mhmhm…I didn’t take a risk a couple of days ago to fly from Belgium to Hungary too cold below and unstable weather forecast for the period. The o degrees was still@3000…Now it has significantly heated up I see past OLIVI..
Anyway without TKS I wouldn’t go..:-), the Belgian part doesn’t look good. Clouds are mostly not the issue unless convective its the 0 degree level…LNO- SUXIM over the Ardennes
Peter wrote:
It isn’t a uniform 3D wx model. The GFS model separates clouds into low medium and high
Actually, it is 3D, with 60-ish vertical levels. The low/medium/high cloud fraction is a diagnostic output for when you want to look at a horizontal projection and not click through all 60 layers.
and often gets them totally wrong
Clouds are hard.
Actually, it is 3D, with 60-ish vertical levels. The low/medium/high cloud fraction is a diagnostic output for when you want to look at a horizontal projection and not click through all 60 layers.
That’s really interesting. I didn’t know that. What’s amazing is that every wx website which presents GFS data (just about every wx website that presents wx for Europe, beyond the free products produced by European met offices e.g. MSLP) presents the cloud as low / medium / high and not something generated out of the 3D model.
So why do they do that?
I’ve been using “3D” presentations since the original Meteoblue, and NOAA READY may have been even earlier (2005?), yet it’s been obvious to me that they all often get clouds wildly wrong. Especially low cloud, say below 10000ft. And if I notice it I am sure others have too.
Clouds are hard.
They should be easy, if you know the temp and DP and a few other bits. I can only assume that the model doesn’t contain that data because it’s the most obvious shortfall of GFS.
GRAMET PDF issues
It has already happened to me before, but on last week’s trip to Friedrichshafen it was quite serious, so I think it’s worth reporting here: Adobe Acrobat occasionally refuses to display GRAMET PDFs and reports an error. I have not found any reliable and reproducible way to trigger such an error or to eliminate it if it occurs; however, requesting GRAMET with the same route but a slightly different departure time (possibly as little as 15 minutes away) may sometimes help. Apparently, it’s some strange combination of content elements that causes Acrobat to stumble. Importantly, even if Acrobat (I’m currently using Acrobat DC) reports an error, a Ghostscript-based viewer (in my case, Irfanview with a PDF plugin) displays it just fine. I flew to EDNY on Saturday morning and was planning to fly back on Saturday afternoon, so the diagram was really saturated with various types of clouds, icing, etc.
Another issue is with printing. When a PDF displays correctly and I send it for printing, Acrobat pops up a box saying it’s flattening the image, and this process takes quite a while – as long as several minutes on a newish quad-core i7. It eventually prints fine, but such a delay is really strange. It’s only happening on GRAMET pages, all other pages in the full briefing back get printed almost instantly.
Yes; this is because the PDFs contain a huge number of elements, and/or halftones.
Skydemon does this too – here
This is a problem with a load of other PDFs e.g. Jeppesen VFR Approach Charts. I recall the one for LSGL 10-1V taking 60 seconds to render on one 1.8GHz 80×86 tablet. On the Samsung S6 the same PDF (though obviously not using the same 80×86 acrobat reader) takes 20 secs, on the S7 it takes 3 secs. On a dual core 3GHz PC it takes 4 secs. An approach plate which takes a minute to come up is obviously useless.
I reported it last week but we agreed to close it as Acrobat bug rather than GRAMET’s. PDF was normally shown on iPad and iPhone.
You need moisture, instability and lifting to start a thunderstorm.
The picture shows a blue sky and yet a very high storm index.
My understanding is that it just means that the air will be very unstable, but dry, and hence that no thunderstorm will occur. Just a great day for gliding.
Am I right?
I don’t know much about this but the first thing that comes to mind is that the GRAMET usually fails to show nonconvective (stratus) cloud.
Thanks to the generous and clever people behind the autorouter, I just created a Gramet for my projected flight next Thursday. I am however inexperienced at interpreting these images. As I see it, my flight cannot take place: I see a solid layer of cloud very close to terrain, at one place even touching. And no, I will not fly VFR above, certainly not above a layer as solid as this. I am not carrying any kind of gyroscopic instrument so entry into solid cloud is a very good recipe for disaster.
By the way, the homeflight would be on Sunday next, but there seems frontal weather to come in over my homefield so the whole trip might well need to be cancelled. Of course I am aware 99% of my trips are likely to be cancelled because of weather, given my extremely limited equipment.
The Gramet is here .
I don´t know if things will improve but I am certain they will change.
