Question about F215's

[dublinpilot]

I've had a little difficulty interpreting the new F215's. I haven't been able to find the answer on the Met Office site.

Here's a typical example of the area that is confusing me.

http://img129.imageshack.us/img129/8671/image1ak3.jpg

Look at the cloud section. In the first line we have scattered ac with mod icing and mod turbulence from 8000ft to over 10000ft.

The second line indicated sct/bkn cu sc (with mod ice in the north) and mod turbulence starting at between 2000ft & 3000ft, and topping out at 8000ft.

The bit that confuses me is, are these two layers existent thought zone B, or is it a case that the first line is the prevailing conditions (where the 30km viz exists) and the second line exists only where the ISOL 7km SHRA exists?

I could read it either way, and can't find an answer on the met office website.

Anyone got a definitive answer?

dp

[gcolyer]

The way i read it is the first column is the general conditions, the cloud column is the layers of clouds. And obviously they apply to areas B

[bookworm]

The bit that confuses me is, are these two layers existent thought zone B, or is it a case that the first line is the prevailing conditions (where the 30km viz exists) and the second line exists only where the ISOL 7km SHRA exists?

The former. I raised exactly this issue in the consultation.

(My comment) The "surface vis and wx" entries don't appear to pair up with the "cloud" entries as they do on the F215. This is confusing. Is a cloud group, for example, associated with OCNL reduced vis in SHRA, or is it independent of them?

(Response) There is no longer a need to pair up cloud with vis and weather but the forecasters can if they wish when constructing the charts.

I think that's a needless loss of information, but compared to some of the other shortcomings of the "new and improved" F215, it's no big deal.

[dublinpilot]

Thanks for your replies.

It always fustrates me when I don't fully understand the information that I'm using.

dp

[Wrong Stuff]

I think that's a needless loss of information, but compared to some of the other shortcomings of the "new and improved" F215, it's no big deal.
I found both the consultation process and subsequent comments provided through the Met Office "Feedback" once they came into use rather disappointing. Despite taking some time providing them with the feedback they requested, in neither case did I receive anything beyond a cursory acknowledgement. More to the point, the F215s we now get seem to be exactly the same as those published at the beginning of the consultation, implying that none of the feedback has ever resulted in any changes and the consultation process was just for show.

Bookworm, you seem to at least have got some sort of explanation out of them for the retrograde changes we seem to have to live with. I remember you also mentioned the removal of freezing levels from the graphic and the use of XXX for levels above 10,000 feet in your initial response. Did they provide any reasonable excuse for these changes?

[bookworm]

(My comment) The printing of the FZL in the text is a retrograde step. Much easier to visualize on the graphic

(Response) It is easy to visualise on the chart but was a way of reducing the amount of data on the chart area and making the chart less cluttered - a common user complaint.

(My comment) The use of XXX to signify "above 10,000 ft" is a huge loss of information compared to the original F215.

(Response) Data for above FL100 is available on the EUR WAFC chart and it was agreed with CAA that a high cut off (10000 FT/FL100) was preferable to an overlap. The chart top must stop somewhere and 10000 FT was thought to be better than 15000 FT.

[IO540]

Given the # of exams a PPL has to pass, I would have thought the CAA could reasonably assume he/she has a brain, and provide a bit more information.

I haven't looked at F215 for ages; I prefer the MSLP charts, skew-t charts, and TAFs for airfields along the route. For higher levels, the SigWx is good, but nothing beats the vertical profiles.

However I do print off a F215 so if they can find the hard copy on my body and authorise the insurance payout :)

[Wrong Stuff]

Thanks for that Bookworm.

(Response) It is easy to visualise on the chart but was a way of reducing the amount of data on the chart area and making the chart less cluttered - a common user complaint.
I'm amazed that anybody complained those charts were cluttered. And a little sceptical, although I can't see why they would make something like that up. Unless they just wanted to justify the design decisions already made, I suppose.

(Response) Data for above FL100 is available on the EUR WAFC chart and it was agreed with CAA that a high cut off (10000 FT/FL100) was preferable to an overlap. The chart top must stop somewhere and 10000 FT was thought to be better than 15000 FT.Although it's nice and tidy for them not to have any overlap, I can't see why it's a feature of the charts that's so important it's decided by an agreement between the Met Office and the CAA and so set in stone that it overrides user comment.

Whilst much of the data is indeed available on the WAFC charts, it does mean the user having to have both to hand in order to build a full picture of what's going on. Also, not all the missing data is available on the WAFC charts - in particular the freezing level which is very relevant for non-deiced airways traffic. Whilst available by interpolating between the FL100 and FL180 wind and temperature charts, that does mean taking data from an additional two charts to complete the weather picture which was previously available on the single old one.

As I said before, a rather disappointing consultation process that didn't seem to result in any changes to the initial presentation which appears in retrospect to have been a fait accompli.

[MichaelJP59]

The former. I raised exactly this issue in the consultation.
(My comment) The "surface vis and wx" entries don't appear to pair up with the "cloud" entries as they do on the F215. This is confusing. Is a cloud group, for example, associated with OCNL reduced vis in SHRA, or is it independent of them?
(Response) There is no longer a need to pair up cloud with vis and weather but the forecasters can if they wish when constructing the charts.


So the different lines on the F215 may or may not pair up, depending on the whim of the forecaster, whose mind we must attempt to somehow read.

I found it confusing before, but that's just added a whole new layer of obfuscation:(