Model Output Discussion 18z 28/07/13

[Summer Sun]

what is this i see! Tho, as its at t360... Usual caveats apply! But at least this is interesting, as opposed to the benign weather on offer over the next 10 days or so

 

Based on what the 00z GFS ensemble was showing its probably a wild outlier

 

 

A good ensemble mean there it has to be said no end in sight at present

 

Edited September 8, 2013 by Summer Sun

[Frosty.]

Based on what the 00z GFS ensemble was showing its probably a wild outlier

 

 

A good ensemble mean there it has to be said no end in sight at present

 

Yes I think there is huge potential going forwards, a late september heatwave is a possibility for sure.

[Captain Shortwave]

what is this i see! Tho, as its at t360... Usual caveats apply! But at least this is interesting, as opposed to the benign weather on offer over the next 10 days or so

This is more of a heat lovers chart than an unsettled lovers chart to be honest, that storm will really struggle to get into the UK given it is building quite a ridge over central/northern Europe

Look at the uppers

 

 

If only 

As for this week, our problem seems very clear on the pressure charts

 

 

So many weather fronts!!!

Edited September 8, 2013 by Captain shortwave

[Frosty.]

This is more of a heat lovers chart than an unsettled lovers chart to be honest, that storm will really struggle to get into the UK given it is building quite a ridge over central/northern Europe

Look at the uppers

 

 

If only 

I believe in miracles after this record busting summer, why not have a few more heat records before the autumn gets too advanced, bring on the heat..again

[Captain Shortwave]

I think it's more in hope than anything else at the moment. Still the bbc forecast has highs of 22C by the end of the week so it should warm up eventually. After it rains for 24 hours over the triangle of doom first 

[Methuselah]

Yes I think there is huge potential going forwards, a late september heatwave is a possibility for sure.

It screams potential! 

[Frosty.]

I think it's more in hope than anything else at the moment. Still the bbc forecast has highs of 22C by the end of the week so it should warm up eventually. After it rains for 24 hours over the triangle of doom first 

Yes captain, and it's not such a leap of faith to change that 22c to 25c+  ...on  current evidence, a very warm mid to late september is far more likely than a cool and unsettled one with the PFJ up near Greenland...yes pete, it screams potential

[Tamara]

A rather changeable week ahead, most especially further north but the prospects for further fine weather are still intact after a band of rain, probably weakening as it does so, later in the week comes south and leaves a few residual showers.

 

The models have comes to terms with the troughing to the east of the Azores High and associated atlantic ridge and I think that the modelled fairly deep low to the north of Scotland rather echoes a similar deep low we saw within this cyclical rinse and repeat sequence a week or two back. The models, especially the ECM, tried to dig the trough south in that instance but the emphasis of this was modified as time grew closer. There is good agreement at this autumnal depth low pressure system, and its general position, for later this week amongst the EPS members - which I think nicely depict the overall suggestions of the other modelling too besides the ECM itself

 

 

Thereafter, for next weekend there are some amplified solutions once more in the ensemble map solutions to try to dig the trough south in accordance to what is suggested above  - but overall good support for the Azores High to be ridging closer and settling things down from the south west

 

The further outlook from next weekend? Always uncertain very obviously at this distance but I think that there is a high chance of the modelled tropical activity in western and south western atlantic serving to help bolster the Azores/atlantic mid latitude ridge downstream into Europe and the flatter pattern associated with the deep low to the north of the UK late this week/next weekend to then buckle ahead of these upstream developments and send WAA (warm air advection) in the form of tropical maritime/tropical continental airmasses ahead of it. The GEFS ensembles, as posted by Frosty, in this respect look to have a reasonable handle at a distance as to how things might evolve from next weekend and more especially through the following week onwards

 

So, with that in mind, I think that the ferrel cell has one, or maybe two, more dice to throw in terms of lasting reminders of summer yet - so whilst these rather more changeable and cooler interludes increasingly take on the chillier feel more especially overnight and first thing in the morning, there is a reasonably good chance (at least) of a more widespread evolving fine spell through this month and even (maybe?) into October too

Edited September 8, 2013 by Tamara Road

[A.J]

It screams potential! 

but will it snow in Carlisle?

 

interesting chart posted by Draztik, also mentioned in the convective thread.....total conjecture though as it's in the outer realms of FI but you can't deny, it would make for interesting weather, a late season spanish plume with some serious WAA....All we need now is for the low to verify and stall out....lol

[Frosty.]

The latest GEFS 06z mean again shows huge potential for a warm & anticyclonic spell later in the month, probably the last 10 days or so of september will be settled and warm or possibly very warm for the time of year with the azores/atlantic anticyclone building in and then becoming centred just to the east or southeast of the uk which would enable very warm continental air to drift up into the uk. In the meantime, the azores/atlantic anticyclone will push a flat ridge across the uk in the week ahead displacing the remnants of the showery trough by midweek, the further south you are, the weather looks better with sunny spells and lighter winds with temps nudging into the 70's F but progressively cooler and more unsettled further to the northwest, we are all likely to see some rain for a time later in the week but this should be shortlived across the south with another rise in pressure but scotland & n.ireland are likely to become more generally unsettled with spells of rain and strengthening sw'ly to w'ly winds and feeling cool in the oceanic airmass, however, beyond T+240 hours the trend continues to indicate high pressure building in strongly once things quieten down a bit around the greenland/iceland region and the PFJ should be forced to retreat ever further north by northwest. The latest met office update is again sounding increasingly promising towards the end of the 6-15 day period onwards with fine and warm weather gradually taking over more and more of the uk as time goes on.

[Summer Sun]

Tuesday is looking like a wet one for the SE with the low in the north sea looking like bringing some much needed rainfall

 

 

Longer term GFS is going steady with pressure moving further east

 

Edited September 8, 2013 by Summer Sun

[Summer Sun]

The period of the 16th and 17th looks to be the time when the models are showing a deep low crossing to the north of Scotland this introduces some cooler air for a short time

 

 

Before you guessed it high pressure returns

 

 

ECM's take on the low (00z run at the time of posting 17:56)

 

 

Before it too quickly rebuilds pressure

 

 

The weekend looks a north south split according to UKMO

 

Edited September 8, 2013 by Summer Sun

[Frosty.]

Being a cold fan, this first chart is an eye opener with the 528 dam line sweeping towards the northwest corner of the uk in mid september, it's just a reminder that potential cold weather is only a matter of weeks away.

 

The Gfs 12z shows another warm and settled FI with high pressure taking control during the second half of the month bringing very pleasant benign weather with temps around 22 celsius but chilly nights with patches of dense fog which could take until late mornings to clear, before then, the week ahead starts with sunshine and scattered heavy showers, much as today, on tuesday there is a risk of a glancing blow of persistent rain for the far east of the uk but for many it will be sunshine and showers again, wednesday looks best across england and wales with a mainly dry day with sunny spells and temps recovering towards 21 c in the south but again there is a risk of a few showers towards the southeast, wednesday night brings a band of rain southeast across england and wales but means thursday will be brighter with sunny spells and a few showers but wetter across n.ireland and most of scotland, friday brings that band of rain from the north across the east & southeast but clearing up behind it with sunny spells for the afternoon, most of the north and west having a window of fine weather on friday, more rain pushing across the south on friday night from west to east before clearing to a brighter drier saturday, especially further west and north although turning wet and windy across the far north, then it's the far north of the uk which gets most of the rain on sunday before wet weather sweeps southeastwards during the early part of the following week, that brings about the end of the unsettled weather for the southern half of the uk as the azores/atlantic anticyclone begins to build in but it takes longer for the north to improve but eventually it becomes dry, sunnier and warmer across most of the uk with a very pleasant spell for all.

[bluearmy]

but will it snow in Carlisle?  interesting chart posted by Draztik, also mentioned in the convective thread.....total conjecture though as it's in the outer realms of FI but you can't deny, it would make for interesting weather, a late season spanish plume with some serious WAA....All we need now is for the low to verify and stall out....lol

Given the persistant signal on naefs for heights to build during week 2, we can expect further gfs fi ops which stall the atlantic trough and throw up a plume. That mid month deep low now a mean feature to the n of the uk on gefs. slowly but surely, the week 2 signals seem to be coming closer and the apparent lack of consistancy is the summer output maybe dropping away ??

[ANYWEATHER]

"Being a cold fan, this first chart is an eye opener with the 528 dam line sweeping towards the northwest corner of the uk in mid september, it's just a reminder that potential cold weather is only a matter of weeks away."

 

Hi Frosty. well you've gone looking for heatwaves to cold waves with-in 12 hours! Anyway, youre in the right camp  

[Frosty.]

 

"Being a cold fan, this first chart is an eye opener with the 528 dam line sweeping towards the northwest corner of the uk in mid september, it's just a reminder that potential cold weather is only a matter of weeks away."

 

Hi Frosty. well you've gone looking for heatwaves to cold waves with-in 12 hours! Anyway, youre in the right camp  

 

Yes the first sign of the 528 dam line heading towards the uk in autumn stirs my interest but I want more warmth before all that and there seems likely to be a warm settled spell later this month....... plenty of time for

[Captain Shortwave]

Nasty looking low, even the Azores high is scared 

[Man With Beard]

Lots of cross-model agreement this week:

 

 

 

 

To me this translates as follows: after tomorrow, a lot of dry weather though not always sunny, one or two weak fronts crossing the country, but, as they are running into fairly high pressure, probably nothing more than drizzle by the time they get to central areas. Next weekend a little more tricky - will a system push into northern areas? I feel blocking to the south-west is still strong so wouldn't be surprised to see only the far north affected by longer periods of rain - further south it could be a nice weekend. Never particularly warm, I think we'll be doing well to get much above 70F this week.

[Summer Sun]

Not much change from ECM so far other than the low is moving further north on tonight's run which doesn't surprise me ECM has done this already a few weeks back

 

Nasty looking low, even the Azores high is scared 

 

Nasty but its further north tonight when compared to 12 hours ago remember a few weeks back when ECM had a low only for it to miss the UK in the end with the exception of northern Scotland

[Frosty.]

Nasty looking low, even the Azores high is scared 

Yeah it looks like it's about to...............

[Summer Sun]

t216 see's that low moving further away with high pressure coming back in

 

 

t240 ends with high pressure over the UK and low pressure anchored over Greenland and Iceland

 

Edited September 8, 2013 by Summer Sun

[Frosty.]

The GEFS 12z mean shows a brief blast of polar maritime air shearing across the far north of the uk as a vigorous depression pushes eastwards from iceland but then the recovery begins as the azores/atlantic anticyclone builds in across the south of the uk and bringing a very pleasant spell to most of the uk, sunniest and warmest across the southern half of the uk but with cool nights and fog patches, in the meantime, it's a topsy turvy spell ahead of us with a mix of fine and pleasant weather alternating with wet and windier spells although the north of the uk will be hardest hit, more benign at times further south before trending fine and warm for all areas for around the last 10 days of the month, maybe lasting into early october across the south & east.

[Frosty.]

The GEFS 12z control run eventually turns into a late september sizzler with a very warm or hot and anticyclonic spell with temps widely in excess of 25 celsius, nearer 30 celsius for the south, this is not the first time today that the control run has delivered an autumn heatwave, if the anticyclone does become centred to the east or southeast of the uk, we will get hot & humid continental air drifting into the uk from southern europe as this run shows.

[ANYWEATHER]

The GEFS 12z control run eventually turns into a late september sizzler with a very warm or hot and anticyclonic spell with temps widely in excess of 25 celsius, nearer 30 celsius for the south, this is not the first time today that the control run has delivered an autumn heatwave, if the anticyclone does become centred to the east or southeast of the uk, we will get hot & humid continental air drifting into the uk from southern europe as this run shows.

I think youre worried  

[Summer Sun]

There is no summary from Gibby tonight as he has been busy at the craft fair