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

[damianslaw]

Reliable timeframe - a rather benign period overall, another dry cloudy day tomorrow, before we see the first atlantic frontal attack of the month (very late it has to be said), Sat an inbetween day before further rain on Sunday.

 

Thereafter all models show a renewed build of pressure heading our way from the SW, this high looks like a cloudy affair with moist conditions bringing grey clag but mild overall, eastern parts should hopefully see some sunny breaks where it could get notably mild for a time middle next week.

 

Longer term - GFS and ECM both showing the high backing westwards with a trough dropping down from the north to the NE - signs of an amplified flow with colder outbreak for the latter part of the month.

[Frosty.]

I'm still seeing signs of future deeper cold beyond T+240 hours, I saw it on the Ecm 00z / 12z operational and now on the Ecm 12z ensemble mean, it looks like our high starts to pull further back into the Atlantic and a deepening low swinging down from the NW would introduce a cold outbreak later this month. There are also signs of this occurring among the GEFS 12z perturbations.

[Daniel*]

On the north flank of the sinking low you'd see the possibility of a spell of snow however the uppers are dismal and there's no cold at all embedded. Meaning rain for all, fine margins involved.

[polar vortex]

The strong convection near the date line is obviously being modelled to interact with the polar westerlies (PFJ)

in the mid to long range to produce significant ridging up over Alaska and into the Arctic which will amplify 

(hopefully ) the ridge in the Atlantic.

I remember American meteorologist L. Cosgrove who often spoke of this when he forecast a plus PNA and 

meridonal pattern setting up over the states and the UK.

The GFS 18z run is again locking onto this synoptic outcome.

[TEITS]

With the emphasis on the word 'later'. That's T360. I mean, I know we're all desperately rooting around for something before official end of winter 17 days from now but T300+ is pushing our luck somewhat?!

 

Still time for another cold snap before we're through. We've had two here: one between Christmas and New Year and the other the one beginning of Feb. Both produced a sprinkle of snow and some frosts. Better than last year, for sure. A third would complete the sequence.

We may see another cold spell sooner than +360 mate.

 

http://www.wetterzentrale.de/pics/Rtavn2521.gif

 

Im liking this trend and noted the potential from the N a few days ago.

 

 

Do members remember when I was drooling at the N Hemisphere charts for the USA referring to the cross polar flow? Well this time the GFS says its our turn and you don't have to tip your laptops to the side to see this!

 

http://modeles.meteociel.fr/modeles/gfs/runs/2015021118/gfsnh-0-288.png?18

Edited February 11, 2015 by TEITS

[Argyle1980]

Do you want to split that PV now GFS

Edited February 11, 2015 by Argyle1980

[Cloud 10]

Proper hatchet job on the Polar Vortex from the 18z,very entertaining.

 

[TEITS]

Im sure some will post and say "no chance of this happening". However the fact remains that so far this winter charts like the 18Z have been very rare even in F.I, so its nice to even discuss such charts. Also the GFS is king at spotting this particular trend in F.I.

 

 

Shame the run stops at +384 because beyond we get even better.

 

http://www.wetterzentrale.de/pics/Rtavn3841.gif

[davehsug]

Judging by what's happened this week, they were wrong at t72, so I don't fancy the chances somehow

[fergieweather]

Some here have quite rightly expressed caution re MJO signal. Indeed, in briefings over last few days, it's been an issue repeatedly stressed by UKMO thus:

"The MJO, apparently in a weak phase 8 in some products (e.g. latest EC) is probably contaminated by other areas of tropical convection in the West Pacific and Indian Ocean, rendering it less useful in terms of prediction. Indeed, predictions indicate it becoming ill-defined, reinforcing this aspect."

[East_England_Stormchaser91]

Actually wouldn't bank on not seeing a real blizzard before April at least is here anyway. Its often the case and has been over history where some of our winters redeem themselves at the tail end. Can remember hearing my grandparents saying quite a few times they've experienced some tremendous blizzards in March and in April ! 

As the saying goes, when the days get longer, the cold grows stronger. And as the current far trend is heading, we could be in for a little treat before spring kicks in.

[Eugene]

You gotta laugh at GFS 18Z T+384 hrs, building a deep cold pool to our northeast and putting northern europe into the freezer just a few days before Spring starts. 

 

Spring = The New Winter.

[bluearmy]

Note the ECM 00z latter frames looking remarkably like its ens spread from the 12z = reasonable confidence. Coldies need to hope that the entire pattern can retrogress 500 miles at least.

Again, I don't buy any sustained block nw Europe

[knocker]

I see it's dragging that nasty low a bit further south. If that panned out it would bring some nasty weather to the north.

[IDO]

The three main models at D10 offer variations on what the GEFS were showing yesterday re the placement of the HP:

 

GEM:  ECM: GFS:

 

Anyone of these are possible or none. The GEFS offer little clarity; as per yesterday lots of spread at D9-10:

 

 

Its the same as this upcoming unsettled spell, phasing of the HP systems allow the lower heights a chance to dig south. Just a matter as to how this develops? Not much point looking beyond this but the GEFS do continue to show as expected more interesting synoptics.

 

In the more reliable nothing but ordinary, average Feb weather at best. The London ensembles: 

 

Looks mainly dry as well till D10. The main rain will be tomorrow as a low enters Ireland and tracks SSE giving heavy rain to some but may break down in the east. Accumulations according to the hi-res model:

 

 

 

Very little rain at the weekend and more in line with the GFS forecasts earlier this week rather than ECM or UKMO.

Edited February 12, 2015 by IDO

[Gibby]

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS.

THE CURRENT GENERAL SITUATION A light Southerly flow over the UK will strengthen later as troughs of Low pressure move into Western Britain tomorrow moving East.

http://www.wetterzentrale.de/pics/Rtavn001.gif

MODELS-2 WEEK HEADLINE Changeable at first and then becoming largely dry and quiet if rather cloudy. Temperatures generally near average.

THE GFS JET STREAM ENSEMBLE FORECAST The Jet Stream Ensemble Forecast shows the flow ebbing and flowing in peaks and troughs around the UK as the unsettled period develops over the coming days. The flow then reverts back North of the UK and strengthens markedly later as it orientates more SE over Europe around a UK High pressure area before subsiding later to a more relaxed flow North of the British Isles.

http://www.netweather.tv/index.cgi?action=jetstream

GFS OPERATIONAL The GFS operational today shows the current influence of High pressure to the East will be lost over the coming days as troughs of Low pressure cross the UK from the West with some rain and showers for all. Pressure then builds strongly next week with fine quiet weather returning with some frost and fog patches by night. Therefater High pressure of one sort or another continues to dominate the weather intensifying later in response to a cold plunge of NW winds over Europe. This will turn the air cold across the UK too with more widespread frost and fog by night but compensatory dry and bright days. the run ends with the High declining slowly to the SE but only the far NW falling under the influence of milder SW winds.

http://www.wetterzentrale.de/pics/Rtavn1441.gif

http://www.wetterzentrale.de/pics/Rtavn3841.gif
 
THE GFS CONTROL The GFS control run is very similar in its course of events with High pressure well in control of the UK weather following the up and coming unsettled period that clears early next week..

THE GFS CLUSTERS The GFS Clusters today show a variation of possibilities in two weeks time all revolving around the positioning of High pressure and its proximity to the South of the British Isles. The majority of members show it far enough away to the SW to feed something of an Atlantic feed across the British Isles albeit from the West or NW with the risk of rain and showers at times though 20% show it far enough in to cover Southern England and another 20% showing a UK High keeping things settled and dry. This suggests the jury is still out on whether dry and quiet weather still dominates in 14 days time or not.

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=euro&MODELL=gefs&MODELLTYP=2&BASE=-&VAR=cpre&HH=372&ZOOM=0&ARCHIV=0&RES=0&WMO=&PERIOD=

UKMO UKMO this morning shows the cool NW flow in the wake of the unsettled interlude giving way to a broad warm sector in strong SW winds setting up across the UK towards the middle of next week with rather cloudy, damp and mild conditions likely then.

http://www.wetterzentrale.de/pics/Rukm1441.gif

THE FAX CHARTS The Fax Charts this morning show a complex structure of troughs crossing East over the UK over the coming 2-5 days with rain at times in variable, sometimes strong winds and temperatures close to average.

http://www.weathercharts.org/ukmomslp.htm#t120.

GEM GEM shows a return to High pressure based conditions from early next week, lasting through to the end of the run with the weather revolving around a centre building to the SW of the UK. A maritime NW flow is likely across the North and the High is likely to infill with a lot of cloud again  from the North in the second half of the run despite many areas staying dry.

http://www.wetterzentrale.de/pics/Rgem2401.gif

NAVGEM NAVGEM takes the UKMO route on setting up a mild SW'ly next week as High pressure lies to the SE. After a very mild but windy period especially over the North some cooler but likely very cloudy weather will develop across the South later as winds back more towards the South or SE though staying light.

http://www.wetterzentrale.de/pics/Rnvg1681.gif.

ECM ECM also looks like UKMO up tp 144hrs before a further cold front crosses SE to give rise to a cooler interlude again behind a spell of light rain. High pressure then reasserts itself to the SW but this time an incursion of stronger NW winds in association with Low pressure near Scandinavia brings the threat of colder NW'lies into the UK from Day 10.

http://www.wetterzentrale.de/pics/Recm2401.gif

ECM 10 DAY MEAN The 10 Day Mean this morning maintains a displaced Azores High over the Atlantic and Low pressure over Scandinavia. Several options make up this result but a generally benign period of weather is favoured with rain or showers most likely restricted to the North with the driest conditions towards the South and SW in West or NW winds.

http://www.wetterzentrale.de/pics/Reem2401.gif

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The long term trend continues to show High pressure to the SW still dictating the UK weather over the period although positioning of this differs between the output.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKM & ECM The current verification statistics for the past 31 days shows ECM leading the way at 3 days with 97.4 pts followed by UKM at 97.0 pts and GFS at 96.4. At 5 days ECM just about leads the field at 89.9 pts over UKMO at 89.2 pts and GFS at 87.0. At 8 days ECM remains the leader with 63.0 pts over GFS's 62.0 pts. Then at Day 10 ECM retains superiority at 46.9 pts over GFS at 44.2.

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day3_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day5_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day8_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day10_PMSL_MSL_G2NHX.prig
 

MY THOUGHTS There seems little immediate change in the domination of High pressure near the UK over the coming two weeks especially once we remove the short unsettled weather phase imminently upon us. From this most areas will see several days when rain will be a risk before High pressure builds back over the Uk from the SW early next week. Thereafter it's all about the positioning of High pressure in relation to the type of weather it gives at the surface with combinations of centres to the SE and SW and over the UK all shown in some of the output this morning. From this we can ascertain that there will be a lot of dry weather to be found for many areas through the remainder of the period but the question will be how cloudy will it be and how cold or mild will it be too. Most output keeps High pressure bottled near to Southern Britain which keeps an Atlantic influence of maritime winds across the North at least and this could give a very mild interlude in the middle of next week but thereafter there could be several opportunities for something rather chillier and clearer to move down from the NW later as the High nudges back out into the Atlantic and this scenario has at least some support from the ensembles. What isn't shown this morning is any sign of Northern blocking High pressure with the Jet flow always riding on the Northern flank of High pressure near, over  or to the South of the UK too strongly to allow any build substantially North of High pressure to a position which would enhance a  risk of continental or polar cold weather. Instead we maintain fairly benign conditions with just chasing cloud amounts and small temperature variations day to day being the likely extent of interest in weather terms in what is turning out to be a very dry February if this morning's and recent output verifies.  

Issued at 08:30 Thursday February 12th 2015

[carinthian]

The latest Deutschen model has the advance of this weeklends Atlantic fronts making slower progress than some other models. I think the UKMO FAX Charts will show this to be the case. Agreed that pressure will rise again after clearance but the delay could allow a general fall of pressure over mainland Western Europe, hence the high pressure could hold its position further North and West. Something to watch in todays later runs which may allow a change of forecast ( ie ) to look to the south rather than the north . Just a thought in discussion this morning.

C

Edited February 12, 2015 by carinthian

[IDO]

Looking at week 2 on the updated JMA and the next anomalous heights from the Azores looks like it may displace further west, sending a trough into Europe. The JMA suggests that the core cold will be too far east for a significant cold spell, with the UK again on the border between the two air masses:

 

 

Week 3-4 anomaly continues with the Pacific/Alaskan Ridge positive heights, with a trough into Europe and the UK caught between systems sliding down from Greenland and the TM ridges from the Azores. So cooler than average as a whole but borderline for snow for sea level for most:

 

 

The GFS 06z hinting at the JMA and one of its ensemble clusters: 

 

Early days but that could develop into a cold shot with some adjustments west, assuming this remains the trend, though again the pattern is really hit and miss again for the UK as the admittedly rather fickle snow charts suggest:

 

 Sinking Ridge:

 

On this run the Pacific Ridge blows up (unlikely, bias probably showing) and pushes the low pressure over Canada onto the Atlantic ridge and sinks it with the UK ending up in a flatter pattern. Will all change again the next run as this is a very fluid situation after around D9.

 

 

[nick sussex]

Some signs this morning that the Azores high will displace further west towards days 9 and 10.

 

The GFS 06hrs run retrogresses the pattern and brings the troughing further west at T240hrs. The issue remains however how much upstream amplification will show up and the nuisance PV chunk over ne Canada.

 

The lower resolution is quick though to transfer the Russian PV back west and does seem far too progressive in doing so.

 

Still too early to say whether the cold will just remain to the east or whether it can effect the UK, at least theres some cold to tap into if the upstream pattern plays ball but that's a big if!

[shaky]

The latest Deutschen model has the advance of this weeklends Atlantic fronts making slower progress than some other models. I think the UKMO FAX Charts will show this to be the case. Agreed that pressure will rise again after clearance but the delay could allow a general fall of pressure over mainland Western Europe, hence the high pressure could hold its position further North and West. Something to watch in todays later runs which may allow a change of forecast ( ie ) to look to the south rather than the north . Just a thought in discussion this morning.C

do you think there will be snow from that trough disruption over the uk? Dunno if there is enough cold air over the uk though! ! I am talking about events between 96 to 120 hours! !

[Severe Siberian icy blast]

Some signs this morning that the Azores high will displace further west towards days 9 and 10.

 

The GFS 06hrs run retrogresses the pattern and brings the troughing further west at T240hrs. The issue remains however how much upstream amplification will show up and the nuisance PV chunk over ne Canada.

 

The lower resolution is quick though to transfer the Russian PV back west and does seem far too progressive in doing so.

 

Still too early to say whether the cold will just remain to the east or whether it can effect the UK, at least theres some cold to tap into if the upstream pattern plays ball but that's a big if!

To be honest we'v been waiting for the upstream pattern to play ball for the last 2 years . 2 years without any high lat blocking , so I find it difficult to believe it's gonna happen in the next 3 wks . I think if there were any realistic chance of the uk going into the freezer or even just cold then Ian f would of given us a heads up.

The trough will dig into europe and we will get a quick glimpsing 2 day cold spell where the uppers don't hang around long enough to drop the temp much so with uppers of -5/6/7 will give us temps ranging from 3-7c as we head south .

Wish it was different this year given the early promise but it's been another snowless year for many below 150m away from Scotland and northern England .

[nick sussex]

To be honest we'v been waiting for the upstream pattern to play ball for the last 2 years . 2 years without any high lat blocking , so I find it difficult to believe it's gonna happen in the next 3 wks . I think if there were any realistic chance of the uk going into the freezer or even just cold then Ian f would of given us a heads up.

The trough will dig into europe and we will get a quick glimpsing 2 day cold spell where the uppers don't hang around long enough to drop the temp much so with uppers of -5/6/7 will give us temps ranging from 3-7c as we head south .

Wish it was different this year given the early promise but it's been another snowless year for many below 150m away from Scotland and northern England .

Agreed I don't see any HLB happening, by playing ball I mean enough amplification to pull the cold south.Then a more favourable toppling of any ridge to bring in a ne flow before the inevitable sinking of the high. At the moment I think that's the absolute best that might happen.

 

I think this is last chance saloon time for at least a spell that could deliver snow and cold temps sufficient to actually last on the ground for a few days.

 

I know people will bring up March 2013 but that had some amazingly cold uppers for the time of year, personally I'm not a great lover of spring cold as its often a case of what might have been as any snow away from higher ground is gone before you've finished your morning coffee!

[karlos1983]

To be honest we'v been waiting for the upstream pattern to play ball for the last 2 years . 2 years without any high lat blocking , so I find it difficult to believe it's gonna happen in the next 3 wks . I think if there were any realistic chance of the uk going into the freezer or even just cold then Ian f would of given us a heads up.

The trough will dig into europe and we will get a quick glimpsing 2 day cold spell where the uppers don't hang around long enough to drop the temp much so with uppers of -5/6/7 will give us temps ranging from 3-7c as we head south .

Wish it was different this year given the early promise but it's been another snowless year for many below 150m away from Scotland and northern England .

 

Blocking to the North has been lacking for some time now, this is true. But it has still been a much better Winter in terms of snow for more than just Northern England and Scotland. You don't get any further south than my location without getting your feet wet and only last Tuesday we had pushing on for 2 inches of snow. Granted it didn't hang around for long, but this winter has been a sharp contrast to last year.

 

It's a shame because the Azores High has really hindered our chances of sustained cold IMO this winter, however on the flip side it has been the reason for our cold spells(terms used loosely) when it has ridged into a favourable position in the Atlantic. At least we have managed to avoid the onslaught from the Atlantic that we saw last year, although I must say I would prefer deep areas of low pressure bring at least some excitement rather than a benign HP sitting over the top of us, as it has the past days.

 

Still time yet, March can bring snow and has done previously.

[Frosty.]

Never known it so dead in here at this time of year..Anyway, Gfs 12z shows a risk of snow showers in the far northwest on Monday, and a brief wintry interlude in the far northeast at the end of next week with another shot of arctic maritime brushing the eastern side of the UK later in FI. Most of the run is dominated by high pressure shifting into different positions either over or close to the UK, most of any unsettled weather is confined to the far north of the UK beyond next Monday. In the short term, a spell of rain tomorrow then a largely dry weekend before we all have another wet spell either Sunday night or Monday morning.

[knocker]

Interesting anomaly for next Weds.The PV all the way down to the southern states with another trough Greenland south with HP UK and eastern Europe. Slightly meridional methinks.

Chart courtesy weathbell

Edited February 12, 2015 by knocker