Model Output Discussion 12z 10/05/13

[Frosty.]

The models have generally taken a turn for the worse overnight and the 00z shows a cool cyclonic spell into next week instead of high pressure which dominated the majority of the 12z output yesterday. It's a sunshine and heavy showers outlook currently but the ukmo 00z  offers an olive branch of hope with rather higher pressure next weekend which could evolve further into the new week. The Ecm 00z shows a brief improvement from the west during the weekend but then quickly becomes unsettled and showery although later next week high pressure builds from the west/nw which would eventually bring a settled and warmer spell to all areas.

 

Finally, I would just like to mention the Tornado (approx 1½ miles wide) which has ripped through Oklahoma City overnight with a devastating loss of life, our thoughts and prayers are with them all.

Edited May 21, 2013 by Frosty039

[Gibby]

Discussing Model Output here in the UK pales into insignificance when comparing our 'will it rain or not' weather with the dynamic force of Nature and the devastating effect it has had on infrastructure and human life in Oklahoma USA overnight.

 

However, Hi everyone. Here is the report on the 12 midnight output from GFS, UKMO, GEM, NAVGEM and ECM for today Tuesday May 21st 2013.

 

All models show a slowly strengthening Northerly flow through the coming few days as the pressure gradient steepens over the UK between High pressure over the Eastern Atlantic and Low pressure sliding South from Scandinavia later. After a few dry and bright days with temperatures steadily falling back towards average and then below showers will develop towards the East on Thursday and more especially on Friday when winds will become strong and very cool for a time towards the SE. By the weekend the offending Low will loosen it's grip as it moves away into Europe with isobars opening up over the UK with a much better day likely on Saturday for many with just well spaced showers.

 

GFS then shows a slack NW flow over Sunday backing West on Monday as a weak ridge crosses the UK. These two days should be largely dry and bright and without the wind of previous days it would feel rather warmer. Then through the week Low pressure becomes the dominating force as it sinks across the UK with rain and showers for all in a cyclonic wind flow. Through the end of the week and start of the second weekend the Low moves slowly away to the East leaving behind Northerly winds again with scattered showers and good sunny spells, these most prolific in the West. Things then gently continue to improve though High pressure never takes complete control of the weather with the continuing risk of the odd shower in temperatures which should recover to at least more average levels for early June.

 

The GFS Ensembles continue to show a return to average value uppers after the cool dip over the coming days. There are plenty of precipitation spikes throughout the run after the next few days though Eastern Scotland continues to look to see very little of this with dry weather there for much of the time.

 

The Jet Stream continues to show a rather broken pattern across the UK in the coming days with the flow generally from the NW down over the UK. Later on the return of a UK trough in the flow looks likely late in the weekend and into next week.

 

UKMO today shows very quiet conditions over the second half of the Bank Holiday weekend with plenty of sunshine in what is shown to be light winds. A few showers would be possible here and there but many places would stay dry, bright and reasonably warm in the sun but with chilly nights where skies clear.

 

GEM today also has a slack pressure gradient over the UK later in the weekend with sunshine and the odd shower to see out the weekend. Through the following week Low pressure becomes more dominant over or close to the South of the UK increasing the risk of shower activity in very average temperatures for late May. The NW would see the best of the bright and sunnier conditions.

 

NAVGEM today shows shallow Low pressure over the UK to start next week with a sunshine and shower mix most likely in light cyclonic winds. Good sunny spells between the showers would maintain an OK feel about conditions between any showers.

 

ECM finally also shows a more showery look about events beyond next weekend with temperatures close to average but with only light winds and sunny spells between the showers things would feel OK. Showers are shown to become more confined to the East later as the culprit Lo exits SE of the UK leaving a slack north flow over the UK to end the run.

 

In Summary it appears the models have taken a step back again this morning. There is still considerable doubt about the High making it's way far enough into the UK to kill off any risk of showers and to assure dry and warm summery weather. However, the Bank Holiday weekend looks far from a washout with some good sunny spells for all areas and with light winds it will feel quite warm in the sunshine. As next week transpires though the risk of showers increases with good suport for shallow low pressure to take control of the weather over most areas with more widespread showers and temperatures no better than normal in a cyclonic wind flow. There is no overall signs of any heatwave type weather yet but it's early days yet and it wouldn't take too much of a shift in synoptics around that High pressure to the West to offer something much more promising but I think we may well have to be patient.

[Summer Sun]

The ECM monthly ensemble for Birmingham shows temperatures getting to and staying around average from around June 3rd to at least the 20th

 

 

Yes we know they should be there but after the year we've had so far with cool weather it will make a change to get some seasonal temperatures

 

Rainfall looks like hovering around average before a slight increase mid June

 

[NeilN]

Even if stays average throughout June, that's something

[Tamara]

The first ECM operational this evening that shows a flatter jetstream in the way it evolves and as a consequence the Azores high is ridging closer to the UK on this particular output.  The 12z operational looks a better match for this mornings ensemble mean and backs up the GFS for changes to drier and warmer conditions perhaps as we get to the start of June. But it is a long way off and the cool and unsettled pattern has proved hard to shift with previous false dawns.

 

 

Just using this simply to pick up from yesterday - it does seem indeed to have been just a brief suggestion, on what was based on low confidence anyway, as this mornings models are very much back to the predominant amplified theme we have seen for so long, and an outlook that suggests cool, fairly unsettled weather with further showers and spells of rain from time to time. But as others have rightly said, everything is very relative indeed in comparison to the shocking news from the other side of the atlantic.

[Frosty.]

The Gfs 00z is a very unsettled run but right at the end we finally see the back of those horrible cool troughs and pressure begins to rise strongly at long last through early June, The Gem 00z also shows signs of pressure rise in FI but still with those pesky embedded cool troughs.

Edited May 21, 2013 by Frosty039

[Summer Sun]

GFS 06z is dominated by high pressure again into June this has been a theme over the past few days now on a number of runs

 

http://www.null/ds/gfs.htm

 

The latest met office outlook for most of June remains unchanged from the past few days

 

Edited May 21, 2013 by Gavin.

[Frosty.]

Yes the Gfs 06z shows a big improvement through FI with the atlantic/azores anticyclone building a strong ridge across the uk, initially it's a north-south split with unsettled weather to the north of the high but eventually all areas become dry, sunny and warmer, it's a massive improvement on the 00z and is probably more reflective of the overall trend for a change in pattern to more settled/benign conditions as we move out of spring into early summer.

Edited May 21, 2013 by Frosty039

[bluearmy]

, it's a massive improvement on the 00z and is probably WRONG

 

 

corrected Karl !

[CongletonHeat]

Probably get good output on the 12z's and wake up to rubbish again on tomorrow's 0z's, that's how it has gone the last few days.

Edited May 21, 2013 by CongletonHeat

[Frosty.]

corrected Karl !

you won't mind if I edit your posts then

 

As for the 6z, it may well be wrong but so may the unsettled 00z, it's the overall trend i'm most interested in as we head into summer and to finally see a more sustained settled and warmer spell, that's what i'm looking for.

[bluearmy]

you won't mind if I edit your posts then

 

As for the 6z, it may well be wrong but so may the unsettled 00z, it's the overall trend i'm most interested in as we head into summer and to finally see a more sustained settled and warmer spell, that's what i'm looking for.

 

Only teasing mate!   from where i'm sitting, the azores/mid atlantic and west russian/sceuro blocks look like keeping the trough headed our way. the wavelength and therefore the depth may slowly retreat north but thats likely a gradual process. 

[Frosty.]

Only teasing mate!   from where i'm sitting, the azores/mid atlantic and west russian/sceuro blocks look like keeping the trough headed our way. the wavelength and therefore the depth may slowly retreat north but thats likely a gradual process. 

I know mate, that's why I put the smiley face on, yes it will take time, more patience will be needed, there is no quick escape from this   pattern, snowking was spot on as usual.

Edited May 21, 2013 by Frosty039

[Summer Sun]

Fantastic output from the GFS ensemble to follow the Op

 

 

[Frosty.]

Fantastic output from the GFS ensemble to follow the Op

 

 

That's the best GEFS mean I have seen so far, also backs up the 6z op run in FI : - )

[Thundery wintry showers]

The problem is that, with the UK being an island at the downwind end of the Atlantic, high pressure has to be in the right place for it to bring warm dry sunny weather.  The GFS operational and GEFS charts would most likely give us a west-east, or maybe NW-SE, split, with the Azores High ridging into the west and north-west promising warm dry sunny weather for western Scotland, Ireland, much of Wales and the western side of England, but the north-easterly flow over England would most likely bring suppressed temperatures and frequent stratus for central and eastern parts.  The GFS operational run's temperature and cloud/rainfall outputs also support this scenario- there are two or three days in FI that would be warm and sunny away from the east coast, but at other times the outputs suggest cloud and cool temperatures penetrating well inland.

 

The other main hurdle with regards a warm dry sunny spell is the issue that the ECMWF and its ensembles generally have the high pressure further west than the GFS/GEFS- ideally from that perspective it would need to be further east.

 

In the meantime there could be some rather cool, grey and rainy weather in eastern England on Thursday/Friday as the models have toned up the low in the North Sea, and also downgraded the convective potential due to the presence of the frontal rain belt, though the GFS is probably overdeepening the low a touch.

http://cdn.nwstatic.co.uk/gfsimages/gfs.20130521/06/60/ukprec.png

http://cdn.nwstatic.co.uk/gfsimages/gfs.20130521/06/60/h500slp.png

 

The weekend is now looking like a mixed bag with generally lower pressure than was previously projected, though not a complete washout- probably just ordinary stuff with a couple of rain belts and some brighter, showery interludes.  The upcoming pattern is not unusual at this time of year- traditionally northerlies do tend to reach their maximum frequency in May and into early June, before the Atlantic depressions and Azores High and associated westerlies strengthen between mid-June and early July.

Edited May 21, 2013 by Thundery wintry showers

[summer blizzard]

GFS ensembles say a ridge at day 9 which develops into a much more substantive high for us at day 13.

[Tony27]

Somebody needs to sort out this silly problem with the min temps the GFS is showing, it has -5c for ireland on friday night, really?  why does the GFS always over do min temps? however on the other hand UKMO underestimates min temps. 

 

http://cdn.nwstatic.co.uk/gfsimages/gfs.20130521/12/90/ukmintemp.png

Edited May 21, 2013 by Tony27

[Summer Sun]

Somebody needs to sort out this silly problem with the min temps the GFS is showing, it has -5c for ireland on friday night, really?  why does the GFS always over do min temps? however on the other hand UKMO underestimates min temps. 

 

http://cdn.nwstatic.co.uk/gfsimages/gfs.20130521/12/90/ukmintemp.png

 

Thats only the lowest they could possible reach its always best to look at the maximum they could get too as well

 

[Summer Sun]

Big differences between GFS and UKMO at t120 and t144 with UKMO looking better for something settled. Its fair to say GFS has gone off on one this afternoon

 

GFS

 

 

UKMO

 

 

Then at t144 GFS is just laughable talk about "going off on one"

 

GFS

 

 

Then we have UKMO

 

 

UKMO leads the way again

 

Edited May 21, 2013 by Gavin.

[Tony27]

so it could be 5c or -5c then, its like me telling someone tomorrow it could be 10c or 20c, i do find them night time temps predictions very strange, they are usually ok for day time temps though

Edited May 21, 2013 by Tony27

[Summer Sun]

so it could be 5c or -5c then, its like me telling someone tomorrow it could be 10c or 20c? i do find them night time temps predictions very strange, they are usually ok for day time temps though

 

This is one reason why UKMO (the met office) take little note of GFS they stick to they own model (as expected) probably ECM (as its the other European model where as GFS is American), and there in house models GFS is just laughable sometimes and this afternoon is a perfect example (see post 619)

 

If you want a consistent model I'd suggest you stick to UKMO

Edited May 21, 2013 by Gavin.

[Tony27]

GFS looks awful, same old story,  lows going underneath that scandi blocking, slap bank over the UK, nothing will grow at the allotments i am already way behind, 

UKMO looks better with high pressure taking control by the weekend, hopefully UKMO is right but i won't dismiss the GFS as it can get some things right

Edited May 21, 2013 by Tony27

[Cheshire Freeze]

Big differences between GFS and UKMO at t120 and t144 with UKMO looking better for something settled. Its fair to say GFS has gone off on one this afternoon

GFS

UKMO

Then at t144 GFS is just laughable talk about "going off on one"

GFS

Then we have UKMO

UKMO leads the way again

The GFS solution is entirely plausible. It's what happens when enough energy gets dragged SE, preventing AH ridging.

[AWD]

The GFS Op could indeed be "off on one" but it's probably best to wait until the GEFS suite and further model output such as the ECM is out before being too confident that it's wrong isn't it?