Please correct me if im wrong VATSIM ATC Training-WEATHER

Christopher Burrow

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Please correct me if im wrong VATSIM ATC Training-WEATHER
« on: August 10, 2019, 03:08:53 PM »
Hi all..

Please correct me if i'm wrong but i'm new to the ATC portion of VATSIM and am going through the online training currently. I have come across a topic i am confused about under WEATHER...specifically Horizontal and vertical visibility.

On slide 6 of the weather training in section one it states that Vertical Visibility is measured in Statute Miles not NM. Wouldn't the Vertical visibility be in Feet MSL? and not SM???? because vertical would be your Up and down visibility??

it also say that Horizontal Visibility is measured in Feet MSL....wouldn't that be Vertical visibility instead of horizontal?? Wouldn't Horizontal be the SM visibility???

Please let me know if i'm way off on this and have Horizontal and vertical confused because right now i think i'm having a brain fart  :)

Thank you all :-)

Ryan Parry

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Re: Please correct me if im wrong VATSIM ATC Training-WEATHER
« Reply #1 on: August 10, 2019, 05:03:19 PM »
I think the slide might be worded poorly, but basically it works like this...

Quote
KSFO 102056Z 27013KT 10SM FEW007 SCT022 SCT035 24/15 A2999 RMK
    AO2 SLP156 T02440150 50004

In the first paragraph I think they are talking about the visibility out the window, known as prevailing visibility and sometimes minimum visibility. This is how far you can see from the reporting point. We measure that in Statue Miles and it appears in both a METAR and a TAF. In the above example it is reporting that you can see 10SM from the reporting point on the field.

It doesn't seem to mention RVR at all, but just know that during bad weather you will see something like R01L/0600V1000FT which is giving you the RVR for the specified runway. I'm not sure if RVR is in the purview of that lesson so I won't get too into it, but just be aware it is a thing and hopefully you'll learn about that later on in training.

Quote
KSFO 102056Z 27013KT 10SM FEW007 SCT022 SCT035 24/15 A2999 RMK
    AO2 SLP156 T02440150 50004

The second paragraph I think is referring to the sky conditions. In the above METAR example it is reporting few clouds at 700 AGL, scattered 2,200 AGL, and scattered 3,500 AGL. I am not sure why it says MSL, but a METAR and TAF report AGL.

The last blurb is about vertical visibility, also known as indefinite ceiling (VV) and is reported in hundreds of feet. So VV002 is 200 feet.

Hope that helps!

Rick Rump

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Re: Please correct me if im wrong VATSIM ATC Training-WEATHER
« Reply #2 on: August 10, 2019, 07:39:47 PM »
I will clarify in the next update. As for RVR it is covered in the S2 material.