General Model Output Discussion:

[Duane S.]

That is exactly the point :lol: You will so you have no complaints... Love to hear what you would say if it was a North Westerly giving snow to Western areas and leaving you with cold dry conditions

Personally I'd say "Brilliant! For once I've got dry cold conditions, now I have this pre-requisite I can start looking for wintery PPN."

Edited December 30, 2009 by s4lancia

[CLH the red dragon]

Jesus. The bickering on here is unreal. Get a grip. Its simple. Established cold air, plus being surrounded by water equals snow. Forget what is being shown on the ppn charts at the moment, for next wk. My 4 yr old could do just an accurate job with a crayon. Showers and longers spells of snow can crop up anywhere. The main thing is getting the cold in place first. Unless you want wrong side of marginal stuff. Chill out and ignore the ppn distribution for now.

Someone make this a sticky! Just that, it HAS to be better to have all this good cold stuff going on than constant 2 week mild spells with clutching at straws. I, for one, am enjoying this winter, and I'm snowless!

[winter watcher]

South east could get some good local in the slow moving trough on fax charts

http://www.meteociel.fr/modeles/ukmo2.php?ech=48&carte=2000

Convergence line

A slow-moving trough, which is parallel to the isobars and tends to be persistent over many hours or days. They are quite common in cold northerly outbreaks down the Irish Sea, affecting west Wales, Devon and Cornwall in particular, but can be found in other areas also. This convergence line can gives hours of persistent precipitation over very localised areas, whilst a few miles down the road it is relatively dry, leading to some heavy snowfall/rainfall. In summer the convergence lines are not as easy to forecast, but then can still occur due to sea-breeze convergence, and are over the land, whilst in winter they are over the sea.

I agree and possibly a Thames streamer also Se Areas in a favourable set up here wind direction very very good. People who are after cold and snowy weather moaning over the current output should not be here in my opinion just for one minute use your brains and think NO COLD = NO SNOW [ COLD = Possible Snow down the line im off gotta pop down b&q get me self a shovel

Edited December 30, 2009 by winter watcher

[Kiwi]

Jesus. The bickering on here is unreal. Get a grip. Its simple. Established cold air, plus being surrounded by water equals snow. Forget what is being shown on the ppn charts at the moment, for next wk. My 4 yr old could do just an accurate job with a crayon. Showers and longers spells of snow can crop up anywhere. The main thing is getting the cold in place first. Unless you want wrong side of marginal stuff. Chill out and ignore the ppn distribution for now.

Sanity !!!

Let's just worry about the cold and forget about the dryish precipitation outlook. The models will change/ not pickup troughs etc.

By the way .... will it snow in...

[Michael Fishermans Friend]

Hows the GEM 12Z progressing anybody?

[MR EXTREMES]

excellent stuff being thrown up by the models.

firstly id like to add frosty you have a name that would suggest your chilled and you like the cold,

but your not acting chilled and trying to convince people that there wrong is pointless,

why well because last febuary we had a cold event with easterly winds that brought snow across lots of southern britain they where showers with streamers thrown in for good messure.

to finish this off i remember the 80s and north easterlys brought some brillant snow event even here on the sunny southcoast.

this is a brillant setup and even though its mild here now its about to get colder and im 100% certain snow will fall in one form or another.

the models are giving us some of the best we have seen in many years ukmo 144h is simply sexy.

so lets be upbeat and listen to the big guns tells us what they think.

[Neilsouth]

I agree and possibly a Thames streamer also Se Areas in a favourable set up here wind direction very very good. People who are after cold and snowy weather moaning over the current output should not be here in my opinion just for one minute use your brains and think NO COLD = NO SNOW [ COLD = Possible Snow down the line im off gotta pop down b&q get me self a shovel

Not always , cold doesn't always = snow down the line. Although the models do look good for our se part thursday night and at some point next week , there are many factors which could mean just a small area gets snow or we all do. At the moment i'm not getting excited because last time it wasn't just the mild sector which caused this part problems.

[johnholmes]

Jesus. The bickering on here is unreal. Get a grip. Its simple. Established cold air, plus being surrounded by water equals snow. Forget what is being shown on the ppn charts at the moment, for next wk. My 4 yr old could do just an accurate job with a crayon. Showers and longers spells of snow can crop up anywhere. The main thing is getting the cold in place first. Unless you want wrong side of marginal stuff. Chill out and ignore the ppn distribution for now.

what a very sensible post

[Yeti]

Hows the GEM 12Z progressing anybody?

It's very good, better than the 0z. At 144 it's similar to the UKMO but the low is even further S:

http://91.121.94.83/modeles/gem/run/gem-0-144.png

I did comment on this a minute ago but it must have got lost in all the bickering!

[aspire27]

I asked earlier but didnt get an answer, i will try again.

Are the models still showing the EPIC (not my words) severe cold the S.Murr and others was talking about for Jan 1st?

[Lewis]

Well Well Well,

The 12z does it again!

Lovely agreement between the 12z GFS and ECM, over the past few day's it is these models being the most consistent at this time frame.

Hopefully more to come :lol:

[Cecil Hogmanay Melchett]

I asked earlier but didnt get an answer, i will try again.

Are the models still showing the EPIC (not my words) severe cold the S.Murr and others was talking about for Jan 1st?

Potential is there for eric cold.BBC have maxima of 1 degree in towns and cities on saturday,and thats before

the colder air gets established.

I'd say a severe cold spell is looking very likely.

[Alex95]

I asked earlier but didnt get an answer, i will try again.

Are the models still showing the EPIC (not my words) severe cold the S.Murr and others was talking about for Jan 1st?

Jan 1st might not necessarily be epic, but there could be some significant snow in the N and E. As the spell progresses it has the potential to become something very memorable indeed, there are some very good charts about for next week and the snow could build up if you get it. These situations in the past with NE winds have been particularly good for NE England, think March 1979, 50cm in Newcastle :lol:

[johnholmes]

oh for the day prior to computers and certainly prior to www. and we all took as gospel the sticky chart symbols (when they did not fall off) from Bill, Ian etc. Even those of us who worked in the aviation side used to watch them believe it or not.

24 hours ahead and maybe a further outlook for 24 hours-oh to bring it back.

lots of silly posting in here which has rightly been picked up on by other more sensible and moderate posters.

as someone has already said for heaven sake-chill out-some will be lucky some not so lucky-its never been any different.

Its going to stay cold or become cold even very cold-severe frost will feature quite often over the coming week and yes- snow will fall in a fair number of places.

[Guest North Sea Snow Convection]

Jesus. The bickering on here is unreal. Get a grip. Its simple. Established cold air, plus being surrounded by water equals snow. Forget what is being shown on the ppn charts at the moment, for next wk. My 4 yr old could do just an accurate job with a crayon. Showers and longers spells of snow can crop up anywhere. The main thing is getting the cold in place first. Unless you want wrong side of marginal stuff. Chill out and ignore the ppn distribution for now.

to you for that post!

We need the cold air in place, and to stay in place. It is the principle ingredient needed to make the cake - otherwise it will fail - ie no snow!

Great output this evening. Pleased to see that the GFS came out with something more sensible after this morning and has kept the trend observed since this time yesterday. very good UKMO and the GEM is a gem! Very happy if that happens

Edited December 30, 2009 by North Sea Snow Convection

[J10]

It's a long-established fact that prolonged cold spells in winter tend to have winds blowing from the north and east, snow showers peppering northern and eastern regions (and sometimes the south when we pick up an easterly), with marginal frontal rain/sleet/snow events affecting central and southern districts at times. Meanwhile a large part of north-west England and west Wales and west Scotland, particularly near the west coast, tends to pick up just the odd flurry here and there.

For widespread snow in sheltered western areas you need more of an Atlantic influence, be it a frontal battleground with fronts aligned N-S pushing against continental air, or some sort of Irish Sea-related disturbance when northerlies take over- usually a polar low or a westerly component to the airflow bringing showers in from the Irish Sea. 20-23 December was a good example of the latter scenario. But this "northerly" scenario often relies upon a west based -ve NAO which can lead in the long run to milder weather coming up from the SW.

This is the main reason why snow cover frequencies are higher near the east coast than they are near the west coast. Western coastal areas rely upon synoptics for widespread snow events that are generally less sustainable for long periods and less cold.

Unfortunately for snow fans living in said sheltered western areas, the above will need to be taken into account when surveying these old-school cold synoptics. For eastern areas, a spell of cold and snowy weather is looking likely.

Western areas tend to do best out of situations like this, when there are Northerly and Easterly fluctuating winds, when the winds turn round to more of a NNW direction. When this happens we tend to get streamers of snow that can easily deposit 4-5 inches of snow in a night.

Unfortunately before Christmas there was a warm sector associated with thus, which cut off our snow potential.

However Ian is totally right in saying that quite often such winds are associated with "topplers" which gives us the snow, but mild weather can follow a few days later.

Up until 2-3 years, locally we did very well out of NNW winds, however the last 3 winters, we have not done so well, it this just a coincidence or a start of a new trend.

[Michael Fishermans Friend]

GEM 12z at +144 looking pretty good!

[Thundery wintry showers]

It's worth mentioning that in Tyne & Wear we had that aforementioned scenario from 20-25 December, with the weather coming in from the west, and us relying upon troughs and bands of organised shower activity to send precipitation across. Admittedly, we did have a snow cover by then from the falls of the 17th-19th, but we were looking at six days of mainly cold dry weather, leading to some nail-biting occasions when it looked like the snow cover would melt by Christmas Day.

As it happens, showers did work their way across on the 21st, and again overnight 22nd/23rd although on the latter occasion they were tied in with the remnants of an occlusion and fell as sleet or even rain at low levels. Then we had a marginal event from a trough on Christmas Eve.

Also, regarding the earlier references to north-west England often staying dry in these setups, during the north-easterly outbreak of 19-21 February 1996, showers were unexpectedly widespread over north-west England. The easterly outbreaks in January 1985 also succeeded in bringing a fair number of snow showers across the Pennines at times. And in the Midlands (the region spawning a large number of the complaints) there are no Pennines to get past.

The output for around T+144 is very interesting. It is looking increasingly as if we may see a repeat of what happened around 19-20 December but with the trough that introduces the Arctic air being positioned, crucially, much further east, exposing the British Isles to the full force of the cold air instead of drawing modified stuff across from the west. On the other hand, the further east the trough, the less likely it is that western areas will see streamers move in from a temporary westerly component to the airflow.

[weather eater]

GEM is excellent, Its simply really, we have a developing situation, get the cold air entrenched then see what happens from there. Lets put things in perspective this is the best opening month of winter I can remember in a very long time and the best could be yet to come.

[TEITS]

I was just wondering if anyone has the links to the AO ensembles other than the link below. The reason being is despite these being altered to accomadate an index of -6C the AO ensembles still go off the scale. Im curious to see what some of the AO ensembles are suggesting?

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gif

Just add that the AO for Dec is incredible.

[Matt12]

It looks like it is very likely to remain cold until at least the 10th of Jan. All in all, good chances of some proper cold weather, I'd say.

[J10]

http://forum.netweather.tv/index.php?app=forums&module=post&section=post&do=new_post&f=1

A new thread has been set up and this thread will be closing in a few minutes.

[PB22]

ECM 12z is now on the way out, and the T+72 chart is here: http://www.wzkarten.de/pics/Recm721.html

Not too dis-similar to the GFS 12Z and UKMO 12z at this stage...

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

I was just wondering if anyone has the links to the AO ensembles other than the link below. The reason being is despite these being altered to accomadate an index of -6C the AO ensembles still go off the scale. Im curious to see what some of the AO ensembles are suggesting?

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gif

Just add that the AO for Dec is incredible.

What is the mean AO for Dec?

[J10]

This thread is now closed