Model Output Discussion 31/07/14 onwards.

[knocker]

The ECM ens not dissimilar to last night.

 

[phil nw.]

Looking at the 00z ens shows quite a strong signal for an Azores High build as we go into the first few days of September.

The GFS stamps for day 10

 and clusters

 

about 90% in favour ?

ECM mean and spread for around the same time

 

the green colour as i understand it indicates quite a low spread.

link here

http://www.ecmwf.int/en/forecasts/charts/medium/ensemble-mean-and-spread-four-standard-parameters?area=Europe&step=240&relative_archive_date=2014082500&parameter=MSLP

 

After a changeable end to Summer it seems the prospect of a warmer and sunnier start to Autumn,especially further south,looks quite possible this morning.

 

[Summer Sun]

UKMO now showing high pressure at t144 with warmer air making a welcome return

 

[Polar Maritime]

GFS making more of the Push of High Pressure at the turn of the Month.. With a cut-off Low to our S/E aiding a minor expansion the the Model'd settled/transient spell. Before Lows swing in off the Atlantic towards the end of the run.. It will be interesting how long this more settled/warmer spell will last, And how the Models handle the return of the Atlantic.

 

Edited August 25, 2014 by Polar Maritime
To add transient as well as spell..

[summer blizzard]

Models do try and build pressure at day 6-8 but the Euro and GEM suggest it's a transient affair.

 

Ensembles suggest no defined pressure build until day 10.

GFS making more of the Push of High Pressure at the turn of the Month.. With a cut-off Low to our S/E aiding a minor expansion the the Model'd settled spell. Before Lows swing in off the Atlantic towards the end of the run.. It will be interesting how long this more settled/warmer spell will last, And how the Models handle the return of the Atlantic.

 

 

Extreme caution urged in the low resolution timeframe, the tropical system near the Azores it shows has not even dropped off Africa yet.

[Polar Maritime]

Models do try and build pressure at day 6-8 but the Euro and GEM suggest it's a transient affair.

Extreme caution urged in the low resolution timeframe, the tropical system near the Azores it shows has not even dropped off Africa yet.

 

It's always been Model'd as being a transient affair as far as the GFS is concerned, And was the first to pick this detail out in low res, The interest for me lies in how the low resolution time-frame handles the return of the Atlantic, As always "with caution" at this range, Especially when TS's are involverd as you say. But interesting all the same..

Edited August 25, 2014 by Polar Maritime

[Milhouse]

Increasingly summery from the ECM12z with the jet stream moving north allowing the Azores high to ridge northwards next weekend. At t+168 a cold front looks to be moving south but the track of the low to the northwest would suggest a bigger build of high pressure coming in behind for the final 3 frames of the run. We shall see.

 

[Frosty.]

The GFS 12z op run shows our patience being rewarded once we reach the start of next week with the azores and scandi anticyclones eventually linking up and before that happens, both areas of high pressure really put the squeeze on that in-situ showery trough and high pressure delivers the knock out blow by early next week with the azores high then building in strongly and bringing a spell of fine and pleasantly warm weather with temperatures gradually rising into the low / mid 20's celsius across the southern half of the uk, nearer high teens celsius further north...I would bank the gfs low res without a shadow of doubt..i'm cautiously optimistic about next weeks prospects for a fine spell taking over..August has been poor but early september is looking much better, how long will it last? well lets get it here first and then see about that.  

[Polar Maritime]

Yes Mill, Once again the ECMWF is making a little more of the Pressure rise, As per the GFS tonight, As you say, We shall see.. But tonight's run's are looking much better for a more settled and prolonged/transient spell at the turn of the Month. Spot on Frosty let's get it here first 

 

Edited August 25, 2014 by Polar Maritime

[Frosty.]

One word..starts with B..ends with K..you know the rest..nuff said

 

Seriously, the Ecm 12z op ends fantastic, the Gefs 12z mean is showing a warm settled outlook with the PFJ forced well north so I think there are significant grounds for optimism to bring summer back during early autumn

 

PS..thanks lucy you are welcome

Edited August 25, 2014 by Frosty.

[ANYWEATHER]

Yet again models have serious issues with Tropical storms out in the Atlantic. Any ridge which is default by computer models in this scenario is always out at the Fantasy Island stage.

[Captain Shortwave]

A lot of promise from the models, but with any pattern change seemingly coming from tropical storms ejecting into the Atlantic jet then caution must be urged, we do see good agreement from the models on a system deepening out in the Atlantic which then passes north of the UK, shown on most output.

Decent agreement here, the GfS handles things downstream differently due to more robust heights over Scandinavia

GEM/UKMO and GEM show a much warmer weekend as opposed to this one with the south being fine an dry throughout. But no guarantees as of yet.

 

There is promise of something more decent into week 2, highlighted in the GFS ens

This mornings ECM ens were even more bullish, but will wait for the 12z ensembles before drawing any more conclusions.

A mixed week coming up with some showers or longer spells of rain, but with more respectable temperatures thanks to a warmer airmass.

[Frosty.]

Yet again models have serious issues with Tropical storms out in the Atlantic. Any ridge which is default by computer models in this scenario is always out at the Fantasy Island stage.

have you considered the possibility that the tropical storms impact could in fact make the outlook for the uk even better than it already looks, just looking through the latest output there is rapidly increasing support for a warm anticyclonic outlook beyond this week. :-)

[Polar Maritime]

Aye it works both ways, That's where the uncertainty lies as always in TS Atlantic driven set-ups.

 

But the output of late as we have seen, Suggest's the UK favouring settled warmer conditions, At least for a time for now.

Edited August 25, 2014 by Polar Maritime

[Frosty.]

Aye it works both ways, That's where the uncertainty lies as always in TS Atlantic driven set-ups.

 

But the output of late as we have seen, Suggest's the UK favouring settled warmer conditions, At least for a time for now.

Spot on..the weather is a beast which cannot be controlled but just going by what the models are currently showing, everything points to a summery spell developing from early next week..hopefully the models will firm up on this in the days ahead..I am prepared to wait for the cold, windy and unsettled weather that october will probably bring and hopefully a wintry winter ahead. :-)

[Captain Shortwave]

In all honesty

That's a pretty big signal from the ECM ens, the south turns dry from Saturday onwards with the north mixed for an extra couple of days.

GEM ens

Still plenty of time for change but that is pretty decent. As BA suggests, there is that typical sense of inevitability to all this.

[knocker]

Looking at the anomalies for the weekend and after.

 

NOAA on both the 6-10 and 8-14 is building HP over the UK. The GFS  is still going for an upper low over the UK on Saturday but also builds HP after that although later goes for a more zonal flow. Thus the surface low at the weekend gives way to dominance from the Azores subsequently.

 

The ECM has a slightly different interpretation for the weekend with a trough lying west/east east Atlantic to Scotland with the high pressure pushing up from the south. By mid week HP is dominating This  analysis applies equally for the surface.

 

There is of course the proviso that Christobal might throw a spanner in the works on its travels.

 

[mushymanrob]

trouble is with the anomaly charts... they a- dont agree and b- change with every run...remember they need to be in broad agreement over several runs before they can be relied on.  so whilst the noaa look great, yesterday they were different and supported a scandinavian/northeastern block, today its an azores ridge, ridging towards/over us.the uncertainty is reflected in the ops, the ecm (12z, 00z is coming out about now but im off to work) suggesting the azores high coming into play whilst in the semi reliable the gfs (00z) keeps the northeastern block.as i see it its completely uncertain, with an unsettled theme most likely to prevail but with a chance of something more settled developing (for more then the odd day or two). of course its tempting to chose a set of data that displays a prefered weather type.... but this morning theres no strong signal for anything.

[Polar Maritime]

ECMWF & GFS continue to show a push of High Pressure for the turn of the Month this Morning. With Lows off the Atlantic pushing North with the Jet Stream. How strong and lasting this will be remains to be seen..

 

Edited August 26, 2014 by Polar Maritime

[Frosty.]

The Gfs 00z op run shows high pressure to the northeast and southwest linking up by the end of the week and destroying what remains of that pesky in-situ trough and then it's high pressure all the way to the end of the run and beyond, a truly blocked pattern gradually develops and the atlantic systems / ex tropical storms, as far as the uk is concerned are dead in the water. This run shows summery weather returning to all parts of the uk from early next week onwards with temperatures soaring into the low to mid 20's celsius during early to mid september..the summery trend continues to gain momentum.

[Frosty.]

have you considered the possibility that the tropical storms impact could in fact make the outlook for the uk even better than it already looks, just looking through the latest output there is rapidly increasing support for a warm anticyclonic outlook beyond this week. :-)

I certainly have, and the gfs is very bullish about summer returning to our shores during early autumn..BRING IT ON

[Man With Beard]

In all honesty

That's a pretty big signal from the ECM ens, the south turns dry from Saturday onwards with the north mixed for an extra couple of days.

GEM ens

Still plenty of time for change but that is pretty decent. As BA suggests, there is that typical sense of inevitability to all this.

Yes, looking very good for the first week in September - maxes at the moment looking like 23C/24C - but could reach 27C/28C if HP sets up slightly further SE and we get a southerly draw for a few days.

Inevitability? ... if recent years are considered, it's fast becoming the most reliable "summer" week of the year:

[Timmytour]

While I like the promise the models are showing for beyond this week, I also remain wary that  the Bank Holiday weekend and this week were being touted as  looking reasonable from two weeks away.I can't help thinking that there's more consistency in the models  being wrong from that distance than usual this year.  Not saying I expect them to be always right from that distance, nor that they've never been right this year....just the percentage of getting it right seems to be lower of late. 

[ANYWEATHER]

While I like the promise the models are showing for beyond this week, I also remain wary that  the Bank Holiday weekend and this week were being touted as  looking reasonable from two weeks away.I can't help thinking that there's more consistency in the models  being wrong from that distance than usual this year.  Not saying I expect them to be always right from that distance, nor that they've never been right this year....just the percentage of getting it right seems to be lower of late. 

Indeed! What throws the spanner in the works is the modelling of tropical storms, something the models are having some really difficulty at the moment. The 06z gfs is completely different from its previous run, and to say what the weather will be doing next week just seems almost impossible to call...

[Polar Maritime]

Once again the GFS continues the theme reg the transient affair..