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GRAMET (merged thread)

Take a look at http://peter-ftp.co.uk/screenshots/2018090202860623.jpg

Ignoring the CBs, does this look doable VFR?

Given the ''freq CB'' in the over Belgium I won't be going. Is it really possible that CBs are the only real hazard below FL150 through a cold front? Does Gramet miss out a lot of cloud (making it useless for VFR planning)?

EGEO

Were you planning to stick at FL100 or go down below those cloud with a base of about 3000 ft?

Yes, of course. You are VMC so you won't be surprised by a CB. If they are too frequent, then you turn around or land somewhere.

No reason to cancel IMO. The cloud base will be sufficiently high for VFR.

Were you planning to stick at FL100 or go down below those cloud with a base of about 3000 ft?

through Belgium I like to fly between 4500FT and FL100 (in the class C)

Yes, of course. You are VMC so you won't be surprised by a CB. If they are too frequent, then you turn around or land somewhere.

Fair enough, I might give it a go and see. I guess you never learn how to interpret these things unless you match them up to real world weather...

EGEO

Johannes, of course things can change, but I flew over a line like this today in Belgium, very clear isolated CBs and I think it would have been OK VFR down low.

At least it looked OK from FL270 :). Actually there was a lot of vertical development up to FL300+ so perhaps worse higher than under them.

EGTK Oxford

At least it looked OK from FL270

My next plane will be turbonormalised and have full TKS. Although I can't quite justify a turbine for my flying, the number of flights I cancelled last winter was simply depressing.

EGEO

GRAMET looks very good and promising for flight planning. But, in my experience, I've found a lot of times a cloud coverage/vertical extension much worse than forecasted. In several ocassions I've seen a forecast like that, showing only a few CB, and has turned out completely different, with BKN or OVC. So in my opinion, yes, GRAMET miss out a lot of cloud.

Give it a try and tell us later on...

LECU - Madrid, Spain

I've seen a forecast like that, showing only a few CB, and has turned out completely different, with BKN or OVC.

Sure but that is a limitation of the GFS model.

Give it a try and tell us later on...

Today the Gramet looked like that and it was right.

EGTK Oxford

It is certainly my experience that the GRAMET site doesn't at all reliably forecast a "thin" cloud layer; say 1000ft base and 2000ft tops.

Such a cloud is going to make VFR difficult or impossible - depending on the terrain and other obstacles.

Perhaps the best thing is to use the TAFs for some big airports to get an idea of the low level cloud for the next day.

Cloud top forecasting remains an inexact science - despite the impressive graphics presented. It's much better if you have an IR because then a lot of the errors just don't matter, much of the time.

Administrator
Shoreham EGKA, United Kingdom

I would say that in summer, you can always fly VFR in continental Europe. Not the whole day but every day. The spread will be sufficiently high to give you an acceptable cloud base and cold fronts move fast and the rest are thermal thunderstorms which are local and temporary.

I would just takeoff, try to get to my destination and deviate or pause on the way if I encounter weather I cannot pass.

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