Stratus / T-Storm Clouds in FS Meteo?

[Damian Clark 1,031]

Hi,As stated, METAR reports do not give cloud type information. They also do not give cloud info above any layer that blocks the measuring equipment, including heavy broken or overcast. Most AWOS equipment that makes METARS at many airports is also limited to 12,000ft AGL for measurements (TAF forecasts have upper altitude cloud layers in the reports).However, it is quite easy to compute the cloud type based on these factors:AltitudeTemperaturePressureFS gives us the choice of CUMULUS, STRATUS, CIRRUS or THUNDERSTORM. We can use the METAR data to guestimate which of these 4 would be most likely to be seen.CUMULUS clouds are generally associated with unstable and/or vertical-movement airmasses. Unstable air that is prone to vertical movement is detected by checking the barometric pressure. Lower pressure = more unstable air. Temperature also affects this. The higher the surface temperature the more prone the air is the vertical movement (warm air rising pushing the unstable air upwards).STRATUS clouds are generally associated with stable airmasses. High pressure assisted with cooler temperatures will provoke the formation of stratus.CIRRUS clouds are composed of ice crystals, and are seen in the upper altitudes where the temperatures are freezing.CUMULONIMBUS (thunderstorm) clouds are basically towering cumulus clouds that generate rain. They require 3 conditions to form: unstable airmass, upward movement of air (to start the formation), and high humidity. Further there are 3 stages of the CB - developing, mature, and dissipating. Each stage is characterized by different movement of air (mostly updrafts in developing, up/down in mature, and down in dissipating).Fortunately, by applying these guidelines and comparing against existing and forecasted weather information, a pretty good picture can be drawn about what the weather will look like. Intelligent cloud type selection based on these factors is only one of the things we can do to make our FS skies more realistic. There are tons of possibilities here that are barely even touched upon yet... But soon we will start to see this. I am working hard on the next version of ActiveSky which will utilize these intelligent selection techniques (current version already does this to a certain degree). I presume that FS2K4 will give us more cloud types and additional manipulation of cloud 'objects' which should really make things tons better.-Damian Clark

[alastairmonk 0]

As promised here are five shots from my trip. Judge for yourself on the clouds.

[Guest cornclose]

No-one seems to have mentioned the following :-Thunderstorms are reported in METARs as TS, TS- or TS+ which means Thunderstorms, Light Thunderstorms or Heavy Thunderstorms respectively. These qualifiers are similar to the rain qualifiers which are RA, RA- and RA+. There are a host of other qualifiers too.These can all co-exist with upto three cloud layers. So, you could in theory get the following elements in the same METAR report :-FEW020 SCT035 OVC070 TS...which would mean a few clouds at 2000ft, scattered clouds at 3500ft, overcast at 7000ft with thunderstorms.There is also the 'VC' qualifier, which means thunderstorms in vacinity.I don't know what FSMeteo decodes and uses, but I do know that X-Plane (along with X-METAR which I wrote) will decode and support all these weather phenomena and more besides.I've never been a fan of FSMeteo, for me it doesn't do anything that the freeware Real Weather & GPS for FS98 didn't do, and this still works flawlessly with FS2002.Chris Ehttp://www.circle-software.co.ukhttp://website.lineone.net/~flightsimukAvoid AGP texturing = Better Performance ;)

[Guest]

I have to agree here. I have often loaded the 'real weather' and has been nothing like the actuals. I can't understand how the sim translates the information, because for most UK/ European airfields the data is meaningless. The viz is always shown as unlimited -if ever, as you say you are lucky if you get more than one cloud layer and I have yet to get rain appearing, even when it is actaully raining. I was interested to see those pictures, they look great. Tell me did the clouds actually have some body, or were they the thin images that you sometimes get?Also where can you get the other weather programs?Thanks,Keith