Model Output Discussion 12z 10/05/13

[weather_it_will]

... and right on cue, here we go yet again.

Central areas seem particularly wet on the GEFS ensembles compared to other areas.

I can't see anything settled for June so far.

It just looks milder and wetter, and the control and GFS OP run at the end do not look good to say the least.

Edited May 22, 2013 by Hot Wet Windy Cold No Snow

[Evening thunder]

Time to panic people, summer or June is over based on one GFS run in FI 

 

The same model that was so correct with a much shorter-range pattern the other day and which people haled as such a great model (possible sarcasm)

[Methuselah]

What's wrong with 'warmer and wetter', anyway? Personally, I'm quite happy that the models are not indicating 15 days' unbroken sunshine...

[Frosty.]

A nice ridge of high pressure for this coming weekend on the Ecm 12z op run with mainly dry and fairly sunny and pleasantly warm weather, even Bank holiday monday looks fine for the southeast of the uk but turning unsettled for the north & west.

[AWD]

Surprised you seem disappointed. You're a storm enthusiast, so would have thought you'd be pleased with what current NWP is showing for next week- which is a few days of decent convective storm potential. Wouldn't feel particularly cool either, given slack winds and likelihood of strong sunshine inbetween showers/storms.

I am relatively pleased really but I'm a wimp and I didn't want to say that in here as I would get jumped on and shot within 60 seconds, so I thought it best to blend in a little.

But yep, as you say, plenty of interesting weather if (and of course it is just an "if" at this stage) the GFS and indeed the UKMO bridged, with thundery showers and elevated thunderstorms possible in the Pm flow.

[Cheshire Freeze]

A pressure rise over Greenland at 192 hours....backs up the scenario shown on GFS earlier. This wasn't in the script was it?

 

 

I think what we're seeing here is the ensembles not being able to resolve energy distribution around the UK again....hence we have been seeing ensemble means skewed by the majority who couldn't foresee the leakage of energy S and E. We've got 2 main HP cores around our shores at the minute; one well to our east and one to the SW. The trough is exploiting the weakness between the two.

 

This is a concern when looking at the CFS pressure mean for next month as the link between the 2 HP cores looks rather tenuous

 

Edited May 22, 2013 by CreweCold

[Frosty.]

After the pleasantly warm and sunny weekend under the nice ridge of high pressure, next week descends into a very unsettled spell, becoming cooler and cyclonic with sunshine and heavy showers with hail and thunder, winds becoming generally lighter but with squally winds when there are showers occuring or in the vicinity but feeling pleasant in the sunny periods between the showers.

[Tamara]

A pressure rise over Greenland at 192 hours....backs up the scenario shown on GFS earlier. This wasn't in the script was it?

 

What an awful chart as we end the month and head in towards June  .  Deja vu the previous summers with blocking back over Greenland and low pressure firmly ensconced over the UK. Well the reasons for this continued pattern have been said often enough. Lets hope that the mooted (relative) improvement suggested by the METO comes to fruition for the start of new month It has to be said there is anything but signs of moving towards it in the current modelling

Edited May 22, 2013 by Tamara Road

[049balt]

What are the reasons for this continued pattern?

[mountain shadow]

Quite awful awful output today for anything settled or warm.

One thing is for sure the fact that both the ECM and GEFS ensembles have for some time being pointing towards the Azores ridge becoming a key player yet they have not even come close to fruition.

What is the key player here driving the persisting UK trough?

[phil nw.]

What an awful chart as we end the month and head in towards June  .  Deja vu the previous summers with blocking back over Greenland and low pressure firmly ensconced over the UK. Well the reasons for this continued pattern have been said often enough. Lets hope that the mooted (relative) improvement suggested by the METO comes to fruition for the start of new month It has to be said there is anything but signs of moving towards it in the current modelling

 

A different perspective though looking at the hemisphere view Tamara.Gaps appearing up north as the vortex continues to fragment rather than a persisting block maybe.

The main upper heights are still more mid-latitude around the Azores out to T240hrs on the ECM Op as they also are on the GFS mean chart along with those height anomaly charts posted above by Crewe Cold.

Our main fly in the ointment wrt to next week's prospects for more settled weather is still the mean trough draining south east across the UK again.

[CongletonHeat]

Abysmal output today, looks a bit like last year, a low pressure just lands on us and spins around with nowhere to go, pitiful.

[Tamara]

Like many recent years, there has been a late and very strong rebound final warming of the stratosphere with temperatures a fair way above average values. This will accentuate the HLB signal. This is on top of the underlying very amplified pattern that has been with us for some time, whereby we see trough disruption as the jet stream stream loops to a much more southerly track than we were used to seeing. Factors underlying the amplification of the jet stream are the situation in the arctic ice profile which exacerbates northern blocking, and also the relative weakness of the solar cycle which affects ozone transportation and distribution and can make the stratospheric temperatures less stable.

[Tamara]

A different perspective though looking at the hemisphere view Tamara.Gaps appearing up north as the vortex continues to fragment rather than a persisting block maybe.

The main upper heights are still more mid-latitude around the Azores out to T240hrs on the ECM Op as they also are on the GFS mean chart along with those height anomaly charts posted above by Crewe Cold.

Our main fly in the ointment wrt to next week's prospects for more settled weather is still the mean trough draining south east across the UK again.

I was looking at the NH maps Phil as usual.   As long as the current jet pattern continues to be modelled with trough disruption and the jet stream at lower latitudes, then the Azores High will not be able to influence our weather. Pressure is clearly higher in the wrong places than we want it to be for warmer and settled weather and on the ECM the jetstream is suppressed with all the energy headed south.

 

The Azores High on current modelling is very much in its native home, like previous years, and not reflective (at this time) of its traditional summertime position

Edited May 22, 2013 by Tamara Road

[tinybill]

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=2&ech=204

 

all i  say  people  who whant  wall  to wall sunshine  shut your  eyes if  your looking  in to  fatasy  land  at the   moment not looking  very nice to say  the  least!!!

[Gibby]

Hi everyone. Here is this evening's report on the midday outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Wednesday May 22nd 2013.

All models now seem to be singing from the same hymn sheet with regard to the sequence of events over the next 4-5 days. All areas begin this period with an increasingly cold, strong and showery NNW flow over the coming 24 hours as Low pressure develops out to the NE and slips slowly South down the North Sea towards NE England by tomorrow evening. This movement continues on Friday so that the Low will be off the SE English Coast by late evening. The weather would see a very showery day for all tomorrow with hail, thunder and even sleet possible over the hills in a strong and gusty wind with just brief bright intervals. On Friday Scotland and Northern Ireland will become drier and quieter while England and Wales maintain cold and cloudy weather with further rain or showers in a strong North wind. Over the weekend the weather moderates substantially as a slacker flow follows over the UK with a lot of dry and sunny weather for many over the weekend in temperatures recovering to average for a time. However by Bank Holiday Monday a new Low begins to move down from the NW over the UK renewing the risk of cloud and rain and cool weather again for many by the end of the day.

GFS then shows this becoming the dominating feature over the UK for the rest of the week with rain or showers at times and some brief drier and brighter interludes for the lucky ones. By the weekend the Low has filled up with a weak ridge crossing from the West giving a spell of dry and sunny weather for all with temperatures close to average. Through the latter stages of FI there are indications of yet another Low feeding in slowly from the West with outbreaks of rain or showers returning to all areas.

The GFS Ensembles show a mediocre pattern tonight once we have seen the back of the unseasonably cold uppers over the coming 48 hours. Rainfall is still fairly common over England and Wales with the best of the drier weather likely towards Scotland.

The Jet Stream maintains a pattern which guarantees changeable and often unsettled weather over the UK as it is increasing it's persistence in maintaining a SE flow across the UK or just to the West and subsequently joins the Southern arm of the flow over Southern Europe.

UKMO shows the UK covered by shallow Low pressure by next Tuesday with the unsettled conditions of Monday turning into a showery spell on Tuesday and probably beyond. As the model shows a less deep Low than it's partner models then the showers may be more scattered with some places seeing rather longer drier and sunnier spells over the UK.

GEM shows the Low as a deeper feature slipping down over the UK next week and in no hurry to leave thereafter. Spells of rain and showers would occur over the UK with some drier and brighter spells too especially later in the week as the Low fills and moves out to the East of the UK bringing back a slack Northerly with very average temperatures at best through the period.

NAVGEM is a little different in as much that it keeps next weeks Low towards the NW which lessens the longevity of it's influence somewhat to more Northern and Eastern areas with the SW gradually seeing drier and brighter weather albeit with a cool NW breeze gradually spreading NE towards other areas too by the end of the run.

ECM tonight looks pretty grim to be honest bringing the Low down over the Nation following a set of troughs on Monday to be centred slap bang over the top of the UK by midweek. The remainder of the week sees this feature as a slow moving affair with a gentle migration East and North at the end of the week only serving to renew a chilly feed of air down from the North or Northwest in very showery conditions.

In Summary there is very little good news tonight if it's High pressure based warm and settled weather your looking for. The Post bank Holiday period looks generally unsettled with Low pressure never straying far from the UK. With cool air in tow the best we can hope for are average temperatures in the drier periods between the showers or rain bands. ECM is the worst of a pretty bad bunch with just NAVGEM holding the long term candle tonight. I'm not quite sure what to make of the 144hr chart from UKMO but with High pressure both well to the West and North my feelings are that the slow moving Low has nowhere to go except spawn new centres around the area of NW Europe in the following days. So a disappointing set of output tonight, lets hope for better tomorrow.

[ANYWEATHER]

Unsually windy and cold ,with I dare say it at this time of year a wind chill  During Friday, in picticular for southern uk!... then in the unreliable time frame t+168 keeps us in the unsettled cool spell  from the great models of gfs and ecm!!      

[JK1]

any chance of a thunder in south these coming days +next week? I was hoping for warm sunny weather but it doesn't look that way, so if were stuck with rain I would love some thunder & lighting

Edited May 22, 2013 by JK1

[DR(S)NO]

What's wrong with 'warmer and wetter', anyway? Personally, I'm quite happy that the models are not indicating 15 days' unbroken sunshine...

Indeed....but I'm sure they will do in FI!!

[samadamsuk]

hey all.

 

Pretty abysmal charts, although a trough setting up residence does bring some good convective activity (although imo not my favourite type). As to where the summer looks to be heading, we are seeing the artic drain over us again, which is worrying, but we've also seen a change this year where warmth over northern Europe is getting dragged over the northern reaches of the LP's that are setting up - Scotland has just seen that happen, with attendant convection and warm temps - as the summer gets going proper I suppose the hope is this an amplified pattern - a progression of the last couple of years, and we see this mechanism cut each trough in half and link up the azores with the European heights - in which case, a summer pattern of northerly, then NE, then easterly, and cycling round again .. 1995 ish... we shall see hey

 

Samos

[Frosty.]

In Summary there is very good news tonight if it's High pressure based warm and settled weather your looking for.

I'm sure this will be your summary when we get into June Gibby  once the Azores high ridges across, until then it's  weather to continue.... but with a fine Bank holiday weekend for many although deteriorating from the west during monday.

[phil nw.]

Again this evening some signs of an improvement to the pattern into June.

The Height anomalies f/c for days 8-14 indicates next week's  trough becomes cutoff from the parent vortex as it moves into France with heights rising over the top and across the UK.

 

 

when comparing the 2 images we can see this change with those hts from the Atlantic easing eastwards towards the UK.

The 12Z GFS Ens graph also shows the warming out of the trough later as the mean temperature line of the 500hPa level is trending up.

 

MJO is currently quiet but i am thinking as it`s forecast to re-emerge further east in  the tropical Pacific soon this could be the kick to the hemisphere pattern we need to modify the jet flow in our favour.

 

Phase 1 for June

 

Of course no certainties in this game but some background data to chew on other than the operational runs which continue to swing to and fro.

 

 

 

 

[ANYWEATHER]

I'm sure this will be your summary when we get into June Gibby  once the Azores high ridges across, until then it's  weather to continue.... but with a fine Bank holiday weekend for many although deteriorating from the west during monday.

Is that a recent post from Gibby?!! Anyway June greets us in fine fashion!

[Cloud 10]

The 12z ECM ensemble mean height anomalies for the 1st of June look worryingly familiar

as we stumble into summer. 

 

 

 

[049balt]

Again this evening some signs of an improvement to the pattern into June.

The Height anomalies f/c for days 8-14 indicates next week's  trough becomes cutoff from the parent vortex as it moves into France with heights rising over the top and across the UK.

 

610day.03.gif814day.03.gif

 

when comparing the 2 images we can see this change with those hts from the Atlantic easing eastwards towards the UK.

The 12Z GFS Ens graph also shows the warming out of the trough later as the mean temperature line of the 500hPa level is trending up.

graphe_ens3.php.gif

 

MJO is currently quiet but i am thinking as it`s forecast to re-emerge further east in  the tropical Pacific soon this could be the kick to the hemisphere pattern we need to modify the jet flow in our favour.

NCPE_phase_21m_small.gif

 

Phase 1 for June

JunePhase1500mb.gif

 

Of course no certainties in this game but some background data to chew on other than the operational runs which continue to swing to and fro.

Sorry to sound stupid but what is the  "MJO"