Winter Model Discussion - Cold Hunting -23/12/12

[Panayiotis]

Ensembles seem to show average temperatures with one mild blip (incoming low) then a cold blip (NW winds following the low) after that it turns average with upper temperatures staying near the 0C line, to me this suggests that there is uncertainty in the models. For my area: http://modeles.meteo...28301&runpara=0

Edited December 24, 2012 by Panayiotis

[Polar Maritime]

Yes Merry Christmas everyone, I hope everyone enjoys...

Models do look bad for cold this evening, but we all know how fast they can turn around, who knows in a day or to we could be looking at something very different.. The background signals are there, we shall see, im pretty confident, as i am every year

Edited December 24, 2012 by Polar Maritime

[karyo]

On the positive side, the models always come up with crazy outputs over Xmas due to limited data.

So have a drink and enjoy some entertaining charts over the next day or two!

Karyo

[mulzy]

On the positive side, the models always come up with crazy outputs over Xmas due to limited data.

So have a drink and enjoy some entertaining charts over the next day or two!

Karyo

Evidence? This myth is always trotted out every Xmas.

[Geordiesnow]

I laugh how the models look bad for cold when the -10hpa nearly touches mainland Scotland, infact the detail at 72 hours between the GFS and UKMO are quite different in how shallow they want the low to phase through the UK with very shallow heights ridging down from Greenland. It looks like the ECM follows the UKMO at 72 hours, its not as cold as the UKMO but its colder than the GFS. I just wonder if the population in Scotland was greater, there be a little more interest and we won't fully see the words of a poor outlook but I think its mis-leading to fully say, the outlook is a mild one although it does look like we may get some TM air by the end of the week.

Admittedly though, the outlook despite this does look one for a strong Atlantic low to develop, keeping an eye on this as it could become another "weather event".

[karyo]

Evidence? This myth is always trotted out every Xmas.

The evidence is that it always happens all of a sudden on Xmas day!

Karyo

[Panayiotis]

BOM at 240hrs looks ok, that low to the east of America is causing WAA towards Greenland and if you look at the frames before it doesnt seem to head north and just stalls there, i wonder if the HP can ridge into Greenland. However the BOM isnt the best of models. http://www.meteociel...ode=0&archive=0

Edited December 24, 2012 by Panayiotis

[bluearmy]

JMA at 240hrs looks ok, that low to the east of America is causing WAA towards Greenland and if you look at the frames before it doesnt seem to head north and just stalls there, i wonder if the HP can ridge into Greenland. However the JMA isnt the best of models. http://www.meteociel.fr/modeles/bome_cartes.php?ech=240&code=0&carte=0&mode=0&archive=0

The jma is quite reasonable. The BOM, which is the model you linked to is rather less reliable.

Edited December 24, 2012 by bluearmy

[Grimsby Snow Lover]

JMA at 240hrs looks ok, that low to the east of America is causing WAA towards Greenland and if you look at the frames before it doesnt seem to head north and just stalls there, i wonder if the HP can ridge into Greenland. However the JMA isnt the best of models. http://www.meteociel...ode=0&archive=0

Going by what I've read recently the Japanese have invested heavily in this model and our own UKMO hold the JMA quite highly in their estimations. Don't dismiss it straight away.

Edited December 24, 2012 by Grimsby Snow Lover

[Panayiotis]

The jma is quite reasonable. The BOM, which is the model you linked to is rather less good.

Oops my bad yes BOM is what i meant :L

[syed2878]

hey guys a qs. If the models have limited data during christmas time wouldnt that make the forecast wrong? And lot of people rely on a acuret forecasts in their field of work. Happy christmas and new year every1.

[Buzz]

It's a myth - ignore it.

[I remember Atlantic 252]

It's a myth - ignore it.

Was often used as a straw clutch, model looks mild, but its because of missing data at Xmas, agree its a myth though

[Weathizard]

I know people say its myth but surely there are less flights (crucial for data in the S.Greenland area and people working around this season so surely it COULD cause some disrepensies? Either way? Sorry for being off topic just interested in whether its true or not.

[Paul_1978]

I know its FI but GFS remain keen on building pressure from the south in early January this is the 2nd day running its shown this

The first attempt fails after 2 days

...............

But it quickly builds again

Basically we're looking for a big erection from the south! (Just to add a Christmas giggle!)

Edited December 24, 2012 by Paul_1978

[Panayiotis]

ECM similar to the GFS, ie no cold except for the 30th, however at 240hrs at least it will start to get drier as the Azores ridges north.

Edited December 24, 2012 by Panayiotis

[Summer Sun]

ECM is out now and short term its more of the same really but maybe the rain won't be as heavy at times and the sun will shine but that doesn't rule out flooding

Into 2013 and again ECM is showing high pressure to edge closer to the UK as per GFS

[UV-RAY]

I know people say its myth but surely there are less flights (crucial for data in the S.Greenland area and people working around this season so surely it COULD cause some disrepensies? Either way? Sorry for being off topic just interested in whether its true or not.

Most of the important data doesn't come from flights, the one thing I would agree on is during the Xmas period data from far Northern latitudes is lacking, which obviously has a knock on effect for modelling heights to our North

[Weathizard]

Most of the important data doesn't come from flights, the one thing I would agree on is during the Xmas period data from far Northern latitudes is lacking, which obviously has a knock on effect for modelling heights to our North

I was told on this thread a while back commercial flight data is used by certain models, infact I think there was a chart saying about certain models accepting/rejecting data given by aircraft over southern Greenland.

[Panayiotis]

Can someone explain why there is no dam line on the fax 24hrs chart whereas on the 36hrs there is?

Edited December 24, 2012 by Panayiotis

[nick sussex]

I wonder what NOAA will have to say about the pattern when their discussions come out because the outputs bear no resemblance to what they last suggested on Friday.

How does a negative AO, NAO and plus PNA give us the sum total of the ECM 240hrs!

Even looking at these:

http://www.esrl.noaa.../compare.pn.png

The NAO is expected to spike temporarily before returning to negative values.

Maybe NOAA will change their tune this evening, we'll see soon.

Edited December 24, 2012 by nick sussex

[Cloud 10]

Looks like some wintry weather for Scotland on Thursday if the fax chart/ukmo is correct,and

very unsettled further south unfortunately.

[bradymk]

I wonder what NOAA will have to say about the pattern when their discussions come out because the outputs bear no resemblance to what they last suggested on Friday.

How does a negative AO, NAO and plus PNA give us the sum total of the ECM 240hrs!

Even looking at these:

http://www.esrl.noaa.../compare.pn.png

The NAO is expected to spike temporarily before returning to negative values.

Maybe NOAA will change their tune this evening, we'll see soon.

These charts have been puzzling me all day Nick. If the chart you just posted is correct then surely the operationals are wrong? But are those ensembles correct because if they are, thats pretty good agreement for +PNA and -NAO which surely would produce a better output than what is currently showing on the operationals. One of them is badly wrong. I eagerly await news from our friends at the NOAA.

[Cal]

I wonder what NOAA will have to say about the pattern when their discussions come out because the outputs bear no resemblance to what they last suggested on Friday.

How does a negative AO, NAO and plus PNA give us the sum total of the ECM 240hrs!

Even looking at these:

http://www.esrl.noaa.../compare.pn.png

The NAO is expected to spike temporarily before returning to negative values.

Maybe NOAA will change their tune this evening, we'll see soon.

Bit of a confusing picture there Nick considering the model output. I believe it will become a lot more clearer as we head into the new year.

[Methuselah]

hey guys a qs. If the models have limited data during christmas time wouldnt that make the forecast wrong? And lot of people rely on a acuret forecasts in their field of work. Happy christmas and new year every1.

Someone always suggests that one, syed. It only gets 'forgotten' when Xmas is cold and white...