true or magnetic??

[Flying_Corporal]

I was trying to determine if winds are true or magnetic for the following reports. Here is what I found out from AIM:

ATIS - true
Metar/Taf - true
Winds Aloft - true

However, recently I checked Metars right after landing and saw that the winds on the report were identical to the ones advertised in ATIS.

Anyone can explain? Thanks.

 

[Tired]

If winds on the ATIS are true, and winds in the METAR are true, shouldn't they be equal?

Ok, in order to answer your question when you figure out where you went wrong, what airport are you talking about?

 

[EatSleepFly]

As far as I know, ATIS, and any wind check given by tower is supposed to be given in Magnetic. This is to save you from having to figure out the diff. between Mag and True for wind correction purposes.

METAR's are referenced to true (according to my good 'ol Aviation Weather Services book).

My guess would be that maybe ATC just read the METAR when they broadcast the ATIS.

 

[Tired]

Yep, ATIS is in magnetic. I'll bet the magnetic varation at the OP's airport is small enough that they don't need to convert from mag to true when doing the METAR.

 

[triple7]

If you hear it they are magnetic...if you read it they are true. with the exception of a winds aloft and metar brief from a FSS briefer. Of course hes reading those anyways....

 

[Flying_Corporal]

[ QUOTE ]
ATIS - true
Metar/Taf - true
Winds Aloft - true


[/ QUOTE ]

Sorry, I meant

ATIS - MAGNETIC.

I was on an autopilot when I typed it up

[ QUOTE ]

I'll bet the magnetic varation at the OP's airport is small enough that they don't need to convert from mag to true when doing the METAR.


[/ QUOTE ]

No, it's in NY area. The variation is 14 degrees.

 

[sixpack]

Visibility is in statute miles.
Wind speed is in nautical miles / hour.
Don't you just love it!

 

[Jonnyb1225]

When meteorologists first determine the wind is it in true or magnetic direction?

 

[Alchemy]

Not to state the obvious, but are you sure a new METAR wasn't put out between the time you heard the ATIS and the time you checked the METAR after getting out of the plane? The ATIS is usually changed at 53 minutes passed the hour, but it can be done upon reciept of any official weather.