Model Output Discussion - 1st August 00z---------->

[knocker]

A quick look at the GFS ops this morning for a change. It's really about the dance of the depressions and relatively unusual movement thereof. On Tuesday it has moved the low nipping up from the SE further east missing the UK whilst the other low is way to the NW. Clearly seen on the 250mb streamline chart. But by Wednesday another low nips in from the west on the jet and brings a band of frontal rain across the UK. But the low itself turns north allowing brief ridging.

 

I say brief because by midday Saturday the jet is running around the upper trough just to our west and then turning north guided by the blocking HP to the north east. Result another low just the west and one moving up from France which phase together bringing a wet weekend to the UK.

 

But one run one model so plenty of time for the backend of next week to be adjusted. Even so that upper trough has much to answer for.

 

EDIT

Ah I see PM has already posted still may as well leave it.

http://www.tropicaltidbits.com/

Edited August 15, 2015 by knocker

[mushymanrob]

for what its worth... my take on the outlook is appearing to centre on the coming 'battle' between the scandinavian high, and next atlantic system later in the week. until then its looking pleasant enough with a lot of dry weather with sunny intervals.

the noaa shows



which supports the op runs ( friday)



so we expect the atlantic trough, we expect the scandinavian high, the question is, just which feature will develop the strongest? it looks like itll make a big difference to the weather we get. the three charts posted above whilst are different in the detail, generally they are the same and are within what the noaa chart suggests will be the upper air pattern for later next week.

a stronger scandi high/weaker atlantic trough would see us in sunnier, warmer conditions with the possibility of the low undercutting and pushing up some warm continental air.

a weaker scandi high/stronger atlantic trough would see us in a more unsettled, mobile, wetter regime.  so an interesting interaction ahead as these two features fight for dominancy over the uk.

oh.... and just for a laugh



SUMMER ARRIVES!

 

[knocker]

This morning's ECM ops has a similar evolution as the GFS up to Weds But thereafter differs. It brings the depression in from the west but no low moving north from France. Thus the low reaches the western approaches before swinging north on the jet along the eastern flank of the upper trough. As mushy has mentioned the position of this trough is vital so watch this space.

http://www.tropicaltidbits.com/.

Edited August 15, 2015 by knocker

[johnholmes]

As mushy suggests above the 'battle' if you want to use that term continues to show as the upper +ve heights and the trough in the contours show little sign of either taking command. The EC-GFS version this morning suggests the trough will be dominant but NOAA has, for the last 2 days, shown, see below that the outcome is far from clear.

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

and as you can see the 8-14 outlook is pretty similar.

Edited August 15, 2015 by johnholmes

[knocker]

For what it's worth the GEFS and ECM are definitely favouring the trough.

http://www.tropicaltidbits.com/

 

[summer blizzard]

Possible complete agreement. Scandi High will capitulate by day 8 unless the models turn back.

[mushymanrob]

As mshy suggests above the 'battle' if you want to use that term continues to show as the upper +ve heights and the trough in the contours show little sign of either taking command. The EC-GFS version this morning suggests the trough will be dominant but NOAA has, for the last 2 days, shown, see below that the outcome is far from clear.

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

and as you can see the 8-14 outlook is pretty similar.

 

not overly happy with that term either john, but im not sure what else fits....

its worth a mention that the ops appear to have dropped the undercutting low, (in this timeframe) and appear to be going for a straight gradual progression eastwards of the mean upper trough. not yet overly sold on that idea myself... the anoms seem to keep the scandinavian high more intact.

[mushymanrob]

Possible complete agreement. Scandi High will capitulate by day 8 unless the models turn back.

 

possibly, but thats at day 8, if it showed high pressure dominance at day 8 wouldnt you nay-sayers be dismissing it as its in fi?

[Scorcher]

Possible complete agreement. Scandi High will capitulate by day 8 unless the models turn back.

 

Day 8 is well into FI, as much as you want it to happen. The ECM op is more than decent for most of us this morning, with the trough holding off to the north west and a relatively fine and warmish week ahead next week. In fact the ECM run is better than yesterday evening's offering.

[knocker]

Day 8 is well into FI, as much as you want it to happen. The ECM op is more than decent for most of us this morning, with the trough holding off to the north west and a relatively fine and warmish week ahead next week. In fact the ECM run is better than yesterday evening's offering.

 

That's as maybe but if we can't use the GEFS and ECM anomalies for day eight as a decent guide, assuming they are being fairly consistent, then it throws the idea of using the anomalies out of the window. I do not see that one or two ops runs justifies this. And in any case this morning's ECM ops run supports the GEFS and ens anomalies.

Edited August 15, 2015 by knocker

[Eugene]

possibly, but thats at day 8, if it showed high pressure dominance at day 8 wouldnt you nay-sayers be dismissing it as its in fi?

 

 

And they would be right to going by the form horse this summer, when was the last HP dominance for any length of time, Slack nothingness is the form horse this summer.

[Nouska]

Looking very trough dominated to the north west according to ecm ensembles 00z by day 10. Wheras southern and eastern parts aren't too bad, although nowhere particularly settled:

http://www.meteociel.fr/modeles/ecmwf.php?ech=240&mode=1&map=0&type=1&archive=0

Pretty much the story that has told this summer really . I hope noaa cfs v2 are correct and an Indian summer is going to merge as we've been pretty much stuck in a rut with our summer weather really with patterns that have recurred time and time again.

Here we have the pressure anomoly for September:

http://www.cpc.ncep.noaa.gov/products/CFSv2/imagesInd3/glbz700MonInd1.gif

 

Maybe...... but, it's a case of confused.com as far as the MJO outlook.

 

 

If the big two (ECM and GFS) are on the right route to the Indian ocean, the composites for September are not inspiring.

 

http://www.americanwx.com/raleighwx/MJO/MJO.html

[mushymanrob]

And they would be right to going by the form horse this summer, when was the last HP dominance for any length of time, Slack nothingness is the form horse this summer.

 

thats true and i completely agree..... but thats not the point.

 

[East_England_Stormchaser91]

GFS sticks to its guns and keeps the Scandi High theme right throughout the run. We just need a little more support from the others and for them to come on board, on what potentially looks to be a decent enough August, especially towards the latter part. Something we have not seen for quite some time!

Edited August 15, 2015 by East_England_Stormchaser91

[Milhouse]

The big issue for eastern coastal parts early next week looks to be the proximity to the band of rain thats going to be out in the North Sea. The 12z has it sat about 300 miles offshore for around 48hrs. Cool and wet for those stuck under it but we look to be just about escaping it.

 

Becoming more unsettled from the NW from midweek but increasingly warm and dry further SE.

 

[knocker]

The GEFS anomalies to tonight continue with the theme of the upper trough being more influential next weekend but it then retrogresses it to mid Atlantic. This could portend a couple of scenarios such as a weak linkage of the Azores ridge with HP to the NE or some funny stuff drifting up from the south.

Charts weatherbell

 

Just to add there is a post above that states, "GFS sticks to its guns and keeps the Scandi High theme right throughout the run".

This is simply not correct.

Edited August 15, 2015 by knocker

[knocker]

The NOAA 6-10 has the upper trough as the dominant feature with the 8-14 retrogressing it slightly. I would go a for generally unsettled with brighter interludes in the mainly W/SW airflow. But I stand to be corrected

Edited August 15, 2015 by knocker

[Man With Beard]

Knocker I think given the mean of GEFS and ECM ensembles tonight, we suddenly have strong agreement on a complete return to square 1 by next weekend, with a trough to our NW dominating the weather, progressively less so as you head SE, and once again it is only the SE corner who will have anything significant to get excited about warmth-wise. Incredible how this pattern has repeated over and over again this summer and looks likely to reassert itself once again. Surely September will herald a change - just when was the last September that didn't begin with a decent spell of High Pressure??

[MP-R]

Knocker I think given the mean of GEFS and ECM ensembles tonight, we suddenly have strong agreement on a complete return to square 1 by next weekend, with a trough to our NW dominating the weather, progressively less so as you head SE, and once again it is only the SE corner who will have anything significant to get excited about warmth-wise. Incredible how this pattern has repeated over and over again this summer and looks likely to reassert itself once again. Surely September will herald a change - just when was the last September that didn't begin with a decent spell of High Pressure??

 

To answer this question: 2006 and 2008-2011 were unsettled to start, in fact 2006 stayed changeable all month, 2008 was very unsettled until midmonth and 2010 & 2011 were both unsettled or changeable throughout. 2012 and 2014 had anticylonic weather for the first 10 days, 2014 continuing much longer but 2012 deteriorating. 2013 began settled and had settled bits later in the month was often unsettled in the middle.

 

Looking at the models as they are, they bare similarities to this week in 2013 which was warm, sometimes hot, often sunny and pretty dry throughout in the south, but cloudier and closer to the rain in the northwest. I suppose not a lot of change from much of this summer, just a warmer version of it and sometimes feeling humid in the south. 

[knocker]

Well looking at the ext ECM anomalies there seems little light at the end of the tunnel. Although perhaps because the trough is mid Atlantic there is scope for the Azores HP to push north and ridge into the UK. I'd like a pound for every time I've said that this summer. At the end of the day it looks like we will have to live with this and trust for some periods of pleasant weather which is quite possible in this set up.

[summer blizzard]

Euro and GEM tonight recover somewhat, ironically tonight its GFS which is the most unsettled.

[Gibby]

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS ISSUED AT 08:00 ON SUNDAY AUG 16TH 2015

 

THE CURRENT GENERAL SITUATION. An area of slack winds will continue to affect all of the UK for the next 24-48hrs at least.

 

http://www.wetterzentrale.de/pics/Rtavn001.gif 

 

MODELS-2 WEEK HEADLINE Remaining somewhat mixed with a lot of dry weather for all but with occasional rain too at times.

 

THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast shows the main arm of the flow moving SE over the Atlantic to the Pyrenees with a returning arm North over the North Sea. The Spanish end of the flow breaks up in a few days while the flow is steered more NE over Scotland as the process of developing a sharp trough in the flow just to the West of the UK is shown late next week and through Week 2. Thereafter, the forecast becomes complex with the flow appearing to break up and become light around the UK.

 

http://www.netweather.tv/index.cgi?action=jetstream 

 

GFS OPERATIONAL The GFS Operational Run today shows High pressure to the NE for some considerable time this morning. There will be a deepening depression to the NW later this week with rain at times from midweek, first in the North and West then elsewhere too as the Low moves South close to the UK and down to the South with time. This focuses rain and showers more towards the South briefly before pressure builds again with warm and dry weather returning at least to the South while the North and West return to cloudier weather with occasional rain and winds from the SW.

 

http://www.wetterzentrale.de/pics/Rtavn1441.gif

 

http://www.wetterzentrale.de/pics/Rtavn3841.gif 

 

THE GFS CONTROL  The GFS Control Run today also shows High pressure to the NE with slack winds over the UK slowly giving way to Westerlies with rain at times from midweek as Low pressure to the NW gradually extends influence to all areas with time. A changeable period for all is shown then with rain at times but some dry and fine weather too especially late in the period when High pressure builds across the UK from the SW with warm and fine conditions for most to end the run. 

 

THE GFS CLUSTERS(14 Days) The GFS Clusters this morning show a good set this morning very much biased towards High pressure close to the South of the UK in 14 days with fine weather for many with any influence of low pressure affecting the UK from the Atlantic coming in at less than 20% of members today.

 

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=euro&MODELL=gefs&MODELLTYP=2&BASE=-&VAR=cpre&HH=372&ZOOM=0&ARCHIV=0&RES=0&WMO=&PERIOD=

 

UKMO UKMO today shows Low pressure from mid Atlantic gradually becoming influential across the UK from midweek. The North and West will see most effects from this with rain and showers while effects for the South and East will be more minimal with High pressure closer by to the South and SE.

 

http://www.wetterzentrale.de/pics/Rukm1441.gif 

 

THE FAX CHARTS The Fax Charts this morning show the slack pressure gradients across the UK continuing for a while yet before Low pressure developing up to the NW pushes a series of weakening fronts East with some rain from midweek.

 

http://www.weathercharts.org/ukmomslp.htm#t120.

 

GEM GEM today has an air of Autumn about it as it replaces the benign weather pattern at the moment for something much more mobile thereafter, The bening weather will last until midweek for many when Low pressure up to the NW deepens and pushes troughs across the UK followed by other with some strong winds too later as deepening Low pressure moves NE over the UK. Some recovery of pressure is close at hand to the SE early next week but SW winds still blowing for most will continue to bring rain at times in association with deep Atlantic Low pressure close to the North and West. 

 

http://www.wetterzentrale.de/pics/Rgem2401.gif 

 

NAVGEM NAVGEM shows slack synopics too to begin this week with fine and benign conditions for many. A trough crossing east midweek in assoc iation with a slowly expanding and deepening Low close to the NW becomes the dominant pressure system over the UK from then as it extends down across the UK with rain and showers for all at times a week from now.

 

http://www.wetterzentrale.de/pics/Rnvg1681.gif.

 

ECM ECM this morning shows a lot of slack pressure about early this week as no one pressure system has overall control over the UK weather. So bright weather with a few showers is likely. From midweek a steepening of the pressure gradient is shown as Low pressure moves in closer to the NW with SW winds ushering some rain across the UK though precious little in the SE. The trend is then for lower pressure under Westerly winds with some showery rain at times to see us through next weekend and the start of the following week with temperatures remaining near to average.

 

http://www.wetterzentrale.de/pics/Recm2401.gif

 

ECM 10 DAY MEAN The ECM 10 Day Mean Chart  from last evening likes the idea of Low pressure to lie to the NW of the UK with a SW or West flow threatening rain at times to the UK especially but by no means exclusively towards the North and West.

 

http://www.wetterzentrale.de/pics/Reem2401.gif 

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models are trending towards another more unsettled interlude later this week with the longer term models from GFS hinting at High pressure again in two weeks, strongly supported by it's ensembles.

 

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The Verification Statistics of GFS, UKMO and ECM. This morning's verification statistics show ECM leading the way at 3 days with 95.7 pts followed by UKMO at 95.3 pts and GFS at 94.5pts. At 5 days ECM is stll king at 85.9 pts followed by UKMO at 84.8 and GFS at 83.1 pts. Then at 8 Days ECM still leads at 59.8 pts over GFS's 54.7 pts. Finally at Day 10 ECM leads GFS at 40.7 pts to 35.6 pts from GFS.

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day3_PMSL_MSL_G2NHX.png 

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day5_PMSL_MSL_G2NHX.png

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day8_PMSL_MSL_G2NHX.png

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day10_PMSL_MSL_G2NHX.prig

 

MY THOUGHTS Another morning and another set of mixed messages from the outputs. The first week does show some support for a theme of slack pressure gradients over the coming days slowly giving way to more changeable weather under the influence of a deepening Low up to the NW. Much output has this gradually deepening and extending reach to the SE too where complications from the South might develop something more thundery for a time late in the week ahead of the Atlantic SW feed. Thereafter, it looks like that a period of changeable weather is likely under a SW or West flow with some rain at times for all and temperatures suppressed as a result. Then later in the period GFS does show us a way towards fine and settled conditions for many as High pressure builds across the UK towards the Bank Holiday weekend. However, GEM has gone off on excursion to early Autumn this morning as deepening Atlantic Low pressure has the UK in it's sights in a week or so. ECM on the other hand goes to halfway house between GFS and GEM with the 10 day point illustrating a deep mid Atlantic Low throwing some influence across the UK coupled with a 10 Day mean chart which shows pressure below 1015mbs countrywide. From all this we have to rely on GFS having a long term handle that it's late rise of pressure is right and that the Bank Holiday looks set fair and warm for many. I must add it is disappointing that the whole of this Summer has seen the UK plagued by a Jet flow too far South and cool uppers hardly ever able to leave the UK as result except for the odd day or so. Whereas Europe as a whole has seen a splendid Summer with almost continuous high temperatures and away from the usual thunderstorms not much in the way of rain. While this Summer hasn't delivered that much rain for many here either especially in the South and East temperatures and sunshine amounts have been disappointingly suppressed. Unfortunately this morning's output does little to change this theme as the pattern looks all too familiar this morning to that we have seen virtually all Summer across and around the UK. 

 

Next update from 09:00 Monday Aug 17th 2015

[Polar Maritime]

An interesting set-up showing for next weekend,  As the Low to the S/W of the UK pulls some pretty warm/moist air over the South, With Temps possibly touching 30c and storms in places. Only a short lived feature for now at least, And a week out.. But certainly worth keeping an eye on as to how the models handle the small detail predicted over us. The ECMWF has the Low a little further North to the West of the UK, Drawing warm air up sooner from the South for Friday/Sat, With surface temperatures not quite as hot as the GFS..

 

That aside, A fine week coming up shown in the Models. A typical late Summer affair, With some warm days and cool nights and plenty of dry weather to be had for the majority of the UK.

Edited August 16, 2015 by Polar Maritime

[Milhouse]

It does look like August will continue the rairly reasonable conditions that we have experienced so far. Nothing really to spark any excitement but increasingly warm winds from the SW then S should ensure a summery feeling week. Low pressure does look like coming closer next weekend but winds likely to remain from a fairly warm direction.

[IanR]

looks a slight day by day increase in temps 17c today,  maybe 22c here by the end of the week, not remarkable though, but not bad by this summers mid to high teens default setting

 

cant see august cet being above the 81 - 10 average though, maybe  a little above in the 'all years' cet,