://http://hifi.avsim.net/activesky/ima...][/tr][/table

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