Model Output Discussion 12z 10/05/13

[Milhouse]

If winds fall light towards the end of the week and into the weekend it will give temperatures a chance to rise towards average for the time of year. GFS 12z shows this quite nicely. Before then its a cool and unsettled picture but i very much believe its a different pattern to what we saw last year with no extremely wet weather forecast. A reasonable day to come tomorrow for some with more lengthy settled weather in the east.

[Frosty.]

Following the reasonable Gfs 06z, the 12z is a similar run with some settled and warmer spells mixed with cooler and more unsettled, the coolest and most intense showery period with torrential rain and storms looks like being next tuesday into wednesday but thereafter it's an improving picture with less showers and more in the way of sunshine and temperatures also recovering into the 16-18c range for southern britain but nearer 12-15c for scotland & n.ireland. According to the gfs 12z, next weekend looks fine and pleasantly warm and then it briefly becomes cooler and unsettled but soon after, the azores/atlantic high ridges towards the uk but there continues to be some unsettled weather around, at least it looks rather warmer towards the end of the run compared to the next five days or so, the 6z was better with the fully formed scandi high but I think this run is not bad at all considering.

Edited May 11, 2013 by Frosty039

[johnholmes]

Quite. The 500mb anomaly charts give us a synoptic pattern but are not always great for surface conditions.

Interpreting the 500mb charts to the surface is far from easy even for experienced meteorologists but there is a good chance that conditions will remain unsettled and cooler at the surface in my view into next week possibly longer.

[Purga]

T 2M temps barely peaking at 15C for the near and medium term and getting very close to 0C with ground frost posible in some prone spots.

 

When it is warmer there is still the signal for a lot of rain

 

John's right with the cool & wet outlook.

Edited May 11, 2013 by Purga

[Frosty.]

Significant differences between the Ecm 12z and Gfs 12z which have a big impact on next weekend, the ecm continues unsettled all next week with heavy showers and sunny spells with hail and thunder and also spells of persistent rain & windy weather at times with low pressure just off the east coast with NE'ly winds, the ecm has the overall pattern further west which means the atlantic ridge that pushes into the uk later next week and weekend on the Gfs 12z is much further west on the ecm so next week would be very unsettled, the ridge eventually makes it by the following monday but is soon chased away by another deepening low bearing down on the uk from the northwest to keep the unsettled pattern going well beyond T+240 hours. As far as temperatures go, most of next week looks coolish or just below average but then recovering to average as the uppers warm up later next week but then cooler air sourced from the north atlantic spreads southeast so apart from maybe 1 or 2 fair days, generally it looks very showery and windy at times with persistent and heavy rain at times with a risk of thunder, especially across the south and east during the second half of next week which is also exactly what the met office described in their update today.

 

 

[Gibby]

Hi folks. Here is tonight's review of the 12 noon outputs from GFS, UKMO, GEM, NAVGEM and ECM for tonight Saturday May 11th 2013.

All models look depressingly similar over the period of next week with Low pressure gently moving South over the UK over several days to arrive near to Southern Britain late in the week where most models prove it very reluctant to move away thereon. It means a spell of rain over the coming days along with gusty West winds before an unusually cool and showery Westerly flow arrives for all on Monday with heavy showers and thunderstorms in abundance over the UK throughout the course of next week's working week. With Low pressure over the UK some places will see longer periods of thundery rain too but in among all the gloom there will be a few short not to be relied upon sunny spells when it will feel reasonably pleasant. It may be Mid May but some prone areas may see showers fall as snow over the hills and frost at night is a distinct possibility in notorious frost hollows through the week.

GFS then takes us into next weekend trying to rescue the UK from the continuing cold trough over the UK and partly succeeds for a time as a weak ridge dampens down the showers although temperatures remain remarkably chilly for this time in May. However, it is only a partial and temporary respite as Low pressure from the NW is back on the scene by the end of the run with a return to heavy showers and storms and temperatures no better than average.

The GFS Ensembles show the pattern as before with cool and showery conditions over the UK for the foreseeable future with disappointing temperatures throughout. The operational was a cold outlier in the drier phase described above, thankfully.

The Jet Stream shows the UK entering a very unusually deep cold pool trough with the Jet buckling South then North west and East of the UK respectively over the coming week.

UKMO shows little sign of let up late next week with showery rain and cool conditions maintained from the slack Low pressure areas maintained over and to the South of the UK.

GEM is as depressing as the rest with Low pressure not releasing it's grip at all with Low pressure spiralling around over all of the UK with rain or showers at times.

NAVGEM is the Gem in the pack tonight as it builds a ridge NE from the Azores High later next week and beyond with drier weather with longer sunny spells and relatively few if any showers by the end of next weekend.

ECM tonight shows little mercy tonight with winds from between West and North for much of the outputs course. With Low pressure to the East and disturbances running SE in the flow we can forget any heat or warm sunshine as cool NW winds propel showers or outbreaks of rain SE at times with just the briefest sunny intervals.

In Summary there is little change in the general theme tonight and just differences on specifics in synoptics. NAVGEM though does throw a lifeline in an overall mundane set of models. With the winds shown repeatedly between the models favouring the direction between North and West temperatures will never be very inspiring. The best advice is to enjoy the bright and sunny intervals between the all too frequent showers and hope for better models runs tomorrow.

[nitro_deluxe]

Looking forward to June already..

[Milhouse]

A noticeable improvement on the ECM 12z mean compared to the 0z. Mean pressure a lot higher over the UK at T+240.

 

[Milhouse]

T 2M temps barely peaking at 15C for the near and medium term and getting very close to 0C with ground frost posible in some prone spots.

 

When it is warmer there is still the signal for a lot of rain

 

John's right with the cool & wet outlook.

I notice the GFS op was a cool outlier in FI. The rain spikes do look noticeable but the mean is going along at or very near average for much of the run with a definite drying trend showing up for the final 3rd of the month (after the 20th)

[Gibby]

A noticeable improvement on the ECM 12z mean compared to the 0z. Mean pressure a lot higher over the UK at T+240.

 

Quite true but there is still a noticeable trough evident over the UK from the cold uppers troughed down over the UK indicated by the colour profile. Plenty of showers would still be frequent and heavy over the UK with the High pressure still miles away averaged sitting over the Azores.

[Milhouse]

Quite true but there is still a noticeable trough evident over the UK from the cold uppers troughed down over the UK indicated by the colour profile. Plenty of showers would still be frequent and heavy over the UK with the High pressure still miles away averaged sitting over the Azores.

Yes, it would still place the UK between the Azores high to the southwest and all the heat over Europe. But from the 0z that was showing a well defined area of low pressure to the north of the UK we now have higher average pressure over the UK, but still with the trough likely to be still situated over the UK at day 10. Upper temperatures on the mean at day 10 are where we would expect them for this time of year. They are made to look worse by the above average warmth over Europe.

[johnholmes]

T 2M temps barely peaking at 15C for the near and medium term and getting very close to 0C with ground frost posible in some prone spots.

 

When it is warmer there is still the signal for a lot of rain

 

John's right with the cool & wet outlook.

I do wish folk would actually post what I suggested.

I did NOT say that, I gave the charts and my interpetation of them, cool and showery NOT cool and wet was what I TRIED to infer, obviously not very well.

I do agree there is no sign, looking at the 8-14 day outlook on the NOAA charts this evening of anything that suggests dry and warm.

But I do try to post unbiased comments so please Purga and one or two others can you try the same?

It must be rather confusing for those not really able to interpret the upper air charts to read these remarks.

To repeat I did NOT say cool and wet.

to emphasise what I ACTUALLY wrote

I think it fairly obvious to everyone whatever experience level you have with these charts that if

you look at the pattern shown by the contour lines,mostly black on the ECMWF-GFS outputs and

green on the NOAA version, you can see that all three, not totally similar for sure, but overall the

pattern they are suggesting 6-15 days or so ahead are for the 500mb flow to be from a cold

origin rather than a warm one. Essentially that flow comes from north of west of the UK so is not

going to be very warm either at 500mb (see commentsabout heights) nor at the surface. With

the trough still very much in evidence then it is not realistic to expect much settled weather in the

time frame 6-15 days ahead.

The Fax chart at T+120 is probably as good as anyone can show for the expected surface pattern

for next week and quite possibly into the followingweek with low pressure affecting the country

at times. The main surface highs again well shown for the most likely positions in general terms

for much of the time with the upper trough ensuringsurface low pressure tends to be more

dominant than high pressure over the UK

Now where in there do I use the words Purga uses?

Edited May 11, 2013 by johnholmes

[davehsug]

I do wish folk would actually post what I suggested.

I did NOT say that, I gave the charts and my interpetation of them, cool and showery NOT cool and wet was what I TRIED to infer, obviously not very well.

I do agree there is no sign, looking at the 8-14 day outlook on the NOAA charts this evening of anything that suggests dry and warm.

But I do try to post unbiased comments so please Purga and one or two others can you try the same?

It must be rather confusing for those not really able to interpret the upper air charts to read these remarks.

To repeat I did NOT say cool and wet.

I wouldn't bother with anything the poster in question says John. He only appears when the weather looks poor & there's some stirring to be done!

Have to say I'd rather we had a more mobile pattern than this persistent troughing. At least then we'd get some drier & warmer days between the bands of rain. It's not the most promising start to May, but things can change - well at least before 2007 they could - Fingers crossed!

[Polar Maritime]

Well put JH, It's about time someone nipped it in bud... And coming from you, I'm sure it will be taken on board. 

Edited May 11, 2013 by Polar Maritime

[samadamsuk]

I don't think Purga was a million miles away -  cool and wet, compared to cool and showery - considering the guy was attempting to agree with John, with a thumbs up, then I think using caps lock to spell out the logic for the rest of us mentally impaired folk wasn't particularly well put either... I say this because 1) This is a place where SOME people come for accurate information, and importantly 2) this is the 'Model Output Discussion' where OTHER people come to discuss things without worrying about pin point accuracy, and don't deserve to be talked down to.  

 

I hope I haven't offended anyone here, but I'll say what I think needs to be said. I would comment on the charts, but it's a waiting game now to find some warmer output as far as I'm concerned!

 

Sam

[Guest pjl20101]

What I have noticed of late and I don't know whether its model related is a surge in angular momentum hence a Nino type of atmosphere and I am no expert on this but surely it should bode for something better later in the month.

[fine wine]

Charts still look terrible. High pressure is still a long way away and the warm humid potential for later next week has now gone

Edited May 12, 2013 by fine wine

[Gibby]

Good morning. Here is the report from the midnight outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Sunday May 12th 2013.

All models continue to show a cool and showery week to become as Low pressure slips down over the Uk through the week to become a shallow Low complex near Southern and Eastern Britain by the weekend. This will mean showers and longer spells of rain at times with some drier and brighter interludes between times. It will stay rather cool in the rain and showers but might not feel too bad in the sunnier interludes.

GFS then takes us through next weekend and beyond with little overall change as Low pressure remains in control coming down from the NW or settled over the UK with further showers or rain. However, later in the run there is evidence of the Azores ridge extending across Southern areas restricting more unsettled conditions to the far North while the South become dry, bright and warmer by the end of the period.

The GFS Ensembles does show a gentle rise in uppers this morning over the next few week. However, they are hardly indicative of high summer and will encourage things to feel more normal for the time of year in among the outbreaks of rain and showers still evident throughout, lessening somewhat later. The operational was a cold outlier in the North for a while.

The Jet Profile remains the same today with a sharp troughing of the flow over the UK next week while the flow over the Atlantic largely disintegrates next weekend.

UKMO today keeps Low pressure over the UK next weekend, albeit in a slack format. This would deliver further showers and outbreaks of rain across the UK from time to time with some drier and brighter interludes too with light winds trending from the North.

GEM today also keeps the unsettled theme going through the duration this morning with further pulses of Low pressure energy moving down from the NW periodically maintaining the cool and unsettled theme. however, towards the end of the run there is a push of energy from the Azores High which could dampen down the showers from the NW by Day 10.

NAVGEM is not quite a s good as last night's 12z run maintaining an unstable and cool NW feed over the UK with occasional showers or rain throughout.

ECM today looks like holding the unsettled theme throughout the extended part of it's run with Low pressure either over or close to the UK with continuing bands of rain or thundery showers encircling the UK. Temperatures will be held to near normal values or slightly below in the rainfall.

In Summary today there is little to get excited about yet again. There are a few suggestions in deep FI that High pressure from the Azores might ridge towards Britain, hinted at as well from GEM and it's from here that I feel is the most likely way we eventually leave this pattern. However, I feel patience is going to have to be needed as it looks more likely that the weather remains unsettled and cool with Low pressure from the NW continuing to feed into the UK. There will be some drier and brighter spells in between the rain and in these it will probably feel OK. ECM looks a bit of a horror show this morning and gets the 'booby' prize from me while GFS is the best though it's improvements are still a long way out into 'neverland'.

[IDO]

Charts still look terrible. High pressure is still a long way away and the warm humid potential for later next week has now gone

This morning's GFS 0z similar to yesterday's 12z for next week. A wet Tuesday as the front passes through:

Then heavy showers Wednesday:

Thursday-Sunday has average temperatures for many:

Thursday: Friday:

Saturday: Sunday:

This is a showery setup.It does not appear to be too windy so when the sun comes out it should feel OK. Obviously stuck in a decaying trough we are not going to get anything remotely hot, but this is not like the faux zonal low centric train of wet weather we had last year (at the moment).

The weakness of the trough again highlights the chances for the AH to break in from the SW, T240: :

And by the end of FI:

This looks like the best case scenario for a return to a milder setup according to the GEFS pressure charts (op above the mean throughout):

However there is a clear trend to dampen the low heights longevity and bring higher pressure to the south. The trough is being pressurised by highs to either side so I am not sure if GFS have it right with the AH pushing in, or that ECM has it right with the Scandi High being more dominant: Though I know which one I prefer.

So as others have said, as per the 500mb charts, trough dominated for the next 10 days remains the likely scenario, but better in FI, maybe. Hopefully later next week won't be as dire as some are forecasting, as GFS is not too bad.

Edited May 12, 2013 by i'm dreaming of...

[Frosty.]

Hill walkers & Mountain climbers beware, there is snow in the forecast for the hills/mountains in n.ireland and especially scotland later today , tonight and tomorrow with unusually cold air by mid may standards, arctic air, it looks like tonight and tomorrow there will be frequent heavy, squally showers with hail and sleet to low levels but a lot of snow above 400 metres and that is only half the story, there will also be gale to severe gale force westerly winds so a wintry spell for northern britain, even some wintryness to the higher northern pennines in england. The models are showing a very unsettled week ahead, torrential rain spreading across southern britain on tuesday and with sunshine and heavy showers throughout the week with hail and thunder, the gfs 00z shows less showers and more sunshine next weekend and warmer and through FI the weather improves, especially across the southern half of the uk with the azores/atlantic anticyclone ridging towards the uk with unsettled weather eventually becoming restricted to more northern areas, next week looks cool but feeling pleasant in the sunny spells but with a risk of overnight ground frosts where skies clear but then the mornings starting sunny but the early sunshine is the trigger for the big showers to develop through the afternoons and evenings.

 

As for today, driest and sunniest in the far east of the uk for longest but cloud and rain in the west spreading to most areas by late afternoon/evening, mildest in the east, 14c in aberdeen, 15c in london and southeast and east anglia maybe 16c.

[tinybill]

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=2&ech=6

 

 

morning all i can say up to  192 hr  is  that we  wont be far away from the wet  weather  this week

[bluearmy]

the trend for something more seasonal tempwise as we progress through week 2 remains. At this stage, it doesnt look too settled though and the ops are beginning to sniff around more energy being ejected towards us from the nw so it may be a false dawn.

Edited May 12, 2013 by bluearmy

[Summer Sun]

Looking at the GFS 00z ensemble this morning and there is a hint of lower precipitation as we move towards the final week and a half of the month

 

 

At the same point GFS shows high pressure forcing its way through from the west during the same period

 

[Frosty.]

The GEM 00z offers an olive branch of hope at the end with the Azores anticyclone about to ridge into the uk, the Gfs 00z shows a relatively warmer, sunnier and less showery spell next weekend with temperatures recovering to 18c in the south but the next five days look very unsettled according to all the models with sunshine and heavy showers with hail and thunder and cold enough for wintry showers for the hills and mountains of northern britain tonight and tomorrow. Tuesday needs watching closely as there looks like being a spell of torrential rain moving northeastwards across the southern half of the uk, 

 

The Gefs 00z mean shows a much warmer and more settled end to the run with the nadir being towards the middle of the week ahead but then the only way is up, however it still remains unsettled until well into FI, the Ecm 00z ensemble mean also looks rather better by T+240 hours with more respectable temperatures and more in the way of fine weather but still a risk of showers.

Edited May 12, 2013 by Frosty039

[Guest pjl20101]

Hope that is the case Gavin and that the ECM are over exaggerating things at the moment.

Apparently the ao/nao are predicted to go a bit negative. My perception of that would be some cold overnights with some frosts hence a bit of high lattitude blocking and possible northerlies.

How unsettled it will be is open to question I feel currently.