Coptic Storms

[JimX]

Coptic storm, when will this myth disappear as Coptic storms do.

[Dominic]

Nonsense! Look, there is a coptic cloud forming over Polemi as we speak.
 

coptic.jpg (125.05 KiB) Viewed 7610 times

[Dominic]

Well we had a strong gale last night, but it's too early for a coptic. The next one is due next tuesday. According to the calendar it is supposed to be a big one. But will it materialise or will it be a damp squib like most of them have been so far?

[PaphosAL]

Oh ye of little faith...

[Dominic]

Well so far this season, NONE of the dates have produced a coptic storm. Out of four dates, there has been zilch. zip. nout. bugger all.

One more chance this year, on 20th December, but let's face it, it's not looking good.

Which is a shame, as we could REALLY do with the rain.

[Devil]

Which is a shame, as we could REALLY do with the rain.

The Coptic storms are supposedly about gales; nowt to do with rain, snow or sand!

[Dominic]

Yes, but when a good gale blows it often rains too. I wish it didn't. When it does, stuff which you think is sheltered gets soaked, because it can't cope with 45 degree rain. I would rather the rain arrive after the gale, to help clean up the mess.

[Mike J]

Not sure what grace you give them but the forecast is for increased wind velocity on Dec 22nd and then rain arriving on the 23rd with half an inch of rain on the 24th accompanied by stronger winds. Christmas Day will also have rain . Mind you it looks more like a simple low pressure system that often forms over Turkey . Still it gives the 'believers" some hope I guess.

[Devil]

Not sure what grace you give them but the forecast is for increased wind velocity on Dec 22nd and then rain arriving on the 23rd with half an inch of rain on the 24th accompanied by stronger winds. Christmas Day will also have rain . Mind you it looks more like a simple low pressure system that often forms over Turkey . Still it gives the 'believers" some hope I guess.

Have you ever wondered why the general UK Met Office usually give only 5-day forecasts? Within hours, they are usually very accurate; the following day are most often reasonably accurate; after that, they usually pepper the forecasts with 'may', 'might', 'possible' and other let-outs. They estimate the accuracy at 5 days as better than 50%, on an average. They don't give, as a rule, more than 5 days because they don't like to chance their arm, knowing it is probable that any longer forecast is too iffy.

Your forecast for 22-25 Dec. may possibly be right, but there is a more than equal chance that it isn't. I have been forecasting for this region every 3 hours for many years at http://weather.bnellis.eu/forecast/ using very complex algorithms and the same data used by Met Offices and, generally, it is remarkably accurate, although one can often see a progression with time in the 3-5 day forecasts as they become nearer the present time. For more details, see http://weather.bnellis.eu/notes/forecas ... ation.html

Let's see whether you are right or not

[boycott]

In other words Mr Devil looks out of the window and sees its either sunny/raining or about to rain!

[Dominic]

The law of averages indicates they will be right at least some of the time anyway.

[Mike J]

Devil, I'm sure you are right and indeed the weekday crew at weather underground have already lowered the chance of rain and that often happens so I guess the weekend crew are still learning their trade as this is a regular Monday occurrence . As you say 5 days would seem the limit of decent forecasting. However strangely weather underground has a tendency, especially with their rain forecasts, to suggest rain with a 50% chance at 10 days out. They then lower it as, I guess, other forecasts don't predict it only to have to increase it about 3 days out and down it comes as their original 10 day out forecast predicted. As you say we shall see but thanks for the links they are really useful.
Cheers, Mike

[Mike J]

Ho ho , here we go again. Weather Underground are busy changing their forecast back to to rain on Saturday and Sunday as the other sites start to change theirs. Interesting to see if tomorrow they also start to change Monday back to their original forecast too .

[Dominic]

I think the weather over the last few days will make the Dec 20 eligible for a YES in the Coptic Storm chart, as it is supposed to be light. There was certainly plenty of dust around.

However, the calendar has only been right two times out of nine since we started monitoring. That is no better than randomly predicting the dates, given the margins for error allowed. We will see what happens in the next three months.

11 January Gale (very strong) Result: N/A
19 January Large Feeder Gale Result: N/A
28 January Gale Result: N/A
18 February Small sun gale (very strong) Result: N/A
10 March Equinox Gale (lasts about 6 days) Result: Yes storm on the 10th, plus heavy dust clouds on the 9th.
20 March Big Sun Gale (very strong) Result: NO.
25 March Wind Gale: NO
29 April Sand laden winds (hot and sunny) NO
27 September Cross-winds NO
21 October Crusade NO
28 November Broom Gale (very strong) NO
6 December Gale NO
20 December Small Gale YES

[Devil]

And the 'gales' were strongest on 23 Dec between 20:00 and 23:50, a wee bit outside the ±2 days???

[Devil]

OK, it looks like, by coincidence, it will blow hard tomorrow, day and night. A chance to show the odds for the Copts (both direction and force!)

[Dominic]

Well it certainly didn't do anything on the 11th. We had thunder and lightning late on the 13th, but no wind to speak of, and certainly not a very strong gale.

[Dominic]

Just updated the chart to include the storm that matched the Coptic Storm of the 18th Feb. We have to give them that one.

Next up is a biggie due on March 10th. Or is it?

It strikes me that we should also be recording when we get storms we could class as "coptic" that fall outside of these days. The only problem there is, some of the definitions for a coptic storm are so vague. Anything from a light warm breeze to a 6 day gale.

[Maggie B]

I do love the fact you are recording this 'stuff' Dominic. You and 'our Dev' will - I hope - be comparing statistics. X

How long you folks would have to do this to completely dismiss or prove the theory . . . . I do not know?

Interesting nevertheless.

Maggie B

[Maggie B]

I'm with 'our Brian.'

But, I reckon Dom is with him too.

MB