Weather forecast

[Lister Noble]

I use Metcheck and BBC to try and get a true 5 day forecast,often they disagree and often both are wrong.
I realise it's more difficult in the UK because of our geographical situation,but does anyone have a more reliable forecast provider?
Lister:D

[Aussie Andy]

The farther out the forecast, the greater the likely error, especially of the timing of weather systems and fronts.

Best thing is to learn more about met and learn to make your own interpretation of the charts.

Irv Lee's columns in Flyer (and his seminars ref. http://www.higherplane.flyer.co.uk/seminars.htm) are very good - covers weather and more general post-PPL stuff.

I would also recommend attending a weather-focussed seminar such as those run occasionally for sailors and airmen by either the Met Office or http://www.weatherweb.net/aviation.htm for example.

No-one has the right answer! Hope this helps,

Andy :ok:

[stiknruda]

Lister - the met bods at our local fighter base have a 60% record on weather guessing.

They get it WRONG 60% of the time!:\ :\

Stik

[J.A.F.O.]

Horoscopes with numbers.

I once called the forecaster at midnight to ask how long the thunderstorm overhead might last and he didn't know that there was a storm. Given that we were on the same base and I was equipped with a window whereas he had weather radar and a window one would have hoped he'd have spotted it.

I look at loads, though.

I like:

http://www.weatheronline.co.uk

and

http://uk.weather.com

with a little bit of:

http://skylinkweather.com

and a touch of:

http://www.metcheck.com/V40/UK/HOME/

but you might as well use seaweed and your bunions.

[nipper1]

The trick is to look at lots of different sources of information. If they correlate well, then it's a fair bet that the weather is in a reasonably predictable mood and you have half a chance of knowing what is going to happen.

If the various sources are divergent then you can be sure that at least some of them are wrong.

I find it is usually best to go back to the source data (models) rather than rely on something that has been 'interpreted' by a (series of) forecaster(s) .

Try www.westwind.ch for a huge variety of wether sources for Europe. You will need to spend at least a hour working out what is what.

[pulse1]

I once asked an RAF forecaster if the rain was going to stop. He said that it always had up to now.

On another occasion I drove 30 miles to the airfield through the thickest fog I have ever seen. Looking out at a fog covered airfield, I rang the RAF met office at Upavon for the official RAF forecast which was absolutely cracking.
So I suggested that the fog would clear pretty quickly.

"Fog?" he said. "You've got fog?"

[Lister Noble]

I have sailed a lot and the marine forecasts have always been reasonably OK when looking ahead max 24 hours and the synoptic charts are a good guide.
Metcheck use several models for their forecasts but I have never looked at the "raw data".
So it's back to the seaweed and fir cones!
Lister:D

[robin]

Even the TAFs were wrong on Saturday......

[FlyingForFun]

FFF's method of forecasting: the more lines there are in the TAF, the more chance there is you'll be spending the day on the ground.

And then there's the method one of the ATC guys at my home airfield uses: he forecasts that tomorrow's weather will be the same as today's. He reckons this gives him something like a 60% success rate, which he says is similar to what the Met Office achieve.

Seriously, though, looking ahead as much as 5 days, I don't know of any forecast which gets it right consistantly. But what normally happens is that they get the general weather right, but the exact speed at which it's moving and the exact direction they might get slightly wrong.

What this means is that if they forecast a front that's going to stretch from the Scottish Highlands down to Devon 4 days from now, there will definitely be a front, but it might only go as far south as Birmingham and it might arrive 3 or 5 days from now (when they have no doubt forecasted good weather).

On the other hand, if the forecast is for three days of high pressure, with no frontal activity, then the chances are there won't be any frontal activity, and there will be a period of high pressure when the weather will be fine. Even if they get the exact arrival date of this high pressure slightly wrong, if you plan your "big flight" for the middle of this period the chances are you'll be ok.

FFF
------------------

[dublinpilot]

I find this site (http://ows.public.sembach.af.mil/asp/syn00120_looperb.asp?name=synoptic&loc=GifImages) to be excellent for understanding what the fronts are doing. Thank you to 2Donkeys for pointing it out in his Transatlantic Blog!

Like FFF & others have said, it's not that the Forecasts generally get it wrong, more that they can't reliably predict the time. The above site is good for looking at what is happening generally, and then seeing how it is changing as you get closer to the day your interested in.

dp

[IO540]

Here's my input, having flown VFR to pretty far bits of Europe and having had to get the weather "right".

Today's weather is (according to something I read years ago) likely to be substantially same as today's, 47% of the time, so this is really useless.

Also there are as many "weather" sites as there are fronts on their way from the USA at any one time! And a lot of them have duff data. And often it isn't obvious. I've seen MSLP charts which were 1-2 days older than the current ones from the UK MO or from Avbrief. The only way you spot that the chart is older than one can get elsewhere is by working out the preparation time by subtracting its forward time from the time/date it was prepared for; not something people normally check.

Also I've had TAFs over a day old, and ones which were several hours older than one could get elsewhere, from some sites which can do it via SMS. So beware, even with TAFs.

So there is zero point in going to some of these sites just to get stuff which is available FOR FREE from the reputable providers such as UKMO or Avbrief. This is basically TAFs, METARs, MSLP charts.

I believe there is NO point in playing at amateur weather forecasting. Lots of people say they have a JAA ATPL which gives them a superb understanding of how weather works. I'd suggest they get themselves employed as consultants for the UKMO and help all of us! In fact anybody who can do a much better job, and can support their expertise statistically, can make money out of it, because much of industry/commerce pays money for this data.

The TAFs are produced by people that do it all day long, and they have access to data which nobody else gets - certainly which nobody else gets unless they pay serious money. So, I doubt that, statistically, anybody is going to beat a TAF for reliability.

The problem is further ahead, say 2-3 days. The free MO data is only the MSLP charts, and they are wide open to interpretation. So people use other stuff, and typically this is based on GFS. One of the many graphical gateways into GFS is this one

http://www.arl.noaa.gov/ready/cmet.html

which I've been using for a few years. The temp/dewpoint graph is particularly handy in indicating the likely cloudbase.

Some experts have said to me that the UKMO model is more accurate than the GFS model for the UK, so one can use GFS for the rough idea, and use the UKMO MSLP charts for timing (as seen from the positions of the fronts).

I've used the Sembach site for its "cloud progs" but usually I find it wide of the mark.

Other than the above, any forecast past a few days is likely to be imagination!

[foxmoth]

As said, a 5 day forecast or more is probably not even worth looking at. Usually the next day forecast is pretty reliable but at present they even seem to be getting that wrong, at least for southern UK- anyone know why?
(Glad to say they are forecasting grotty and is ending up much better):cool:

[FlyingForFun]

The TAFs are produced by people that do it all day long, and they have access to data which nobody else gets - certainly which nobody else gets unless they pay serious money. So, I doubt that, statistically, anybody is going to beat a TAF for reliabilityIt would be great if the above statement were true. But I very often look at the TAF, and then look at other information from the Met Office (predominantly MetForm 215, rainfall radar, and METARs from places a weather system is coming from), and see discrepencies between them. And when this occurs, it is invariably the graphical data which is more accurate. I don't know whether the people who write TAFs make use of this same information, but it seems to me they don't.

And while we're on the subject, I'm informed by a source that I believe to be reliable that a station must produce 3 consecutive METARs before producing a TAF, because the information in the METARs is used in deriving the TAF. I am also informed by the same source that the advice given to licensed Met Observers when creating a METAR includes reading the TAF. I'm sure you can see the obvious problem.....

I certainly don't claim to have a "superb understanding of how weather works", but I do claim to have access to a wide range of official weather data from the Met Office, as well as from other sources, and to be able to interpret all of this information, and I believe this gives me a far better understanding of what the weather is going to do in the short term than reading just one source of information (a TAF or anything else) would give me.

But none of this is any help for forecaasting over longer periods.

FFF
--------------

[IO540]

FFF

Have you asked the UKMO about this apparent discrepancy? It's worth asking. They would need real examples.

If you can demonstrate objectively (with long term data) that you can generate more accurate TAFs than the existing ones, please do so.

You mention F215. That one is like the old joke about British Standards - they are wonderful, so many to choose from :O On any given day and for any of the areas listed by number, there is usually a choice of very different conditions - for the same spot.

Which is not to say that TAFs are particularly accurate. They aren't. Chaos will never be abolished - except when the weather comprises of a high pressure that has been in place for last few weeks and doesn't look like it will shift (summer 2003 perhaps) in which case anybody can do it well enough themselves by looking out of the window and looking at the MSLP chart.

Incidentally, I am pretty sure that virtually all of the free weather sites display data which is either directly from GFS, or is lifted from other websites which use GFS. A lot of "lifting" goes on in this business, with websites getting data off one another. The NOAA site I gave before had put in a graphic thingy to stop this. Nobody running a free website is going to put data online which they pay money for to the UKMO. The only exception I can think of is stuff which the UKMO charges for but which it is obliged to distribute under international agreements, and which some foreign (typically American) very kindly put online ;)

Obviously you know this but it's worth stating in case somebody has a go at me. In the end, forecasts will never be accurate enough to rely on, so a Plan B is always needed. Having an instrument rating of some sort provides additional options there, and even more options if the flight is carried out IFR to start with.

p.s. I think an airfield needs to generate just *one* METAR before the TAF comes out, but could be wrong.

Foxmoth

This sort of fast moving weather is not forecastable more than a day ahead, I think.

[got caught]

The NHS is currently on "amber alert" as they have recieved information that there are an indications for a "drier and colder winter than average."

Someones getting paid for this nonsence (or "non science")-

happy taxpaying !:}

[Brooklands]

Even the TAFs were wrong on Saturday......
There's a nice explanation of what went wrong with the Saturday forecast on the Flyer site (http://forums.flyer.co.uk/viewtopic.php?t=17754). Essentially the weather didn't do as the computer said it would!

Brooklands

[IO540]

TH UKMO put out a press release (don't have the URL handy) essentially trying to distance themelves from the sensationalist stuff in the papers, and saying that the last 10 winters have been pretty warm and there is a 2/3 chance that his one will be back to the more usual sort.

Nothing special then, IMV, but I might get myself a cheap generator on Ebay just in case, to run the central heating pump :O