Model Output Discussion - 23rd Jan - 12z onwards

[shaky]

We have to hope the op and control are right as the 06z GEFS are poor as a whole with many flattening the pattern around D8-9 due to that spoiler low. The mean at D10:

 

gens-21-1-240.png   Control gens-0-1-240.png

i guess with the control and op being similar you would rather have that than the other way round! ! And with them being run at a higher resolution they will pick up on things ensembles will not up to 190 hours!!

[stratty]

Think I'm going to remain cautious of the output at the moment. We have been here so many times this winter. Yes the ECM looks great this morning but I think it has performed poor this winter. As Steve Murr has said the temps don't look great for a big freeze. Think I will wait to see if gfs ECM ukmo are still showing intrest around tues/weds until then I will look at the output and take it with a huge pinch of salt.

...........how big is 'a huge pinch of salt.'

[Weather-history]

We have to hope the op and control are right as the 06z GEFS are poor as a whole with many flattening the pattern around D8-9 due to that spoiler low. The mean at D10:

 

gens-21-1-240.png   Control gens-0-1-240.png

It has to be said, was GFS even interested in such an outcome just a couple of days ago? I looked at the Manchester 850hpa ensembles for Thursday GFS 0z and it wasn't.

If it comes off, it seems to have snuck up on GFS this one.

[nick sussex]

Hi Nick, new in here. Surely the cold enough uppers with follow though if the predicted pattern can set in long enough which hopefully it can this time. This looks our best shot of the winter I think.

I agree re the best shot of the winter because theres scope to extend the cold and the uppers might get upgraded nearer the time. If we can get a stronger block to the nw that would increase the chances of getting some deeper cold.

 

The set up is turning into a two stage scenario, the Euro troughing over Europe then a low tracking se and behind this possible high pressure to the nw.

 

The Euro trough you can tick as certain to verify given the level of support for this, however the low tracking se with high following is still not certain. And its that bit that has more scope to deliver the deeper cold.

 

You'll see by comments from NCEP that we can be cautiously optimistic:

 

THE WPC LARGER SCALE PATTERN SHOWS AN AMPLIFIED NRN STREAM FLOW

ALOFT THAT EARLY NEXT WEEK OFFERS A WRN NOAM CENTERED RIDGE AND

COOLING/UNSETTLING ERN NOAM TROUGH WITH LESS CERTAIN DETAILS ON A

SERIES OF EMBEDDED CLIPPERS/COLD SURGES AND LEAD SURFACE

LOWS/PCPN. THE MID-UPPER LEVEL TROUGH WORKS OFF THE ERN COAST

MIDWEEK AS PACIFIC ENERGIES WORK INLAND TO FORCE THE WRN RIDGE

PROGRESSIVELY EASTWARD. A NEW AMPLIFIED RIDGE REFORMS WELL

UPSTREAM NEAR THE PAC NW/WRN CANADIAN COAST BY FRI/SAT IN RESPONSE

TO NERN PACIFIC STORMS FURTHER UPSTREAM EFFECTING ALASKA. THIS

ALLOWS STRONG DOWNSTREAM AMPLIFICATION ALOFT AS NRN STREAM

IMPULSES DIG INTO A DEEPER COOLING E-CENTRAL US TROUGH AND A

THREAT FOR WINTERY CYCLOGENSIS/PCPN.

 

[bluearmy]

I agree re the best shot of the winter because theres scope to extend the cold and the uppers might get upgraded nearer the time. If we can get a stronger block to the nw that would increase the chances of getting some deeper cold.

 

The set up is turning into a two stage scenario, the Euro troughing over Europe then a low tracking se and behind this possible high pressure to the nw.

 

The Euro trough you can tick as certain to verify given the level of support for this, however the low tracking se with high following is still not certain. And its that bit that has more scope to deliver the deeper cold.

 

You'll see by comments from NCEP that we can be cautiously optimistic:

 

THE WPC LARGER SCALE PATTERN SHOWS AN AMPLIFIED NRN STREAM FLOW

ALOFT THAT EARLY NEXT WEEK OFFERS A WRN NOAM CENTERED RIDGE AND

COOLING/UNSETTLING ERN NOAM TROUGH WITH LESS CERTAIN DETAILS ON A

SERIES OF EMBEDDED CLIPPERS/COLD SURGES AND LEAD SURFACE

LOWS/PCPN. THE MID-UPPER LEVEL TROUGH WORKS OFF THE ERN COAST

MIDWEEK AS PACIFIC ENERGIES WORK INLAND TO FORCE THE WRN RIDGE

PROGRESSIVELY EASTWARD. A NEW AMPLIFIED RIDGE REFORMS WELL

UPSTREAM NEAR THE PAC NW/WRN CANADIAN COAST BY FRI/SAT IN RESPONSE

TO NERN PACIFIC STORMS FURTHER UPSTREAM EFFECTING ALASKA. THIS

ALLOWS STRONG DOWNSTREAM AMPLIFICATION ALOFT AS NRN STREAM

IMPULSES DIG INTO A DEEPER COOLING E-CENTRAL US TROUGH AND A

THREAT FOR WINTERY CYCLOGENSIS/PCPN.

Wintery?

Damn yanks get the cold and can't even spell! Perhaps if the metoffice were less literate, we would get colder weather?

[IDO]

Wintery?

Damn yanks get the cold and can't even spell! Perhaps if the metoffice were less literate, we would get colder weather?

 

Wintery! That is still a way of spelling wintry: http://grammarist.com/spelling/wintery-wintry/ http://www.thefreedictionary.com/wintery

Edited January 24, 2015 by i'm dreaming of...

[The Enforcer]

Wintery?

Damn yanks get the cold and can't even spell! Perhaps if the metoffice were less literate, we would get colder weather?

In addition, why do they always feel the need to SHOUT?

[nick sussex]

Wintery?

Damn yanks get the cold and can't even spell! Perhaps if the metoffice were less literate, we would get colder weather?

LMAO!!! So BA what do you think re that NCEP update, deep amplified eastern USA trough surely means cold for the UK. I'm trying to refrain from overselling this but if the UK cant get cold from that upstream set up then really the weather Gods are just being vindictive!

[Eugene]

The 0z ECM ensembles for London

 

 

Not bad but the cold temperatures still 5-6 days away and even then it's unlikely to be the 'brutal cold' that we all want.  Northerlies look great on the charts but deliver rarely away from costs and high ground in the North.  Loved to be proved wrong though...

 

 

Yes as ever we need cold with a more continental influence, Arctic maritime will deliver lovely crisp weather but mainly dry, need atlantic approach after initial cold for lasting snow cover like early to mid Feb 2012.

[Frosty.]

We have endured a lot of sub standard weather this winter but we now look on course for better times for those who prefer cold because Arctic winds, for the first time this winter are on the way, yes we have been let down by promising charts before with easterlies that went Pete tong but I believe we are on course for an increasingly disturbed and cold spell from midweek onwards, first wave of cold air rushes in next Wednesday on 6z and then it gets better..and better..and better...although it's too early to say how much snow there will be and who gets it, I have a feeling that some parts of the UK will see substantial falls through the end of Jan and early Feb.

Edited January 24, 2015 by Frosty.

[Jason M]

Just looked through the GEFS expecting to see the opp as something of a warmer run compared to the GEFS as a whole and unfortunately it wasn't. I can see opinion is mixed on here this morning and I have to say I'm underwhelmed really. Looks like a bog standard winter cold spell to me.

As others have said this morning northerlies always look dramatic when modelled but a closer look suggests it won't be in practice. Everything points to a PM airflow with a long sea track albeit from a slightly colder source than normal.

So, as per normal this winter, marginal upper air temps, favouring higher ground further north. Can't rule out snow anywhere, but it's not a deep freeze.

Maybe the one difference here is that there is room for upgrades, whereas this weeks cold spell was really about squeezing the absolute best from a rubbish set up.

[bluearmy]

LMAO!!! So BA what do you think re that NCEP update, deep amplified eastern USA trough surely means cold for the UK. I'm trying to refrain from overselling this but if the UK cant get cold from that upstream set up then really the weather Gods are just being vindictive!

Nick - it's going to be cold. Cold enough for widespread snowfall away from the obvious places? who knows? Plenty of chances that the system progged around day 9/10 will have a different track to what is currently modelled. Could contribute positively or negatively re snowfall.

Thereafter, yes, the upstream amplification is positive for both lengthening the cold and reloading with a colder source this side of the Atlantic. this is clearly where it gets complex. Does the split vortex really go with the lobe back to Canada so quickly? If the split stays for longer, then the Atlantic profile is likely to stay conducive to continued cold with a potential greeny ridge. At the moment, I would say the favoured evolution is the second USA trough digs deep and then fires up the northern arm which , as the vortex split goes, flattens the Atlantic ridge somewhat and we get a similar solution to the current set up. However, if that split doesn't go (and there were enough differences over the pole on the 00z op to make one wonder what will verify up there) then we could see a proper greeny ridge driven by WAA off the eastern seaboard. I couldn't even discount a cut off feature if the split is maintained. That would be the best solution as it would translate into a southerly jet. Weirdly the NOAA analogue for day 11 from the GEFS super ens had such a solution yesterday. Couldn't see it from the output but then as I have said before, nothing we see verify has never happened before whereas some of the charts modelled have likely never done so!

As the story on the split comes within the ECM ens higher res over the next day or two, things should get a tad clearer on this.

[IDO]

^^^ Yes the current GFS and ECM D7 height bias does not feel you with confidence that the ops are going to verify:

 

  

 

You can also see how poorly the ECM D10 charts have performed (compared to their usual dominance) for the current cold period, averaging below 0.4 (last 5-6 runs) and the last 31 days below GFS:

 

 

So lots of caution on the current ECM output past D8!

Edited January 24, 2015 by i'm dreaming of...

[Frosty.]

I don't think anyone has mentioned deep freeze have they? But I can see winds sourced from the arctic on the way, and the arctic is pretty cold at this time of year...so it's realistic to expect snow is on the way :-)

[karlos1983]

I struggle to see from looking at the models the past 24-36 hours what people are worried about for this progged cold spell? Apart from the fact we have to get it to within reliable time frame of course, I'm not worried about will it or won't it snow or the depth of cold. To me this looks a much much better setup for the UK to feel the effects of this spell on a wider scale than the last one. Let's get the pattern into the reliable and then worry about the detail, I'm a lot more upbeat about chances further south this time.

[Hammer]

Some making the same mistakes as always, writing off events way to early and trying to put detail to things is really frustrating.

From the model output cold trend looking quite possible, snow risk increasing mid week onwards, further details to come.

[Airedalejoe]

Sorry but whilst its fairly quiet could I just ask what the difference is between the last cold spell that promised so much but got watered down to well one day compared to next weeks upcoming cold spell ? I read Steve murrs post last night saying that the uppers weren't very good at all with the spell or snap showing at the end of next week so I'm a little confused thankyou

I suppose it also depends where you are. It's been cold here for some time now with snow falling several days plenty frost and ice, temp currently 4.3 so even today struggling just to get to average! Everything seems to have been 'average' for about a year now with no real extremes, record warm average monthly or yearly temps which are occurring in other places seem to have missed this location, unless I'm having selective memory and I certainly don't have the figures to back it up!

If the charts do verify as they're currently shown for the end of the week I expect to see more snow falling in my location, no extreme cold but nice and 'wintry'!

Apologies but I don't have the knowledge to forecast other areas!

Edited January 24, 2015 by Airedalejoe

[Ali1977]

Even with some great cold charts from all models people always look for negatives, too many let downs maybe. GEFS still has some great charts, let's hope for a better set with the 12zs though. If UKMO is similar as 00z that would be a good start.

[sunnijim]

A lot of people writing off any Northerly,'not cold enough' 'never delivers to this area or that'

Cast your minds back to April 6th 2008. A Low got caught up in a Northerly flow and delivered a Sunday afternoon snowfall on the South coast with 3pm maximums of -1c. Given the date only a Northerly would have delivered that.

[cyclonic happiness]

Looks like the GFS is coming up with its latest 'Tuts take charts'. I've already braced myself for the downgrades and ordered a fresh supply of Xanax :-D

 

If we get another let down from that model, I think quite a few people on here will have started to wonder whether the GFS' recent upgrade was for the better?

[bluearmy]

^^^ Yes the current GFS and ECM D7 height bias does not feel you with confidence that the ops are going to verify:

 

NOAA_NWS_NCEP_WPC_MODEL_DIAGNOSTIC_-_INTERACTIVE_MODEL_BIAS_PAGE 2.png NOAA_NWS_NCEP_WPC_MODEL_DIAGNOSTIC_-_INTERACTIVE_MODEL_BIAS_PAGE.png 

 

You can also see how poorly the ECM D10 charts have performed (compared to their usual dominance) for the current cold period, averaging below 0.4 (last 5-6 runs) and the last 31 days below GFS:

 

cor_day10_HGT_P500_G2NHX.png

 

So lots of caution on the current ECM output past D8!

IDO, do you have the stats for the ECM Ens and gefs, gem ens fir the 6/10 day period?

[Jason M]

Even with some great cold charts from all models people always look for negatives, too many let downs maybe. GEFS still has some great charts, let's hope for a better set with the 12zs though. If UKMO is similar as 00z that would be a good start.

I Disagree, nobody is looking for negatives, just posting on what is actually shown, rather than what we hope is actually going to happen.

The very fact that this debate is occurring within the thread illustrates the issue nicely IMHO.

As I commented on earlier, the plus point here is that there is room for upgrades, whereas this week that wasn't the case.

Edited January 24, 2015 by Jason M

[bluearmy]

Looks like the GFS is coming up with its latest 'Tuts take charts'. I've already braced myself for the downgrades and ordered a fresh supply of Xanax :-D

 

If we get another let down from that model, I think quite a few people on here will have started to wonder whether the GFS' recent upgrade was for the better?

For those misty eyed for the old gfs, perhaps view the NCMRWF model on meteociel as that was often quite similar to the old output and it is based on the model.

[IDO]

IDO, do you have the stats for the ECM Ens and gefs, gem ens fir the 6/10 day period?

 

The ECM mean verification is not always included but the link for the others is: http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/ensm/

[TEITS]

Even with some great cold charts from all models people always look for negatives, too many let downs maybe. GEFS still has some great charts, let's hope for a better set with the 12zs though. If UKMO is similar as 00z that would be a good start.

Do you remember prior to our last cold spell I was suggesting members need to be cautious to avoid disappointment. Sadly many didn't take this advice and continued to have OTT expectations and then moaned because it rained instead of snow.Today I have seen posts referring to drifting snow and whilst that might be correct for some locations these are the exceptions.

 

Lets be realistic the current output would bring snow via showers and maybe even frontal snowfall. However the risk is greater for Scotland and higher elevations of N England. This does not mean no snow for low lying areas in the S but any snowfall here is likely to be marginal.

 

The ensembles say it all to me with even Aberdeenshire struggling to drop below -5C.

http://max.nwstatic.co.uk/ensimages/ens.20150124/06/t850Aberdeenshire.png

 

So at the moment my excitement levels are pretty low but could increase if we see the models upgrade the depth of cold.