Winter Model Discussion 12Z 15/1/13 onwards.

[Essan]

Kev's pic was a 2m temp ensemble rather than 850s.

May apologies, I didn't notice

But looking at wetterzentrale's temp charts for Manchester, it still looks like a glitch

[k19]

May apologies, I didn't notice

But looking at wetterzentrale's temp charts for Manchester, it still looks like a glitch

Not only that but look at the first peak, its completely different to the netweather one. I suppose your chart is from manchester though, mine was lancashire, do wetter have a lancashire one?

EDIT: Still talking about the 2m temps here

Edited January 15, 2013 by kev19

[Snowman.]

Some really cold 850's pushing up against the front on the UKMO. An all powder snow event on this run.

-12 Uppers over my head!!

Yeh boi!!

[Methuselah]

Are the fronts and the potential snow expected to reach the far east?

Not really sure about that, but Hong Kong should just about miss it!

[steelermark]

Quick question for the experts on here. As the models show the fronts moving further north east or staying further south west would I be correct in thinking that shower activity would be greatly increased for areas just North of the front with the increase in windspeed and lowering of 850's etc?

[Mucka]

What is happening with the fax charts? They only seem to be updated to 72h on Wetter. Anyone have the later charts?

[snowking]

Fridays ECM ens mean almost identical to the det:

SK

[nick sussex]

Just been looking at the ECM postage stamps and its becoming evident that if we see a separation of energy upstream then high pressure could ridge north in the mid Atlantic delaying the ejection of troughing in the eastern USA.

Because of that there is a cluster of solutions that take the low at 168hrs further south with a strong easterly flow developing on the northern flank.

So thats the area to look out for upstream you want to see a nose of high pressure and a clean break of energy.

Edited January 15, 2013 by nick sussex

[Liam J]

A few charts I've taken from the ECM 12z run on Wunderground, valid for midday Friday. Some very wintry weather ahead for some of us with the risk of conditions potentially not seen for many years, a very interesting few days coming up as the finer details become more clear.

Precipitation Snowfall

Surface temps 850 temps

Edited January 15, 2013 by Liam J

[ChartViewer]

Just been looking at the ECM postage stamps and its becoming evident that if we see a separation of energy upstream then high pressure could ridge north in the mid Atlantic delaying the ejection of troughing in the eastern USA.

There is a cluster of solutions that take the low at 168hrs further south with a strong easterly developing on the northern flank.

So thats the area to look out for upstream you want to see a nose of high pressure and a clean break of energy.

CMA esque possibly

Edited January 15, 2013 by ChartViewer

[ARB]

Quick question for the experts on here. As the models show the fronts moving further north east or staying further south west would I be correct in thinking that shower activity would be greatly increased for areas just North of the front with the increase in windspeed and lowering of 850's etc?

Not necessarily usually shower and convective activity in general is surpressed ahead of the main precipitation zones.

[chionomaniac]

Please keep on topic - this is not a historic weather thread. Thanks.

[snowking]

ECM mean @ 240;

Colder uppers coming back in from the NE - sub -4c 850's the whole run with a shallow, mean east/south-east cyclonic flow.

Oh boy!

SK

[nick sussex]

CMA esque possibly

That looks a bit messy we just want one low heading se'wards. Check out the GEFS ensemble 6 at 150hrs, thats what we need to see with that high ridging north.

This will give the low a chance to clear se and pressure to build to the n/ne.

The main thing is to have a separation of the energy out of the eastern seaboard so that you don't get phasing as the eastern USA troughing edges east.

[Matty M]

Excellent ECM EPS tonight.

The mean shows a prolonged cold spell with heights rising to the north and the jet sinking further and further south.

[bluearmy]

ECM mean @ 240;

Colder uppers coming back in from the NE - sub -4c 850's the whole run with a shallow, mean east/south-east cyclonic flow.

Oh boy!

SK

and the trend is to move the mean ridge towards iceland/se greenland in the longer term.

[Snowman.]

A few charts I've taken from the ECM 12z run on Wunderground, valid for midday Friday. Some very wintry weather ahead for some of us with the risk of conditions potentially not seen for many years, a very interesting few days coming up as the finer details become more clear.

Precipitation Snowfall

Surface temps 850 temps

Is that settled snow or what?

[Matty M]

Hi Matty,

what do you think will happen at your location following the latest runs?

We are going to need a 50 mile westward correction from the ECM mean at T72hrs to bring a risk to the east coast and north.

Very possible but a real knife edge situation. The models will be being watched very closely in the next few days.

[Rob K]

Question about the UKMO model - is it somehow lower resolution than GFS/ECM? I ask because the UKMO charts always seem to have very "clean", smooth isobars, compared to outher models.

E.g. see this link comparing ECM, UKMO and GFS side by side at 144hrs:

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&VAR=model_pslv&CONT=ukuk&MODELL=modens&BASE=-&MODELLTYP=1&VAR=model_pslv&WMO=&ZOOM=0&PANEL=0&ARCHIV=0&HH=144&modeladd=gfs&modeladd=ukmo&modeladd=ecmwf&modeladd=nae&submit=go

GFS in particular has shortwaves and troughs all over the place. ECM has little kinks here and there. UKMO just has a big round dartboard!

[ChartViewer]

That looks a bit messy we just want one low heading se'wards. Check out the GEFS ensemble 6 at 150hrs, thats what we need to see with that high ridging north.

This will give the low a chance to clear se and pressure to build to the n/ne.

The main thing is to have a separation of the energy out of the eastern seaboard so that you don't get phasing as the eastern USA troughing edges east.

Yes cracking chart Nick......

[Carlrg]

The PV looks like it's done 12 rounds with Mike Tyson.

http://www.meteociel...rte=1&archive=0

Edited January 15, 2013 by Carlrg

[ianshortall]

From Matt Hugo

Matthew Hugo â€@MattHugo81

Remarkably the 12z EC ENS mean supports the ECM model at 120hr and 144hr with a particularly cold and wintry theme continuing Sun/Mon

Its looking good for widespread snow

[chionomaniac]

Whats even better is we havent even felt the full effects of ssw yet . Maybe that december let down is fate for this snow event

We are feeling the full effects now as in the stopped Atlantic - so that is misinformation. We may also feel further effects (highly likely) but the pattern we are in now is fully SSW induced.

[Jason M]

Not necessarily usually shower and convective activity in general is surpressed ahead of the main precipitation zones.

Just to add to this, it tends to be the cloud shield that kills the convection. Ahead of a warm front the cloud shield can spread out several hundred miles ahead of the front. It was this impact that in effect led to parts of east angla missing out on snow a couple of year back as there was snow to the south and convection to the north. I'm a bit hazy on the dates, but I'd wager TEITS would help out on this as I seem to recall he was really rather sad at the time as it was only a narrow band of EA that missed out :-)

Jason

[Liam J]

Is that settled snow or what?

No it's not like the GFS snow depth charts, this one highlights where any precipitation is likely to be falling as snow.