Model Output Discussion 00z 19/07/13

[Frosty.]

The Ecm 00z ensemble mean shows the heat & humidity intensifying from tomorrow and through to around midweek with temperatures rocketing into the low to mid 30's celsius, low to mid 90's F with blazing but increasingly hazy sunshine and an increase in thunderstorms being triggered by the intense heat and humidity, some violent storms are likely to brew up next week, isolated on monday but then becoming more and more widespread, the nights will be very warm and muggy, after midweek, the temperatures slowly moderate from hot and humid to very warm and by next weekend onwards it still looks warm and humid with sunshine and thundery showers with a trough over the uk.

[nitro_deluxe]

Here's to replacing 30s with storms to 20s with a few storms? Keep that Atlantic mush at bay

Enjoying the potential transition already...

[Man With Beard]

It's interesting comparing the forecasts for next week with what happened in July 2006. From what I remember, the hot spell was not forecast to last as long as it did, but expected attacks from the atlantic were held at bay, often at the last minute - as a result, the hot spell went on a little longer, then a little longer and so on.

The chart for 19th July 2006, which produced temperatures of 36C, is a little hotter but otherwise not dissimilar to todays GFS 06Z for Monday

 

 

Looking again at 19th July 2006, you would expect the heat to be quickly pushed away by the incoming low (and I think this was the forecast). However, the block was surprisingly resilient. By 21st July, this was the situation:

The low just kept rotating to the west, and pressure rose again across the south - temperatures remained above 32C and sunny skies prevailed.

 

Interestingly, the most recent model output is trending in a similar direction. For example, ECM for Friday (T144).

 

 

 

Now that's not a million miles away from the 2006 scenario. And I must add, in 10 years of model watching on the web (and many more years following the weather in other ways), I'd guess that in 75% of these situations (i.e. low pressure moving from the west against an established block), the eastward progress of the low ends up slower than modeled, with big adjustments to forecasts even 24 hours before the event. 

 

So though the models have been banging the pattern change drum for a few days now, the pattern change may end up being something like a 2006 scenario with a low pressure stalled off Ireland for several days pulling up southerlies over the bulk of the UK.

 

(Just a theory!)

[Summer Sun]

The met office have now issued early warnings for Thunderstorms on Tuesday and Wednesday most of north west England and north east England are in the clear at this stage along with all of Scotland and Northern Ireland all other parts of England and wales are under a yellow warning- http://www.metoffice.gov.uk/public/weather/warnings/#?tab=map&map=Warnings&fcTime=1374274800

Edited July 20, 2013 by Summer Sun

[storm1080]

Nice theory, but wont the force of the jetstream this time round make a difference...Hope you're right...

[mushymanrob]

Does the remnants of the current high /warm uppers etc prevent the low from passing over us to the NE (so says the GFS). Will it 100% make it spin/move back west and then south, repeating the process?

 

who knows?... the high is expected to drift away and its influence decline. but IF it held its ground and IF it intensified it MIGHT hold the low with nowhere to go but orbit upon itself. so thats a possibility, but a very small one, and theres no real support for that evolution in any model..... but things might change! lol.

[Weather-history]

who knows?... the high is expected to drift away and its influence decline. but IF it held its ground and IF it intensified it MIGHT hold the low with nowhere to go but orbit upon itself. so thats a possibility, but a very small one, and theres no real support for that evolution in any model..... but things might change! lol.

Yes but then again if I had wings and if I didn't have to breathe, I might be able to fly to the moon......

[jesusfernandez]

Yes but then again if I had wings and if I didn't have to breathe, I might be able to fly to the moon......

 

Love that phrase ! can I use it in my signature??

[Weather-history]

Love that phrase ! can I use it in my signature??

By all means.

I was reading Paul Blight's UKWeatherworld synoptic analysis and he gives it straight. He is not giving much hope that this summer spell will last much longer not through his expert eyes.

http://www.ukweatherworld.co.uk/forum/index.php?/topic/98680-synoptic-discussion-the-end-of-the-heatwave/page__pid__864717#entry864717

Edited July 20, 2013 by Weather-history

[TEITS]

A clear shift today in the models.

 

At first it appeared like a classic breakdown of storms followed quickly by fresher W,lys. The output today suggests the low pressure makes less eastward progress so we remain under a warm, humid, unstable S,ly flow. At this stage the fresher W,lys might not arrive until early next week and this is subject to change.

 

What is certain is a thundery breakdown is looking very likely and the long hot, dry, sunny days will vanish. However keep an eye on the models extending the warmth and storm risk though.

 

One thing is certain though. During next week we have plenty of exciting weather coming our way and at times, especially at night, it will feel as though the UK is in a tropical rainforest!

[Man With Beard]

Nice theory, but wont the force of the jetstream this time round make a difference...Hope you're right...

Possibly!

[Mini tiger]

A clear shift today in the models.

 

At first it appeared like a classic breakdown of storms followed quickly by fresher W,lys. The output today suggests the low pressure makes less eastward progress so we remain under a warm, humid, unstable S,ly flow. At this stage the fresher W,lys might not arrive until early next week and this is subject to change.

 

What is certain is a thundery breakdown is looking very likely and the long hot, dry, sunny days will vanish. However keep an eye on the models extending the warmth and storm risk though.

 

One thing is certain though. During next week we have plenty of exciting weather coming our way and at times, especially at night, it will feel as though the UK is in a tropical rainforest!

I was beginning to wonder if the long hot sunny days have gone already as London is a very overcast and cooler day today at 21oC.. i.e Has the breakdown commenced already from the north east..

 

The other question I have for the experts is when the cold front crosses the UK from the west on Wednesday will this be where the thunderstorms are and will they

increase as thundery showers just behind the cold front ?

[The PIT]

Differences between the big two GFS wanting to keep the heat much longer and reintroduce it further north ecm wanting to shunt it away eventually re-introducing the Atlantic. GFS pushes everything further south. Looks like the key player will be the placement of the low in the next few days and which model gets the best hang on it.

[Mini tiger]

The met office have now issued early warnings for Thunderstorms on Tuesday and Wednesday most of north west England and north east England are in the clear at this stage along with all of Scotland and Northern Ireland all other parts of England and wales are under a yellow warning- http://www.metoffice.gov.uk/public/weather/warnings/#?tab=map&map=Warnings&fcTime=1374274800

 

 

Will there be any thunderstorms in the south east if this low cloud continues to drift in over us. As its keeping the temps down almost 10oC compared to recent days. WIll the storms still form above the low cloud, or will we miss out ?

[gottolovethisweather]

The other question I have for the experts is when the cold front crosses the UK from the west on Wednesday will this be where the thunderstorms are and will they increase as thundery showers just behind the cold front ?

 

Far too early to tell at this stage, but I would advise you follow the thread below for updates nearer the time.

 

http://forum.netweather.tv/topic/77285-convective-storm-risk-discussion-17th-july-2013-onwards/?p=2742065

 

The MetO Fax Charts are good guidance tools right up to t-24 hours. However, I suspect there will be some home grown storms thrown in and the main breakdown will arrive rather unexpectedly overnight from the South. Worth realising that the models generally struggle with these MCS types up from the South.

Edited July 20, 2013 by gottolovethisweather

[gottolovethisweather]

Will there be any thunderstorms in the south east if this low cloud continues to drift in over us. As its keeping the temps down almost 10oC compared to recent days. WIll the storms still form above the low cloud, or will we miss out ?

 

Don't worry, the heat and humidity is yet to build and it will go bang in prone locations.

Edited July 20, 2013 by gottolovethisweather

[MR EXTREMES]

A clear shift today in the models.

 

At first it appeared like a classic breakdown of storms followed quickly by fresher W,lys. The output today suggests the low pressure makes less eastward progress so we remain under a warm, humid, unstable S,ly flow. At this stage the fresher W,lys might not arrive until early next week and this is subject to change.

 

What is certain is a thundery breakdown is looking very likely and the long hot, dry, sunny days will vanish. However keep an eye on the models extending the warmth and storm risk though.

 

One thing is certain though. During next week we have plenty of exciting weather coming our way and at times, especially at night, it will feel as though the UK is in a tropical rainforest!

 

its also worth noting that pressure could well rise again from the azores and other than the low heights mid week the alantic is not in the mood for a onslaught so keep an eye on the models I feel a rebuild after a short cooler spell, very excited about storms and although cooler it will still be humid and sticky much more like the summers of the 80s and early 90s.

[Barry12]

A comparison between the models:

 

ECM vs UKMO vs GFS at 120

 

 

 

 

ECM vs UKMO vs GFS at 144

 

 

 

Differences at just 120 hours, the ECM and UKMO look more alike.

Edited July 20, 2013 by Barry95

[forecaster]

I was beginning to wonder if the long hot sunny days have gone already as London is a very overcast and cooler day today at 21oC.. i.e Has the breakdown commenced already from the north east..

 

The other question I have for the experts is when the cold front crosses the UK from the west on Wednesday will this be where the thunderstorms are and will they

increase as thundery showers just behind the cold front ?

 

 

I wouldn't call it a "breakdown". The cooler weather today is due to fluctuations in the position of the high (bringing a NE drift), coupled with a shallow layer of moisture trapped around 2500ft off the ground beneath a huge area of subsiding air. There's still a good few days of anticyclonic settled weather to come for London.

[Cheshire Freeze]

I wouldn't call it a "breakdown". The cooler weather today is due to fluctuations in the position of the high (bringing a NE drift), coupled with a shallow layer of moisture trapped around 2500ft off the ground beneath a huge area of subsiding air. There's still a good few days of anticyclonic settled weather to come for London.

 

Just a quick question after noticing your recent posts. Are you a trained meteorologist by any chance? I say this as I see you're from Reading aswell which is quite a famous location for meteorology training; plus your profile name makes me wonder

 

It's always good to have a couple more pros knocking about!

Edited July 20, 2013 by CreweCold

[nitro_deluxe]

It could be Bond..James Bond

Jesting..please see the humorous side, please? Pretty please lol.

[Frosty.]

The humidity levels are already rising and will be rising a lot more in the coming days, as will the heat, becoming very hot and sticky during the first half of next week and sunny at first but becoming increasingly thundery, the Gefs 06z mean shows the continental hot plume reaching further and further north and a lot of violent thunderstorms breaking out next week, early warnings already issued, looks like being a very exciting week for storm enthusiasts with a very tropical feeling spell. Even by next weekend it still looks warm with sunshine and thundery showers but this incredible heatwave still hasn't reached it's peak, but it will next week and so will the STORMS.

[Average Joe]

The humidity levels are already rising and will be rising a lot more in the coming days, as will the heat, becoming very hot and sticky during the first half of next week and sunny at first but becoming increasingly thundery, the Gefs 06z mean shows the continental hot plume reaching further and further north and a lot of violent thunderstorms breaking out next week, early warnings already issued, looks like being a very exciting week for storm enthusiasts with a very tropical feeling spell. Even by next weekend it still looks warm with sunshine and thundery showers but this incredible heatwave still hasn't reached it's peak, but it will next week and so will the STORMS.

Come on Frosty, keep posting these nice red coloured charts please. Off on hollibobs once the schools break next week, and don't like the comments of these Atlantic systems returning to coincide with it!! I'm relying on you!!

[Barry12]

For the north of the UK temperatures look like reaching 25C max, which is warm but certainly not hot. Hot in the south though with 90F possibly being reached on Monday. Looking at the output, by midweek it looks like a cool down with a few isolated thunderstorms. Nothing spectacular really

 

[Cheshire Freeze]

Holy moly! GFS 12z for Monday afternoon....

 

 

 

Edited July 20, 2013 by CreweCold