Model Output Discussion 18z 28/07/13

[Dancerwithwings]

Atlantic still looks dead even in FI. Water companies could be getting worried soon!

Cheers ! That reminds me i've got to water the garden

[Yarmy]

Cheers ! That reminds me i've got to water the garden

 

I'd just wait until Friday and let Nature do it for you.

[Summer Sun]

Hurricane season has not really kicked into gear yet either. Are the two related?

 

This should help http://www.bbc.co.uk/weather/features/23868987

[Tim Bland]

Hurricane season has not really kicked into gear yet either. Are the two related?

Yes hurricane season has been very quiet so far. This has an effect as the reminants are often steered towards us. Interesting video above from BBC explains that we could still have 5-6 major hurricanes. Perhaps this will stir things up and lead to a more zonal period for the uk in Oct / Nov? Edited September 4, 2013 by Tim Bland

[summer blizzard]

This should help http://www.bbc.co.uk/weather/features/23868987

 

 

Yes hurricane season has been very quiet so far. This has an effect as the reminants are often steered towards us.

Interesting video above from BBC explains that we could still have 5-6 major hurricanes. Perhaps this will stir things up and lead to a more zonal period for the uk in Oct / Nov?

 

Tropical Depression 7 has just formed which (if it avoids Haiti) could become a hurricane, it will also be fishing so towards day 10 the models could be changing a lot each run.

Edited September 4, 2013 by summer blizzard

[Summer Sun]

Here is the latest from Gibby on the models

 

Good evening. Here is the report on the 12 noon outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Wednesday September 4th 2013.

 

All models show the ridge of high pressure over Southern and Eastern Britain currently giving way to a cold front slowly working it's way down from the NW. This feature though fairly innocuous at the moment peps up considerably tomorrow night as it makes it's way into the hot air over Central and Eastern England late tomorrow. At the same time Low pressure forms near SE England and sets up a very volatile situation with some very heavy and possible disruptive rainfall on Friday and Saturday. By Sunday the worst of the rain will probably become more showery in nature but still with some heavy bursts here and there. As well as the rain from Friday it is shown to become much cooler as well with distinct difference in the feel of things for all. Most models also show tonight the Low or by then trough moves away East from the UK on Monday as pressure is shown to rise steadily from the west or SW.

 

GFS shows High pressure building in steadily from the SW through the week replacing the cool and showery start to the week with dry and brighter weather with cool nights leading to the possibility of fog in the South by night. Through the extended part of the run High pressure locks firmly down on the UK with fine, settled and warm weather developing Nationwide once more with sunny spells by day and mist and fog overnight and in the mornings. At the end of the run the fog risk limits to the North as a warm SE flow develops over the South as high pressure slips further to the NE.

 

The GFS Ensembles show a lot of spread and confusion tonight behind the certainty of the breakdown on Friday. There are a few occasions of possibly notable rain across some areas before the trend for steadily less and less rain develops with time as High pressure makes inroads into UK air space once more.

 

The Jet Stream shows a sharp change in direction as it plunges South to the West of the UK later tomorrow setting up a circulation around the developing Low near SE England on Friday. After a few days the main flow powering across the Atlantic whisks this little feature away and sets up a more direct West to East flow across the UK in a week to 10 days time.

 

UKMO tonight shows pressure rising steadily over the UK towards the middle of next week with scattered showers in a cool NW flow as a ridge of High pressure advances in from the West soon after the close of the run.

 

GEM tonight has a somewhat slower progression towards High pressure later next week as several days of NW winds and fairly benign conditions affect the UK up until  midweek before a more definitive lean towards fine and warm weather looks possible towards the end of the run as High pressure builds in.

 

NAVGEM keeps Low pressure trapped down near the SW of England with unsettled and showery conditions maintained down here while drier and brighter conditions affect the North and east of the UK.

 

ECM tonight shows High pressure well established again by the middle of next week with the 10 day chart illustrating a High pressure belt all the way from mid Atlantic across Britain and East into Europe although things would be less warm than currently despite being dry and bright by day but with the risk of cool foggy nights. 

 

In Summary tonight the trend towards High pressure re-establishing itself again over the UK later next week is gathering pace with all but NAVGEM indicating this trend to a greater or lesser degree tonight. In the shorter term a short but possibly quite sharp unsettled period looks likely between Friday and Tuesday across many parts of the UK when we will be reminded that it is September now with more Autumnal weather very possible at times

 

http://www.norton-radstockweather.co.uk/Model-Analysis%282859336%29.htm

[Yarmy]

Goldilocks output overall after the weekend. Not too cold, not too hot. Nothing much to complain about, whatever your preference.

[Frosty.]

The Gfs 00z operational run is showing a very autumnal spell from friday onwards with cool cyclonic weather and lots of heavy rain and then during next week the trough responsible for the bad weather becomes anchored limpet like just to the east which holds high pressure further west and the uk is trapped in a run of very cool Northerly winds with showers peppering the far east of the uk but at least most inland areas tending to dry up with sunny spells, overnights would be chilly. There is a silver lining though, eventually the trough fills and clears off allowing high pressure to build in and brings a pleasantly warm and increasingly anticyclonic spell with lots of sunshine and light winds but with a growing risk of overnight fog, temperatures eventually recovering into the low 20's celsius.

Edited September 5, 2013 by Frosty.

[joggs]

I'm running the great north run a week on sunday so cmon models please extend this autumnal spell lol.

[Man With Beard]

ECM goes dry again Monday/Tuesday onwards. Looking a strong bet now.

For the first time it brings back higher temps too - quite plausible if we get HP running across us towards the end of next week - 26C possible if this chart verifies, cooler as you head north.

[No Balls Like Snow Balls]

Bit of a yawn fest setting up for next week if the 00z ECM and UKMO were to verify. Not to warm not to cold.

GFS 00z would provide some interesting weather and stop some of us dropping off while viewing the models.

[shedhead]

No denying the trend across the last 24hrs has been to build pressure next week, but again I'd advise caution in assuming ECM is correct and one look at the London MSLP ensembles shows the GFS Op was pretty much top of the shop.  Expect equally as much chopping and changing across the next day or so as the models struggle to nail the details for next week, but I'd be very surprised if things turn out to be as settled as the current guidance suggests, at least across the south where ECM remains bullish about a return to summer.. 

 

 

Edited September 5, 2013 by shedhead

[Summer Sun]

ECM remains very consistent this morning that's 3 successive runs now its going for high pressure to rebuild from next Tuesday keeping things dry, quiet and pleasant by day

 

http://www.null/ds/ecm.htm

 

UKMO is on board nicely as well now

 

 

 

That only leaves GFS to play catch up

[Yarmy]

ECM remains very consistent this morning that's 3 successive runs now its going for high pressure to rebuild from next Tuesday keeping things dry, quiet and pleasant by day

 

http://www.null/ds/ecm.htm

 

UKMO is on board nicely as well now

 

 

 

That only leaves GFS to play catch up

 

ECM and UKMO still significantly better than the rest at that range too:

 

[Wayneywoo]

Hi all,

Loving the summer however I generally get involved when there's snow around :-)

I'm just posting now while its relatively quiet.

I've just checked the archives for 26th September 1996 as that was my 21st birthday and I remember coming back from Spain to Blue skies and decent temperatures.

Can anyone tell me what the temperature on the ground would've been on that day?

Just curious as it was so late in the year, reminded of it because of where we are now.

[draztik]

Well the GEM certainly sees things different this morning, and the GFS is rather reluctant to build HP in as strongly. The ECM maintains its outlook, though with less support from its friends this morning.

[bluearmy]

just a note that a cluster of ecm runs maintains troughing just wsw of the uk next week. i assume this cluster will disappear over the next run or so. however, dont be too shocked if the 12z op decides to follow that solution. wouldnt be the first time. 

[Summer Sun]

Here is the latest on the models from Gibby as he says some usable weather for what will be mid September

 

Good morning folks. Here is the report on the midnight outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Thursday 5th September 2013.

 

All models continue to show a cold front moving in from the West today gradually replacing the hot and humid conditions in the SE today with very much fresher air reaching the north and west today and other areas tonight. As the cool air engages the warmth over the East the cold front will develop strongly with Low pressure forming near SE England and moving NW over the weekend with all areas experiencing rain or showers and cool winds. By Monday the low will of filled near the NW and it will clear East as a showery trough through Monday. In its wake pressure is shown to rise from the SW again as a High pressure ridge develops over the UK by midweek though with a few exceptions between the models by this point noted below.

 

The Fax Charts illustrate an unsettled weekend for all leading into a showery start to the new week as the Low forming near the SE tonight trundles NW and then back east by the weekend to be in the north sea by Monday. A complex array of troughs is shown in association with this feature with nowhere immune to rain on all of the covered days.

 

GFS is a little slower rising pressure from the West next week with Low pressure to the East still giving Eastern areas a cool and showery feed as late as Thursday before a much more slender ridge collapses over the UK on Friday followed by a trough giving the weekend a cloudier and more unsettled look about it again with some rain at times for all. It's not until we get into Week 2 that pressure rises strongly over the UK with fine and sunny weather with warm conditions by day but with cool and misty nights.

 

The GFS Ensembles show a sharp drop in uppers over the coming 36 hours as a cold front introduces Autumn to the UK. Thereafter conditions slowly improve again with less rainfall the deeper into the run we go, especially across the South. The strong anticyclonic theme of the operational later in the run makes this run a warm outlier in Week 2 but there is scope for improvements shown by other members to be sufficient to make for some pleasant and fine weather to be found at times almost anywhere.

 

The Jet Stream today is currently troughing South over the UK as the Low over SE England forms. The cut off circulation in the Jet flow around this depression weakens over the weekend as it migrates North to join the main Northern Jet which then settles on a traditional and undulating West to East flow later close to Northern Britain.

 

UKMO today shows high pressure close to SW Britain next Wednesday with fine and dry weather for most having replaced the showers from early in the week. With a NW feed over the UK the weather will not be as warm as currently in the South with average temperatures, broken cloud and sunny spells the most likely.

 

GEM today shows Low pressure closer to the SE still by early next week which has the net result of allowing extensions of Atlantic depressions to sink SE across the UK very much diluting the effects of the ridge that other outputs show. in fact much of the week is shown to be rather cool with troughs delivering rain or showers at times especially but not exclusively to more northern and Eastern locations in average temperatures at best.

 

NAVGEM continues to maintain it's theory which has stuck too for days now in holding Low pressure close to Southern Britain well into the middle of next week with showers or rain at times continuing in the South whereas any High pressure ridge is only shown to affect the North.

 

ECM looks OK next week once the early week showers have cleared away East. With high pressure transferring East across Southern Britain midweek some fine and warm conditions would develop for a time away from the cloudier north though by the weekend things are looking a little bit more tentative as High pressure begins to seep away somewhat.

 

In Summary there is still the trend for High pressure to build into the UK again next week. However, there are many different guises in how the models show this likely to happen both in speed of developments as well as extent. It does appear almost guaranteed that the weekend Low will move NW over Britain and fill which allows Westerly winds developing to its South to usher in a showery trough and subsequent ridge by midweek. NAVGEM is the exception to this rule maintaining Low pressure close to the South well into next week while GEM and GFS are reluctant to bring High pressure in quite as quickly today. Instead it's down to the Euro models today who both show fine prospects under high pressure from midweek next week. Even given the charts don't show conditions being as warm or as sunny as conditions in the South and East of Britain have seen recently some very useable and benign weather is not to be sniffed at for what will be mid September.

 

http://www.norton-radstockweather.co.uk/Model-Analysis%282859336%29.htm

 

[Frank Trough]

just a note that a cluster of ecm runs maintains troughing just wsw of the uk next week. i assume this cluster will disappear over the next run or so. however, dont be too shocked if the 12z op decides to follow that solution. wouldnt be the first time. 

 

interesting....have they been present in the last few ECM outputs or have they just appeared on the 00Z suite? 

 

I haven't looked at the charts for a little while and to be honest i'd pretty much resigned myself to a much wetter and unsettled outlook after the weekend (as that's what was being shown). But then i looked at the BBC forecast for bournemouth and was a bit surprised to see it looking predominantly dry after the weekend:

 

http://www.bbc.co.uk/weather/2655095

 

I won't bother re-posting the ECM  etc but i was quite surprised to see high pressure nudging in instead of a cut off low pressure rattling around. Another spell of dry weather will do me nicely but given the swing i think i'll remain cautious. 

 

*perhaps the positioning, longevity and strength of the troughing to our northeast is now the major question rather than the cut off low scenario originally being touted?* 

 

GFS 06Z still keen to keep the troughing as a major feature, preventing high pressure ridging in:

 

 

 

mind you, how much credence should be given to any models (esp. gfs 06z) beyond t+96 given the way things have developed over the last few days? 

Edited September 5, 2013 by Pharaoh Clutchstraw

[No Balls Like Snow Balls]

Well well well the GFS 06Z still wants to maintain LP near the UK. Going completely against the ECM and UKMO 00z runs.

i can only see one outcome though and that is GFS eventually coming into line with ECM and UKMO. From my own personal pref i would love to see GFS come to fruition.

 

 

 

 

 

 

 

[Yarmy]

GFS 06Z op still not interested and keeps us in a coolish Northerly flow out to next Thursday. Be surprised if it maintains the trend on later runs because

 

a. it is very different to ECM/UKMO which are objectively better models

 

and 

 

b. it would shred my September CET forecast

Edited September 5, 2013 by Yarmy

[Alexis]

Yes hurricane season has been very quiet so far. This has an effect as the reminants are often steered towards us.Interesting video above from BBC explains that we could still have 5-6 major hurricanes. Perhaps this will stir things up and lead to a more zonal period for the uk in Oct / Nov?

 

You often get ex-hurricanes inflating areas of high pressure as well, so it's quite possible for an increase in hurricanes to actually lead to more high pressure over us. It's all down to positioning though and as you say, we can also see the remnants heading straight for us whereas other countries have pressure shunted towards them.

Edited September 5, 2013 by Alexis

[draztik]

A new trend emerging maybe? The gfs less keen to build pressure next week, with the 6z keeping things cool, with lower pressure. We will have to see if the ecm picks up on this later, but next week is not clear at all now.

[Methuselah]

It doesn't surprise me that the models are hinting at a rebuild of HP, next week...We are currently stuck in the same, stubborn pattern that has persisted (with minor differences, of course) since June...Thus, irrespective of mode-output, something has to happen, in order for any major pattern-change to occur.

[No Balls Like Snow Balls]

GFS 06Z short ensembles firming up on  much cooler temps next week.

 

 

Very much looking forward to some cool nights and mornings and much fresher air during the day.

 

Latest ECM 00Z ensembles also show much cooler temps next week. Big rise again from the op run on the 13th but very much a outlier.

 

 

 

 

 

Edited September 5, 2013 by No balls like Snow Balls