Model Output Discussion 31/07/14 onwards.

[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.

 

... well bugger me!between going to work and getting home all indications are, that there should be high pressure dominance next week, making that post i made this morning obsolete!

 

 

 

 

[knocker]

Looking at the GFS I can't say I've noticed any major changes in the track of Cristobal in recent runs.

 

 

[vladthemert]

Looking at the GFS I can't say I've noticed any major changes in the track of Cristobal in recent runs.

 

 Knocker was looking this morning NOAA report on the web had the track towards iceland so changed thanks.  Also noaa latest discussion interesting

 

http://www.nhc.noaa.gov/text/refresh/MIATCDAT4+shtml/261442.shtml?

 

I also noticed yesterday on earth wind map that second eye developed was pulled by the trough mentioned in the noaa report.  There was comments in the reply's  in Jeff Master's blog about it.  What is the impact to Cristobal storm.  

[Captain Shortwave]

Still some uncertainty on how things progress from Sunday onwards, but we have good agreement between the GFS and GEM

Both send low pressure up towards Iceland with a big Euro block developing, week 2 sees the heat build on both models with high twenties likely.

 

UKMO looks more modest

The track has a more easterly element and travels south of Iceland, this means the chance of rain for the north at times still, but this could develop into something better in time. For the south, the future looks good with fine and warm weather returning.

 

GEM and GFS into week 2 and beyond look epic for those of the warm and sunny disposition.

Edited August 26, 2014 by Captain shortwave

[Milhouse]

What a transformation we would see if the GFS 12z came true. Upper temps of between 10c and 14c for the start of next week producing temps in the mid to possibly high 20s.

 

[IDO]

Strong background signal for some days from GFS and GEM for heights to build in our region. It looks like the Polar lower heights are on the move away from our side of the NH so no strong resistance for the Azores to re-assert itself. With the Greenland trough it looks like the Azores to Scandi route through the UK opens up nicely.

 

GEM   GFS 

 

However, although UKMO agrees on the slack flow of lower pressure (apart from the Tropical storm energy) it is less meridional than GFS. This is due to how it handles the upper low later this week. GFS (and its ensembles) and GEM cut off this upper low and it supports the pressure build in week 2 as the ridge builds over it.

 

UKMO:   GFS  GEFS: 

 

UKMO mixes this upper low out and keeps any residue further east; this morning's ECM similar to UKMO. ECM still manages to build heights eventually but is a lot more messy than GFS/GEM and with a 2-3 day delay. The heights also look less secure. GFS has been very consistent with this outlook, and ECM has been swinging back and forth, so at the moment I will go with the GFS. NAVGEM is also supporting this:

 

 

After D12 GFS have been indicating a further Tropical storm mixing it up again: 

 

So it could all be change again, dependent on where this (possible) storm tracks. Long way away from that.

 

So Autumn looks like starting on a warm note, especially for the Midlands south, and after the last few days in the SE, the warmth will be welcomed back.

 

[Captain Shortwave]

Well the ECM has a similar evolution to the UKMO, but has the pattern further north

Excellent for the south with 850s of 12-14C in the south so if the sun comes out then the high twenties would certainly be on, the north will see some rain though unlike the GFS and GEM evolutions which are dry for all. The next wave can be seen developing behind the low over Iceland so expect heights to build more strongly over the UK from here.

Day 7

There's your UK/Ireland high. It stays put out to day 10 and beyond.

Edited August 26, 2014 by Captain shortwave

[Polar Maritime]

Yes the GFS picked up another push of heights out in the run this morning, And again showing. Also this transient affair seems to be growing and extending with every run, Just don't forget the bear in mind them pesky ex TS's!

 

Edited August 26, 2014 by Polar Maritime

[knocker]

GFS 12z has Hurricane Cristobal bombing prior to extratropical transition ... 949 mb is record territory for MSLP pic.twitter.com/ipuLpqUmVm

[Frosty.]

Feels very worthwhile now that some of us have been banging the drum supporting the gfs with it's settled outlook, from being a possibility it now looks to be a cast iron certainty that high pressure will build from the south from the end of this week and throughout next week..high pressure and high temperatures on the way during early september, even the bbc news 24 weather forecasters are talking about an anticyclonic outlook...BANK or as alan partridge would say, back of the net

[damianslaw]

Early September is traditionally one if not the most 'quiet' benign period of the year - once again it looks like September will start on a dry settled warm note. GFS and ECM show strong support for build of heights out of the azores towards our shores and on into Europe/south Scandinavia with the jet taking a northerly course.

 

So we could well be looking at a decent spell of dry settled warm weather next week - locally very warm for the south, better late than never, but we could have done with this likely change 2 or 3 weeks back it has to be said.

 

Longer term - don't be surprised to see retrogression of heights as the jet pulls back south again thanks to interaction with ex tropical storms, there does appear to be a force wanting to send heights north at the moment..

[Captain Shortwave]

ECM ens

High pressure builds through the UK and is centred over or just east of the UK, doesn't get much better than that for placement. If this occurs as forecast then this could be at least a solid 7-10 days of warm sunny weather. We are probably owed it from the August we have just experienced.

[Blessed Weather]

After the negative impact of hurricane Bertha, it’s nice to have cross-model agreement that Cristobal should have a positive impact on the UK. As the vigorous low resulting from Cristobal tracks NW close to Iceland, the warm air advection brings us a welcome rise in temperatures and allows high pressure to build in from the SW. In fairness to the ECM it was showing this evolution several days back whilst other models struggled somewhat.

Latest Cristobal forecast track from the US NHC for today until Sun 31^st Aug:

 

ECM and GFS 850 hPa charts for Sun 31^st Aug in agreement:

[Milhouse]

Suspect we will still see some decent warmth from these lovely looking charts. We are about a month past the warmest time of year so you can probably knock 2/3c of the kind of temperatures we saw in July 2013 from similar looking charts. Widespread mid 20s easily achievable looking at the ECM, GEM and GFS.

[h2005__uk__]

Suspect we will still see some decent warmth from these lovely looking charts. We are about a month past the warmest time of year so you can probably knock 2/3c of the kind of temperatures we saw in July 2013 from similar looking charts. Widespread mid 20s easily achievable looking at the ECM, GEM and GFS.

Some places got to 32/33 in July 2013 so these models could be hinting at a possible 30C somewhere then.

[draztik]

Looking at the ecm ens tonight, this still looks to be transient. 4 or so days before a return to westerlies. Those suggesting a 7-10 day spell of sun are merely hopecasting I'm afraid.

The above may be a day 13,chart, so normal caveats apply. But the signal isn't for hp to be in control exerting its goodness. The mjo shows us in phase 3 by this time, adding support of a return to more unsettled Atlantic based conditions.

[Captain Shortwave]

Looking at the ecm ens tonight, this still looks to be transient. 4 or so days before a return to westerlies. Those suggesting a 7-10 day spell of sun are merely hopecasting I'm afraid.

The above may be a day 13,chart, so normal caveats apply. But the signal isn't for hp to be in control exerting its goodness. The mjo shows us in phase 3 by this time, adding support of a return to more unsettled Atlantic based conditions.

Trusting a day 13 ensemble mean is probably pushing it to be honest, given how the models usually tend to move towards a normalised (westerly pattern) anyway then the usual cautions should apply. There are many examples of blocking highs which will stick around for a considerable period of time. This one looks like it could possibly be one of those block, so I wouldn't be surprised to see any FI breakdowns to turn out to be false dawns.

All models agree on settled weather for most if not all of the UK from days 5-10, that's solid enough for now........ worth noting the gfs ens are settled al the way to the end so there's not even agreement on that, day 13 (insert chocolate teapot reference)

 

The pub run is settled well into low resolution again

Edited August 26, 2014 by Captain shortwave

[Gael_Force]

We usually see these maps in the winter but I find they are a good indicator in the summer as well - GFS has been very consistent, over many runs, of the idea of a strong ridge centred over or close to the UK.

 

[IDO]

The GEFS remain bullish for an extended period of HP over the UK. The D10 mean and spread show this and the latter for the south suggests very high confidence:

 

 

 

There is no sign of any trigger to change the pattern in the medium term with the PV quiet and the two Tropical storms currently forecast to mix with the Atlantic trough aiding our locale for the associated ridge. Even at D16 the GFS op has HP in  charge:

 

 

 

Though as a whole around the 11th is when there are tentative signs it may get more unsettled. GEM is a variation on the GFS theme:

 

D10:   

 

Warm uppers for the south should send the lucky ones temps of 25-28c by the first weekend of September. Temps returning to average by next week, by mid-week 2-4c above average (south). I agree that at least for the south there should be around 8-10 days of higher pressure dominated weather from this Sunday. The mean currently suggest that:

 

 

Enjoy.

 

 

[mushymanrob]

Feels very worthwhile now that some of us have been banging the drum supporting the gfs with it's settled outlook, from being a possibility it now looks to be a cast iron certainty that high pressure will build from the south from the end of this week and throughout next week..high pressure and high temperatures on the way during early september, even the bbc news 24 weather forecasters are talking about an anticyclonic outlook...BANK or as alan partridge would say, back of the net

 

 

Its worth mentioning that there is now strong support from the anomaly charts, where previously there was non.

Edited August 27, 2014 by Polar Maritime
To remove off-topic comment.

[Captain Shortwave]

ECM follows suit nicely

High pressure looks odds on to take control from the end of this coming weekend, with warm air continuing to be pumped up from the south then mid-high twenties should be possible, the key will be the orientation of the high, for widespread warmth then having the high drift just east of the UK is probably the best bet, looks very possible from the broad output. GEM is probably the warmest option with a strong block over northern Europe and a east/south easterly flow setting up.

UKMO this morning is also an improvement on yesterdays runs

 

So all in all a good set of runs, shame about it being early September and not early August, but in the end you can't be too fussy

[Polar Maritime]

I have Edited/Deleted some posts to keep the peace...

 

Yes Frosty the GFS was the first to pick up this signal and maintain it, Well before the Anomaly charts, As has been shown over the past few days. With this morning continuing the theme of a push of Heights at the turn of the Month.

 

Edited August 27, 2014 by Polar Maritime

[SMU]

Morning all-

 

Spectacular ECM this morning with about the best charts you could hope for for the UK, Once we get through a bit of murk over the next few days as the weekend rolls on things look to improve dramatically. With the heat beginning to build from the south-

 

Chart of the day

http://www.meteociel.fr/modeles/ecmwf/runs/2014082700/ECH1-168.GIF?27-12

 

Becoming hot in the south - With the heat pushing north.

 

some Early season snow for Svalbard & the far North of Finland / Norway.

 

Exciting conditions.

 

 

S

[SteveB]

Love stuff on show this morning,

 

I always book holiday for the beginning of September as I find the weather is generally good, and it looks like that's the case again.

 

 

[Frosty.]

The Gfs 00z op run is very easy on the eye this morning with a prolonged very warm anticyclonic outlook, the azores high builds in and keeps building in, only the far northwest of the BI is occasionally clipped by atlantic systems which are diverted up past iceland. It's a glorious outlook and fair play to the gfs for picking up this signal a while ago and running with it...summery weather has been very patchy throughout august but early september looks peachy...nice to see the anomaly charts have finally woken up to this settled outlook. hats off to the gfs, a much maligned model but deserving of praise this morning..from sunday onwards, summer is back with a bang  ..boom  

 

you will have to take my word for it guys..the charts won't upload