AGL or MSL?

by Jason Schappert

So are the ceilings in METARS AGL or MSL? What about Winds Aloft? Area Forecasts? Let me debunk any misconceptions you may have with AGL vs MSL in regards to weather in todays video… Enjoy

AGL
METARS
TAFS
ATIS, AWOS, & ASOS

MSL
Area Forecasts (FA)
Winds Aloft (FD)
PIREPS

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Tagged as: AGL, MSL

Nick

Hi Jason, Another good one is wind direction. When is it true and when is it magnetic?
Josh

Jason, get a remote mic for your audio!!!
A Good Pilot

Thank you, someone finally said it!
OMAR

All is true, except in the ATIS.
Regards
Charlie

Thank you Jason. Let me make sure I understand.6A2 (Griffin GA) is at about 950′. A TAF says broken at 4000, then clouds would be at 5000. Right? Flying VFR WEST at 4500′ would give me little room to be at 4500 and make sure that I’m at 500′ below them. Secondly, what is the more important thing to do? Stay at 4500 or keep 500+ below the clouds?
If I’m doing Flight Following would I need to let them know that I’m flying a lower altitude to avoid clouds? By lower I mean flying at 4000 or 4200 for instance. Or should I decend to 2500 so that I’m even plus 500?
http://www.facebook.com/tedirelan Theodore J. Irelan

Good video. Really enjoyed the ending. I guess someone wanted a cameo.
Ken

When planning a long cross-country and you want to select an altitude to stay under the clouds, its a lot of work to check each airport elev along the route to see what the MSL cloud layer is… any good tools to give you this in an easier method?
Ken

When planning a long cross-country trip and selecting an altitude to stay under the cloud layer, checking each airport along the route (it’s elev and TAF/METAR) to determine the MSL cloud layer — that’s a lot of work! Are any tools available to do this automatically or an easier way? (Getting that IFR rating is looking better and better)…
Kathy

Well, don’t know about y’all…. but to me, that was clear as mud (not you Jason, just…. why does it have to be so confusing??) Anybody have an acronym for this?

Thanks for all you do, Jason. Love the videos! Look forward to them every week.
http://www.thesquawkshoppe.com/ The Squawk Shoppe

man that rooster was right on cue!!! Thanks for the vid.
Peter King

One way to help remember is to associate it with the rules that apply. When in the airport environment, we are concerned with ceilings (AGL) to determine if we can takeoff and land VFR or if the instrument procedures will be available. While enroute, we want to know how weather relates to our cruise altitude (MSL).

The coastal weather in the Area Forecast is a funny exception that you don’t need to worry about because over the water, AGL is the same as MSL.
Peter King

Both rules always apply, you can only choose to break a rule in an emergency. That said, the 500 plus rule only applies above 3,000 AGL. At or below 3,000 AGL, you can legally cruise at any altitude. So, pick an altitude that is at least 500 below the clouds and keep an eye out!

With regards to flight following, ATC does have you on radar, and they can see your altitude changes. But it is helpful to report changes in cruise altitude as a courtesy so they can better anticipate conflicts. Something like “1AS leaving 4,500, descending VFR 3,000″ will usually get you a “Roger.”
Dave

Jason,
Have watched you for almost a year now, great job, great videos! I am now 170hrs and almost done with IFR training. You have helped a lot.

But, one thing you haven’t done is buy a good microphone. You need to use a Lav. Wireless is better for moving around but even a wired one would give you that final professional touch..

Here is a decent priced wireless:
Sennheiser EW 100ENG G2 – wireless microphone system
$156 online

Keep up the great work. I don’t plan to stop watching..
GKDave