Cold Spell Prospects and Discussion (January + Early Feb 2012)

M.T. Cranium

I think there's a general if slight upgrade of potential on all models this morning (my time). Previous posters have covered the range of possible outcomes. All I would add is that the models are challenged by a rather difficult pattern and you should assume that anything past 96 hours is subject to considerable change in any direction. The largest scale of change is at the furthest point from western Europe (the central Pacific) which makes hemispheric modelling rather complicated. It's generally a case of slowly retrograde upper features in eastern North America interacting with a reduced energy budget for low pressure as the storm track shifts well away from the Gulf of Mexico and the gulf stream towards a track through central North America. Europe is left in a bit of a void that can be filled up with various signals that may start out similar but can end up vastly different as we saw a few days ago with the conflicting ECM vs GFS output. That conflict is slowly being resolved towards one outcome, which seems to be cold northerly semi-blocking. But the less you have in the way of Siberian high pressure, the faster this can transform into something even better at some point in late January. This is what I would expect from the hemispheric synoptics, at least one spell of true winter weather between next weekend and the first week of February. It could even turn out better than that, but for me, the over-under for the period 19 Jan to 5 Feb would be temperatures 2 to 3 deg below normal and one snowfall event giving an average of 5-10 cms snow cover. That can be taken as a statistical forecast rather than anything specific for any particular date.

Iancar29

nacho libre wrote: »

Ian there has been a heatwave in Kiruna. All the snow is gone:p

It's a great place. You'll have a wonderful time. It is Kiruna you're going to. I hope i'm not mixing you up with someone else.

hahaha ... CHeers Nacho , i must grab a picture of the MELTED Ice hotel then for you if we get a chance to go there ha ! :pac:

Temp. there last night was................. -19 o C !

Sunspots and a energetic solar wind coming into view aswell so its looking fairly positive

Madpaddy79

davidsr20 wrote: »

How was this got so wrong guys?

Because the professional chart readers are doing just that " looking at charts ", not actually forecasting weather. I think most here can have a good aul go at defining what the charts actually mean, but don't see much actual forecasting, ie wtf did they do before super computers!! Then they change and all get grumpy. Ps, not many left here that will have a go at forecasting other than just looking at pictures drawn by a machine! That's is where it's going wrong. And to the few who do an actual forecast, well done and thanks.

ninebeanrows

iyu

Wild Bill

Madpaddy79 wrote: »

And to the few who do an actual forecast, well done and thanks.

Thanks !

I'm still sticking with my blizzard on the 20th.....only five days to go now

Irish Steve

UKMO seem to have upgraded their forecast for cold between the country walks and the countryfile forecast this evening. We're not looking at anything massive, there isn't about to be any sort of blizzard or the like, but they certainly are suggesting snow showers coming down from the North West from about Thursday onwards, which is a clarification of earlier, in that forecast they said quite specifically that there was a conflict between the models, and they could not be sure of which way things were going to go. By this evening, they've nailed their colours to the mast a bit more firmly, and a spell of colder weather is on the forecast, but nothing serious in the scale of things, and for sure, many of the people here are going to be disappointed with the result. As I have a UK trip with a trailer coming up, that's OK by me, I'd prefer to get where I need to go and back again without too much hassle.

Eastcoastryan

I'm just glad to see some people here tonight, last night in here kinda felt like going to an empty Nightclub on a Monday night that is usually hopping at the weekend! I'm getting addicted to this place so keep it up guys!!!

darkman2

Duiske wrote: »

Darkman, what charts were you looking at to come up with that forecast ? GFS (as it stands now) shows zero snow, and shows minimum temps for Saturday night rangeing from 3 in the east, to 7 in the west.

My preferred set is always a blend of ECM/UKMO/GEM. The UKMO is my favoured outcome next week FWIW. I don't pay much attention to the GFS medium term anymore. With good reason aswell. It's forecast verification record in recent years post 120hrs has gone from ok to awful. But that is just my opinion. I am sure others may disagree. I'd generally stick with the ECM and UKMO for consistency reasons.

Here is the UKMO 120hrs

nacho libre

yorlum11 wrote: »

Have you a link for that Nacho?

As far as I'm aware they do not make it available to the public.

lostinashford

Funny how for most everything was off last night, now it's on again, lets be patient and see what comes over the next couple of days - here's hoping that something interesting will manifest it's self in the coming weeks:D Stay positive

darkman2

Weathercheck wrote: »

From Saturday it would turn a bit milder in the west coast but a shortwave moves across the country which would bring a spell of rain, sleet and snow, potentially snow inland of the east coast.

Depends on the strength of the wind which incidentally would be off shore for most of passage of the developing shortwave. Unlikely to happen like that atm in any case.

blackius

Eastcoastryan wrote: »

I'm just glad to see some people here tonight, last night in here kinda felt like going to an empty Nightclub on a Monday night that is usually hopping at the weekend! I'm getting addicted to this place so keep it up guys!!!

Ah but Ryan, you're in Wicklow like myself so its weather off the Irish sea you want with north east winds and air sourced up from Lapland somewhere or an easterly.
Northwesterlies are generally dry in bray greystones and arklow .
I wasn't inspired by darkman's forecast earlier because it looked like early December to me (were you building snowmen at east coast fm then? No).

Tonight's ecm provides another minor tease for the east but as MT said earlier models are having serious problems resolving things past 96hrs.
It's rare you hear ukmo forecasters emphasize that as strongly as today.

I do hope mind you that I don't have to wait for my trip to Moscow in march to see deep cold and proper snow (do ya hear me Iancar ).

lostinashford

blackius wrote: »

Ah but Ryan, you're in Wicklow like myself so its weather off the Irish sea you want with north east winds and air sourced up from Lapland somewhere or an easterly.
Northwesterlies are generally dry in bray greystones and arklow .
I wasn't inspired by darkman's forecast earlier because it looked like early December to me (were you building snowmen at east coast fm then? No).

Tonight's ecm provides another minor tease for the east but as MT said earlier models are having serious problems resolving things past 96hrs.
It's rare you hear ukmo forecasters emphasize that as strongly as today.

I do hope mind you that I don't have to wait for my trip to Moscow in march to see deep cold and proper snow (do ya hear me Iancar ).

East coast needs snow, don't care how, we just need to see it:D

je55ie

lostinashford wrote: »

Funny how for most everything was off last night, now it's on again, lets be patient and see what comes over the next couple of days - here's hoping that something interesting will manifest it's self in the coming weeks:D Stay positive

Its one serious rollercoaster this winter that's for sure..Im seriously dizzy at this stage but very hopeful..



Chat room still going if anyone wants to join here's the link:

http://client16.addonchat.com/chat.php?id=539786&s

jo06555

So its back on for cold spell next weekend????? Changes so quickly its probably better off coming back next Thursday to find out .

Su Campu

Well one thing I'm really happy about is that weatheronline.co.uk now have the YR.no and Spanish Hirlam models, with a host more parameters than anywhere else. These will come in really handy within a few days of any cold spells (Spanish goes to 60 hours).

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=ukuk&MODELL=aemet&MODELLTYP=1&VAR=pslv&HH=3&BASE=-&WMO=&ZOOM=0

Regarding the end of this week, I feel I'm only back and already I'm slightly disagreeing again! :rolleyes: The UKMO chart above shows lowest 500-1000 thicknesses of around 524 dam in the northeast early Friday, and with ridging moving in from the west at this stage, the cold 850 hPa temperatures will be that bit higher and showery activity will be surpressed. The GFS seems to be agreeing fairly well with the setup, and with the extra parameters available for that I would say that the Ulster and north Leinster will have the best chance of seeing anything snowy, but on higher ground. Further east in England it's a different story, and we could see the first proper snowfall down the east of the country there through Thursday and Friday.

Pinch of salt of course, with a lot likely to change, but that's the way I see it at this stage. Something to get excited about if your on a hill in the northeast, but not much else.

Ahorseofaman

Su Campu wrote: »

Well one thing I'm really happy about is that weatheronline.co.uk now have the YR.no and Spanish Hirlam models, with a host more parameters than anywhere else. These will come in really handy within a few days of any cold spells (Spanish goes to 60 hours).

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=ukuk&MODELL=aemet&MODELLTYP=1&VAR=pslv&HH=3&BASE=-&WMO=&ZOOM=0

Regarding the end of this week, I feel I'm only back and already I'm slightly disagreeing again! :rolleyes: The UKMO chart above shows lowest 500-1000 thicknesses of around 524 dam in the northeast early Friday, and with ridging moving in from the west at this stage, the cold 850 hPa temperatures will be that bit higher and showery activity will be surpressed. The GFS seems to be agreeing fairly well with the setup, and with the extra parameters available for that I would say that the Ulster and north Leinster will have the best chance of seeing anything snowy, but on higher ground. Further east in England it's a different story, and we could see the first proper snowfall down the east of the country there through Thursday and Friday.

Pinch of salt of course, with a lot likely to change, but that's the way I see it at this stage. Something to get excited about if your on a hill in the northeast, but not much else.

great to see you back

kittyn

Good to see you back posting Su ...... Here's hoping to see some of the white fluffy stuff

Iancar29

Su Campu wrote: »

Well one thing I'm really happy about is that weatheronline.co.uk now have the YR.no and Spanish Hirlam models, with a host more parameters than anywhere else. These will come in really handy within a few days of any cold spells (Spanish goes to 60 hours).

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=ukuk&MODELL=aemet&MODELLTYP=1&VAR=pslv&HH=3&BASE=-&WMO=&ZOOM=0

Regarding the end of this week, I feel I'm only back and already I'm slightly disagreeing again! :rolleyes: The UKMO chart above shows lowest 500-1000 thicknesses of around 524 dam in the northeast early Friday, and with ridging moving in from the west at this stage, the cold 850 hPa temperatures will be that bit higher and showery activity will be surpressed. The GFS seems to be agreeing fairly well with the setup, and with the extra parameters available for that I would say that the Ulster and north Leinster will have the best chance of seeing anything snowy, but on higher ground. Further east in England it's a different story, and we could see the first proper snowfall down the east of the country there through Thursday and Friday.

Pinch of salt of course, with a lot likely to change, but that's the way I see it at this stage. Something to get excited about if your on a hill in the northeast, but not much else.

Thinknesses..... 524 Dam.... OF COURSE.... ITS SU CAMPU!!

Glad to see your input once again Su. Im still debating on going down to put a random bet on for snow next weekend. Checking the odds for london too if i was able .


@ Blackius ....... CHALLENGE ACCEPTED! ... :pac:

Deep Easterly

I did up this little chart sequence, using the ECMWF 12z 500hpa Ensemble mean charts, just to show how the ECMWF ensemble mean is handling the situation.

The animation below shows what en mean has been showing for the Sunday the 22nd over the last 4 12z runs (sequence from the 12th at 240hrs, 13th at 216hrs, 14th at 192hrs and the 15th - today - at 168hrs)



Relative consistent trend in what the ECMWF Ens have been showing for the 22nd over the last 4 12z runs and which basically shows a much modified WNW polar maritime air mass (yuk) being squeezed down over Ireland between ridging to the WSW and troughing to the ESE / ENE.

Just to note that the En mean charts never once (I think) hinted at a more easterly scenario to develop over the last week or so even when the deterministic run did which is why I think these ensemble mean charts are better to look at to get a sense of overall trend than each individual op run which can throw out some head-wreakering outputs at times.

Only my opinion though..!

Eastcoastryan

Su Campu wrote: »

Well one thing I'm really happy about is that weatheronline.co.uk now have the YR.no and Spanish Hirlam models, with a host more parameters than anywhere else. These will come in really handy within a few days of any cold spells (Spanish goes to 60 hours).

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=ukuk&MODELL=aemet&MODELLTYP=1&VAR=pslv&HH=3&BASE=-&WMO=&ZOOM=0

Regarding the end of this week, I feel I'm only back and already I'm slightly disagreeing again! :rolleyes: The UKMO chart above shows lowest 500-1000 thicknesses of around 524 dam in the northeast early Friday, and with ridging moving in from the west at this stage, the cold 850 hPa temperatures will be that bit higher and showery activity will be surpressed. The GFS seems to be agreeing fairly well with the setup, and with the extra parameters available for that I would say that the Ulster and north Leinster will have the best chance of seeing anything snowy, but on higher ground. Further east in England it's a different story, and we could see the first proper snowfall down the east of the country there through Thursday and Friday.

Pinch of salt of course, with a lot likely to change, but that's the way I see it at this stage. Something to get excited about if your on a hill in the northeast, but not much else.

Welcome Back, Talk earlier was of a NW affair.. Met Eireann on their forecast talked about Connaught and Munster most at risk of wintry showers. Has this now shifted to Ulster / N Leinster?

Irish Steve

Su Campu wrote: »

Regarding the end of this week, I feel I'm only back

Great to have you back,

and already I'm slightly disagreeing again! :rolleyes:

And that's exactly what makes this place so good, there are people with knowledge and access to the information that enables good opinions who are not afraid to stick their heads above the parapet and say that they don't agree.

Long may it continue, that's how the rest of us learn more about the subject:D

Irish Steve

Eastcoastryan wrote: »

Welcome Back, Talk earlier was of a NW affair.. Met Eireann on their forecast talked about Connaught and Munster most at risk of wintry showers. Has this now shifted to Ulster / N Leinster?

UKMO seemed to be implying that it would be more of a North South split somewhere around the Midlands, covering pretty much the whole Northern half of the country, but very non commital about quantities of precipitation. I suspect that this is where the difference is between the models that the 2 organisations are using, and as to the extent and penetration of the warmer air into the North Westerly flow. Could well turn into another week of nowcasting, wouldn't be the first or last time it's happened.

nelly17

kittyn wrote: »

Good to see you back posting Su ...... Here's hoping to see some of the white fluffy stuff

+1

Musicman2000

GFS 18z has lost the plot again, BUT the gefs control run looking much better even a hint of an north easterly.

darkman2

GFS is coming round. Op run was one of only a couple of mild solutions

Elmer Blooker

Musicman2000 wrote: »

GFS 18z has lost the plot again, BUT the gefs control run looking much better even a hint of an north easterly.

How do you mean lost the plot? This chart is +144 and I dont pay much attention to charts beyond that. In my opinion the GFS has been performing a lot better than the ECM lately.

TheMilkyPirate

The ensembles are great for cold and the 18z OP is a big outlier. Very happy with the ensembles and I think I might stay up for the 00z as I think it will be a lot different than the 18z

Musicman2000

Elmer Blooker wrote: »

How do you mean lost the plot? This chart is +144 and I dont pay much attention to charts beyond that. In my opinion the GFS has been performing a lot better than the ECM lately.

If you read the above posts the run is a complete outlier, The ECM has handled the last week or so a hell of a lot better than the GFS.

patneve2

Great 18Z ensembles, good chance that the final third of the month will be a nice bit below average temperature wise...expect more changes though :cool: