Radar color decoding

[rumpletumbler]

Ok...so green means go.....red means dead.....what about the other colors?

 

[typhoonpilot]

Ok...so green means go.....red means dead.....what about the other colors?

They mean be careful .

Just off the top of my head. Green means 29 or less Decibels, Yellow means 30 to 39, Red means 40 or more. It could be 40 or it could be 60, you don't really know. Magenta on newer Radar displays means turbulence and usually only works on 40nm range or less.

The trick is understanding what you are looking at and where you are. Red in the tropics is a whole lot different than red in Texas or Oklahoma. How is the gradient ? In other words how quickly does it change from green to yellow to red ( if at all ). What is the shape of the return ? any hooks ? any shadowing ?

Look for Archie Trammel or Dave Gwynn ( sp ? ) courses on interpreting wx radar. They are well worth the time and effort if you are going to be using a radar for the rest of your career.


TP

 

[METARMan]

WX Radar

It all depends what graphic you are looking at and from what vendor. For example, NWS WSR-88D's (NEXRAD) operate in clear air mode (very sensitive) and precipitation mode (less sensitive). Each has different scales.

NWS DIFAX radar composite maps have I believe 5 scales, while radar composite's from Accu-Weather and Intellicast (WSI) can have more.

Airborne weather radar usually only has three or four.

There should be a scale on most maps.

METARMan

 

[FN FAL]

Ok...so green means go.....red means dead.....what about the other colors?

It's more than just looking at the screen. Last saturday I had a flight where eventually I had no choice but to go through a lot of yellow, red and magenta. I found myself panning the antenna down, just to make sure that edges of the returns being displayed weren't attenuation.

To be fair, most of these returns didn't even show up untill you were close to them, so it wasn't like I was penetrating contouring cells that were being depicted 100 miles up ahead. These were areas that returned green on the 40 mile scale and were not seen up until then. They all appeared green at first, then as I got closer to them they became a fuzzy yellow or red with magenta fuzzy blobs inside them.

Funny part was, the turbulence was actually smoother in the depicted areas of yellow, red and magenta, than it was out of them. Since I was IMC, I couldn't make out sh!t from inside the cockpit...except when I was in the return, it got dark out...really dark out.

It was pretty confusing at first, but the radar images I looked at on the ground before I left, didn't indicate any real thunderstorms...just rain.

I wouldn't have pushed on, but the ADF needle never budged and I had the audio on for the entire time and there wasn't even a cackle of static electricity.

Most of the rain I went through was not even close to what I would consider heavy...so I'm wondering if the returns were not enhanced by some other factor such as temperature of the rain? It was mostly about +4C at the time.

You're going to get out there one day and find the same situation if you are in a plane that won't be going above most weather and I found it real hard to think that a guy could just steer himself around the worst returns, because there was no rhyme or reason to it...not like on a summer day where you paint a cell out on the 80 mile range and it's got contouring like a mofo.

 

[FN FAL]

On the contrary, today with the same airplane, I was passing by some TCU's that weren't all that tall but the looked like miniature thunderstorms...tops may have went into the mid twenties. I was monitoring the ADF as cheap backup to the radar and not much was going on, however the awos/asos at the airport was calling VCTS!

I never even had a return painting on the unit...so I called down to dispatch and one of our pilots was waiting in the office to get the heck out of there (vis was less than 1/4 at the time) and he verified there was a T-storm by the airport.

Kind of wierd, but there is more to radar than just looking at some returns and making your way around them. Maybe if your're in a jet and you zoom around a bunch of stuff, that's great...but you'll get your cherry popped once you get your first 135 job and you are dealing with returns on your screen IMC.

In my previous post, I was no way implying that you should just disregard training or common sense and fly blindly into areas of yellow and red on your radar, but sooner or later you're going to get into some green that changes colors on you once you are commited...it sucks, it's scary and it happened to me last saturday. Eventually there was so much time spent in the yellow, I got out of the fetal position on the floor and got up and took a leak.

 

[JediNein]

Green means rain.
Yellow means hail.
Red means dead.
Magenta means you go home in a ziploc 'cause their ain't enough left to fit in a body bag.

Yellow can be fun, in controlled circumstances and a willingness to accept some paint chips and dents. What can your airframe, ego, and payload withstand?

Archie Trammel is now on DVD, so no excuse for not getting his course. If you're in Socal, I'm giving a seminar on WX Radar sometime in January, PM me if you want more details. It's really a teaser to motivate pilots to get serious weather training or stay the bleep out of the colored murk.

Fly SAFE!
Jedi Nein

 

[414Flyer]

I will also recommend that Archie Trammel tape/dvd. Its a lot of information at once, and it will take multiple watchings followed by trying it in the airplane, and watching it again to grasp it all . You cant just watch it once and remember it all.

but its good stuff.

 

[FN FAL]

Green means rain.
Yellow means hail.
Red means dead.
Magenta means you go home in a ziploc 'cause their ain't enough left to fit in a body bag.

Yellow can be fun, in controlled circumstances and a willingness to accept some paint chips and dents. What can your airframe, ego, and payload withstand?

Fly SAFE!
Jedi Nein

**CENSORED****CENSORED****CENSORED****CENSORED****CENSORED** off Jedi...you don't know what you are talking about.

The catagory wasn't chick fo's with no PIC time for a hundred bucks.

 

[seethru]

I will also recommend that Archie Trammel tape/dvd. Its a lot of information at once, and it will take multiple watchings followed by trying it in the airplane, and watching it again to grasp it all . You cant just watch it once and remember it all.

but its good stuff.

I've been looking for the Archie Trammel tape, but so far all I've found is a 4 CD set from Sporty's which costs about $370. Is there another tape you are referring to?

Thanks,

Greg

 

[typhoonpilot]

I've been looking for the Archie Trammel tape, but so far all I've found is a 4 CD set from Sporty's which costs about $370. Is there another tape you are referring to?

Check out Aircraft Spruce and Specialty, they may be cheaper, or just read the Bendix King RDR-4B guide below as it has some very good and practical info.

Green means rain.
Yellow means hail.
Red means dead.
Magenta means you go home in a ziploc 'cause their ain't enough left to fit in a body bag.

I've got to wonder how you come up with how yellow means hail . That makes no sense. The colors are a level of reflectivity measured in Dbz.

Download this and read it: http://www.flwsradar.com/Tech_Lit/Pilots_Guide/006-18167-0000.pdf

The cliff notes version:

Airborne Weather Radar color signifies a set intensity of precipitation. I've already talked about the unit of measurement but to put it in easier terms ( rainfall rate ) it goes like this:

Black = Less than 0.7 mm/hr
Green = 0.7 - 4 mm/hr
Yellow = 4 - 12 mm/hr
Red = Greater than 12 mm/hr
Magenta = Turbulence

Magenta is the one most often confused because on some learning material you might see it as a higher precipitation rate. In fact that might apply to ground based weather radar, but it doesn't to any of the airborne units I've ever read about. On an airborne unit magenta is provided by a Doppler Turbulence Detection circuit that measures the variations in horizontal speed of precipitation particles. It is not uncommon to see magenta overlayed on a green return. That means that the rainfall rate is between 0.7 and 4 mm/hr and there is random relative radial motion of the raindrops or perhaps a difference in fall speeds of varying size raindrops.

Now, as for yellow meaning hail, I think we've covered that is not the case, it merely means a higher precipitation rate. How to detect hail though does bare some thought. Hail usually has a film of water on its surface; consequently, a hailstone is often reflected as a very large water particle. Because of this film and because hailstones usually are larger than raindrops, thunderstorms with large amounts of wet hail return stronger signals than those with rain. They also tend to have some shape characteristics that give you a clue. Some strong indicators of hail are: U-Shape, Fingers, Scalloped Edges, and Hooks. Check the guide for examples.

If the link doesn't work try this:

https://www3.bendixking.com/static/main/leftBKLink.jsp?pageid=http://www.honeywellaerospace.com/products.htm

Click on Products By Families, Aerospace Electrical Systems, Safety Products, Radar, Technical Literature Page.


Typhoonpilot

 

[exagony]

you've got it all wrong!!! Magenta is the same color as Barney the Dinosaur - ie "happy zone" go straight for the magenta and enter the "happy zone"!