Model Output Discussions 12z 01/06/2017

[Frosty.]

1 minute ago, cheese said:

Cool and cloudy all day in Wakefield Frosty. Bet you enjoyed that. 

I look at the bigger picture!

[Paul]

I was going to hide an off topic post thanks to a report, but going through the thread, it seems the majority have been off topic this afternoon. Please can we keep it to the model output in here, more loosely model related moans, ramps and banter need to go here. 

Thanks

[Scorcher]

8 minutes ago, cheese said:

Cool and cloudy all day in Wakefield Frosty. Bet you enjoyed that. 

Funny how different it can be just on the other side of the Pennines- another very nice day here if a bit hazy this evening, and up to around 25C. Notably fresher though with the easterly.

[wellington boot]

Sadly I don't spend as much time on here as I used to for various reasons, but when I do, it's funny and comfortingly familiar to find people gloomy and negative just when I thought that was impossible. Even looking at the models recently, I've been seeing nothing to worry about, as a break from the heat is no problem, and a cloudy day or two, mixed in with days of sunshine and showers, might make a nice change (and allow me to get some work done for once...).

Coming on here does also remind me that other parts of the country endure very different conditions than we do in the far South East. As far as I'm concerned, this summer has been a stonker, starting in early April. Several long, dry, mostly sunny spells, and very little cold, wet rubbish. I do feel sorry for those who haven't enjoyed such good fortune.

[Interitus]

2 hours ago, knocker said:

Worth remembering that not very far north it's not sweltering. (lucky people). The Nottingham midday sounding indicates some quite thick low level Ci, and some lower level stuff, and some cooler air in the boundary layer. Thus 850mb temp of 13.4C and a surface of 17.0C with a 3C inversion. The cloud confirmed by the h/s Modis at 1300z courtesy Dundee Satellite Station.

This set-up is reminiscent of an article in the journal Weather regarding a sea-breeze front in June 1995 during a spell of the then highest June temperatures since 1976. Not strictly the same synoptics as not a pure sea breeze in this instance, but the similar effect of the penetration of low level cool maritime boundary layer and associated cloud from the North Sea, it's an interesting read - 'Sea breeze front reaches Birmingham and beyond!' http://onlinelibrary.wiley.com/doi/10.1002/j.1477-8696.1997.tb06266.x/pdf

In the 1995 instance, temperatures had been in the 30s before falling back into the teens, with falls of 10 degrees within an hour.

Edited June 20, 2017 by Interitus

[Dominic Carey]

2 hours ago, Singularity said:

 

12z has the jet stream dipping south in the mid-Atlantic much more sharply as of Sunday afternoon than was the case on the previous few (or probably more) runs.

This could have interesting results over the following few days given the setup over Europe;

At least there's something of interest to keep an eye on while my brain slowly stews 

 What temperatures are possible with this setup?

[Frosty.]

3 minutes ago, Dominic Carey said:

 What temperatures are possible with this setup?

Mid 20's celsius across southern uk, low 20's down to upper teens c further north.

[knocker]

25 minutes ago, Interitus said:

This set-up is reminiscent of an article in the journal Weather regarding a sea-breeze front in June 1995 during a spell of the then highest June temperatures since 1976. Not strictly the same synoptics as not a pure sea breeze in this instance, but the similar effect of the penetration of low level cool maritime boundary layer and associated cloud from the North Sea, it's an interesting read - 'Sea breeze front reaches Birmingham and beyond!' http://onlinelibrary.wiley.com/doi/10.1002/j.1477-8696.1997.tb06266.x/pdf

In the 1995 instance, temperatures had been in the 30s before falling back into the teens, with falls of 10 degrees within an hour.

Cheers Interitus, will give it a read

[mb018538]

UKMO certainly the pick tonight, making much less of the low pressure at 144 hours, and thus its effects not being as severe. GFS and ECM keen to plough this low into the UK at varying intensities. 

[Allseasons-Si]

Is it me or does this low forecast for 144hrs+  look to be pulling more and more west,it looks like it to me.

[Dominic Carey]

10 minutes ago, Allseasons-si said:

Is it me or does this low forecast for 144hrs+  look to be pulling more and more west,it looks like it to me.

Does this mean more heat?

[carinthian]

15 minutes ago, mb018538 said:

UKMO certainly the pick tonight, making much less of the low pressure at 144 hours, and thus its effects not being as severe. GFS and ECM keen to plough this low into the UK at varying intensities. 

Yes, UKMO on its own on this one. Low over Newfoundland not going anywhere, according to UKMO , just deepens and becomes slow moving, allowing Azores ridge  across the British Isles.  More runs like this and then another pulse of hot air from the sub tropics could get  back on the agenda post 144t.  Whether this is a transient feature or not, there is now a difference taking place between the UK Model and the rest. GEM now moves to ECM and GFS. Interesting to see the extended models later. C

Edited June 20, 2017 by carinthian

[Frosty.]

3 minutes ago, Dominic Carey said:

Does this mean more heat?

At least warmer and drier for the south.

[Captain Shortwave]

GFS and ECM day 7

   

Atlantic trough with a pretty strong jetstream, but like the BBC the pattern still holds a ridge over Europe throughout the period, as such some very warm or hot air is never far away from the south and east, it wouldn't take much to develop a southerly flow across parts of the UK which would give much higher temperatures. The pattern is unusually moblie with lows zipping across pretty quickly, could we see the models slow this pattern down enough to bring some hot air back towards the UK. Otherwise it looks chageable but never that cool, indeed it could still be warm or very warm at times in the south. 

[Frosty.]

Actually most of the Ecm 12z indicates plenty of warm weather for the south in particular with temps into the low 20's c occasionally very warm into the mid 20's ..not a cool unsettled washout by any means!

Edited June 20, 2017 by Frosty.

[knocker]

The GEFS anomalies this evening are not budging from the trough domination in the near future and the ecm det. is also not at variance with this which is no great surprise unless it is going to do an about flip in a minute.

The ecm this evening is running the upper trough east to be over the Faeroes by 12z Saturday. Thus a NW flow with showery rain in Scotland with some transient ridging pushing into the south.

The trough moves away rapidly into Scandinavia whilst the next frontal system encroaches from the west to bring rain to the north by 12z Monday

This in turn gives way to the main upper low which is mid Atlantic with associated fronts sweeping across the UK Tuesday/Weds bring rain and strong winds to all parts.

So becoming generally unsettled with a north/south bias with temps nearer average. Perhaps a little above in the south and below in the north

 

[mb018538]

Looks lovely for October...I mean June! That deep trough could be a bugger to shift.

[Andy Bown]

22 minutes ago, mb018538 said:

Looks lovely for October...I mean June! That deep trough could be a bugger to shift.

Several weeks ago when it turned unsettled there were model predictions of weeks of bad conditions with people writing off the rest of June. Look how wrong those were!!

 I can see a similar evolution again with perhaps a few active fronts / lows then a gradual backtrack by models towards better conditions again as the continental conditions gain strength.

Granted this would probably favour the East/South more than further North/West but a nationwide long term unsettled period isn't likely.

[carinthian]

1 hour ago, carinthian said:

Yes, UKMO on its own on this one. Low over Newfoundland not going anywhere, according to UKMO , just deepens and becomes slow moving, allowing Azores ridge  across the British Isles.  More runs like this and then another pulse of hot air from the sub tropics could get  back on the agenda post 144t.  Whether this is a transient feature or not, there is now a difference taking place between the UK Model and the rest. GEM now moves to ECM and GFS. Interesting to see the extended models later. C

Extended N Atlantic chart from UKMO brings Tropical Storm Bret  into the equation. Only formed yesterday so the track is probably historical at this stage. Its future development and forecast track could throw a whole lot of different data into the models as early as 168t. Maybe one to watch  !

 C

[ANYWEATHER]

Unseasonably warm conditions followed by gfs and ecm to unseasonably unsettled conditions    .Who could make it up

[Allseasons-Si]

4 minutes ago, carinthian said:

Extended N Atlantic chart from UKMO brings Tropical Storm Bret  into the equation. Only formed yesterday so the track is probably historical at this stage. Its future development and forecast track could throw a whole lot of different data into the models as early as 168t. Maybe one to watch  !

 C

Is that it off the eastern seaboard with the number 43 on it?

[mb018538]

Yep...I mentioned this in a post earlier. Even though it's not a major storm, it will still have warmth and energy to disperse, and these usually disrupt the jetstream in one way or another. Models notoriously struggle with extra tropical features as they head to higher latitudes.

[Singularity]

1 hour ago, Captain Shortwave said:

GFS and ECM day 7

   

Atlantic trough with a pretty strong jetstream, but like the BBC the pattern still holds a ridge over Europe throughout the period, as such some very warm or hot air is never far away from the south and east, it wouldn't take much to develop a southerly flow across parts of the UK which would give much higher temperatures. The pattern is unusually moblie with lows zipping across pretty quickly, could we see the models slow this pattern down enough to bring some hot air back towards the UK. Otherwise it looks chageable but never that cool, indeed it could still be warm or very warm at times in the south. 

You've done a great job summarising my own suspicions given comments by the likes of GP a couple of days ago plus known model tendencies during times of increasing jet stream strength (i.e. going too far).

We see ECM making the trough sharper (more of a southward elongation) on day 8 compared to GFS' (typical of that model) bowling-ball low.

Then that possibility of the trough not making the journey in the first place, though it's 3 against 1 with the best performing models (ECM, GFS and GEM v. UKMO with JMA a curious and unfortunately still changeable hybrid of both ways forward) so not one to hang your hat on - hopefully the trend tomorrow will at least be to have the crossing trough putting on the brakes while further west - which would naturally be encouraged if the jet stream was toned down - or better still to keep it away altogether and let the Azores High continue to be our friend. Not sure though that I can quite believe that we could keep it with us right through the week or so of time that looks to be influenced by the La Nina-like swing in the atmospheric base state. It'd seem a minor miracle but that doesn't rule it out now does it? 

[knocker]

If the talk is going to be of tropical storms then I would have thought the one forecast to bring some huge rainfall figures to the southern states. Cindy, more relevant

Meanwhile back at the ranch NOAA and the EPS this evening are still looking at the Atlantic trough dominating with the continuing low pressure over the Arctic slipping towards N. Canada which should facilitate the quite strong west-east jet running across, or just to the south, of the UK. Thus a westerly upper flow portends changeable weather with temps generally around average but perhaps dipping a bit later remains as being  the percentage play. This doesn't, or shouldn't.t, translate into unrelenting rain and gales but periods of rain and quite windy with a N/S bias interspersed with quieter interludes. And as always this is just the suggested framework within which the det. models operate and as always they will sort the details.

Edited June 20, 2017 by knocker

[knocker]

A quick resume for today. Very much a N/S split with the north of England, NI and Scotland in 18-23C range with outbreaks of thundery showers particularly in Central Scotland.  In the south much warmer with 30C in the Cardiff and Bristol area and 33-34C around London/ Cooler around the coasts. Slight possibility of some thundery outbreaks. Tomorrow the joy of some cooler weather although still very warm on the pier at Margate.

But to move on. For the next few days the UK is under the influence of the upper trough to the NW and the Azores ridging from the SW. On the surface this translates to an Atlantic depression tracking north east then E/SE to be around the Faeroes at 00z Sunday  Thus the brief ridging and a weak cold front tend to be squashed as a north westerly flow is established with further fronts traversing the country. Temps over the weekend ranging from 13C in N. Scotland to 20-22C in southern England

As this upper low move rapidly east the door is ajar for the Atlantic to step through which it duly does with the next low arriving west of the Hebrides by 12z Tuesday with more fronts traversing the country and thus sustaining a tendency for a N/S split. Temps around average.

From this point the trough in the eastern Atlantic gets more organised and a large low pressure area develops over the UK with quite strong jet running south into France,