Model output discussion 14/04/18

[Mike Poole]

So the ECM ensemble mean close to the GEFS mean at T240:

GEFS at same time:

Jet going north, opportunities for high pressure to build across the UK, late May looking good to me.

[Mike Poole]

This one will get overwritten by the 0z, this will mean nothing in the morning ! ,I tried to upload the actual pictures but this annoying new software won't even allow that, but you know how dogs like to sniff each other's behinds, here's the ICON 18z:

Edited May 5, 2018 by Mike Poole

[Mike Poole]

I've seen enough of the GFS 18z to feel confident that good times are coming, 

Sorry that won't enlarge, I've tried saving and uploading on the iPad but it doesn't work.  

It looks like this summer is going to be a classic, like we've not seen for a while, jet heading nicely north.  As much as we  can say this far out, what's  not to like?  GFS at T216 

Edited May 5, 2018 by Mike Poole

[Cheshire Freeze]

3 hours ago, Mike Poole said:

I've seen enough of the GFS 18z to feel confident that good times are coming, 

Sorry that won't enlarge, I've tried saving and uploading on the iPad but it doesn't work.  

It looks like this summer is going to be a classic, like we've not seen for a while, jet heading nicely north.  As much as we  can say this far out, what's  not to like?  GFS at T216 

Far too early to be making assumptions about the blueprint for the summer pattern...

A good period of weather coming up, no doubt, but just the hint that some are getting a little carried away. 

Hints in the extended range that the HP positioning may not stay favourable for us to continue with the warm and settled weather with a mean tendency for HP to locate further to our N. Little agreement at present as to whether this blocking locates to the NE or the NW of us...though those wanting a continuation of the settled weather would probably prefer the former.

The GEFS 12z suite had the mean HP signal to the NE of us well into FI which would imply a generally warm/very warm pattern continuing well into May, albeit with the enhanced risk of troughiness encroaching from the S or SE...so the potential for some convective shenanigans (more especially in the S).

 The second scenario which is possibly less likely (for the time being) is for HP to head further NW...the far reaches of the 18z show this scenario...

The 12z ECM also showing this retrogression scenario (though not really backed by its ensemble mean at this juncture)

Moving further on, I am still of the opinion that May will quite possibly feature the best that 'summer' has to offer this year with a general deterioration thereafter. 

 

[Mike Poole]

4 hours ago, CreweCold said:

Far too early to be making assumptions about the blueprint for the summer pattern...

Moving further on, I am still of the opinion that May will quite possibly feature the best that 'summer' has to offer this year with a general deterioration thereafter. 

 

Pot. Kettle.

You've made this assertion about a poor summer some time ago on one of the other threads, and if that proves right, fair play to you.

My comments on the 18z may have been on the bullish side, although they were caveated, but from the recent output I have to say I do see a good chance of summer starting well - and I am as entitled to my bet as anyone else.  Let's see what happens.

Edited May 6, 2018 by Mike Poole

[Matthew.]

The Gfs and stalling trough on the Ukmo continue with the perfect summer charts this morning NAO going nicely positive 

[ANYWEATHER]

17 minutes ago, Matthew. said:

The Gfs and stalling trough on the Ukmo continue with the perfect summer charts this morning NAO going nicely positive 

Not sure what you mean to be honest, by mid week all the UK is under the influence of a large low pressure system out to the Northwest of the uk with its attendant rain ,showers and chilly Atlantic air. Of course there will be some sunshine but for the forseable the uk remains under the influence of the Atlantic and not the continental stuff

[Summer Sun]

00z ECM ens still pointing to a rise in pressure after an unsettled blip during next week

The further south and east you are it still doesn't look like you'll see a huge amount of rain during the next 10 days

[summer blizzard]

The current spell of good weather is probably being driven by tropical westerlies which moved across the Pacific over the past month (from the Indian Ocean to around the dateline) and look to largely filter out to neutral. 

Whether the atmosphere generates another wave or enhances the trades (as happened last summer) will to some degree be a good guide of what to expect this summer in terms of amplication vs a zonal pattern. 

[Summer Sun]

High pressure moving back in at t168 on UKMO 00z

[bluearmy]

The upper sceuro ridge remains the main player and it’s interaction with the systems heading in from the Atlantic continue to cause issues, run to run. one would expect that as the spring progresses towards summer, the Atlantic systems will lose some of their oomph  (technical term ) and that upper ridge will edge further west in general. 

[Derecho]

With data for April coming through it's a good time to look at SSTs as certain patterns (such as ENSO) can persist for the next couple of months, potentially giving an indicator of medium to long range variability too in some areas also.

We are currently in a La Nina, though April 2018 is likely to be in the top 5 warmest globally. Despite this quite a large area of North America had its coldest April on record but this was more than offset elsewhere (left). The cold over the US often poured out into the Atlantic so SSTs anomalies changed a fair bit as a result.

Record warmth was seen at times in the Southern US, central Europe, Argentina, Australia and the Arctic circle. In the UK it was a warm April thanks to the mid-month heatwave though there were some big swings in temperature. The US saw a pattern driven by the La Nina no doubt, whereas the UK / Europe was probably influenced by the cold pooling in the North Atlantic

Which of these features is relevant to the UK? So far this May the cold blob in the North Atlantic appears to be making a return (right). Such a pattern could mean a very hot summer for central and southern Europe if it were to persist. In the UK i wouldn't want to make a call but I will say that westerlies are more likely then usual over the next few month if it carries on, with above average rainfall in the North and West more likely.

La Nina looks like as though it may persist. I can't think of many recent analogues. 2009 and 2015 had similar SST patterns in the North Atlantic but El Nino's were developing at that time. 

Other notable things are a cool tropical North Atlantic which means the Atlantic hurricane season may be a quiet one. Though any warm up could change that markedly with the La Nina still in place. Active hurricane seasons can trigger changes in patterns if tropical storms get caught up in the jet, so its something to bear in mind.

The arctic looks like getting some extreme warmth for the time of year. After a lucky couple of Summers, arctic sea ice is at risk of setting new record lows. This may also be worth keeping an eye on.

In the UK this week? Looks like the warm weather will last till Wednesday before the Atlantic takes charge for the rest of the week, driven by cold pooling from Greenland evident in the right panel of the first plot. Some hints it may settle down again come next Sunday. If the Atlantic is shunted north, we should tap into some very warm air very quickly. Its shaping up to be a very warm May across central Europe.

[Cheshire Freeze]

5 hours ago, Mike Poole said:

Pot. Kettle.

You've made this assertion about a poor summer some time ago on one of the other threads, and if that proves right, fair play to you.

My comments on the 18z may have been on the bullish side, although they were caveated, but from the recent output I have to say I do see a good chance of summer starting well - and I am as entitled to my bet as anyone else.  Let's see what happens.

I haven't made any assertion for a poor summer anywhere. 

I have, on balance, suggested a summer more likely to be closer to '07 than '76. That's no 100% assertion. In fact, the balance between ridge and trough I feel will be more critical than usual this year... We could just as easily end up in a plume after plume scenario should troughing hold off just enough. 

Either way, I think rainfall will leave a notable signature at times this summer. 

Excellent post by Q above btw. 

[Mike Poole]

1 hour ago, CreweCold said:

I haven't made any assertion for a poor summer anywhere. 

I have, on balance, suggested a summer more likely to be closer to '07 than '76. That's no 100% assertion. In fact, the balance between ridge and trough I feel will be more critical than usual this year... We could just as easily end up in a plume after plume scenario should troughing hold off just enough. 

Either way, I think rainfall will leave a notable signature at times this summer. 

Excellent post by Q above btw. 

Thanks, I think I can see where you're coming from now.  I do still think a memorable summer is possible, but for what reasons remains to be seen.

Meanwhile, the GFS 6z brings warm settled spells back at T240 and the end of the run:

Edited May 6, 2018 by Mike Poole

[Summer Sun]

12z GEM shows an improving picture through next weekend and into the following week as high pressure makes a quick return

Becoming warmer again as well

[Mike Poole]

GEM loving the UK in the hot flow:

GFS possibly better though,  here at T240 and T 348:

Warmth on the way, I think

Edited May 6, 2018 by Mike Poole

[Singularity]

Vast difference, for this weekend through to the middle of next week, between the ECM 00z with HP focusing NE then NW of the UK and the GFS 12z with HP across southern parts and struggling even there as the jet stream reaches over 200 mph in the N Atlantic although this seems a bit it over the top for the time of year. 

The GEM 12z sits nicely in the middle while the UKMO 12z is headed down a similar route via trough disruption and LP dropping down into NW Europe at +144.

That EPS are predominantly in favour of a more GEM-like outcome makes this middle ground seem even more of a reasonable bet.

[Frosty.]

A very good recovery towards the end of the Ecm 12z with a warmer / blocked pattern returning...in the meantime, summer warmth and sunshine goes on tomorrow and for the south of the uk tuesday too and for the southeast / east anglia wednesday looks warm as well, progressively cooler and more changeable further n / w and then following a generally cooler changeable blip, the trough gets squeezed by height rises to the sw / ne and summer like conditions return.

[Mike Poole]

Thought it was worth posting the ensemble means from ECM and GEFS at T240.

Both still look promising in terms of the pattern over Europe, actually not that different to my post at the top of this page, maybe seems so after being out in the sun all day.  ECM first:

Edited May 6, 2018 by Mike Poole

[Man With Beard]

18 minutes ago, Mike Poole said:

Thought it was worth posting the ensemble means from ECM and GEFS at T240.

Both still look promising in terms of the pattern over Europe, actually not that different to my post at the top of this page, maybe seems so after being out in the sun all day.  ECM first:

Generally quite good but that trough dropping been the Azores ridge and Scandinavian ridge can be a localised pain for parts of the UK

[Summer Sun]

GFS going for 26c today given its tendency to undercook highs we could be close to 29c in the London area

29.1 or higher will break the daily record which has stood since 1976

[johnholmes]

No total agreement between the 3 anomaly charts I use.

They all, in varying degrees suggest that 500 mb troughing will be the main driver in the 6-14 day outlook. That is as a mean over their time scales, just what the actual weather may be from day to day is not so clear. On the basis of these charts then any prolonged dry weather does seem unlikely.

http://www.cpc.ncep.noaa.gov/products/predictions/610day/500mb.php

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

[Polar Maritime]

NetWx-sr hi rez going for 28c today as SS says records could very well be broken.

[carinthian]

23 minutes ago, Polar Maritime said:

NetWx-sr hi rez going for 28c today as SS says records could very well be broken.

Nice early summer spell over in Blighty. So pleased you for guys. Just wondering if the highest temps today could be in southern parts of Northern England with the longer land flow ? ( outside the heat island of Greater London ). Our mixed spring continues over here , plenty of rain forecast in the extended forecast period and yes we have snow predicted at our elevation for the early part of next week with upper cold pool over Central Euroland. We will see ! 

NB. Of topic just seen highlights of the Tour De Yorkshire, shown widely on Euro TV. The Scenery looked wonderful. A good advert for the county and the crowd numbers just amazing. On par with world cup event, so they report over here. Well done to the super folk of the White Rose County .

 C

[Mike Poole]

I don't think this bank holiday weekend could have been sunnier in my region, I've seen one wispy cloud all weekend!  Yes, the midweek period is less settled, but what then?  ICON 12z has settled weather back by Sunday, and here at T180:

GFS at same time:

Some less settled weather follows, local to the UK, but by the end of the run (T384) a link up of the Azores and Scandi systems:

Heat bubbling to the south, should the wind direction favour us going into summer.

Edited May 7, 2018 by Mike Poole