Model output discussion 14/04/18

[Singularity]

With the more pronounced easterly flow of recent det. runs, we've traded extreme/troubling levels of heat for mainly 'quite hot' conditions which will be easier to manage but yes, does fall short of being of much note in terms of peak temperatures for the very warm/quite hot spell as a whole.

Still plenty of ensembles going hotter though, and it really seems to be that the behaviour of slack areas of low pressure out east has become a guessing game for the models in general.

 

As for the weekend onward, for a while now this has been flagged by modelling as the time that the ridging relaxes in our vicinity, this as Tamara says being in line with the fade away of the Kelvin wave-induced boost to the eastward reaching of the Azores High. 

I have in recent days discussed the potential for extremely hot days to occur, should the hot air become trapped across the UK while winds fall slack. For at least southern parts of the UK, this still seems plausible to me given (as Tamara also points out) the lack of much of a driving force to fully retract the ridge out west of the UK and allow cool air to flood way south. In historical cases with similar forcing, I have observed very shallow ridges hanging on across the far south while low pressure zips across northern parts of the UK.

 

Before long, the models predict AAM trending upward - CFSv2 notably faster than GEFS with this (classic GEFS low AAM bias) - and this has been reflected, albeit without as much gusto as perhaps should be the case, in recent longer-term modelling from EPS and GEFS in which a new ridge from the Azores has featured plentifully.

This usually brings a fresher interlude as whatever's left of the old ridge gives way to the new one, but usually the ridges are 'flat' enough (much more west-east stretched than north-south) that this is limited for much of E&W with temperatures still tending to reach near or into the mid-20s before trending upward again as the ridge moves across.

 

What Tamara talks about going forward from there... well, it's pretty much the ultimate weather pattern if you like seeing multiple heatwaves separated by brief destabilisation events, typically featuring abundant thunderstorm activity. Fingers crossed that the sequence of tropical forcing holds together along the required lines .

[Mike Poole]

Eyes down for the 12s then and a decent effort from the UKMO first up, here at T144:

Have to say, can really feel the difference today, sunny morning giving way to high clouds in Oxfordshire, onwards and upwards!

[mb018538]

Just a shame everything is being pulled out west....if the high was to the east it’d be a jackpot. Still looks decent enough I guess. Looking like eastern coasts may suffer with low cloud by the end of the week.

[The PIT]

Pretty good 12oz GFS very warm to hot which should keep most people should be okay with. Thee easterly breeze should mean nights are comfortable to sleep in as well. No sign of a breakdown with rain generally being away expect very deep in lala land where it plays around with Ireland and northern Scotland and perhaps the channel island. So guaranteed a one of the warmest Junes on record here and a dry one.

[The PIT]

2 minutes ago, mb018538 said:

Just a shame everything is being pulled out west....if the high was to the east it’d be a jackpot. Still looks decent enough I guess. Looking like eastern coasts may suffer with low cloud by the end of the week.

God knows what you're looking at. The high pressure drifts east then north eastward this does allow a weakness to the north west and south east in fantasy Island. However it certainly doesn't retrogress westward.

[mb018538]

I was referring to the core heat plume, which certainly heads west by 144 hours.

[Man With Beard]

21 minutes ago, Mike Poole said:

Eyes down for the 12s then and a decent effort from the UKMO first up, here at T144:

Have to say, can really feel the difference today, sunny morning giving way to high clouds in Oxfordshire, onwards and upwards!

Doesn't look like it will breakdown at the weekend from there

[Mike Poole]

I like the GFS 12z, what has been shown on many of the model runs that go out 10 days or more, is the resurgence of the Azores ridge, no better example from the GFS at T288:

if this keeps happening it will make the summer!  

Edited June 23, 2018 by Mike Poole

[parrotingfantasist]

27 minutes ago, mb018538 said:

I was referring to the core heat plume, which certainly heads west by 144 hours.

Oh give us a chance will you

[Frosty.]

Looking at the GEFS 12z mean, southern uk in particular will be feeling really hot as next week goes on but it's a glorious spell nationwide which doesn't happen often! 

[Derecho]

Minimal risk of any rain for a week at least, warm to hot days and fairly comfortable nights for sleeping for most? (aside from Thursday perhaps)

Sounds like perfect summer weather to me . Maybe yesterdays output was too hot. I only like extreme heat if its got the storm potential to go with it.

I reckon somewhere will still get past 30C in the next week though, 32C at a push with the most likely day being Thursday.

And to think of how bad the weather was back in 2012...

[Frosty.]

Looking further ahead, the GEFS 12z mean indicates the azores high / ridge still looking strong even by 7th July!...I think this is going to be a fabulous spell for most of the uk, hottest across southern uk... perhaps only the far n / nw seeing any atlantic influence at all and even those areas enjoying plenty of warm settled weather too.

[mb018538]

ECM following UKMO quite closely, at a guess it could be Thursday for the warmest day? A very decent week coming up for sure. 

[I remember Atlantic 252]

Ay, good EC, perhaps less chance of north sea mist, hot sunny evening for our match v Belgium

[Mike Poole]

Hmmm, heat building once again on the ECM at T192:

I think the heat wave will be prolonged after this.

Edited June 23, 2018 by Mike Poole

[bradymk]

52 minutes ago, Quicksilver1989 said:

Minimal risk of any rain for a week at least, warm to hot days and fairly comfortable nights for sleeping for most? (aside from Thursday perhaps)

Sounds like perfect summer weather to me . Maybe yesterdays output was too hot. I only like extreme heat if its got the storm potential to go with it.

I reckon somewhere will still get past 30C in the next week though, 32C at a push with the most likely day being Thursday.

And to think of how bad the weather was back in 2012...

Yes. The south west of England looking the hot spot currently. Arpege going for 30c Monday, Tuesday and Wednesday with 31c. Scorcher!

[Frosty.]

The week ahead looks a cracker across most of the uk according to the Ecm 12z with increasingly hot conditions as high pressure dominates bringing lots and lots of strong late June sunshine, just the far n / nw seeing a bit of atlantic weather brushing around the top of the high..the heat holds on across southern uk all next week so unless you don't like hot sunny weather and eventually very humid with a growing risk of thunderstorms .. southern uk looks the best place to be during the next 7 / 10 days at least!

Edited June 23, 2018 by Frosty.

[The Eagle]

Anyone got 12z UKMO @ 168hrs?

[I remember Atlantic 252]

Just now, The Eagle said:

Anyone got 12z UKMO @ 168hrs?

@Summer Sun usually does

[mb018538]

Looking good for the next 7-8 days, I think we can bank those now. After the weekend it’s  very much up in the air, ECM tonight brings the Atlantic in at 240, GFS says Azores rebuild at the same time. Lots of options on the table.

[Mike Poole]

The key thing for me is whether we see periods of unsettled weather or not, does the Azores high continue to build back in. Really good example of this at T288 on the GFS parallel, aka FV3, here.:

as long as this sort of output is showing, summer goes on...

[Frosty.]

In the reliable timeframe (most of the coming week) tonight's Ecm 12z ensemble mean looks sensational with very summery weather pretty much nationwide..Enjoy..I certainly will!

[Mike Poole]

Still musing on the Azores ridging thing, here's some output at T240 from today, GFS, GEM, ECM ensemble mean, FIM9:

Actually the ECM mean is probably the least optimistic.  The rest all show substantial ridging from the Azores.  I think it may take a couple of days yet before we can have confidence that this current setup will have longevity.  Hope it does!

[bluearmy]

Ec op day 10 is with the control run cluster from the 00z eps (was just the largest cluster) . heights still higher than average though 

[Summer Sun]

1 hour ago, I remember Atlantic 252 said:

@Summer Sun usually does

It hasn't updated tonight

Sorry