Model Output Discussion - 1st February Onwards 12z--->

[damianslaw]

Reliable timeframe all models show a cold outlook with high pressure to our SW and a cold northerly then northeasterly drift. Core heights in the high pressure are set to get preety high up to 1045mb which is a significant block against any imminent atlantic attack. Importantly ECM and GFS to a lesser extent are showing central heights ridging northwards as opposed to sinking - all due to projections off the NE USA seaboard i.e. a more amplified flow.

 

All eyes then on the position of the Polar Vortex, some models are predicting a shift towards Scandanavia by the middle of the month and if this occurs with a continued amplified flow, the current high will have no trouble nosediving upwards towards Greenland and we will be back in similar territory to now, i.e. significant trough action dropping through scandi into Europe, but crucially stronger heights to our NW this time enabling true cold arctic air to invade the country rather than the modified flow we are enduring now - which isn't sourced that far north hence the lack of sub -8 uppers..

 

All very interesting, a rinse and repeat episode of recent days next week perhaps followed by a possible more stronger arctic attack thereafter..

 

Certainly no real signs from the models of a sinking high and return to raging westerlies or southwesterlies.. Very seasonal outlook for those who like cold dry sunny conditions, superb weather for winter mountaineering and skiing - those who like to do winter sports with holidays planned over the half time must be very happy with the charts today.. lets not get carried away, and see if the trends of today are cemented over the week.

 

For the Lake District we are looking at a rare period of dry weather with abundant sunshine, there have been many summers when we have only managed a run lasting 4/5 days of such weather, today will be the 4th dry cold sunny day here..

[Mucka]

Well GFS 18z consistent with previous runs, large differences with the Euros upstream even in 72/96h

 

[Hotspur62]

BBCs Long  Range outlook is cold this week with some wintry showers Tues-Thus, then dry for a few days with a brief Northerly with the likelihood of the High in Atlantic due to drift Southwards again towards UK giving a slightly less NW flow. However, Matt Taylor did the usual caveat saying that this "was the most likely scenario" but not definite. I wonder what data they use for this as the most recent runs have tended to push the high further North and West than what he indicated.  

[damianslaw]

BBCs Long  Range outlook is cold this week with some wintry showers Tues-Thus, then dry for a few days with a brief Northerly with the likelihood of the High in Atlantic due to drift Southwards again towards UK giving a slightly less NW flow. However, Matt Taylor did the usual caveat saying that this "was the most likely scenario" but not definite. I wonder what data they use for this as the most recent runs have tended to push the high further North and West than what he indicated.  

 

It ties in with what some of the models are showing - i.e. a tempering of the cold flow middle of next week, with core heights further to the SW before a potential renewed attack from the NW with the high ridging NW again..

[Cloud 10]

GFS  v  ECM at 144 hrs.

 

GFS..  ECM..

 

 

A nice little test to see which one is the winner.

[Ice Day]

GFS  v  ECM at 144 hrs.

 

GFS..gfs-0-144.png  ECM..ECM1-144.gif

 

 

A nice little test to see which one is the winner.

 

Yep, and the UKMO siding with the ECM as well. 

 

 

I wouldn't bet against the GFS though, I think it's been doing pretty well after the upgrade.  We should find out soon enough!

[blizzard81]

I think we will see some sizeable upgrades tomorrow. No technical reasons apart from the fact that the models generally struggle with blocked patterns.

[Cloud 10]

120 hrs fax chart certainly in favour of the UKMO/ECM solution.

 

[Eugene]

GFS 18Z has a quiet spell of anticyclonic weather next week with frosty nights and possible rural valley ice days under fog.

[Jason M]

Looking through the output today I suspect GFS has this nailed. Despite the upgrade its last few opps have been massively supported by the GEFS. In the 06z suite 19 out of 20 ensembles supported the opp.

Beyond days 9 and 10 anything can happen, but the cold is Greece bound before thst I suspect. This is a very common Feb pattern tbh. Classic stuff really, with a football shaped displaced Azures high sitting just to our west with pulses of very cold air being directed into Europe.

[Stationary Front]

A blend of the two is usually the out come. The High being on its East side just off the East Coast

[Jason M]

GEFS are absolutely rock solid behind the opp out to 168.

Very consistent today from the GFS. Doesn't neccersarily mean it's right of course. I want ecm to be right, but in this case GFS surely has to be the front runner as it hasn't waivered from its determination to have a UK high.

[Mair Snaw]

Well I think tomorrow will be the day when we find out if ECM & UKMO are correct or if the GFS has been top dog.... normally you would go with the GFS backtrack toward the other two models..... but its got to happen one day that the GFS will be correct and the others are wrong...

[Mucka]

GFS 00z rock solid with the UK high, perhaps a tad further West.

 

 

UKMO making a move that way as well. 

 

 

Starting look like GFS nailed this and the Euros, ECM especially, have been way off.

Will ECM make a big correction back East this morning? Seems likely.

[KTtom]

Yes next week will have to go down as a near miss as the ECM steps back in line

 

 

The high does flatten around the day 10 mark on GFS and its at this time there are hints at it being dragged north west.

[Captain Shortwave]

Day 6 charts

ECM

UKMO

GFS

GEM

 

All have high pressure over or just west of the UK. The GEM and ECM are the furthest west solutions. All show very cold air pushing into central and eastern Europe, but not really affecting the UK.

[polar vortex]

Well the worst case scenario that I spoke of yesterday seems to the more likely solution. The threat of snowfall 

Wednesday into Thursday looks now to have diminished as the Euro's have fallen in line with the GFS and 

they have also moved to the GFS way of thinking with a more eastward thrust of very cold air into Europe rather 

than over the UK. lose, lose from what I can see this morning.

[Weather-history]

Well the worst case scenario that I spoke of yesterday seems to the more likely solution. The threat of snowfall 

Wednesday into Thursday looks now to have diminished as the Euro's have fallen in line with the GFS and 

they have also moved to the GFS way of thinking with a more eastward thrust of very cold air into Europe rather 

than over the UK. lose, lose from what I can see this morning.

I think the worst case scenario is between what GFS shows and what ECM was showing yesterday evening . It depends on how clean the high is and if it is clean then it is better the high sat over the UK. If it is a bit to the west then you have fronts going around the high and what you end up with are largely cloudy days, little rain, not too cold and limited frosts. Tedium.

I hope the high is clean because anticyclonic gloom is probably the most boring spell of weather you can get.

[nick sussex]

Looks like a wrong call this morning from the ECM, even though it still has a similar type coastal low its less amplified and really to get the northerly the most amplified solution was needed.

 

If theres to be no northerly then its best if the high centres east of the UK rather than west as that would bring in clearer and colder air from the se.

 

Theres still a lot of uncertainty from a close timeframe but unless the ECM suddenly finds more amplification which the others pick up on then it looks like the cold air is heading south into eastern Europe.

 

NCEP don't think much of the ECM's winter performance:

 

THE EUROPEAN CENTRE MODEL SUITE FROM THE 12Z/02 DATA CYCLE WAS A
STARK OUTLIER TO BOTH THE GEFS AND MSC ACROSS CENTRAL NORTH
AMERICA AT THE MEDIUM RANGE--INDICATING A DEEP LOW OVER THE GULF
OF MAINE DAY 3 AND A DEEP LOW OFF THE SOUTHEASTERN COAST OF THE
UNITED STATES DAY 7. NORMALLY, THE ECMWF AND ECENS ARE SKILLFUL
ENOUGH TO OFTEN PREVAIL EVEN WHEN ON THE EDGE OF THE OTHER GLOBAL
NUMERICAL GUIDANCE. FOR SOME REASON, THE EC CAMP HAS NOT VERIFIED
WELL THIS WINTER WITH MOST OF ITS BIGGER FORECAST STORMS--STORMS
THAT ARE DEPICTED MUCH DEEPER AND SOUTHWEST (I.E.- SOONER TO CLOSE
OFF AT MID-LEVELS) THAN THE UNITED STATES AND CANADIAN GUIDANCE.
FOR THESE REASONS, ELECTED TO IGNORE THE MOST RECENT EUROPEAN
CENTRE GUIDANCE AND RELY ON THE MORE ROBUST BLEND AFFORDED BY THE
NAEFS MEAN.

 

The criticism doesn't stop there, the diagnostic discussion:

 

THE 00Z ECMWF ACCELERATED A BIT TOWARD THE
MIDDLE BUT IT IS STILL THE SLOWEST/DEEPEST SOLUTION OUT THERE.
WILL CONTINUE TO REJECT THIS EXTREME SOLUTION. THIS IDEA WAS
COORDINATED WITH WPC MEDIUM RANGE WHICH AGREED IN REMOVING THIS
SOLUTION.
 

[joggs]

Yes i fear with whats on offer this morning the high been a mucky one.The ecm has had a poor performance at times,thats not to say the others have not.But i personally am disappointed in the ecm this winter.Frustrating winter so far and looks like dragging on that way.As a sidenote the met office have been pretty faultless imo.

[EML Network]

well, somebody wake me up in a week, I think by the time we get to Sunday we're all going to be looking into FI for another opportunity for snow to find it's way to the UK. 

 

I still can't understand how this...

 

 

isn't being programmed in to produce snow in the SE, you have the right orientation so that the feed is from the North East, the flow is spending enough time to pick up moisture of the North Sea, the squeeze in the isobars should blow showers inland and the uppers are about right to aid convection. 

 

And yet there's no mention of it on any forecast , yet the GFS has consistently modeled snow for this day...(overnight Thursday and into Friday)

 

indeed going through the ensembles IMO every single GFS run shows PPN coming into the SE during this time frame ?

 

so what gives ? is it too far out to me given a mention ?

 

anyway, to those that have had snowfall tonight well done, seems to have effected a similar area to those that saw snow on Friday night, 

 

As I speak what looks like a thames streamer of sorts is picking up, might just be nothing, but hey h the day is young, the dew points are below freezing across the south east and everywhere else, although as the day wears on it's typical that the Dew points for some (just where I happen to be actually)...go the wrong side of marginal...

 

 

which is hard to believe looking at the actual pattern

 

 

we'll see how the day goes, but from next week onward, I think it's going to be one of those weeks where we need to find something else to do with our time, other than spend it looking at weather charts, cos their probably aint gonna be much a happening 

Edited February 3, 2015 by EML Network

[IDO]

The consistency of the GEFS for many runs for HP to dominate from the upcoming pattern change has eventually been picked up by the ECM and UKMO. The GEFS in FI have further waves of high pressure reinforce the pattern till D16. The op and control:

 

  Mean 

 

So looking at the moment at a very quiet settled spell up till the last week of Feb. The mean supports this strongly and it appears plausible as we finally lose the mid and high latitude upper wedges of higher pressure on the other side of the NH, thus allowing some breathing space for the PV to stretch it's legs and not root itself over NE Canada/Greenland.

 

ECM and GEM at D10 offer variations on that theme:  

 

I am not sure the MJO is driving the pattern at the moment but it puts us into phase 7 (>1 amplitude) till the 16th Feb:

 

 Correlates to: 

 

That has a positive height anomaly dominating our locale. However this is the current trend and it may change, though up till around D10 confidence in HP dominating looks clear. More runs needed to see if the GEFS FI of another week of HP. Temp wise it remains below to average for the next 10 days for London:

 

As for ECM's performance, that is well highlighted and the current D7 height bias shows the continuing problem taking ECM D6 plus charts seriously as they over amplify the whole NH:

 

 

I think the GFS is over doing the UK high for next week, but over all better performance than the ECM.

Edited February 3, 2015 by IDO

[Penrith Snow]

If you love anti cyclonic gloom then this is your morning, with the high situated over Ireland it will not be clean that is obvious with increasing amounts of cloud and as moist milder air crosses very cold ground low level mist will form as well.

It's a classic anti cyclonic gloom set up and one that could last a fortnight.

Shame because if nothing else the weather this winter has been interesting with lots going on but February could go down as a borefest.

Andy

[Evening thunder]

After the confusion and some odd claims it caused it looks like the GFS is heading closer to the BBC's (and possibly ECM and others) way of a max near 6c for London on Thursday (1c out would be viewed as a successful forecast).

 

[The Weather Dragon]

To be realistic - current output suggests a lengthy anticyclonic spell - the like of which we have not seen for some time. As always with the UK the positioning of the system will dictate surface conditions with anything from dull and dreary with little diurnal range in temperature to sparkling sunshine with early & late frost and fog. A classic old style february scenario - however not the most exciting for us model watchers - looking back historically these anticyclones can drift and reposition themselves at relativley short notice - sometimes favourably for more significant cold.

Edited February 3, 2015 by Jonathan Evans