Model Output Discussion 17th Dec.2013-12z onwards.

[fergieweather]

60mph sustained winds into Liverpool Bay @ midday tomorrow! EURO4 model@fergieweather any word on this? 

Much uncertainty & model spread on how things unfold in that region under left exit. Higher confidence, however, on risk of damaging gusts to SW & inland into W Country as high-res products retain a strong signal for LEWP/segmented line convection on cold front, with conditions very ripe for squally winds to 50-60kts tomorrow AM ahead of it's passage.

[Jason M]

Latest GEFS look interesting. They are starting to agree around day 10 on a northerly. Won't be particularly cold but if it gets some colder uppers into NW Europe it could useful down the line if we can pull in some air from the east.

[on the coast]

Much uncertainty & model spread on how things unfold in that region under left exit. Higher confidence, however, on risk of damaging gusts to SW & inland into W Country as high-res products retain a strong signal for LEWP/segmented line convection on cold front, with conditions very ripe for squally winds to 50-60kts tomorrow AM ahead of it's passage.

Looking very windy here tomorrow too. Thought there may be a wind warning?

[mackerel sky]

Maybes i'm misinterpreting things, but when I looked at the sea surface temperatures in the North Atlantic they looked rather average. If the lows were tracking west to east along 50 degrees north along a flat jet then we wouldn't get so much watering down... but kill me, I was taught as an undergraduate about Rossby waves, i.e. its a usually a crock of what not by the time it reaches our shores, irrespective of the sea temperature. 

Edited December 30, 2013 by mackerel sky

[Panayiotis]

Looks like the best ensemble suite in a long time for colder solutions starting around the 11th (for my area)...

Edited December 30, 2013 by Panayiotis

[That ECM]

http://images.meteociel.fr/im/1931/gfsnh-0-228_iet1.png

Last nights GFS

http://images.meteociel.fr/im/1449/gfsnh-0-216_uvg3.png

This mornings GFS.

The ridge building over the pacific and extending up.

http://images.meteociel.fr/im/4049/UN144-21_kgn0.GIF

UKMO at t144 ridge is being shown here as well.

I would like to see the ECM follow with this general theme.

[TSNWK]

http://images.meteociel.fr/im/1931/gfsnh-0-228_iet1.pngLast nights GFS http://images.meteociel.fr/im/1449/gfsnh-0-216_uvg3.pngThis mornings GFS.The ridge building over the pacific and extending up.http://images.meteociel.fr/im/4049/UN144-21_kgn0.GIFUKMO at t144 ridge is being shown here as well.I would like to see the ECM follow with this general theme.

Morning. I think you may well have been granted your wish. ECM looks fairly decent to me this morning, 216 chart looks likes its lining up a scandi high. Maybe not on the scandi high at 240, but it's an ok chart the very least. Small heart shape heights between Iceland and Greenland and the Azores high ridging up to meet up.Not sur how cold it would be over the uk at 216 & 240, but if the low over the uk was only a couple of hundred miles further south then I would have thought we might see a few surprises. I liked this mornings ECM Edited December 30, 2013 by TSNWK

[That ECM]

Morning. I think you may well have been granted your wish. ECM looks fairly decent to me this morning, 216 chart looks likes its lining up a scandi high.

http://images.meteociel.fr/im/894/gfsnh-0-216_gun0.pnghttp://images.meteociel.fr/im/7455/ECH1-216_ivg5.GIFThe differences are large. Little consistency from run to run. Good to see some heights being modeled but they are in different areas and therefore little idea of what we would get. I am losing patience with myself telling myself more runs needed but that is the reality.

[Severe Siberian icy blast]

Their appears to be a lot of warming putting a lot of pressure on the vortex from both sides as we go through jan ,

The one over our side is of interest , if we can get a split from this we may have high pressure build directly to our north , which would bring northeasterly winds .

Along with a very interesting northern hemisphere pattern from quite early on Split vortex hear , "potential" is the word going forward .

Edited December 30, 2013 by Severe Siberian icy blast

[Frosty.]

There are even more wintry solutions on this morning's GEFS 00z perturbations than last night's 12z, here is a sample. What all us coldies are waiting for is to see the trough eventually get to the northeast of the uk (scandinavia) and enable arctic air to blast south with some form of height rises to the northwest and mid-atlantic ridge building north. I think we have a good chance of a higher risk of wintry ppn in the 10-15 day range but in the next 7-10 days we remain locked in a very stormy spell with torrential rain and severe winds with temps fluctuating between on the mild side / cold side of average with wintry showers, especially on hills and in the north with occasional frost and ice...but then perhaps a significantly wintry spell from mid Jan or soon after.

Edited December 30, 2013 by Frosty.

[Cecil Hogmanay Melchett]

Its pretty clear we are going to be looking at mid Jan onwards for any real opportunity of cold.

IMO the ECM at day 10 is moving in the right direction

 

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

Still troubled by that belt of high pressure stretching from North Africa up towards western Russia though,i would imagine Spain/Italy Greece Balkans have had a very very dry winter so farHigh pressure seems to have been sat in that locale for weeks and weeks,and weeks.

[Captain Shortwave]

ECM day 10 mean

GFS for the same time

Both show the Canadian/Greenland lobe reforming after a brief lull.

No pressure on RJS here , you will see two clusters developing from here, one which is straight zonal and will probably put us at the back end of January before we can search for any real cold. The other is where we have heights to the north/north east and can deflect the zonal train south of the UK, helped by a surge of cold/unstable air moving west from Siberia supporting a cut off low in the med. This could give us a memorable winter.

If the ens are right, like in December, we might only have one shot at this. So lets hope we get what we all wish for

Edited December 30, 2013 by Captain shortwave

[Gibby]

Good morning. From yet another morning of wet and windy conditions in the West Country here's this morning's report on the midnight outputs of the NWP for Monday December 30th 2013.

 

All models show a trough moving steadily East over the UK carrying strong winds and rain with it, clearing Eastern Britain later this afternoon. A lull of light Westerly winds follow with just a few showers before another vigorous trough crosses East overnight with further very gusty winds and showery rain. Tomorrow is then shown with SW winds, strong at times with rain turning showery later. Into 2014 and the weather is shown by all models to look every bit as volatile with further spells of heavy rain and strong winds alternating with somewhat colder interludes with heavy showers, especially near Southern and Western coasts.

 

GFS then shows next weekend as very unsettled as another vigorous Low pressure trundles East across the heart of the UK with gales and heavy rain at some point on Saturday giving way to colder and showery conditions for a time before on Sunday a new major Atlantic Low sets up another round of strong WSW winds and rain. From then on through Week 2 absolutely no respite is shown with deep Low pressure to the North with strong Westerly winds and showers and longer spells of rain coupled with gales persisting unabated.

 

UKMO closes it's run next Sunday with a deep and complex Low pressure covering much of the North Atlantic from Newfoundland, Iceland and the UK each affecting the UK with strong winds and very heavy rainfall with flooding becoming a serious issue if these Lows come in with this frequency.

 

GEM is very similar with the main message being of more severe gales at times with periods of rain sweep in from the West regularly with short showery spells in between. The run ends with a 960mb Low centred close to West Wales with all the attendant problems that would bring if verified.

 

NAVGEM closes it's run with Low pressure (965mbs) West of Ireland with strong SSW winds and rain from troughs blown quickly North and East on strong SW winds, especially in the South.

 

ECM today shows little difference although once more Low pressure fills over the UK by Day 10 giving a brief colder spell in 10 days with showers turning wintry for all in lighter North winds. However, with the pressure structure as it is the UK looks to be on the collision course of the next Low pressure exiting Newfoundland by the end of the week as an Atlantic ridge would topple SE over and away from the UK.

 

The ECM Ensemble Mean at Day 10 indicates troughing still over and to the NW of the UK with higher pressure to the South over Southern Europe and the Azores maintaining unsettled weather with rain at times and hardly indicative of anything other than colder transitory polar maritime incursions at times.

 

The GFS Ensemble mean remains little changed from those of late with nothing to suggest anything other than a continuation of wet and windy weather for all areas at times in temperatures overall pretty close to average.

 

The Jet stream continues to be programmed to run powerfully across the Atlantic towards Southern Britain or Northern France throughout this morning's output.

 

The Summary this morning remains doggedly the same as I have been saying for weeks now and that is the very volatile and sometimes powerful unsettled spell is locked in for the foreseeable future. There will be spells of very strong winds and very heavy rain all too frequently through the period creating more misery for flood prone areas with some wind damage too possible at times. There will be some very short showery interludes when winds fall lighter and at these times it may be briefly colder with some snow showers on the hills, especially in the North. However, temperatures overall will not be troublesome maintaining an overall very average level with only limited chances of slight frost under transient ridges.

[Summer Sun]

ECM ensemble at day 10 looks better this morning with this consent run of low pressure systems coming to an end I'm sure those who've suffered flooding over the past few weeks will appreciate some drier settled weather

 

[fergieweather]

ECM ensemble at day 10 looks better this morning with this consent run of low pressure systems coming to an end 

As of yesterday, around 20% of the EC members closed on an anticyclonic theme so it'll be interesting to see if that potential outcome develops further.

[BLAST FROM THE PAST]

 

 

That looks a real problem and I think Ian F and colleagues are looking at that.

Re cold the main body of the LP is anchoring to our NW which although stormy means mainly rPM and at times pM air is only to be had according to current output.  If that main part of LP moves east we'll get in business as the ECM goes on to show.  So the New year storm is on so halfway there, where will it take us....currently continued storminess cool/cold and wet looks favourite...for a little while 

 

As an aside, this is sort of thing I have in mind but a little sooner

 

 

 

BFTP

Edited December 30, 2013 by BLAST FROM THE PAST

[IDO]

The ECM long wave upper profile has about 20% support from the GEFS at around T240: 

 

Those supporting members do go on to develop S.Euro upper troughs with the AH also edging NE. So if ECM is correct, then more interest in D10-15. However with the ECM notorious for over amping, I wait to be convinced. The GFS mean has a flat NH in our sector with the N.Pacific ridging the main LW driver:

 

 

This would put pressure on the Canadian vortex and maintain the push of energy towards the Atlantic. The GEM op in this ballpark:

 

obviously along with the main cluster of GEFS.

 

The clustering at the end of FI suggests the Canadian vortex is in a lull and the 65% zonal clusterings are less disturbed and this appears to allow the AH to push the pattern north:

 

 

Lets see if ECM can get it right for once re phasing of the vortex energy and allow a more amplified pattern.

[Frosty.]

The Ecm 00z ensemble mean looks extremely unsettled with spells of heavy rain and severe gales separated by colder, showery interludes with less windy conditions and possibly some frost. Looking at the T+240 hours chart, it shows a lull in the stormy weather with a rather colder and showery westerly airflow but it's just a suckers gap of less severe weather as looking to the northwest there is another surge of lowering heights energy ready to swing southeast towards the uk and the alignment of the jet looks more promising to send some of that very cold air spilling out of canada into the northwest atlantic our way. I think there are good signs so far today for a trough to eventually get into scandinavia with more of an arctic feed for the uk with height rises to the northwest plus mid-atlantic ridging by mid / late January.

Edited December 30, 2013 by Frosty.

[bluearmy]

there remain notable differences between naefs and ecm at day 10 re height anomolys to our nw and ne. pointless to make predictions, given the importance of these areas to our weather. what should be noted is that the euro heights have proved more resilient than the models had predicted. ecm ens the most guilty party here, ecm and, to an extent, gfs ops the best guidance. we appear to end up with the euro troughing more w iberian with ridging persisting towards se europe and the eastern med. if ecm is right about a more amplified atlantic ridge by days 9/10 (it isnt usually), then there is still a window of opportunity for coldies as the trough sinks below this extending ridge. this is the period of uncertainty. all modelling seems intent on flattening out in the extended period though with weaker anomolys than we've seen recently predicted so i suspect we have to wait and see what happens re this potential atlantic ridging at day 10 before working out the way forward beyond.

 

the east canadian vortex does not seem to be going anywhere long term though the thermal gradient to its southeast looks like lessening off which will allow the jet to relax somewhat through the latter part of week 2. before that, the chance of another deep system coming east cannot be discounted.

[Methuselah]

The ECM long wave upper profile has about 20% support from the GEFS at around T240: ECH1-240 (1).png

 

Those supporting members do go on to develop S.Euro upper troughs with the AH also edging NE. So if ECM is correct, then more interest in D10-15. However with the ECM notorious for over amping, I wait to be convinced. The GFS mean has a flat NH in our sector with the N.Pacific ridging the main LW driver:

 

gensnh-21-1-240 (1).png

 

This would put pressure on the Canadian vortex and maintain the push of energy towards the Atlantic. The GEM op in this ballpark:

 

gemnh-0-240 (5).png obviously along with the main cluster of GEFS.

 

The clustering at the end of FI suggests the Canadian vortex is in a lull and the 65% zonal clusterings are less disturbed and this appears to allow the AH to push the pattern north:

 

Screenshot_30_12_2013_09_44.png

 

Lets see if ECM can get it right for once re phasing of the vortex energy and allow a more amplified pattern.

The what? 

[Blizzardof82]

Epiphany looking rough

Edited December 30, 2013 by Blizzardof82

[Frosty.]

Epiphany looking rough

These are the type of charts we should have had through the autumn instead of the warm benign sept / oct we had...berrr i'll get you for this Butler

[Ali1977]

There is a definite buckle in the jet stream at day 10 on latest GFS, not sure if this will help produce cold. There was no buckle on the 00z

[Nick F]

Yes, quite a bit of uncertainty post t+144 with regards to how far east troughing to our NW pushes. ECM deter and some of 00z GEFS members keen to extend the Canadian vortex east across the UK, ECM eventually splitting the lobe of the vortex heading east into a closed H500 circulation, thanks to an amplifying wave coming out of NE Canada, the upper low eventually fills over UK/NW Europe to allow height rises over Iceland and Scandi.

 

Ens are trending strongly to a locked pattern upstream over N America, with a strong ridge north over Alaska towards the pole and stubborn vortex of E Canada. Not quite so clear cut this side of the N Atlantic.

 

Another week of disturbed wet and windy weather from 06z GFS, next Monday's low looks disturbing. Then a change from 00z, with the mean trough retreating and amplification of the flow across western Europe and an interesting move south of an arctic high toward Svalbard. Certainly a trend for the vortex to retreat or disrupt over the NE Atlantic?

Edited December 30, 2013 by Nick F

[Snowman.]

Almost a split!

 

Edited December 30, 2013 by SN0WM4N