Model Output Discussion - 3rd May Onwards 00z--->

[Frosty.]

The Ecm 00z shows a very warm spell for the south of the UK during the first half of next week with plenty of sunshine and temperatures well into the 20's celsius, Tuesday could be the warmest day of the spring so far, beating the current highest 25c set in April. The northwest of the UK stays more unsettled and cooler and all areas turn unsettled from midweek and gradually cooler from the west but the run ends on a positive note with high pressure set to build in from the southwest beyond T+240 hours.

Edited May 7, 2015 by Frosty.

[joggs]

What i have noticed and what the modes have and are showing is the declining vortex in a similar shape to the past winter roughly elongated pacific to atlantic.

[picog]

What i have noticed and what the modes have and are showing is the declining vortex in a similar shape to the past winter roughly elongated pacific to atlantic.

What is the significance of that for our spring weather, or perhaps longer term out look?

[Frosty.]

The Gfs 6z shows much warmer weather on the way for the southern half of the uk, 20c in the south by Sunday, 21-23c next Monday and 24-26c on Tuesday, I'm hoping somewhere in the south/east will reach 26c because that would be the highest so far this spring. The North/Northwest of the UK are unlikely to see much improvement from current conditions and from the middle of next week the very warm settled weather is swept away eastwards as low pressure and cooler Atlantic air arrives, the unsettled conditions don't last long with the Azores high building in and bringing more settled weather to the south for a time.

Edited May 7, 2015 by Frosty.

[mushymanrob]

well im not so optimistic for the outlook into mid may



that looks like a low pressure dominated spell, with the upper flow switching from a southwesterly to a westerly, even slightly north of west with the upper trough sat over the uk (8-14dayer).
 

a pretty unsettled spell, cool at times with plenty of rain but sunnier spells too.

[AWD]

A lot of focus on the upcoming possible warm snap early next week, which is fair enough, nothing wrong with that but it's worth highlighting the risk of some very heavy rainfall, modelled below by the GFS 12z, for Northern England tomorrow afternoon;

Coinciding with the Friday afternoon/evening rush, could be quite miserable here.

[knocker]

To be honest I think I would rather take my chance with Mystic Meg than GFS rainfall prog. 24 hours hence

[Frosty.]

Superb Ecm 12z T+120 chart for next Tuesday, the best yet in my opinion..high 20's celsius if this verifies, ecm just keeps raising the bar for Tuesday, hopefully will be the warmest day of the year so far.

[Stuie]

Frosty, maybe you can answer this question. I think we are clinging on to a hot blast for Tuesday. You are posting nice looking 850`s whereas the Z500`s are far from it. Which is right?

[Frosty.]

Frosty, maybe you can answer this question. I think we are clinging on to a hot blast for Tuesday. You are posting nice looking 850`s whereas the Z500`s are far from it. Which is right?

Well I think Tuesday will be Hot in the south if it's sunny and as the ecm 12z shows with 564 dam thickness well into the UK, +15 T850 hPA which is what I think would bring very warm or hot surface conditions. I should just add the met office have not indicated anything hot for next week, warmer is what they have said. In summer when you have + 10 T850 hPA you can normally expect 25c plus and with +15 T850 30 celsius plus. Edited May 7, 2015 by Frosty.

[ANYWEATHER]

A quick one from me, Tuesdays plume looks pretty dramatic and very brief! Looking forward to some interesting weather?.....

[Yarmy]

Frosty, maybe you can answer this question. I think we are clinging on to a hot blast for Tuesday. You are posting nice looking 850`s whereas the Z500`s are far from it. Which is right?

 

They are both right. +16C 850s into England (even +18C touching the South coast).

 

 

It's all too brief though and gets wiped out in 24 hours.

[Stuie]

Well I think Tuesday will be Hot in the south if it's sunny and as the ecm 12z shows with 564 dam thickness well into the UK, +15 T850 hPA which is what I think would bring very warm or hot surface conditions. I should just add the met office have not indicated anything hot for next week, warmer is what they have said.

 

Thanks for your answer Frosty, very diplomatic. From that can I take my chart as being "more so" correct if the Met is not going for a blast? I am all for heat but I also want to know what I am looking at. Thanks mate.

[Frosty.]

Thanks for your answer Frosty, very diplomatic. From that can I take my chart as being "more so" correct if the Met is not going for a blast? I am all for heat but I also want to know what I am looking at. Thanks mate.

No problem mate, just to add, the Gfs has been showing +10 T850 hPA and max temps of 25/26c and the current ecm is better than that.

[damianslaw]

Models very similar to yesterday, a predominantly unsettled outlook in the main but with a temporary drier much warmer period Sunday-Wednesday for the SE quarter of the country, unsettled for the NW.

 

Jetstream profile is forecast to sink south again next week, bringing average conditions at best temp wise with further bouts of rain, heights positioned to bring in a NW flow, much like recent days.

 

For the SE there is some good news, for the NW a very poor outlook for what in many a year can be the best month for sunshine, dry warm weather (not always).

[Scorcher]

Yes those are incredibly impressive hPa temperatures for the first half of May. Obviously sunshine amounts will dictate how high temperatures get and we'll have to hope the peak of it comes at a favourable time on Tuesday afternoon as it is a brief affair. It would be a shame to see the warmest air over us during the night for example.

 

Even with cloud I imagine it will feel very warm and humid for England and Wales at least with some potentially very high minima if there is some cloud about.

[Stuie]

Having a look at the jet stream and there is nothing significant. Next Wednesday there is a hint of it wanting to go North but flattens out post that. There is obviously an FI for that too so worth a watch and hopefully some progress from this.

[knocker]

Not a huge change with today's anomalies. Still plugging the trough orientated SE Greenland to the UK with the HP pushed south and east with the ECM maintaining some ridging to the east. The evolution in the ext period is still maintaining the idea of a Scandinavian trough and pressure building from the south west but as yet no agreement ( to be expected) on how much influence the HP will bring to bear on the UK which could be significant as to the origin of the airstream.

Charts weatherbell

 

Oh and the ECM EPS 850mb mean temp for Tuesday is 12C for the SE and 10C for the midlands.

Edited May 7, 2015 by knocker

[Captain Shortwave]

Well the output this afternoon has increased uncertainty during the start of next week.

The ECM operational is fantastic with 850s of +18C getting into the south of England, that would likely bring temperatures of 27/28C across the south eastern third of the country.

 

But on the other hand the GEM and the latest GFS block the pulse of very warm air wafting up from the continent.

Just 20C in the south east, cooler elsewhere.

 

So at the moment I think the BBQ should be kept in the shed, though you would think that the ECM/UKMO solution would be right considering it is 5 days out.

[knocker]

I must admit I'm suspicious of the ECM ops very high temps on Tuesday. The ens downgrades them somewhat and the the wind vectors are not southerly but SW from the approaching depression so I would be surprised if they are not downgraded this morning.

[knocker]

Latest EC32 update.

 

Not surprisingly it has the upper trough over the UK on the 15th bringing a short spell of cyclonic unsettled weather to all parts.

 

This trough quickly moves away east allowing HP to build from the SW. This is well established by the 23rd but the centre of the HP remains to the SW giving a W or NW airflow which dictates slightly lower than average temps.

 

This more or less remains the position until the 8th June with a slight meandering of the centre of the HP but the temps do rise to average or slightly above with more progressive ridging at times..

 

Summary.

 

Nutshell time. Once next weeks troughing is out of the way HP holds sway in the eastern Atlantic and NW Europe with no sign of cyclonic activity so quite pleasant for the most of the second half of May and the first week of June. That's the theory anyway.

Edited May 8, 2015 by knocker

[Frosty.]

The Ecm 00z is still showing a warm/very warm spell early next week across England and Wales with temperatures in the south/se reaching 25/26c. I think the warmth and humidity could end with thundery rain / showers for the south east of england. The second half of next week shows cooler and more unsettled Atlantic weather spreading across the UK.

Edited May 8, 2015 by Frosty.

[knocker]

I find the most interesting point about the last two ECM runs is the difference in the surface analysis for 12z Tuesday. Yesterdays 12z run has a depression about 400 miles west of Ireland 988mb with a SW flow over the UK. The 00z run has a completely different analysis with a weird looking low about 800 miles SW of Cornwall and a very slack flow over the UK. Go figure.

[Nouska]

I find the most interesting point about the last two ECM runs is the difference in the surface analysis for 12z Tuesday. Yesterdays 12z run has a depression about 400 miles west of Ireland 988mb with a SW flow over the UK. The 00z run has a completely different analysis with a weird looking low about 800 miles SW of Cornwall and a very slack flow over the UK. Go figure.

 

Yes, the parity in surface temps between the control and the deterministic is suddenly out of kilter for that time period on the the 00Z EPSgram for Reading.

 

[Captain Shortwave]

12 hours ago we had good agreement on temperatures hitting the mid or even high twenties on Tuesday, now there is pretty good agreement on conditions turning cooler after a warm Monday, only the ECM looks like holding onto the very warm air. The best explanation of this is how the secondary system in the approaching trough is handled.

Todays GFS at day 4

The low has become slow moving and cut off over the Azores, this weakens the trough and also the ridge. There is also a change as a new ridge builds during the middle of the week, possibly northern blocking coming into place again.

 

Compare that with the 12z from yesterday.

Deeper, and more open trough, hence the stronger ridge over the UK.

 

It is shocking to see such a dramatic change at that timeframe. To be honest it is quite a shock, not the first this morning.......