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Model Output Discussion - The Start Of Summer


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This thread = Models, models and more models
Please remember that this thread is for discussing the model output only. If you want to chat about the summer weather more generally, please use the Summer chat and moans thread.

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Potential windchill for next Wednesday 

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14 minutes ago, Mike Poole said:

ECM mean T120:

image.thumb.jpg.33cbd7d5a85df5b6d0cf7f45065d9331.jpgimage.thumb.jpg.0581d6644611651c4dc0030b67fb79f7.jpg

 

Oh it gets much better!!..azores ridge at the end too..like the op..potentially a major scorcher for the s / se next week and everywhere else very warm / hot in places but very humid with hit and miss severe thunderstorms but hopefully plenty of dry and sunny weather too!?? 

 

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EDM0-144.gif

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EDM0-168.gif

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EDM0-192.gif

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Edited by Jon Snow
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The ecm det run fits pretty well within the framework of the EPS mean anomaly which has been indicating the removal of the Atlantic ridge for a while in the medium term

eps.thumb.png.9efad6eec38c9586db14a5c9e2a9ab79.png

Edited by knocker
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Good Evening All and Happy Summer Solstice!? The two models ecm and gfs are just to break this plume apart from the extreme version we had a few days ago, Just like the bitter East winds in Winter which disappear without notice...! Yes there is a plume on the way and yes thunderstorms , But Plumes are notouriously hard to predict....Anyway enjoy the upcoming weather?

plume.png

plumex.png

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13 minutes ago, northwestsnow said:

Acc to the mean image.thumb.png.0f2c4a8bfaa5d2c34c1eecec40ec53c6.pngat day 10 , July will start on a pleasant note with the jet pushed north of the UK..

And this Year  no one can say for a while we need the rain !. 

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Whilst it I might be committing horrendous moderator hypocrisy here, but using my location as an example can explain how very subtle changes could have huge impacts in the surface conditions.

The EURO models are flirting with developing a north easterly coming across the Baltic and North Sea during the middle of the week, quite a large fetch and with warm air aloft, plenty of scope to pick up a lot of low cloud and fog, at this time of year and a fairly cool sea, this could spread well inland overnight which also adds to the modification in temperatures. For eastern areas a slight shift in wind direction could mean the difference between seeing very warm or hot conditions, or temperatures barely reaching average and feeling quite cold on the coast.

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Amazing - North Cornwall is forecast to have uppers of 27C on Friday morning - this is the ECM op run. A new record for our models!

https://weather.us/model-charts/euro/cornwall/temperature-850hpa/20190628-0600z.html

But I'm still scratching my head over these ECM maximums. Especially away from the east coast. On Friday for 1pm ECM raw data is forecasting wall to wall sunshine for most southern/western areas. Winds generally not off the coast (except east coast). A breezy wind, but not ridiculous either (except extreme SW where maybe force 6). Uppers generally 20-23C. Yet maximums in the mid 20s? That would contradict all my experience of easterlies in summertime, which, under such conditions, surely demand a 10C difference between upper air and surface air at least and 15C-17C if the wind dropped further would be possible. 

Perhaps I should ignore these charts and wait and see what happens, hey, no guarantee we'll get such stupid uppers to the UK just yet anyway ?

Edited by Man With Beard
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14 minutes ago, Captain Shortwave said:

Whilst it I might be committing horrendous moderator hypocrisy here, but using my location as an example can explain how very subtle changes could have huge impacts in the surface conditions.

The EURO models are flirting with developing a north easterly coming across the Baltic and North Sea during the middle of the week, quite a large fetch and with warm air aloft, plenty of scope to pick up a lot of low cloud and fog, at this time of year and a fairly cool sea, this could spread well inland overnight which also adds to the modification in temperatures. For eastern areas a slight shift in wind direction could mean the difference between seeing very warm or hot conditions, or temperatures barely reaching average and feeling quite cold on the coast.

This really would be incredibly unlucky for this to happen when we get almost unprecedented uppers over the UK. Hopefully the models are overdoing the impacts of this feature. At first glance the ECM 12Z looks incredible for midweek but it could be less than impressive and rather disappointing at the surface if the BBC forecasts are correct.

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17 minutes ago, Man With Beard said:

Amazing - North Cornwall is forecast to have uppers of 27C on Friday morning - this is the ECM op run. A new record for our models!

https://weather.us/model-charts/euro/cornwall/temperature-850hpa/20190628-0600z.html

But I'm still scratching my head over these ECM maximums. Especially away from the east coast. On Friday for 1pm ECM raw data is forecasting wall to wall sunshine for most southern/western areas. Winds generally not off the coast (except east coast). A breezy wind, but not ridiculous either (except extreme SW where maybe force 6). Uppers generally 20-23C. Yet maximums in the mid 20s? That would contradict all my experience of easterlies in summertime, which, under such conditions, surely demand a 10C difference between upper air and surface air at least and 15C-17C if the wind dropped further would be possible. 

Perhaps I should ignore these charts and wait and see what happens, hey, no guarantee we'll get such stupid uppers to the UK just yet anyway ?

The latter figures would certainly be possible in perfect conditions with dry air, no cloud, and no CAA in the boundary layer as the mean LR would be close to the DALR. But whatever way one hacks it, without these conditions you have to know the characteristics of the boundary layer to make a stab at the lapse rate and in unusual patterns such as this it is next to impossible imo. Frankly I don't see a lot of point in getting to hung up on the forecast temps a few days down the line

Edited by knocker
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In recent years I’ve noticed that there seems to be not enough modification of a low-level cooled airmass as it moves off the sea and over the land. This causes the suppressing effect to reduce too slowly away from land.

It tends to be worst with a flow off the North Sea, which usually has the biggest modifying effect to start with, implying that the error is in some way proportional to the size of the real effect.

This is evident in all modelling to varying degrees. Here on the western fringes of the New Forest, during last summer’s hot easterly spells, I became used to actual max temps exceeding the modelled figures by 1-3*C.

So there’s plenty of substance to the upward adjustments MWB advises to the raw numbers.

Edited by Singularity
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Very nice to see that ECM prolongs the plume until the start of July. 

GFS isn't quite as potent and widespread as it was before, and has the plume ending earlier, but still very warm. My money is on the ECM with this one. Admittedly that is preference bias as I love heat, but the ECM does tend to be more reliable in situations such as these. 

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2 minutes ago, CanadianCoops said:

If you’re talking temp records being broken. It won’t happen. 

I wouldn't be so sure of that. If we are going by the GFS, probably. 

However, with the sort of uppers we are seeing here, it is not unrealistic to think that there is a very good chance of the June record being topped. 

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33 minutes ago, knocker said:

The latter figures would certainly be possible in perfect conditions with dry air, no cloud, and no CAA in the boundary layer as the mean LR would be close to the DALR. But whatever way one hacks it, without these conditions you have to know the characteristics of the boundary layer to make a stab at the lapse rate and in unusual patterns such as this it is next to impossible imo. Frankly I don't see a lot of point in getting to hung up on the forecast temps a few days down the line

I can certainly agree with the last line you wrote, and I'm sure you are absolutely right on the rest. 

We seem to have this discussion every year! I recognize completely that I am an amateur at all this and you have far more knowledge than me - but all the same, I just can't think of a situation in all my many many years (decades really) of watching where even such a remotely low hike on uppers has ever occurred in summer without considerable cloud cover. 

But as you say, pointless getting too hung up, we're a bit of a way from nailing the scenario anyway ?

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8 hours ago, Djdazzle said:

Care to explain why?

Purely based on my belief the models that are the conservative side of temps are closer to the mark. Wind flow. And the fact it takes everything to fall in place to get close to breaking record temps and I don’t believe it’ll be there. As we all say each to their own. Would love to see records fall but just don’t think it’ll all fall into place.

Edited by Blessed Weather
Unnecessary comment removed.
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I can't remember the exact year of the June UK temperature record, but I remember it was set much earlier in the month than now and with lower uppers. 

If we can't beat the June record this coming week with these extreme uppers and near the end of the month, then I don't know when we will. 

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8 minutes ago, matty007 said:

I wouldn't be so sure of that. If we are going by the GFS, probably. 

However, with the sort of uppers we are seeing here, it is not unrealistic to think that there is a very good chance of the June record being topped. 

I’m talking all time temp record. Maybe that’s the difference as June record maybe...we’ll see 

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48 minutes ago, chrisbell-nottheweatherman said:

Also, surface wind flow.

Indeed..that's very important too..the more SE'ly / S'ly the better!!!??

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Just now, CanadianCoops said:

I’m talking all time temp record. Maybe that’s the difference as June record maybe...we’ll see 

Oh, I understand. Yes, the all time record won't go. The ground temps are too low for that and it's not late enough in the year. If we had this setup on July 27th, then I think the all time record would go. 

Around 36c somewhere in London would be my shout, probably Heathrow. 

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4 minutes ago, matty007 said:

I can't remember the exact year of the June UK temperature record, but I remember it was set much earlier in the month than now and with lower uppers. 

If we can't beat the June record this coming week with these extreme uppers and near the end of the month, then I don't know when we will. 

1976 28 June with 35.6 C Southampton

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Just now, johnholmes said:

1976 28 June with 35.6 C Southampton

My mistake sorry. I was probably thinking of the highest daily mean. I think that was the 3rd of June? 

I don't believe the uppers were as high as they will be in this spell were though were they? 

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