In depth (chilled out!) model discussion

[stodge]

Morning all

Another fine and warm start here in London Town but an upper haziness suggesting something more interesting is on its way. Will we get a storm this afternoon or evening ?

Over to the SE Regional or the Convective/Storms Thread if you want to know more - not my place:

I'm looking at medium range model output here taking us to the start of a new working week - Monday June 12th:

Starting with the GEM 00Z OP output this morning and the picture at T+240:

Not perhaps the most summery of charts but quite a lot happens in the evolution though very broad brush it's LP to the north and HP to the south with the British Isles in the middle of the river so to speak. Once the trough breaks through over this weekend and early next week, LP is in charge. There's a fascinating little LP moving west from Scandinavia to Iceland - not sure what that's about but it invigorates a secondary feature which deepens as it moves in from the west next Friday ruining the weekend for many while the next feature from the Atlantic fills and disrupts SE across southern parts though with a strong ridge out of Greenland, a weak Azores HP and a southerly tracking jet it looks as though a chain of LP systems will be moving across the British Isles keeping most parts cool and wet.

ECM 00Z at the same time:

Not a million miles away from yesterday's offering and pretty bleak for those wanting heat apart perhaps from an occasional transient ridge. Successive and quite vigorous LP systems come in off the Atlantic bringing in periods of rain and strong winds  and more worryingly, ECM again, as yesterday, hints at a mid-Atlantic ridge for mid month which suggests a spell of cool N'ly winds might be on offer.

Finally, GFS 00Z OP at the same time:

No point sugar coating this either, it's a poor run for lovers of heat. A significant and quite intense area of LP moves in from the SW toward the end of next week and basically means three or four days of cool and wet weather with rain or showers for all and strong winds for some.

Further into FI, heights build briefly south of Iceland and the weather settles before LP moves in again at the very end of FI.

The 00Z Control is very similar but further into FI sets up an HP in mid-Atlantic leaving the British Isles in a slack northerly (Scenario B).

Looking at the 00Z GEFS , there's still plenty of spread over Scandinavia - some members take the trough over there which would keep the British Isles cool and unsettled while a minority continue to build heights into Scandinavia - that might be from the trough slowing down just to the west of the British isles or possibly through an undercut as the LP disrupts SE into Europe.

The problem with all this variable though it may be the outcome for the British Isles is much the same - LP dominance with the likelihood of rain or showers for many. There's little or no sign of any heat prolonged or otherwise on the charts this morning and, to be honest, I'm left with two thoughts - one, many parts need the rain and second, summer has hardly started and there may be an argument that getting the bad weather out of the way leaves potential for July and August to be better - maybe, maybe not ?

[Singularity]

   

Late June may be hanging in the balance a bit as far as predominantly fine weather is concerned. Phase 1 MJO as favoured by GEFS and UKMO promotes such conditions with the potential for some high temperatures at times too, while phase 2 as favoured by ECM (with GEM borderline 1/2) encourages a more changeable regime albeit with the lows potentially interacting with ridges close to the E/NE such as to produce plume events. Interestingly such events become more likely if the MJO then continues on to phase 3.

GFS, UKMO and ECM have all remained steadfast with their respective predictions over the past few days so trends are not available to aid when trying to figure out which way things will actually go. 

At least one aspect that does look to have an unusually high probability is that of predominantly above-normal temperatures - but by how much is anyone's guess!

[Glacier Point]

Extended range modelling going for lowish heights over the polar field and flatish type mid latitude type pattern as we tip into a more tropically influenced period and away from the polar influence of the spring.

This from GEFS day 15 would be a fair summary of the modelling..

I suspect that once this gets closer to higher resolution, the trough to our west and continental ridge will get picked up better. Currently no real model support for a reboot of the heat days 10 - 15, but I would be hedging towards further heat towards day 15.

[geoffw]

what does hedging your bets mean ?

[bluearmy]

On 19/06/2017 at 18:01, geoffw said:

what does hedging your bets mean ?

It means he's inclined to believe the warm/hot pattern will repeat towards the end week 2 with Atlantic trough and euro ridge 

[geoffw]

i certainly hope GP is right and I hope NI can enjoy some more good weather 

[Singularity]

4 hours ago, geoffw said:

i certainly hope GP is right and I hope NI can enjoy some more good weather 

With the models remaining so stubbornly against it, it's seeming like a tall order, but for some reason when a change in the pattern is forced by tropical developments for example, they do have a habit of making it both too pronounced and too resistant to further change, so some hope remains, albeit rather tenuous.

... but given I'm away hiking in Wales for the period 30th June to 7th July, I'd not be surprised to see GP's predictions prove accurate but at the longest end of the timescales given, so leaving me with at best two better days after six unreliable/dire ones 

Edited June 21, 2017 by Singularity

[damianslaw]

8 hours ago, Singularity said:

With the models remaining so stubbornly against it, it's seeming like a tall order, but for some reason when a change in the pattern is forced by tropical developments for example, they do have a habit of making it both too pronounced and too resistant to further change, so some hope remains, albeit rather tenuous.

... but given I'm away hiking in Wales for the period 30th June to 7th July, I'd not be surprised to see GP's predictions prove accurate but at the longest end of the timescales given, so leaving me with at best two better days after six unreliable/dire ones 

Yes - a return to a trough dominated pattern as we end the month and start July it appears, could we be seeing a summer with trough followed by ridge followed by trough pattern, meaning wetter more average temp periods followed by heat and sun.. would make for an interesting summer. I too will be in Wales from 28 June - 5 July, mmm its looking preety unsettled..