Model Output Discussions 12z 03/05/2016

[northwestsnow]

Yes UKMO looks more favourable compared to a quite frankly horrid GFS12Z.

The trend is for the high to get pulled westwards though, not a trend i or most of us want to see!!

[knocker]

The GFS doesn't build the ridge to any great extent on this run and the unstable low moving north on Thursday is back in the frame and it tends to hang around to the east.

[Frosty.]

11 minutes ago, northwestsnow said:

 compared to a quite frankly horrid GFS12Z.

 

Indeed, horrid is a good way of describing the Gfs 12z op run during low res, I can think of a few expletives too! 

[I remember Atlantic 252]

nothing new there Frosty, Wimbledon spectators in scarf and gloves and coats, June to me isn't really a summer month, Summer is Jul, Aug and Sep

[Frosty.]

1 minute ago, I remember Atlantic 252 said:

nothing new there Frosty, Wimbledon spectators in scarf and gloves and coats

Indeed, but at least centre court has a roof available so they won't have to listen to sir cliff singing summer holiday

Hopefully the outlook won't be as rubbish as the Gfs 12z in Fi shows!

[MP-R]

11 minutes ago, I remember Atlantic 252 said:

nothing new there Frosty, Wimbledon spectators in scarf and gloves and coats, June to me isn't really a summer month, Summer is Jul, Aug and Sep

Don't be daft. Nothing is showing scarf, gloves and coats weather.... Light anorak/umbrella in the wetter spells - that is all! 

[Frosty.]

Anyway, it's not all doom and gloom, the gfs 12z shows a warm up for midweek and the ukmo 12z clearly indicates warmth from the near continent drifting north across southern parts.

Edited June 18, 2016 by Frosty.

[Fourty Point Three Degrees]

What an awful 12z and an awful contrast on the temps next week. It has mid to high 20s in the South yet places just north of Birmingham struggle to reach 18c.  Then heading into July its going to feel much like December 2015 as temps all round are in the mid teens.

[Frosty.]

28 minutes ago, 40*C said:

 Then heading into July its going to feel much like December 2015 as temps all round are in the mid teens.

That's an exaggeration, I don't see anything cooler than upper teens celsius for the southern half of the UK and the sun is very high, as high as it gets so don't agree it would feel like December 2015 and we don't know that there won't be a major summery spell sometime in July do we?

Edited June 18, 2016 by Frosty.

[Frosty.]

The Ecm 12z shows increasing warmth and humidity for the south by wed / thurs with mid 20s celsius for the south / southeast but with that extra warmth and sultry air from the near continent comes an increasing risk of heavy showers and Storms, further NW it's cooler and changeable and the warmth in the SE is shunted away to the east by friday, however, a ridge of high pressure then builds across the south with fine and pleasantly warm conditions for a time but becoming more unsettled further north and the run ends cooler and unsettled for all.

[Guest]

49 minutes ago, Frosty. said:

That's an exaggeration, I don't see anything cooler than upper teens celsius for the southern half of the UK and the sun is very high, as high as it gets so don't agree it would feel like December 2015 and we don't know that there won't be a major summery spell sometime in July do we?

100% agree. It was a very knee-jerk post indeed. Nothing horrendous on the horizon at all. July is a long, long way away in forecasting terms anyway

[Frosty.]

1 hour ago, Stephen James said:

100% agree. It was a very knee-jerk post indeed. Nothing horrendous on the horizon at all. July is a long, long way away in forecasting terms anyway

Cheers

Edited June 18, 2016 by Frosty.

[Frosty.]

Looking at the Ecm 12z ens mean, it doesn't look particularly cool at any stage and next week shows warmer and more humid air (+10 T850s) flirting with the south of England which converts to surface temps potentially in the mid 20s celsius range, maybe 80F in and around London and thundery activity spreading up from the near continent is a reasonable assumption for southern and southeast england on wed / thurs, that warmth is shunted away to the east by Friday but it does return to the far south and is still flirting with the south coast at T+240 hours. Temperatures across the rest of England and Wales look closer to the high teens to low 20s c mid 60s to low 70s F and a bit lower for Scotland and n.Ireland closer to mid to high teens c with some sunshine but showery rain at times too ..could be worse.

Edited June 18, 2016 by Frosty.

[knocker]

The GFS this morning clears today's front by around 18x tomorrow. There tends to be a N/S split after with the north in the circulation of a depression to the NW so prone to quite a few showers. On Thursday a slack unstable area of low pressure moves north bringing thundery outbreaks to many areas in England in warm rather humid air. This then tends to hang around until the weekend before westerlies set in once again. I have to say the ecm picked this up some days ago if indeed it does pan out this way.

Edited June 19, 2016 by knocker

[Captain Shortwave]

Well this mornings output doesn't really offer much confidence in the latter half of the coming week.

GFS/UKMO/ECM

      

The GFS and UKMO have a similar idea slowing down the eastward progression of the trough and sinks a shallow low towards the UK, this engages with the heat and instability moving north so thundery rain is likely followed by sunshine and slow moving downpours with slightly lower temperatures. The GFS does offer temperatures into the mid to high twenties for central/southern England for a time.

   

The ECM however doesn't really want to do this and pushes the trough eastwards, there could be some thunderstorms moving north on Thursday but we are back in a westerly pattern by Friday. How the trough interacts with the ridges to the east and west of this is key to how things will pan out. Any area of low pressure that manages to establish west/south west of the UK could have a drastic effect on conditions for the UK.

Taking this ensemble member as an extreme example

      

A cold pool becomes cut off west of Iberia with the parent trough and low moving away eastwards, the ensemble member then develops heat wave conditions over the UK as high pressure is able build right through the UK aided by a strong heat block forming over Europe which now has the guidance of that cut off low to pump hot air over the UK. This is an extreme example but the method is possible, that said any likely result would be less extreme than this.

The GEM shows something similar but with low pressure cutting off over the UK and then sinking away from the UK.

      

This would be a less extreme version of that GFS ensemble member with unsettled and thundery conditions occurring for a time before becoming more settled and much warmer again.

Quite a few options on the table, we could end up with a much better result for the end of the week than we currently are seeing if we can get low heights into a position to advect hot continental air over us, or it could all end rather tepidly as the ECM operational shows. One to watch for sure.

Edited June 19, 2016 by Captain Shortwave

[Frosty.]

2 minutes ago, Captain Shortwave said:

 

  The trough splits 

Splitting troughs again? Lol where's knocker

[Captain Shortwave]

3 minutes ago, Frosty. said:

Splitting troughs again? Lol where's knocker

Haha, to avoid trouble due to still feeling a little over-indulged in terms of alcohol from last night, the post has been edited 

On topic, the ECM shows a flow west of north throughout the rest of the run with the Azores high stationed in the northern Atlantic, conditions rather mixed and turning cooler again.

       

[knocker]

Well I'll agree with CS that the ecm interpretation is markedly different to the GFS. At 06z it has the very shallow area of low pressure centred over SE Englant with marked convective activity. By 00z this has travelled NE to Oslo.although although there is still a broad band of activity down to Belgium. At the same time the riidge builds from the south west over the weekend but finds Atlantic systems moving in from the NW Sunday/Monday

No trouble from me CS I'm keeping it zipped from now on.

Edited June 19, 2016 by knocker

[northwestsnow]

1 hour ago, knocker said:

Well I'll agree with CS that the ecm interpretation is markedly different to the GFS. At 06z it has the very shallow area of low pressure centred over SE Englant with marked convective activity. By 00z this has travelled NE to Oslo.although although there is still a broad band of activity down to Belgium. At the same time the riidge builds from the south west over the weekend but finds Atlantic systems moving in from the NW Sunday/Monday

No trouble from me CS I'm keeping it zipped from now on.

Yep, as we saw yesterday the trend is certainly for the az high to retrogress west and north west opening the door to incoming troughs.

In the meantime ecm looks best for a short window of Hp influence but one has to say, the output has moved in the wrong direction for those hoping for some sustained heat anytime soon..:(

[Frosty.]

It looks like southern england will warm up and become humid through midweek with temps into the mid 20s celsius as the Ecm 00z shows but also likely to import thundery weather from France for a time but only across the s / se. Less warm and changeable further north west.

Edited June 19, 2016 by Frosty.

[northwestsnow]

That big belt of high pressure across Europe looks like bringing some very hot weather to the Balkans and eastern europe, temps in the low to mid 30's for Bulagria/Poland/Ukraine etc..

Quite notable actually, temps still into the low 20's at night on wednesday across France, spain, and the above mentioned countries, thats impressive, if a little oppressive!!

Edited June 19, 2016 by northwestsnow

[phil nw.]

It looks like one of those weeks where with a suppressed Azores high and Icelandic low we see a weak Atlantic pattern and wiggling weather fronts across the UK.

A snapshot for Weds.T84hrs  UKMO fax

so variable cloud,some rain coming through at times but with warmth and humidity likely to edge into central and south eastern areas at times.

Weds and Thurs on the 06z GFS show how close the heat over the near continent gets

With that boundary so close to the far  se we can't rule out a thundery breakdown ahead of the Atlantic trough expected to head east by the end of the week.

[Frosty.]

28 minutes ago, phil nw. said:

It looks like one of those weeks where with a suppressed Azores high and Icelandic low we see a weak Atlantic pattern and wiggling weather fronts across the UK.

A snapshot for Weds.T84hrs  UKMO fax

so variable cloud,some rain coming through at times but with warmth and humidity likely to edge into central and south eastern areas at times.

Weds and Thurs on the 06z GFS show how close the heat over the near continent gets

With that boundary so close to the far  se we can't rule out a thundery breakdown ahead of the Atlantic trough expected to head east by the end of the week.

It's a shame the rest of the 6z run is rubbish, no heat and plenty of troughs, no charts worth posting!

[phil nw.]

54 minutes ago, Frosty. said:

It's a shame the rest of the 6z run is rubbish, no heat and plenty of troughs, no charts worth posting!

Currently it's not a great outlook for sure Frosty- also going by the ens charts.Still a westerly pattern in week 2 and if anything more trough dominated

Day 10

 and the London temperatures

so quite underwhelming from today's outputs.

 

[Frosty.]

3 minutes ago, phil nw. said:

Currently it's not a great outlook for sure Frosty- also going by the ens charts.Still a westerly pattern in week 2 and if anything more trough dominated

Day 10

 and the London temperatures

so quite underwhelming from today's outputs.

 

Yes Phil that's the polite way of putting it, underwhelming indeed