Faith in ADSB weather

[Scott Dennstaedt 313]

On 8/18/2020 at 9:20 PM, GeeBee said:

https://www.aopa.org/news-and-media/all-news/2012/june/25/ntsb-warns-of-in-cockpit-weather-delays

It does not matter what the age on the screen says, there are other latencies in the system not noted.

These services are strategic, not tactical. 

 

I do agree that you need to be making decisions about your course through/around areas of convection 30 minutes or more ahead of time. Here's what I teach my students. If you are making course changes of more than 30 degrees you are too close to the weather and are likely making decisions too late.  I use a 20 degree rule myself.  Once I deviate from that more than once, I'm looking for an alternate airport to land and wait it out. 

I am not a fan of the 15-20 minute latency edict put out by the NTSB. I think that's just as bad as telling pilots it's real time.  If the depiction is that old, it's likely due to some missed updates. When the system is working fine, you are looking at 5-8 minutes old from the picture out the window when it is refreshed.  Then, depending on the service, you get to stare at that image for 2 to 3 minutes until the next update. So, you are looking at the worst case (barring any missed updates) of a depiction that is 7-10 minutes old. Now that the updates are every two minutes (2.5 min for SiriusXM), it's rare to see a very old mosaic.  

Edited August 30, 2020 by Scott Dennstaedt

[Scott Dennstaedt 313]

On 8/16/2020 at 9:41 PM, toto said:

I've definitely had a few times where the ADS-B radar view disagreed with the window. 

This is a lot more common than you'd think.  In fact, Matt Guthmiller reached out to me to ask me about a similar experience a couple years ago. So I did some research and put together this video.  

 

[Scott Dennstaedt 313]

On 8/16/2020 at 10:02 PM, N201MKTurbo said:

This is great while you are sitting at the console driving the antenna, but when they put it on line, which is what you see on ForeFlight and ADS-B is wherever the operator left the elevation at. If they set it to the lowest setting, you are seeing the ground. If there is a level of virga out there and they left the elevation pointed at that, that is what you see.

Government workers Being lazy or inattentive, who would have thunk? 
 

Not exactly. The radar operator at the NWS WFOs will set the radar using one of many scanning strategies...called volume coverage patterns (VCPs). The VCP they use is based largely on the weather they are expecting.  Light snow or drizzle might cause them to set the radar to one of the slower clear air mode VCPs.  Severe storms will likely trigger them to place the radar in one of the faster precipitation mode VCPs. And with dual-pol and new strategies such as SAILS, mesoSAILS and AVSET, they can get a much better (faster) view of the weather in the area. The radar is never "left" unattended.  Even if so, the radar is always doing multiple elevation scans and is never left to scan on a single elevation angle.  Here's the RPG screen for the Columbia, SC WFO. It sits right there next to the forecasters where they can monitor its status 24/7.

       

Edited August 31, 2020 by Scott Dennstaedt

[philiplane 424]

the best IFR flying set up will include lightning detection for real time weather avoidance. ADSB or XM are good for overall picture, but a Strikefinder or Stormscope are the best tools for weather flying.

Here in Florida, you get good use of a Strikefinder... we are the lightning capital of the US.

Especially since fast moving weather makes the 3 to 15 minute XM delays too risky to rely upon. XM lightning is a useless product.

Edited August 31, 2020 by philiplane

[carusoam 12,477]

If you are wondering why Matt Guthmiller sounds familiar...

https://en.wikipedia.org/wiki/Matt_Guthmiller

-a-

[N201MKTurbo 5,658]

2 hours ago, Scott Dennstaedt said:

Not exactly. The radar operator at the NWS WFOs will set the radar using one of many scanning strategies...called volume coverage patterns (VCPs). The VCP they use is based largely on the weather they are expecting.  Light snow or drizzle might cause them to set the radar to one of the slower clear air mode VCPs.  Severe storms will likely trigger them to place the radar in one of the faster precipitation mode VCPs. And with dual-pol and new strategies such as SAILS, mesoSAILS and AVSET, they can get a much better (faster) view of the weather in the area. The radar is never "left" unattended.  Even if so, the radar is always doing multiple elevation scans and is never left to scan on a single elevation angle.  Here's the RPG screen for the Columbia, SC WFO. It sits right there next to the forecasters where they can monitor its status 24/7.

       

So, when I used to do that, it was in the 80s (85 ish)

I do hope that the software has improved sense then. I should have not projected my experience from the past to current times.

Thanks for showing how it works now.

Im pretty sure they told me it would scan at whatever elevation they set it to. But that was 35 years ago.

[N201MKTurbo 5,658]

This is the console they let me use:

 

This is the equipment out front that put it on the network:

[Scott Dennstaedt 313]

NEXRAD are WSR-88Ds now. You were referring to earlier technology.  Night and day.  

[kortopates 4,234]

2 hours ago, philiplane said:

the best IFR flying set up will include lightning detection for real time weather avoidance. ADSB or XM are good for overall picture, but a Strikefinder or Stormscope are the best tools for weather flying.

Here in Florida, you get good use of a Strikefinder... we are the lightning capital of the US.

Especially since fast moving weather makes the 3 to 15 minute XM delays too risky to rely upon. XM lightning is a useless product.

Actually XM lightning was improved not that long ago. Rather than just ground strikes which was pretty useless XM now provides cloud-cloud strikes and latency is much improved as Scott addressed above.

I still rely on my WX-500 to supplement for real time in close. 

AdsB is limited to ground strikes only and with more latency.

Edited August 31, 2020 by kortopates

[carusoam 12,477]

Computers, data handling, and video image handling... is jumping in leaps and bounds...
 

Both in cloud computing, and at the user level, in planes and autos...
 

I would love to hear the word NVidea computer chips are doing to the work of combining all this graphic data together and delivering...

This would ensure we are getting the fastest delivery of data with the seriousness it deserves...

https://news.developer.nvidia.com/category/graphics-simulation/

It’s one thing to figure out where the weather is going... and a completely different topic of what and where the weather is right now...

It takes really strong scientists, and extra strong tools in their hands....

Other products from NVidea... include vision systems for cars... AI and self driving and automatic braking.... to fast and powerful video displays... typically used for Microsoft flight simulator... 

PP thoughts only, barely scratching the surface of what it takes to deliver the complete window of data to MSers...

Best regards,

-a-

[Scott Dennstaedt 313]

9 hours ago, kortopates said:

Actually XM lightning was improved not that long ago. Rather than just ground strikes which was pretty useless XM now provides cloud-cloud strikes and latency is much improved as Scott addressed above.

I still rely on my WX-500 to supplement for real time in close. 

AdsB is limited to ground strikes only and with more latency.

Nice post.  All correct.  Certainly the sferics devices are real time sensors, but can't be the sole decision point as to whether or not deep, moist convection is dangerous to penetrate. Walter Atkinson (who recently passed away) used to say that if his Stormscope didn't register anything, he'd charge right through it.  Him and I had a huge disagreement here.  Lightning may not always occur even though severe or extreme convective turbulence exists. In other words, the lack of lightning does NOT imply the lack of metal-bending turbulence. Low-topped convection is one of those scenarios. Also, I've seen countless situations where strong microbursts can be generated from deep, moist convection without the presence of any lightning. Here's an example from a microburst in Tucson...no lightning occurred here.  If I were king, I'd eliminate the term "thunderstorm" from a pilot's vocabulary and replace it with "deep, moist convection."  It's foolish to think that a thunderstorm is dangerous, but a rain shower is not.