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Polar Maritime

Model Output Discussion - 30/6/2014 Onwards - Covering July.

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rather more complex than that ba but of course they change as the senior man assesses the latest models output, I'd rather believe him than some of the ott comments we get in here in the 24-120h range, but then of course he should be better than folks on here!

 

Quite agree John except I would change the should to is.

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The models are now getting to grip with how the trough disrupts at the end of the week and where the upper low cuts off to. D5 clusters from ECM halved this morning from 6 to 3 compared to yesterday's 0z and the op is now in the main cluster.

 

At D5 the Atlantic LP sits just south of Iceland on the ECM op: post-14819-0-03474700-1404810082_thumb.g

 

The GFS op, slightly SE of Iceland, so subtle differences: post-14819-0-84428600-1404810131_thumb.p

 

20 members of the ECM support its op cluster and cluster 2 (19 members) are closer to the GFS op. So good agreement.

 

After that we have the low in situ close to Iceland for 3-4 days. With the upper flow active the ECM sees three fronts crossing the UK during that period (ditto GFS Control, am ignoring the GFS op after D5 as it is an outlier solution). So potentially more unsettled than of late.

 

Then on D10 both models suggesting a brief plume of warm uppers from the south: post-14819-0-25881700-1404810646_thumb.g

 

The Atlantic trough/Euro ridge showing as very transient on the GEFS at the moment as the pattern flattens upstream for around 5 days from D11. The d12 mean highlights this:

 

post-14819-0-48578700-1404810798_thumb.p  Early days but GEFS hinting at this type of flow for a few days for that range.

 

Yesterday's 12z GFS op and control sustained pressure rise were showing as outliers and this morning have lost their support. So though both main models have been hinting at more substantial pressure rises they have now backtracked on these (for the moment). GEM (also Navgem) however still showing week 2 pressure build for the south (a la UKMO week 2 forecast from yesterday):

 

post-14819-0-93716600-1404811447_thumb.p  See what the update is today?

 

So a nice mix of weather incoming for the next 10 days with some uncertainty in the D8-14 range.

Edited by i'm dreaming of...
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Just adding to the above. Our pattern for the next two weeks look like it has developed upstream. ECM is more amplified but is similar to GFS. It shows a major trough digging south over the Eastern US. I suspect this is a direct result of the Super Typhoon's (Neoguri) effect on the mid-latitude flow (probably going to mean more uncertainty?), it's effect is that the Pacific ridge is pumped up:

 

post-14819-0-93643600-1404817953_thumb.p

 

This explains the Stalling of the LP system towards Iceland as the NH pattern becomes more meridional as the Atlantic becomes blocked. 

 

So by D10, with that strong Pacific Ridge squeezing the lower heights at the pole towards our side of the NH, it flattens the US trough, flushing the Atlantic energy towards our locale:

 

post-14819-0-89724300-1404818121_thumb.p

 

This ties in with what GFS have been showing, that of a flatter upstream after D11. How that blends with the Azores will likely affect how far south the jet flows. That release of energy looks like blowing the heights to our East away towards Siberia. That along with the Pacific heights will further compress the PV towards our sector of the NH. The 06z view:

 

post-14819-0-77719000-1404818527_thumb.p

 

Certainly a LW pattern change to a more zonal flow. Not a good omen for the second half of July, though the south may benefit from a N/S split.

Edited by i'm dreaming of...
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Well, a look at day 6 (14th) shows that GFS, GEM, UKMO and ECWMF all have pressure below 1020mb with low pressure somewhere west of the UK (they differ on quite how unsettled it is).

 

Out to day 8 and GEM builds pressure while GFS and ECWMF keep pressure sub-1020mb.

 

Posted Image

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Well it looks like as I expected, that the GFS was over-doing the signal for a stronger jet and hence has now backed down to something more akin to the rest of the models/ensembles.

Posted Image

Developing Euro high and Atlantic trough. No point taking much notice of where the jet will lie as it will change from run to run but at least the GFS has the same longwave pattern as the rest now.

 

Typically now the UKMO shows something more unsettled to start next week.

Posted Image

Pressure should still build over Europe to affect some of the UK.

 

Edit - GEM coming out now

Posted Image

Looks good as well for heights building in from the south west next week.

Edited by Captain shortwave
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Well it looks like as I expected, that the GFS was over-doing the signal for a stronger jet and hence has now backed down to something more akin to the rest of the models/ensembles.

Posted Image

Developing Euro high and Atlantic trough. No point taking much notice of where the jet will lie as it will change from run to run but at least the GFS has the same longwave pattern as the rest now.

 

Typically now the UKMO shows something more unsettled to start next week.

Posted Image

Pressure should still build over Europe to affect some of the UK.

 

Edit - GEM coming out now

Posted Image

Looks good as well for heights building in from the south west next week.

 

with no disrespect to you sir,over the last few months theres always been 'high pressure building in' , its been a regular feature of recent weeks, but it never does build, it gets downgraded nearer the time. we have been plagued by these false promises for weeks. il believe it when it happens.

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Lots of chaos in the models. The 12z GFS op has potentially two more typhoons showing up:

 

At T192: post-14819-0-12421800-1404837855_thumb.p  At T276: post-14819-0-31197400-1404837922_thumb.p

 

This morning's GFS op did not forecast this (not on the ECM either). GEM had it this morning and this afternoon, buts sends the D8 one to Japan whereas GFS sends it in the opposite direction!

 

I suspect the models for after D7 will be chopping and changing whilst this new trigger puts the model's algorithms to the test. The current Super Typhoon is the size of the UK and must effect the weather pattern significantly:

 

post-14819-0-43239900-1404838899_thumb.p

 

 

Edited by i'm dreaming of...
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with no disrespect to you sir,over the last few months theres always been 'high pressure building in' , its been a regular feature of recent weeks, but it never does build, it gets downgraded nearer the time. we have been plagued by these false promises for weeks. il believe it when it happens.

Of course the same applies to the cool and unsettled conditions. It's been one of those summers so far where we have neither extreme. Of course ones opinion on the summer so far will differ depending on location.

GFS ens coming out now and well

Posted Image

Posted Image

 

Pretty decent.

As I have said recently I think a NW/SE split is the most likely solution with the jet going through the UK at a more favourable angle. Hence the further south east you are, the more likely that settled and very warm conditions will dominate. The further north west you are, the more likely you are to see more mixed conditions with temperatures near average. 

Edited by Captain shortwave
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Evening all :)

 

Time for a quick peruse of the 12Z output. GFS tonight leads the way and this is where we may be this time next week:

 

http://modeles.meteociel.fr/modeles/gfs/runs/2014070812/gfs-0-168.png?12

 

Not too bad at all. Settled especially for the south with a ridge and pleasantly warm without being unbearably hot.

 

http://modeles.meteociel.fr/modeles/gem/runs/2014070812/gem-0-168.png?12

 

Better still for fans of settled weather - the evolution from there isn't perhaps what might be expected with an E'ly setting up between HP to the north and LP over a hot Europe. The E'ly serves only to deflect the heat and keep the south at risk from showers or storms.

 

UKMO at T+144

 

http://www.meteociel.fr/ukmo/runs/2014070812/UW144-21.GIF?08-19

 

A huge difference and obviously much less settled,

 

http://www.meteociel.fr/modeles/ecmwf/runs/2014070812/ECM1-168.GIF?08-0

 

ECM at the same time frame - closer to GFS than other models so those looking for a settled period have some valuable allies. As ever, though, we'll see what the morning brings.

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UKMO looks the odd one out in phasing the troughing over northern Europe with the low to the north west of the UKMO (though the JMA supports it).

ECM look like a real dogs dinner into week 2, messy surface pressure pattern. A light south westerly drift would bring very warm and humid conditions.

Posted Image

Euro upper ridge/Atlantic trough though so decent agreement between the ECM/GFS and GEM on this, just the surface details to nail down.

Edited by Captain shortwave

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Hot and humid weather from both gfs and ecm on offer just over into the continent in todays runs, Can we tap into it? Looks like we will gets some warmth at times, but there is an Atlantic influence as well. So with no real heatwaves on offer from the models, the weather will be half decent for some, Thundery and at times very warm especially for southeastern Britain. Looks as pressure will be rather slack or even fairly low at times across the uk right up to T+168 and beyond. If you like storms , this output is just fine. The Garden of Eden Summer continues........ :rolleyes:  :good:  :good:

post-6830-0-89518600-1404848981_thumb.pn

post-6830-0-57643600-1404849021_thumb.pn

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with no disrespect to you sir,over the last few months theres always been 'high pressure building in' , its been a regular feature of recent weeks, but it never does build, it gets downgraded nearer the time. we have been plagued by these false promises for weeks. il believe it when it happens.

I really see no high pressure influence in the days ahead, those who do are just hopecasting. Im afraid we will have to rely on slack areas of pressure. even low pressure to bring us warmth,sunshine and perhaps thunderstorms, The Azores high as laid a pillow across the uk  for now.....  :lazy:  :lazy:  :lazy:

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I really see no high pressure influence in the days ahead, those who do are just hopecasting. Im afraid we will have to rely on slack areas of pressure. even low pressure to bring us warmth,sunshine and perhaps thunderstorms, The Azores high as laid a pillow across the uk  for now.....  :lazy:  :lazy:  :lazy:

agree 100% im with you i see nothing to get excited about everything i look at points to nothing really settled at all...although the ECM ens do point to more settled as has been said to the south east of the country, seems to me though the northwest southeast split is getting smaller maybe kent will do alright :nea:

 

the only way is up

 

http://www.weathercast.co.uk/meteo/eps/ensemble-rrrcum-london.gif

Edited by DTHFCJ
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ECM ensembles far less bullish re pressure rise into mid term, as opposed to GEFS.

at t192

Posted Image

 

longer term, days 10-15

Posted Image

height anom.

 

a stark difference to what we had last year, even with the short term.

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Looking towards the last third of the Month again this morning, And the GFS continues to show the Jet South of the UK, With some very warm Heights pushing way up into the Poles drawing in cool/wet Atlantic driven weather from the West.

 

Posted ImagePosted ImagePosted Image

Edited by Polar Maritime
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Good consensus up to day 6 between the models. After the warm front coming in from the east breaks up then a good deal of the UK will see a couple of day of warm and showery weather (perhaps very warm in places). A cold front will spread in from the west on Sunday though the east should stay dry and very warm until the end of the day.

Beyond that, again the Azores high looks likely to ridge into Europe with a split in conditions occuring. No surprise that from the middle of next week, we see a split in solutions developing. The 2 being;

GFS

Posted Image

Euro high and a moist tropical maritime south west flow. Very warm in the sunnier spells but cloudier in the west with more persistent rain in the north west.

 

The other is the GEM/ECM

Posted Image

Posted Image

 

The more amplified solution resulting in a couple of hot days followed by a thundery breakdown from the south.

 

Day 9 from the ECM looks tasty/nasty based on how you feel

Posted Image

Deepening thundery low with a lot of embedded warmth. A very, very wet chart that is.

 

Still lots of runs to decided how things will go. Of course the other variable is where the jet will lie and hence will the warmth simply miss the UK, or maybe it will be more robust and cover more of the UK than is shown in any of these charts.

Edited by Captain shortwave
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Yes I agree with some of the above. For the last week we have been forecast a brief transient ridge for 2-4 days as it collapses east, around 15-18th. Lots of uncertainty on its boundary (NE-SW), but temps for some areas could be warm. I see no HP block building over the UK.

 

Before then we have a stalling warm front tomorrow in the east. Then by the weekend the Icelandic low takes charge till mid next week. Around D7 we get the Azores ridge:

 

GFS: post-14819-0-18392800-1404887506_thumb.p  The placement of the Icelandic low having a direct bearing on how far NE that weak ridge can creep.

 

GEM goes more amplified: post-14819-0-23280900-1404887647_thumb.p  Allowing an Atlantic trough/Euro Ridge. GEM is the most progressive with height builds. Highs of 24c+ for 4 days on that run before the ridge slides east.

 

GEFS have the ridge slowly edging in; the mean taking 3 days to go from 1010 to 1020; member scatter from there but the mean continues its trend down for pressure so last third of July still looks lower pressure dominated.

 

post-14819-0-25323900-1404888237_thumb.g  Temps: post-14819-0-71180300-1404888252_thumb.g

 

Plenty of rain spikes in that period of middling pressure. 

 

ECM is and has been the worse case scenario for the transient ridge. Two days is generous on this morning's run:

 

D7: post-14819-0-95979900-1404888452_thumb.g   D8: post-14819-0-11912300-1404888473_thumb.g  D9: post-14819-0-16592000-1404888614_thumb.g

 

So a pressure build in around 6-7 days time, transient on all models, longevity variable form 2-4 days, with potential for hot and maybe stormy weather. Then the fall in pressure for the rest of July. NOAA 6-10 and 8-14 not showing much of any HP anomaly in our locale:

 

post-14819-0-66094700-1404889566_thumb.g  post-14819-0-93800100-1404889579_thumb.g Confidence is high due to the amplified pattern for D6-10 (5 out of 5).

 

Interestingly the potential typhoon for week 2 is now a clear signal on the GEFS mean, is still modelled on the GEM but ECM continues to not pick this up:

 

GEFS Mean: post-14819-0-09403400-1404888819_thumb.p  GEM: post-14819-0-47957600-1404888845_thumb.p ECMpost-14819-0-11095200-1404891032_thumb.g

 

Too early to knock ECM again but that would be disappointing for a model that is losing its reliability of late.

 

 

 

 

 

Edited by i'm dreaming of...
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One key difference between ECM and the rest by T144 - as usual, ECM makes slightly more of northern blocking, resulting in the Icelandic trough further south. If the ECM has overdone this - again - then the whole pattern will shift north and therefore more hope of better weather in northern areas next week.

Posted Image

Posted Image

Posted Image

The signal for a few warm/hot days is very consistent for the middle of next week, away from the north:

Posted Image

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re this

Confidence is high due to the amplified pattern 

 

That is not a guide to confidence I am afraid. It can if the wave length is 'right' lead to a less changing upper air pattern but not always. There are lots of other things to consider before making such a statement, well in my view there is.

 

Whilst the 3 main anomaly charts do support each other over the last 24 hours, the lack of input from GFS and at times ECMWF and some variability in the NOAA 6-10 day outputs does leave some doubt. What I would suggest based on routine daily checks on these is that a trough, perhaps fairly marked, looks likely to be west, not by much, of the UK, with +ve height anomalies not too far east of the country but not really close enough on current guidance to be of much use for most.

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this mornings ECM ens are definitely starting to look plume like for the middle of next week. so perhaps something to watch there for a spell of thundery weather.

GFS still not keen but still keeps the uk very warm. interestingly the 06z makes very little of the Atlantic breakdown. This is shown by the fact that temperatures do not drop off at all from the values we are likely to get this weekend.

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At day 6 pressure is 1020mb on all models but their is N/S split, models do suggest a plume could develop in the days afterward.

 

Posted Image

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GFS 06z looking borderline hot for some southern parts on Saturday

 

Posted Image

 

Could be wet though maybe thundery given the temps

 

Posted Image

 

Temps fall slightly afterwards but still very warm for the south possibly hot again mid next week warm for all

 

Posted ImagePosted ImagePosted ImagePosted Image

 

Still some rain around at times but not much in the south between Monday and Wednesday

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Looking at tomorrow, it appears that we will have an east-west split, with western areas seeing the best of the weather.

 

Western Britain looks like it will be in for another fine Summer's day with temperatures widely in the low to mid-twenties. In the east however it will feel much more Autumnal with some very poor temperatures (mainly in the low to mid teens) and some potentially very heavy rain, therefore making it a very miserable day in these areas.

 

Quite a large contrast tomorrow.

 

Remember GFS under-cooks temps. Nowhere in East Anglia is going to have a max of 14C tomorrow!

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GFS 12z shows temperatures rising during next week close to 30c by Wednesday in parts of the south

 

The heat starts to build on Saturday humid with rain and thunder possible

 

Posted ImagePosted Image

 

Still very warm for many with a continued risk of thundery showers developing as the day progress

 

Posted ImagePosted Image

 

Drier on Monday still some showers around remaining warm for the south temps around average the further north you are though NW Scotland looks fresher

 

Posted ImagePosted Image

 

Tuesday remains very warm especially for the eastern side with temps starting to rise further north still some showers around but fairly isolated

 

Posted ImagePosted Image

 

The heat starts to build more by Wednesday hitting to high 20's for the south maybe 30c for one or two spots, dry for the south wettest in the north west

 

Posted ImagePosted Image

 

Thursday only goes to 12z but it shows temperatures potentially getting close to 30c in parts of the south fresher the further north you go, potential for some heavy rain in the far south later on more patchy and light the further north you are

 

Posted ImagePosted Image

 

 

 

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So 12 hours on, the GFS and GEM still stick to their own solution. No idea what the UKMO is doing though.

GFS

Posted Image

Classic south westerly scenario, very warm in the south east with sunny spells, wind and rain for the north west.

 

GEM

Posted Image

More amplified, again a classic summer set-up, the high builds east of the UK drawing up a hot southerly plume going into week 2. 30C territory for a few days on this run.

 

UKMO

Posted Image

Doesn't look right to me as the upstream low doesn't phase with the low near Iceland. Though the end game would probably be the same, except unsettled weather probably further south for a time before heights build northwards.

Edited by Captain shortwave
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