Model Output Discussion

[mushymanrob]

But then the GFS 12z brings summer back again - come on everybody look at the ensembles - good agreement out to middle of next week then 'white noise' after that - hence one run cannot be used with any degree of accuracy. The ensembles really are good at indicating where FI is.

well thats true, the gfs op is on the 'poor' side of the general ensebles which dont appear to be painting quite such a 'bad' picture. however at best its only looking 'average', which is pleasant and welcome after the recent rains, but heat lovers are going to be disappointed. (unless you are in the southeast, you might get something approaching 'hot' )

Edited August 7, 2009 by mushymanrob

[Eugene]

Oh no a front moving through on wednesday now, HP just isn't far enough north to affect the midlands northwards.

http://www.wetterzentrale.de/pics/Rtavn1204.png

http://www.wetterzentrale.de/pics/Rtavn1261.png

[Tucco]

GFS 12Z increasing unsettled post Thursday, deepening the low at end of week. Reducing the influence of the Azore's high.

http://www.wetterzentrale.de/pics/Rtavn1681.png

FI very unsettled

Mark

Teesdale,Co Durham

[Frosty.]

Just before the ecmwf 12z rolls out, the gfs & ukmo 12z look reasonable for southern britain during much of next week thanks to a ridge extending across southern england. Further north is more mixed with scotland catching some wet/breezy weather at times, temps look about average in most areas but warmer in the south east. The gfs then turns very unsettled with deep lows crashing through with a more autumnal pattern emerging.

[The PIT]

The downgrade on summer has began. ECM just trickling out and it'll be interesting too see what it says.

[J10]

ECM seems better than earlier with teh lower pressure further north and east, and most of this completeing missing the UK. It does seem liely to break down at T+168, but that is a long way out and things can still change.

[Frosty.]

The downgrade on summer has began. ECM just trickling out and it'll be interesting too see what it says.

Next week looks ok to me the further south you live, only 3 weeks of summer left so yes the clock is ticking. The gfs yesterday was a bit of a tease showing a big high engulfing the uk in hot sunshine but I have already lowered my expectations from now on.

[Eugene]

Not the most promising runs tonight for settled HP it must be said or latest update from the UKMO either, as ever not much for us to get excited about especially the further north and west you are.

　

UK Outlook for Wednesday 12 Aug 2009 to Friday 21 Aug 2009:

A rather changeable and unsettled pattern seems likely to persist throughout this period with winds coming in off the Atlantic and across the UK. The most unsettled and therefore wettest weather is likely in the north, and here further spells of rain will be interspersed with sunnier but still showery conditions, although with some occasional dry days likely as well. The most settled conditions are likely in the south but even here some spells of rain or showers are likely from time to time. The warmest weather then in the south and east, cooler generally in the west and north, with temperatures for the most part near or a little above normal, although some very warm days are likely in the southeast.

Updated: 1201 on Fri 7 Aug 2009

[Derp Patrol]

Well, so far the GFS looks ok untill about Thursday.. after that it all goes horribly wrong with high pressure to our west and low to our east leaving us in a cool northerly flow.. after that the charts would not be out of place in October Looks like we will have to wait untill next year for a proper summer spell, this summer has turned into a horror show

[chapmanslade]

Well, so far the GFS looks ok untill about Thursday.. after that it all goes horribly wrong with high pressure to our west and low to our east leaving us in a cool northerly flow.. after that the charts would not be out of place in October Looks like we will have to wait untill next year for a proper summer spell, this summer has turned into a horror show

Short memories on here - many seem to have forgotten May and June. GFS 18z adds to the yoyo with a HP dominated run if not especially hot. But once again look at the ensembles that are a scatter gun from next Thursday. You simply cannot read any detail from that point forward.

Oh and today was lovely here at 22C and sunny, which is pretty summery if you ask me.

[chionomaniac]

We see the GFS now has come more into line with what the ECM has been hinting out to T+180 and the ensembles have tightened up. Yet again there is a strong correlation with what is forecast and the MJO 500hPa anomaly composite charts for August phases 7/8. I wonder how accurate they will be come winter, when there may be a lot more to take into consideration such as stratospheric state, El Nino and relative AAM levels.

[BLAST FROM THE PAST]

Let's enjoy the current settled weather as come mid month onwards there will be the appearance of 'autumnal' Lps hitting the UK with a distinctly non warm feel. This I think will show more in the chart next week as we are into FI. ecm 12z tinkering with idea 00z not really so. Worth watching as the weather is unlikely to be uninteresting.

Beautiful morning here in Redhill!

BFTP

[Gavin P]

Blast, have you put any thoughts together for autumn yet?

[chionomaniac]

Let's enjoy the current settled weather as come mid month onwards there will be the appearance of 'autumnal' Lps hitting the UK with a distinctly non warm feel. This I think will show more in the chart next week as we are into FI. ecm 12z tinkering with idea 00z not really so. Worth watching as the weather is unlikely to be uninteresting.

Beautiful morning here in Redhill!

BFTP

I reckon the opposite BFTP! Once a trough sets up over Scandinavia I reckon the Atlantic will quieten down considerably with a ridge slowly building over the UK until the end of the month. Always good to have differing opinions though!

[mushymanrob]

.... yes there might be some 'normal' weather for the rest of august, no heat but equally not real monsoon either. guess we ought to make the most of any pleasant sunshine before things settle down to give a settled, mellow, autumn.

[Frosty.]

Something for everyone on the 00z runs this morning, high pressure alternating with low pressure with a fairly even balance between the two. This coming week still looks best for the south but then again it usually does in summer! The north looks more unsettled at times but not a washout by any means. This time next week the gfs & ecm are both showing a significant low spreading across the north with some strong winds wrapped around it especially when the low transfers to the east of the uk but then a ridge of high pressure to follow. The only thing missing is any real heat but temps on the whole look near average to slightly above although warmer towards the south east for much of the time.

[Terminal Moraine]

An unusually deep and active looking low ( for the time of year ) at around 150 hrs on the latest GFS run.

I suspect that what happens with this will dictate what happens for much of the remainder of August.

GFS wants to build in high pressure as the low moves away east and the ensembles from the 00z run showed some support for this, however some members went for an extended run of unsettled weather with further deep lows approaching the country from the west.

It will be interesting to see the next ECM run and the 06z ensembles and no prizes for guessing which outcome I'm hoping for.

Edit;

As an addition to the above the 06z ensembles are now out and the depth of the low pressure is something of an outlier in northern areas of Britain, much less so further south. There seems to be reasonable agreement on a fairly deep low coming through around the 150 hour mark, probably bringing a significant amount of rain, but after that there is very wide divergence on the pressure field, in line with what I posted above.

Edited August 8, 2009 by Terminal Moraine

[Eugene]

Yes as ever as we get nearer the models pick up more atlantic activity, i did say i was concerned over the jet ruining things earlier in the week, looks a pretty poor week now for the midlands with lots of cloud cover with occasional heavier bursts of rain, yuck nothing is worse than overcast TM airmasses and all the cloud they bring with them.

[Tucco]

Yes as ever as we get nearer the models pick up more atlantic activity, i did say i was concerned over the jet ruining things earlier in the week, looks a pretty poor week now for the midlands with lots of cloud cover with occasional heavier bursts of rain, yuck nothing is worse than overcast TM airmasses and all the cloud they bring with them.

Looks pretty good for Midlands and the South next week. Temps in high teens/low 20's, higher in the SE with little rain.

http://www.wetterzentrale.de/pics/Rmgfs144sum.gif

The North of the UK looks cool later in the week, with heavier rain possible.

ECM/GFS both keep flip flopping on the intensity of Friday's low.

Mark

Teesdale,Co Durham

[snowmadchrisuk]

Regarding the low pressure shown for thursday and friday next week . I'm not sure I agree with the track, I think with the shape of the high pressure ridge I think it is more likely to move further north maybe more towards Iceland. I'm sure it will throw some heavy rain/showers for the north but I think the midlands and the south could stay dry during at least thursday and friday next week. I just checked and the Met Office seem to agree with me at the moment on there extended forecast. Also worth noting that cold pooling is trying to get a hand early this year with -10's showing at +90 hours (wednesday) , Infact by +144 -10 850's are widespread over greenland , If this was to continue it would only take the right setup to give us another cold snap in October.I would also go for a max of about 28/29 in London at some point between monday and friday.

Chris

Edited August 8, 2009 by snowmadchrisuk

[The PIT]

Well a steady and very rare downgrade of summer and warmth. The high pressure getting steadily pushed further south. Question is how far south will the finally push be.

[BLAST FROM THE PAST]

Hi Ga and Chim

Gav I have early thoughts but delaying as watching ENSO. Early thoughts are 'mild' autumn, chance of Indian summer conditions.

Ch, I don't think it will be a train of LPs but ceratinly one or two autumnal ones both in depth and temp.

BFTP

[J10]

Signs of the low pressure just before next weekend being further north with each run, and applies to both ECM and GFS.

Hopefully this means it staying dry for at least southern pasrts around that time.

[Thundery wintry showers]

GFS and ECMWF at loggerheads again I see, with the GFS control run suggesting sunshine and showers for the north next weekend and dry with sunny intervals further south as high pressure comes in from the SW- but ECMWF looking pretty dull & wet for Saturday with a vigorous low over the east.

Most of the GEFS ensembles go for something more akin to ECMWF though only a couple are as extreme, and a few go for the GFS control's scenario. So some disagreement but perhaps a cool NW'ly on the way for next weekend, which could be bright and showery or cloudy and damp depending on where the low and associated fronts end up. A long way off at this stage though.

[damianslaw]

Fairly typical August synoptics for the foreseeable future it seems, with the azores high exerting its influence in the south but the jet spoiling the party further north allowing fairy weak fronts and banks of cloud to head through Scotland, N Ireland and NW England from time to time with the 'dregs' affecting N Wales, NE England and N/W Midlands.

Best of the dry sunny and warm weather reserved for the SE, who on the face of things have seen quite a good start to August.

Looking further ahead signs of a more active low pressure appearing for the end of next week, but I think it is only really going to affect the north.

Temperatures remaining about average in the north but a bit above in the south meaning high summer 2009 mid July - mid August (I usually class this period as high summer as it is cumulatively usually the warmest 4 week period of the year and the period when you normally expect to see highest temperature of the year) will go down as particularly unexceptional temperature wise with no recordings above 28 degrees.