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.
This is the key to met planning these days, isn't it? It's not so much about using a synoptic chart to get a picture of the weather as it was 20 years ago. It's more about understanding which aspects of the very detailed models we have are reliable, and which are not.
In my experience, the reliable aspects are:
the less reliable aspects are:
That's not to say that such predictions are useless, just that they need to be treated with caution.
So there was a lot of convective cloud over western Germany and Southern Belgium today. I was in and out of IMC from 50 miles North of Augsburg. Got FL300 neg-RVSM to get on top. Radar cell avoidance the whole way to the Channel. Where there were gaps though it seemed this was all high altitude stuff. So from what I could see it was all pretty accurate this time.
This is the key to met planning these days, isn't it? It's not so much about using a synoptic chart to get a picture of the weather as it was 20 years ago. It's more about understanding which aspects of the very detailed models we have are reliable, and which are not.
Oddly enough I don't think much has improved for the purely-VFR PPL pilot who, for strategic reasons (to avoid getting stuck above an overcast), usually flies below the "boundary layer cloud" (I had to google on that one!).
I have often been asked by those pilots how to forecast the tops, because they wanted to know if they could fly VMC on top at say 3000ft, below the base of CAS of say 4000ft.
Obviously such a forecast is currently impossible and that kills VMC on top in most of southern UK, though not in much of Europe where there is a lot of Class C and a confident request will get you a transit of the whole country at say FL085.
Once you get an IR, a whole chunk of forecasting becomes irrelevant. Any cloud that is well above the IAP DH and which you can climb above (basically most boundary layer cloud) is irrelevant - icing conditions and embedded TCUs/CBs excepted.
Oddly enough I don't think much has improved for the purely-VFR PPL pilot who, for strategic reasons (to avoid getting stuck above an overcast), usually flies below the "boundary layer cloud" (I had to google on that one!).
It depends on how far you are looking back, but there are a number of decent weather websites out there (Gramet particularly) + AeroWeather, AeroPlus, WeatherPro HD and others for the iPad, all of which can allow you to make better judgements than you could say even 3 years ago.
This is the key to met planning these days, isn't it?
Very much agreed!
In Switzerland, fog and south west flow patterns are quite unpredictable.
jwoolard 25-Jul-13 17:42 #06 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.
....
Nice thought .. But if the weather forecast is as was described I would never go up high without a good weather radar .. Most turbocharged do not have that. With a cloudbase starting at 3000ft+ and a forecast for frequent towering cb's I would prefer to stay below and see what is coming than to encounter some nasty cb embedded in a perfectly good cloud.
This is the reason I invested in the ifd540 and the mlx770, however it will be another year or two before that works. In the meantime. I am waiting for the aeroplus thuraya solution. Over continental europe i fly with Sky-map.de. This will overlay the weather on the chart in the same way a weather radar would show it. That in combination with the gramet, the actual tops via sat24 and the taf trends via orbifly will tell me exactly were I should or should not be ... And wether to skudrun or go through or over the clouds.A good stormscope is an extra assurance.
Tc and tks will give you the possibility to climb through a layer and come on top in the winter.
Achim,
I would say that in summer, you can always fly VFR in continental Europe.
Ugh, that is serious news to me. And it really depends on where. It may work in some flatlands of Germany and whereever mountains are not in your way, but every day is a huge statement. It is definitly NOT true in Switzerland.
Actually, in 2012 it was bad enough that ALL my planned trips were cancelled. Yes, that is ALL. Reason was, Alps not VFR for crossing for days or weeks at the time plus a lot of flights N of the Alps went bad due to equally bad situations everywhere. 2013 up to beginning of July, again ALL planned flights were cancelled and the aircraft now has about 1/3rd of the hours it should have. Frankly, anyone who has a schedule to adhere to, who is not working independently and can leave whenever he wants, can just and truely FORGET VFR as a means of transportation.
Bookworm,
This is the key to met planning these days, isn't it? It's not so much about using a synoptic chart to get a picture of the weather as it was 20 years ago. It's more about understanding which aspects of the very detailed models we have are reliable, and which are not.
Well, that depends very strongly on how you go about it. A Synoptic chart (SWC) such as the EUROC or other Low Level SWC products are still quite useful for the fact that that is what the forecasters who KNOW their models and where they are notoriously unreliable and produce these charts out of those models. Especcially the French EUROC chart is one I consult for every flight as well as at work!
Which aspects of models are reliable and which not is something you can only determine by trial and error. Some of them have actually guides available where those who make them try to explain how they see things, but they are books of several thousand pages often enough totally chinese to most of us. Then again, these models are constantly developed further, which of course means, once you have figured out what you THINK are the reliable things, they get changed and whops, the whole thing is upside down.
Watch this space after the apocalyptic springtime we had. Almost no model was able to handle this situation with any degree of accuracy. So now, with hindsight, the model developers are in deep work to change that for the ext time this comes along. The only problem will be: What will they screw up for those situations which are NOT like this spring was? How will what we know now works change as a consequence?
the less reliable aspects are: >mist and fog clearance >boundary layer cloud >cloud tops
Which of course means it is pretty useless for VFR. Yes, following the last discussion about it I had a closer look comparing it with what really happened in daily work and I agree. And no, it is not only GFS and it's limitations. The European models are equally useless for these factors, certainly cloud tops and boundary layer clouds. The trouble is they do not really do cloud tops, but rather temperatures from which they then derive cloud tops.
I did check out the predictions of today and yesterday and have to say, if someone would have relied on GRAMET to fly the Alps VFR he would have either turned back or we'd have read it in the paper now. It is easy to paint CB's in there but it can not possibly say where at a given time. Nobody can. Equally, it does not calculate the effect of these CBs on the clouds around it. CB's can mess whole areas quite severely by producing AC-CBgenitus e.t.c.
precise location of convection
That one is a shipping container full of worms which has thousands of "rocket scientists" working on with no real certifyable success. Yes, models can predict convection to a certain degree, using the lifted indexes, using the old methods of trigger temps and graphical construction of potentials. Local meteorologists know the neuralgic spots, where CB's get manufactured and nutured before being sent on their way of destruction. Which does not prevent them from popping up elsewhere too. Rapid Cyclogenisis is one of the King disciplins of deduction and while we have made tremendous progress in nowcasting, we still have a lot to prove in forecasting.
For VFR, most of this is like playing roulette with a blindfold.
Last year, prior to my cancelled BG trip, I spent a whole week with just about anyone I could annoy in my team to figure out whether our planned departure day was feasible. It was the ONLY day which had a chance within 10 days before and after where a VFR crossing of the Alps was even thinkable. The models agreed on a cloud top of FL120, so after a lot of deliberation we decided to give it a go. The result was an inflight return after looking for that elusive FL120 cover for more than 2 hours: The tops were around FL200, a solid wall with no chance in hell to clear, even in FL170 which we managed to get our plane up to. That was in July too.
I've looked at top predictions for a while afterwards and found, yes you can use them in stratus layers but otherwise the tolerance within the models is +-5000 ft minimum, +- 8000 in the mountains. Likewise, the question arises if there are clouds at all. I checked some routes today where GRAMET said there were no clouds, yet I could see them on sat pics easily enough.
Peter,
I have often been asked by those pilots how to forecast the tops, because they wanted to know if they could fly VMC on top at say 3000ft, below the base of CAS of say 4000ft.
Obviously such a forecast is currently impossible and that kills VMC on top in most of southern UK, though not in much of Europe where there is a lot of Class C and a confident request will get you a transit of the whole country at say FL085.
There is simply no effort to create such a dedicated forecast reliably. I have been pushing to include tops in the GAFOR or GAMET forecasts but the problem is, the models do not really do reliable cloud tops. There are ways to guess them in an educated manner, but you get burned very often, see above.
I would have to say though that reliability below the clouds has improved massively over the last yeras primarly due to the use of webcams and improved modelling for GAFOR predictions. Certainly we can nowadays do much better status assessment than before by looking at the cams.
What really needs to be done in Europe is to duplicate the US systems which allow weather transmission directly to the cockpit also for GA airplanes. Forecasting is one bit, nowcasting is what saves lifes. And where making these available in planes airborne is concerned, Europe is still in the dark ages.
In Switzerland, fog and south west flow patterns are quite unpredictable.
Fog, there are pretty good methods of prediction but they depend on the parameters of wind, humidity and temperature being correct in the models. Often enough you can say easily enough that there will be fog, the one billion question being when it disappears. You take your computer and put all the factors in and get it wrong. I've seen it more than once that the numerical calcs stating when there will be sun were totally off, while old and experienced observers got it right for their particular place.
South West patterns are fairly predictable. You know pretty much WHAT will happen, the question is WHEN. The usual pattern of the SW exposure which brings front after front after front is of course disturbed by the Foehn effect often enough to a degree that it will advance or delay a front by several hours, which of course then means, the forecast can be made totally unusable. However, normal frontal patterns are fairly good to predict short term (less than 36 hours) as opposed to freak situations like this spring.
The conclusive fact is, the representations of models such as Gramet or other such products can't be better than the models themselves. And while they are MUCH advanced over what they were 10 years ago, they still have significant deviations. Mind, now we have models which can predict 10 days or more, when before we only had 2 or 3. What false sense of security this often stirrs is another matter.
But to come back to the statement about VFR, I'd have to agree with people who say that it is totally unsuitable for travelling. That is why my personal hopes are going towards the "new" IR we've been promised. Hopefully they will also abstain from demanding all our planes to be equipped like the lastest Dreamliner before letting us fly IFR and sort out some of the nagging issues which make today's IFR certification something which is written in pencil.
This is the reason I invested in the ifd540 and the mlx770, however it will be another year or two before that works.
Why does your MLX770 not work? Worked fine in the Mirage.
Mooney Driver's post certainly "resonates" with my experience...
South West patterns are fairly predictable. You know pretty much WHAT will happen, the question is WHEN.
Very much the case for the UK SW flow and the UKMO forecasts.
But if you watch the IR images you can see the "forecast" wx actually coming (or not).
I've looked at top predictions for a while afterwards and found, yes you can use them in stratus layers but otherwise the tolerance within the models is +-5000 ft minimum, +- 8000 in the mountains
I'd say the stratus tolerance is perhaps +-3000ft but that's OK if your plane can simply outclimb whatever is forecast plus 3000ft. That is therefore a perfectly reasonable result - but you probably need an IR to make use of it, due to "random" VFR in CAS policies operated around much of Europe.
2012 was tough. It was not so bad if you had employment flexibility though. If OTOH you were a weekend flyer...
VFR was never suitable for "random date preplanned" travelling. If you are talking really legit VFR, the cancellation rate, over the whole year, is maybe 50%. But of course many pilots don't fly exactly legit VFR, which is OK if you know what you are doing.
The IFD540 is currently vapourware; true to Avidyne's marketing philosophy...
The MLX770 works OK, but the install and running costs are not cheap (difficult to get real feedback on real costs of real documented usage though).
The MLX770 offers little in terms of functionality over a loose Thuraya satphone hook-up and the latter will be far cheaper to operate. It's just a lot neater, and the server side seems to be neatly done.
To fly in potentially embedded CBs you have always needed on-board radar - to see the concentrations of water. A stormscope is a lot better than nothing but it shows strikes only and if you picked the "right" conditions (especially in parts of S Europe) you can be flying along in "clean IMC" and suddenly find yourself in the middle of a xmas tree i.e. a TS has rapidly built itself all around you. I know somebody who did that...
Peter,
2012 was tough. It was not so bad if you had employment flexibility though. If OTOH you were a weekend flyer...
Not exactly weekend as I work shifts but with a fixed planning and vaccations fought over and accepted months in advance. Only no go/go, not "ah, well, let's try tomorrow".
I'd say the stratus tolerance is perhaps +-3000ft but that's OK if your plane can simply outclimb whatever is forecast plus 3000ft
With stratus we can do a LOT better than that. It is the mixed layers CU/SC which are a bitch to forecast and which even in nowcasting often fool you unless you have pireps.
VFR was never suitable for "random date preplanned" travelling. If you are talking really legit VFR, the cancellation rate, over the whole year, is maybe 50%.
I am talking very much legit VFR. I would love to remain obnoxious here for many years to come and illegit VFR is a good way to kill oneself... no such intentions :)
My cancellation rate in 2010 and 11 was maybe 50%, yes. In 2012 it was 90%, one out of 10 planned trips worked (to Rijeka, whereby that was planned in a scheduled off period maybe a few days before). This year so far was 100% between January and end of June, I've flown one planned trip since (100 NM away) and I am keeping my fingers crossed and continue to study the models for next week's planned trip to BG.
The IFD540 is currently vapourware; true to Avidyne's marketing philosophy...
a well proven concept as you know. Keep the customers on edge, feed them news every week, while getting the job done. From my experience in Flight Simulation, this results in a megahype with corresponding sales. Frankly, I am glad Avidyne now enters the market because a) I don't believe in monopolies and b) there will be a lot of second hand 430/530 W units around in the near future, which is more realistic for me to be able to afford than the Avidyne offering, which I would like better, anyway. If I want to certify IFR, I will need to get a 2nd GNS430 or possibly have a 430/530 setup (if I rebuild my whole cockpit... which won't happen) probably. The IFD540/440 combo would be a dream come true, combined with an Aspen PFD, but way too expensive to realize.
I know somebody who did that...
Know or knew? You mean he lived to tell the tale?
For me, in an non-de iced and carburetted single engine plane, IFR is mainly ease of planning (no more airspace avoidance and scud running in Italy and France for a start) and occasional IMC flying particularly in Winter, where you can get in and out from low stratus. Fronts, Convection and any other condition remain unchanged to todays VFR limits. REAL IFR requires a much bigger and better equipped airplane than I can ever hope to afford.
