[Fax Charts]

After discussing how the met office position troughs on fax charts from t24 with John Holmes in a separate thread I subsequently emailed the met office

Hi

I wonder if anyone could possibly assist an interested novice

meteorologist. I have been keenly studying the models and charts for a

number of years now, and have wondered how on the fax charts the

positioning and timing of troughs is ascertained. I know that areas of

vorticity, lift, convergence zones at/near the surface can give some

guidance in the short term but from 24 hours out are there other factors

taken into consideration?

Many thanks in anticipation,

and here is their reply:

Sorry for the delay in replying to your email.

As far as I know, there is no difference in forecasting troughs to that

of the other meteorological features. Please excuse me if you already

know how this is achieved.

The basics of forecasting are the hourly observations which are then

plotted on the relevant chart, and the chart analysed adding the fronts,

centres and isobars. A sequence of charts are then compared to see the

speed and direction with which these features are moving, and a forecast

chart is produced with the estimated position of each shown in the

expected position at a given time in the future. Without having a

previous chart, I think the isobars and centres are the easier to drawn,

then the fronts can be found by looking at where there might be

precipitation ar sudden temperature/humidity changes. Other sudden kinks

to the isobars or bands of cloud might be other identifying features.

So whether it is a front (warm, cold or occlusion) or a trough, the

method of forecasting would be the same.

Producing forecast charts is obviously more complicated than the above,

which knowledge would be taught during our in-house courses, plus a

forecaster's experience, but I have tried to explain the basic method.

Forecast charts are now routinely produced by computer, rather than the

'man', with the necessary equations having been included into the

program used by the computer. This program is continually being updated.

I hope this answers your question.

Apologies for the questionnaire, but we have been asked to include the

below with our emails.

Regards

Graham

Its a bit of a general answer but I hope I am right in assuming that forecast=fax charts rather than the model output.

If that is right and fax charts are computer generated how does that account for the times when the metoffice produce fax charts that go against what their own models produce?

c

[December C.E.T]

If this is open to anyone then I would like to go for 4.7 please

This is one degree above solar min average since 1933 .... ie I plucked it from thin air!

Thanks

C

[Fax Charts]

Thanks Essan, sometimes the answer is so obvious that you dont think its right!

[Fax Charts]

Thanks for the replies guys. Does anyone know why they are called fax charts? Is it something as simple as this:

"Fax (short for facsimile, from Latin fac simile, "make similar", i.e. "make a copy") is a telecommunications technology used to transfer copies (facsimiles) of documents, especially using affordable devices operating over the telephone network."

(courtesy of wikipedia)

so that the info could be shared quickly - or is there a hidden meteorological meaning?

[Fax Charts]

Thats a lot of information to sift through to produce 10 fax charts every 12 hours!

[Fax Charts]

Charts have updated since but I originally chose UKMO 0z for 20/11 for demo purposes as I still haven't worked out how to upload the charts!! I'm sure I'll soon work this out!! Any help on this gratefully received.

[Fax Charts]

I have another question for the experts who kindly helped me in the past.

I know the Fax charts are the version that the professionals produce once they have interpreted their own supercomputers model output. But what does Fax actually stand for?

And (I hope this works) how do the met office forecasters get from this:

http://www.netweather.tv/models/meto/20071...ages/met.72.png

to this?

http://212.100.247.145/fax/PPVK89.png

thanks

[The PFJ - How to see it on the charts]

Thanks brickfielder the 500hPa chart you have posted will hopefully allow me to make a quick educated guess where the jet is positioned before confirming this on the 300hPA wind charts.

[The PFJ - How to see it on the charts]

Thank you for your replies.

I have just signed up to netweather extra - the amount of available info is impressive! It is useful to see the 300hPa chart together with the slp.

WIB thanks for this link to TWS BI snow set up article. I have previously read this excellent post a number of times - essential reading for a novice like myself!

[The PFJ - How to see it on the charts]

I wonder could any netweather experts please help me. I have a question regarding the PFJ. Is it possible to work out from the 500hPa charts where this jet boundary is positioned or do I have to refer to the 200hPa or 300hPa wind charts to work this out? I often find these difficult to read when the jet stream is fragmented. Or am I looking in completely wrong place altogether?

Many thanks in anticipation.

[The Great Storm of '87]

I posted in the history section earlier and would like to know who back in 1987 was responsible for drawing in the pencil isobars on the the original met office charts that I have shown on 16 10 1987 at 06z when the local weather stations started recording the data of the great storm? I don't know how to post a link to the history section but would still be interested how the met office worked before the days of instant information on the internet. Were there many copies taken of this original document and would any of the original met office staff be interested in seeing one of the originals again?

Ed

[The great storm of October 1987]

I sadly missed the great storm of 1987 as I lived in Liverpool at the time. I remember waking up and hearing all the reports on the radio but sadly( and luckily) the reports that the storm was heading our way proved to be untrue. We had no more than a gentle breeze!!

Later I have been lucky enough to be given the met office chart from 0600 on the 16th with signed autographed photos of the original met office team!!! I am going to try to upload photos I have of this . Perhaps John Holmes would be good enough if he comes across this thread to reminisce and confirm that the pencil isobar scrawling is how they used to draw the charts back then.

Ed

[African Flooding - Any statistical evidence to future British winter weather]

Hello and good evening

This is my first post after many years of lurking. I love all aspects of weather but would particularly love a cold snowy winter.

( chionomaniac= manic for snow)!

Can anyone out there let me know if there is/are any trends or correlations regarding a particularly wet September in the central bands of Africa and how this may have a knock on effect to our autumn/winter. Or is there no correlation whatsoever?

Here is hoping for a 1947 or 1963 trend but I somehow doubt it?

Regards

Ed

Ps I hope this is posted in the correct area. If not Mods please move to appropriate place.