ASN - Where's the turbulence?

[TrafficPilot 121]

We've had some of the worst storms for years here in the UK over the past 24 hours. Gusts of up to 70mph here in the South East and lots of trees down. Both Heathrow and Gatwick had (and still have..) some major delays and cancellations.

 

So the obvious thing to do last night was boot up FSX and ASN and go flying!

 

Was very disappointed to find very little in the way of turbulence or wind-sheer once I took off from Biggin Hill and headed towards central London. Lots of nice cloud and rain but hardly any turbulence despite the atrocious weather and frightening looking METARS.

 

Thinking I'd done something wrong I went into ASN settings and searched for some bad weather. I found a few thunderstorms and the ASN turbulence kicked in as I was expecting.

 

So am now wondering - does ASN only generate turbulence if it detects CB's in a METAR? There were plenty of SIGMET warnings across the UK last night but ASN didn't appear to replicate the gusting winds and turbulence at low level where I was.

 

Anyone else tried flying in the UK during those storms last night? Did you get the expected turbulence?

 

Regards

 

Adam

 

 

 

 

 

 

[1st fltsimguy 466]

Now that is very revealing.

[vgbaron 3,604]

Post the METAR in the ASN support forum. Could be an anomaly or ASN could be reporting what the METAR said. Since you have the historical date - try re-flying using historical weather and see if it makes a difference - shouldn't but you never know.

 

Also be sure you are using the latest FSUIPC and the hotfix.

 

Vic

[kterz 49]

Hi,

 

that's what I got (looking the conditions with ASN at Gatwick) downloading 1900Z weather:

 

EGKK 241850Z 18004KT 9999 SCT045 07/03 Q0982

 

and at 1630Z:

EGKK 241550Z 21009KT 9999 FEW014 07/04 Q0982

 

EGKK 241702Z 2418/2524 22010KT 9999 SCT030 PROB40 TEMPO 2418/2503 22016G27KT 5000 SHRA PROB40 TEMPO 2503/2518 21015G25KT 4000 SHRAGS BKN014CB BECMG 2515/2518 16005KT PROB30 TEMPO 2518/2524 SHRA

 

The forecast weather gives 40% chance of significant gusting winds temporarily. At this point (and one hour later, when I checked) winds were relatively calm.

 

That is the current active metar (live weather):

EGKK 241950Z 21007KT 9999 SCT032 07/03 Q0982

 

and is the exact same checking with VATSIM:

EGKK 241950Z 21007KT 9999 SCT032 07/03 Q0982

 

 

On the other hand at EGLL:

 

Now with live weather:

EGLL 241950Z AUTO VRB08G20KT 9999 NCD 06/03 Q0981

 

EGLL 241702Z 2418/2524 22010KT 9999 FEW020 PROB30 TEMPO 2418/2424 23015G25KT 4000 SHRAGS TEMPO 2512/2524 6000 SHRA BKN014CB BECMG 2515/2518 15006KT PROB30 TEMPO 2521/2524 3000 SHRAGS

 

while 2 hours ago:

EGLL 241750Z 21011KT CAVOK 07/03 Q0982 NOSIG

 

and 4 hours ago:

EGLL 241550Z 21012KT CAVOK 07/04 Q0981

 

 

 

So, ASN is using the correct data and depicts them well (as far as surface data are concerned). Going now to EGLL, you may get challenging conditions (including possibly wind shears).

About SIGMETS, they are only available unfortunately in live mode and currently I don't get any (I do get however a pirep with bad turbulence 18 miles south of EGPH). At this point sky vector shows sigmets in the EGTT FIR (in the area of the reported pirep), but not close to EGLL or EGKK.

 

So, to answer your question, turbulence is created not only by CBs, but by several other factors (including SIGMETS, winds, terrain variability, atmospheric stability etc).

What were the "frightening looking METARS" you are talking about then?

 

In the next upgrade I promise we'll add to our sources the local news reports (particularly reports of falling trees)

 

Until then, when conditions seem to differ from what you're expecting, please report the specifics so that we can actually check if something is wrong with the way ASN parses and depicts the data (and this is the only honest way to help us eventually fix any issue).

 

Thanks and Merry Christmas to all!

Kostas Terzides

ASN developer

 

 

 

[EDIT]

Just to be fair,

 

I got this one downloading 0500Z weather:

EGKK 240450Z 23018G28KT 180V250 9999 -RA FEW006 BKN009 OVC014 11/09 Q0978

 

If this was the weather reported and you didn't get any turbulence/wind shear(s), then we may have an issue here. Just a reminder, if you were flying with historical weather (or with sim mode) trying to replicate some specific conditions during the day, then in this case any SIGMETs present at the time would not be active (this is something you should all know, that ASN at the moment doesn't support historical SIGMETS).

 

[/EDIT]

[bpbill 0]

Not sure they were the worst storms for years as we have had a fair few of them recently but it was pretty bad.

 

I flew from EGKA Shoreham to EGHI Southampton, using ASN yesterday and the journey was erm, challenging. A lot of turbulence and wind sheer and I was actually frightened (ish) coming in to land, however I was saved by the loud crash coming from the back garden which meant I had to abandon right at the last moment. No missed landing and a go around here it was abandon all and tie down anything that moved.

 

However as ASN is the first live weather program I have used since REX (which I never got the hang of) I can't comment on how good or prototypical it was, but it definitely felt good, which for me is the important thing.

[TrafficPilot 121]

Hi Kostas and thanks for your detailed reply

 

The METAR I am testing with is this below - have copied and pasted from ASN. I took off from EGLL and climbed up to 4000ft then circled and landed back at EGLL. There was a small amount of turbulence entering the cloud but otherwise it was smooth as silk and landing was easy with no turbulence felt on approach. I was at least expecting to feel some gusts or windshear affecting the airframe. Will continue testing! Merry Xmas and despite my lack of turbulence I do love the immersion from the extra weather around and above. No cloud pops either!

 

EGLL 240150Z 20028G43KT 4200 RA BKN015 BKN020 11/10 Q0975 BECMG 22021G31KT 6000 -RA
Decoded textual weather for EGLL

Wind: 200 at 28 knots gusting to 43
Visibility: 2.6 SM (4200m)
Clouds: Overcast at 1000 feet, Broken at 1500 feet, Broken at 2000 feet
Temperature: 11.0C
Dewpoint: 10.0C
Precipitation: Moderate rain
Altimeter: 975 mb (28.79 inches)

This station includes complete surface weather information, interpolation disabled.

Original metar of the stations:
EGLL 240150Z 20028G43KT 4200 RA BKN015 BKN020 11/10 Q0975 BECMG 22021G31KT 6000 -RA

[vr-pilot 11]

Hi folks!

Concerning ASN turbulence simulation on historic weather:

I tried the 2013-12-23 1500Z (SIGMET: severe turbulence GND to 6000ft) departure from EGLL along the Thames westbound to EBBR. As in the forcasts somewhere below FL100 roughly inside a triangle between EGLL-EBBR-LFPO the turbulence was severe on climb and descend.

So my storm chasing tour was really breathtaking but fortunately not wing breaking, as my NGX-800's wings kept hooked to the fuselage... :mellow:

 

Greetings.

Claus

 

BTW: my ASN "enhanced turbulence" is ON and FSX "disable turbulence and thermal effects" is OFF. I will test now what happens when turning the latter to ON, as often recommended.

 

 

[kterz 49]

OK thanks for this

 

You understand that ASN is still new and reports that it doesn't work "as expected" are more or less to be... expected Yet, from my point of view as a developer I will always insist on these reports being as specific as possible so that we can pin the issue down and fix it. So thanks for this. I'll give the "EGLL 240150Z" a try to see how it behaves (whenever I find some time). There may be some adjustments needed there (for example in the rate of windshear generation in relation to reported winds gusting, or in the level of smoothing while the wind speed increases during a gust). 

 

@Claus: I'd like to repeat that SIGMETS don't apply to historical (at the moment). So there may have been other factors generating turbulence in your case. As for fsx option "disable turbulence and thermal effects", ASN bypasses it and directly controls both themals, up/down drafts and turbulence, so it will not matter.

 

Cheers,

Kostas

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[vr-pilot 11]

there may have been other factors generating turbulence in your case

 

I re-flew the situation (2013-12-23 1530Z) 10NM north of EGLL. Surface winds with 40 kts gusts and nice CUs/CBs (and rain below clouds) with bases just from approx. 2000 ft to 6000 ft. So SIGMET forecasted turbulence (as not yet simulated) was actually generated by METAR/TAF reports, which matched "by chance", or better "logically". Very nice speed shifts of +/-15 kts and vertical air drifts...

 

fsx option "disable turbulence and thermal effects", ASN bypasses it

 

There was no real difference to observe between enabling and disabling "turbulence and thermal effects" inside FSX, so option override seems to work ^_^

 

Thanks again for the good product!

 

BTW: I can see the box of "ActiveSky wxRE" (2003) standing in a bookshelf next to me... :rolleyes:

 

Greetings,

Claus

[VPA481 27]

I flew 3 times in TS/CB areas, and turbulences were so hard, that I was unable to click on T7 switches. Works well by my side.

[Guest JustanotherPilot]

We recently experienced severe weather in Eastern Australia. I loaded ASN and planned from YCFS to YBCS a trip of about 1500nm. I flew in the AXE A320. I experienced some of the worst turbulence ever in FSX, the realism and cloud structure was second to none. I can only suggest that something has gone amiss with your installation - the ASN map view for this flight showed exactly what the real time weather was like, and this was transferred to the FSX conditions.

[Guest]

Any chance that you have, by accident or because some addons need this, "Disable turbulence and thermal effects on aircraft" enabled? Just guessing here because I don't own ASN yet and maybe ASN recommends the same. But you never know. ^_^

[Andydigital 93]

The FSX turb settings won't make any difference, the only thing that can interfere with ASN is a few incompatible versions of FSUIPC which were (ironically) created to stop ASN interfering with other weather engines. Make sure you have version 4.927b or later of FSUIPC installed and also for extra measure make sure ALL weather settings in FSUIPC itself are turned off.

[ZKOKQ 984]

And to add to what Andy posted, if you are using Opus Cameras, make sure Turbulence and "Bump" aircraft  is turned off in the DHM settings. ASN works great with those settings.