Nasty severe to extreme turbulence event tomorrow morning west of Denver

[Scott Dennstaedt, PhD]

If you are planning to fly anywhere near Denver early tomorrow morning it’s very likely to see some low- and mid-level severe turbulence along the Front Range. You can see that the EDR values are up near 60 (EDR * 100) just to the west of Denver as shown below on the EZWxBrief route profile. Extreme turbulence starts at 64.

This is all in response to an intense negatively tilted upper-level trough moving through the central Rockies later tonight into early tomorrow morning.

This is even easier to see on the Skew-T Diagram. Notice the wind profile especially at 20,000 feet.

[carusoam]

Let’s see when Travis is heading out this way…. @WrightFlyer… (something interesting regarding flight planning in the Denver area…)

Best regards,

-a-

[Scott Dennstaedt, PhD]

I'm seeing even sporadic areas with EDR values near 70 in this region. Most of that is near the surface further west into the mountains. 

[toto]

Quite a few pireps for severe turbulence tonight. One in Aspen, with a few more in Nebraska, South Dakota, and Wyoming. 

[jetdriven]

I noticed quite a few severe turbulence  pireps in Colorado already today and not by small airplanes…. An embraer 145 and a beechjet 400 and it wasn’t severe turbulence it was extreme.  

[Sixstring2k]

Not a fun flight I would say. 

[WrightFlyer]

10 hours ago, carusoam said:

Let’s see when Travis is heading out this way…. @WrightFlyer… (something interesting regarding flight planning in the Denver area…)

Best regards,

-a-

Keeping an eye on this as I'm doing planning this morning.  Planned flight is for tomorrow and I'm doglegging south through Texas.  Looking at potential overnight locations along the route.  Won't matter much if I miss the first half day of the conference.  

Appreciate the heads up @carusoam!

Also, do you any of you sleep? 

[Scott Dennstaedt, PhD]

Right on time, there have been numerous aircraft this morning reporting moderate and severe reports of turbulence in this area. And, the AWC issued this SIGMET…

Notice the altitude reported by this Vision Jet...

TBM as well...

And a PA46...

[toto]

It’s (maybe just a little) surprising to me that so many pilots are choosing to fly right through a sigmet for severe turbulence.

My typical passengers have nervous stomachs, and I really never experience more than light to occasional moderate. If there’s an airmet for moderate, I’m usually delaying the flight. A turbulence sigmet would have me booking a hotel room and looking for new movies on Netflix

 

[Scott Dennstaedt, PhD]

52 minutes ago, toto said:

It’s (maybe just a little) surprising to me that so many pilots are choosing to fly right through a sigmet for severe turbulence.

Agreed.  But to be fair, these non-convective SIGMETs are rarely issued until pilots begin to report turbulence. Even tho they are technically a forecast, they live and die by PIREPs. Most of the PIREPs of severe turbulence were made prior to the issuance of the non-convective SIGMET at 1423Z.  Here's another one of a TBM9 reporting severe turbulence at 1410Z.

 

[exM20K]

Great early call on the adverse weather, Scott.  This is very interesting stuff.

-dan

[Scott Dennstaedt, PhD]

1 hour ago, exM20K said:

Great early call on the adverse weather, Scott.  This is very interesting stuff.

Dan,

Yes, I have a notification turned on from my website whenever the EDR values jump above 60 was surprised to see a couple of locations where they were 70.  Usually you don't see this unless it is associated with a landfalling hurricane.  

[Vance Harral]

6 hours ago, toto said:

My typical passengers have nervous stomachs, and I really never experience more than light to occasional moderate. If there’s an airmet for moderate, I’m usually delaying the flight. A turbulence sigmet would have me booking a hotel room and looking for new movies on Netflix

I have zero criticism of this attitude.  Completely understand.

That said, one of the frustrations about flying on the front range of the Rockies is that AIRMETs for moderate turbulence are nearly an everyday occurrence in the spring and fall, as the jet stream migrates north of and south of the middle of the country, respectively.  High winds at altitude running over the tops of the mountains bring wicked, katabatic, downsloping winds.  So if you decide to stay on the ground any time there's an AIRMET for moderate, you're going to be grounded for weeks at a time.  After a while, there will finally be a nice day, but then you get to contend with the pent-up demand from hundreds of marginally current pilots who have been waiting weeks for that perfect day to go weekend warrioring.

I hate to be a cynic about it, but after a couple of decades flying here, I tell people not to be fooled by that "300 days of sunshine a year" advertisement when it comes to aviating.  There are a ton of VFR-but-very-unpleasant flying days in Colorado.  You either live with the bumps, or spend a lot of time on the ground.  It's particular frustrating when I have primary students trying to learn to fly in late winter/early spring.  There are so many days when the bumps are bad enough to impede their ability to learn, and I'm inclined to reschedule.  But if we only fly on really nice days, they'll go so long between lessons that there is considerable backsliding.

I'm probably grumpier about this than usual today, because my own (partnership) airplane is currently stranded a mere 15nm from it's home in KLMO.  At the conclusion of our annual at KBJC on Friday, it simply wasn't prudent to fly it home due to high winds.  Today's not a good day either, 50+ gusts at KBJC.  We'll try again tomorrow.  At some point it'll be "safe enough", but likely still unpleasant.  Just gotta hold out until late May or so, when things usually settle down for a few months.

[GeeBee]

The real problem with PIREPS for turbulence is nobody uses the AIM values. I had a guy report "severe turbulence" over the NATS on night. I said, "Are you going to write it up in the log" so there will be a turbulence inspection on the plane........ Well then the story kind of changed. The excitement of the moment often leads too exaggeration. 

 

[toto]

15 minutes ago, GeeBee said:

The real problem with PIREPS for turbulence is nobody uses the AIM values. I had a guy report "severe turbulence" over the NATS on night. I said, "Are you going to write it up in the log" so there will be a turbulence inspection on the plane........ Well then the story kind of changed. The excitement of the moment often leads too exaggeration. 

 

No doubt.  I'm always dubious of turbulence PIREPS -- since the words themselves are descriptive, and people don't take the time to learn the definitions, they see "severe" and go "yep, that's it."

[hais]

1 hour ago, Vance Harral said:

I have zero criticism of this attitude.  Completely understand.

That said, one of the frustrations about flying on the front range of the Rockies is that AIRMETs for moderate turbulence are nearly an everyday occurrence in the spring and fall, as the jet stream migrates north of and south of the middle of the country, respectively.  High winds at altitude running over the tops of the mountains bring wicked, katabatic, downsloping winds.  So if you decide to stay on the ground any time there's an AIRMET for moderate, you're going to be grounded for weeks at a time.  After a while, there will finally be a nice day, but then you get to contend with the pent-up demand from hundreds of marginally current pilots who have been waiting weeks for that perfect day to go weekend warrioring.

I hate to be a cynic about it, but after a couple of decades flying here, I tell people not to be fooled by that "300 days of sunshine a year" advertisement when it comes to aviating.  There are a ton of VFR-but-very-unpleasant flying days in Colorado.  You either live with the bumps, or spend a lot of time on the ground.  It's particular frustrating when I have primary students trying to learn to fly in late winter/early spring.  There are so many days when the bumps are bad enough to impede their ability to learn, and I'm inclined to reschedule.  But if we only fly on really nice days, they'll go so long between lessons that there is considerable backsliding.

I'm probably grumpier about this than usual today, because my own (partnership) airplane is currently stranded a mere 15nm from it's home in KLMO.  At the conclusion of our annual at KBJC on Friday, it simply wasn't prudent to fly it home due to high winds.  Today's not a good day either, 50+ gusts at KBJC.  We'll try again tomorrow.  At some point it'll be "safe enough", but likely still unpleasant.  Just gotta hold out until late May or so, when things usually settle down for a few months.

Not always frustrating if you are heading the right direction, look at my GS. 

[toto]

1 hour ago, Vance Harral said:

AIRMETs for moderate turbulence are nearly an everyday occurrence in the spring and fall, as the jet stream migrates north of and south of the middle of the country, respectively.  High winds at altitude running over the tops of the mountains bring wicked, katabatic, downsloping winds.  So if you decide to stay on the ground any time there's an AIRMET for moderate, you're going to be grounded for weeks at a time.

Yep, understood.  I fly from the plains to the Rockies pretty regularly, and my better half knows that there will almost always be bumps when we get near terrain.  But fortunately for me, that's usually just the last hour or so of the flight, and we've got the Dramamine timing down to a science.  But if there's an airmet for moderate turbulence along the whole flight, that's potentially multiple doses of Dramamine, and that just never ends well... 

 

2 hours ago, Vance Harral said:

I'm probably grumpier about this than usual today, because my own (partnership) airplane is currently stranded a mere 15nm from it's home in KLMO.  At the conclusion of our annual at KBJC on Friday, it simply wasn't prudent to fly it home due to high winds.  Today's not a good day either, 50+ gusts at KBJC.  We'll try again tomorrow. 

Ugh.  Sorry to hear that.  It's been a bad couple of years for annuals, with seemingly everyone waiting for parts - but waiting for wind gusts to die down when you can almost see Longmont from Boulder is a particular PITA.

[carusoam]

21 hours ago, WrightFlyer said:

 

Appreciate the heads up @carusoam!

Also, do you any of you sleep? 

MS operates 24/7…

Our friends in Europe are up early…

Friends on the west coast are going to sleep late…

Friends in Asia fill in the gaps…

 

Follow Dr. Scott D…. He is our weather guru!

He is always teaching aviation weather…

When this popped up… your flight rang a bell….

 

PP thoughts only, not a weatherman…

Best regards,

-a-

[Vance Harral]

19 hours ago, toto said:

Ugh.  Sorry to hear that.  It's been a bad couple of years for annuals, with seemingly everyone waiting for parts - but waiting for wind gusts to die down when you can almost see Longmont from Boulder is a particular PITA.

I appreciate the commiseration.  Today was a little better day, at least this morning.  My airplane partner got our bird home, and I was able to give a discovery flight to a first-time primary student.  Still bumpier than I hoped for the primary student, but first day in a while I would have even considered it.  Winds are forecast to pick up again this afternoon.  Next couple of days look decent, but then back to 15+ gusts in the mid-day forecast for the next 7 days after.  That's not unsafe, just unpleasant, and arguably not a good use of flying dollars for primary students.  We'll try to work around it by flying early morning or late evening, but that's not always practical.  Just par for the course on the Front Range in April.

[Will.iam]

On 4/23/2022 at 6:33 PM, GeeBee said:

The real problem with PIREPS for turbulence is nobody uses the AIM values. I had a guy report "severe turbulence" over the NATS on night. I said, "Are you going to write it up in the log" so there will be a turbulence inspection on the plane........ Well then the story kind of changed. The excitement of the moment often leads too exaggeration. 

 

There was a phenomenal app call LASC that used the ipad’s Accelerometers to measure G forces and would classify the bumps into light moderate severe and upon reaching severe it would automatically pop up the severe penetration speed chart. It also used the gps to record location of the readings and would upload to the cloud that would be available to other people using the app. For the first time it standardized what turbulence was instead of trying to figure out if this is bouncy enough to spill coffee. The app was amazing and then it was taken off the app store. I was so bummed. And when we got new ipads i lost the program because apple backups only store the data and the app is redownloaded instead. 
i can only imagine they got sued or infringed on a copyright somewhere and had to abandon the project. Reminds me of DFW airport used to have live street signs that updated flight gate info so arriving passengers knew which terminal exit to take it was awesome til some asshat clown crashed their car and sued the airport for the distracting signs instead of taking responsibility that they were too stupid to read, drive and follow the road.  Yea he got a new car and then some but screwed everybody else forever as all the signs were replaced with regular standard ones.  Really should be a frivolous lawsuit is met when 90% of the public don’t have a problem then it’s not someone else’s fault it’s you. Like that person that spilled hot coffee on themselves and sued. 

[GeeBee]

In the late 90's, I was part of a working group that was trying to reduce flight attendant injuries. One of things we recommended was wiring in the accelerometers off the IRUs to report turbulence via ACARS. The need of course was for all carriers to do it and place it all into a giant working data base. That system was coming on line just about the time I retired and air carriers have really good turbulence data. It would be easy with present day AHRS and ADSB to do the same thing for GA but the problem of course is money and the cost benefit ratio.

 

[Fly Boomer]

4 hours ago, Will.iam said:

i can only imagine they got sued or infringed on a copyright

What was the cost of the app?

[Will.iam]

I think it was $10 at the time i paid for it. Well worth it even if i only got to use it 3 years. Problem now is there really is not a good gmeter app in the app store the only other one i have found has a -1 g limitation not sure if that is hardware based or software. There is another that charts realtime xyz axis but very hard to see max peak readings as they are not stored and new data over writes the screen too fast to see what it was unless you stop the recording. Not user friendly for max turbulent detection. Abus has a g meter readout but it’s not scaled for 1 g. I.e. it usually shows some .296 number. While it does go up in value when loading g’s you have no idea what the conversion factor is. Again not user friendly. 

[Will.iam]

How nice it would be to report to atc we experience 3 g turbulence everybody would know to avoid that and small GA especially.  

[Scott Dennstaedt, PhD]

On 4/30/2022 at 8:50 AM, GeeBee said:

In the late 90's, I was part of a working group that was trying to reduce flight attendant injuries. One of things we recommended was wiring in the accelerometers off the IRUs to report turbulence via ACARS. The need of course was for all carriers to do it and place it all into a giant working data base. That system was coming on line just about the time I retired and air carriers have really good turbulence data. It would be easy with present day AHRS and ADSB to do the same thing for GA but the problem of course is money and the cost benefit ratio.

 

An in situ turbulence reporting algorithm has been implemented on some U.S. airliner such as United and Delta. There's currently about 200 aircraft in the fleet the last time I checked. The algorithm estimates atmospheric turbulence intensity as inferred from the cube root of the energy or what is called eddy dissipation rate (EDR) that is largely based on estimated vertical wind velocity or aircraft vertical acceleration.

And if you really want to see interesting technology that could be implemented on any aircraft you can read up about GPS Occultation.