Model Output Discussion 12z 03/04/13

[ANYWEATHER]

To be honest the weekends weather looks pretty dismal for many, warm front rain spreading North East on Saturday Sunday seeing a cold front straggling across the best part of the country. The far South East and East of England may well see the top of the temps and of course add on the strong wind factor... So even though we inherit potential warmth, wind cloud and rain is likely to spoil play...For Most!  

Edited April 11, 2013 by ANYWEATHER

[Captain Shortwave]

Will be interesting to see which one is right, as a rule the GFS is good at picking up signals for Greenland blocking but after its woeful performance over the last few months I wouldn't back it just yet.

I think we are in a different ball game now. GFS was the only model not backing a southerly flow through Sunday and well all other models backed the more progressive and flatter pattern. GFS has pulled almost the exact same op (including fi) run for two runs on the bounce.

As for the weekend, it looks pretty forgettable apart from perhaps a bright warm and breezy day in the south east on Sunday.

[Guest pjl20101]

Will be interesting to see which one is right, as a rule the GFS is good at picking up signals for Greenland blocking but after its woeful performance over the last few months I wouldn't back it just yet.

Exactly as the UKMO and the ECM have outperformed the GFS. Think more runs are definitely needed.

[ANYWEATHER]

Just to illustrate, gfs [question for accuracy!] Sunday as usual with these set=ups looks very likely for some spring warmth for East Anglia and the SouthEast..... The rest of the country, forget it!!Cant download the chart....!

Edited April 11, 2013 by ANYWEATHER

[Summer Sun]

Not much change from ECM so far to t120

 

 

 

 

 

[ANYWEATHER]

Not much change from ECM so far to t120

 

Yep .and not much change from your output either!!!

[Summer Sun]

t144 shows a north south split for Wednesday as a low pressure system tracks across the north of Scotland here it will be cooler and whilst whilst England and wales should see temperatures widely in double figures with a range of low teens in Northern England to mid and maybe high teens in the south especially if the sun breaks through

 

 

As per the 00z high pressure builds at t168 no backing down from ECM so far

 

 

t192 sees another burst of warm southerly winds also we are in agreement with GFS which is also showing this at t192

 

 

Given that it would be a southerly sunshine would be plenty-full so temperatures into the 20's seem possible for the south

Edited April 11, 2013 by Gavin.

[Captain Shortwave]

 

Good agreement here with the GFS

[johnholmes]

I think sometimes the GFS goes OTT but there is a strong suggestion that the AO could do negative again as was mentioned Millhouse in one of the latest vids done by Gavin p. It would be very interesting to see what MJO phase 7 or 8 looks like in mid to late April. Because I think that is where we are heading.

That is one of the reasons why the atmosphere is so variable at the moment and having massive implications not just here but worldwide.

why should the MJO move to 7 it is in 4/5 and looks like remaining in either of those two to me?

4=trough over/just west of uk and 5=blocked?

link to MJO and 500mb most likely charts.

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

[Gael_Force]

why should the MJO move to 7 it is in 4/5 and looks like remaining in either of those two to me?

4=trough over/just west of uk and 5=blocked?

link to MJO and 500mb most likely charts.

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

One of the forecast agencies has a transition to phase 7 by months end - maybe this is where PJ's thoughts originate?

 

http://cawcr.gov.au/staff/mwheeler/maproom/RMM/fcsts/pd.MW05.Last.gif

 

Composite picture for May, not out of sync with what GFS showing for 15 days time.

 

http://raleighwx.americanwx.com/MJO/MayPhase7500mb.gif

[Guest pjl20101]

Pretty respectable ECM tonight with one HP moving with another. Pretty good I have to say, oh and I checked the GFS 12Z ensembles and it looks like the operational model was a lot colder than the control output.

[shaky]

My word anyone seen the latest ecmwf 240 hour chart!!am pretty certain that would go on to show a potent heatwave a day or two later!!immense heat coming up from africa and into spain and eventually the uk!!

[Gibby]

Good evening. here is the report of the 12z output from the 12z output of GFS, UKMO, GEM, NAVGEM and ECM for tonight Thursday April 11th 2013.

 

All models show a trend to milder conditions already over Southern Britain extending to all areas over the weekend. Low pressure moving East over the South tonight will enhance the showers here while some rain over Central areas marks the dividing line between the cold weather to the North and the milder air over the South. a deep Low develops in the Atlantic over the weekend spreads a trough quickly NE across the UK on Saturday with rain and strong winds at times for many. On Sunday a weakening cold front will spread further outbreaks of rain East through the day followed by a mixed set of fortunes from the models as we move through next week.

 

GFS then shows a trend to warmer and more settled conditions around midweek as a High pressure develops over and then East of the UK with winds backing South or SE on Thursday. Late in the week a band of potentially thundery showers will move NE over the South from Biscay followed by a change to High pressure conditions again to the North and eventually NW of the UK. Low pressure moving South over Europe towards the end of the run sends cold Arctic winds South over Scandinavia then SW over Britain with a return to cold conditions with wintry showers and frost at night should it verify.

 

The GFS Ensembles show the operational with it's cold and frosty end is rather isolated but it should be noted in week 2 that there are some rather cold options shown which would incur frosts at night. In essence though the main theme is for rather milder conditions with some rain at times and temperatures into comfortable levels at least for late April.

 

The Jet Stream continues to move further North than of late as it moves in a general north-easterly direction through the British Isles next week.

 

UKMO tonight shows Low pressure passing NE to the NW of Scotland. Northern and Western areas will see spells of rain or showers in fresh to strong SW winds. A little rain is likely in the South and East too at times but with longer, drier and warmer interludes too in the overall milder than average temperatures.

 

GEM tonight also shows a similar setup as UKMO as a Low passes NE to the NW of Scotland with rain at times, heaviest in the North and West in reasonably mild but windy conditions.

 

NAVGEM shows little difference with rain at times from similar synoptics early in the week with high pressure building later in the week to offer some fine and warm conditions first in the South and then more generally.

 

ECM finally shows a similar scenario, building pressure from the South midweek to bring a spell of potentially warm and sunny weather with light winds and misty nights. Towards the end of the run things could turn very warm as the airflow becomes slack and with higher humidities and the fragments of an upper trough drifting slowly North the odd thundery shower looks very possible by the weekend.

 

In summary it appears that the weather is finally realising that we are well into Spring and it's about time we had some Spring conditions. The charts for the next few weeks with just a few exceptions look largely set fair with a more than evens chance of a spell of fine and reasonably warm conditions developing later next week. This following what will be a rather unsettled four or five days to come with rain and wind at times, though at least temperatures reaching more respectable levels if not better in a few Eastern areas over this coming weekend. In the far out reaches of the output tonight apart from a rather disturbing operational run in two weeks time from GFS things look fairly decent with high pressure never far away with ECM showing the converse outcome to GFS with a potential plume affecting the British Isles next weekend.

 

 

[Guest pjl20101]

Cheers Martin for that my friend, by the way no change to the CPC 8-14 day output tonight and looks like predominatley settled by the 25th of this month, with two areas of HP drawing force together:

http://www.cpc.ncep.noaa.gov/products/predictions/814day/814day.03.gif

Pretty good really.

[Milhouse]

T240 on the ECM encouraging in the way it has low pressure very much concentrated over Greenland with a very strong area of high pressure over the UK. The only question is can we remain under the warm airmass or will we pull in a cooler one from the east. With all that heat building into France we could see some very high temperatures if a southerly was to persist for several days.

[Argyle1980]

My word anyone seen the latest ecmwf 240 hour chart!!am pretty certain that would go on to show a potent heatwave a day or two later!!immense heat coming up from africa and into spain and eventually the uk!![/quote here is the chart to back you up my friend.

Will be lovely to see this happen for next weekend.

[Carlrg]

The Spanish plume never gets here on the BOM.

http://www.meteociel.fr/modeles/bome_cartes.php?ech=6&code=0&carte=0&mode=1&archive=0

http://www.meteociel.fr/modeles/bome_cartes.php?ech=6&code=0&carte=0&mode=1&archive=0

Edited April 11, 2013 by Carlrg

[shaky]

My word anyone seen the latest ecmwf 240 hour chart!!am pretty certain that would go on to show a potent heatwave a day or two later!!immense heat coming up from africa and into spain and eventually the uk!![/quote here is the chart to back you up my friend.

Will be lovely to see this happen for next weekend. image.jpg

If only mate!!come tomorrow morning it will probably have dissapeared and instead will show low pressure more dominant or the high to far north allowing a cold easterly to come in!'

[Argyle1980]

ame="Argyle1980" post="2679870" timestamp="1365709611"]

If only mate!!come tomorrow morning it will probably have dissapeared and instead will show low pressure more dominant or the high to far north allowing a cold easterly to come in!'

well that's why we all like our model watching and like you have said we could well get an easterly once again but also with all that warmth to our south there is still plenty of time for anything to verify .

[Summer Sun]

Lovely end to ECM with some decent heat coming up from Africa +12 uppers just clipping the south

 

 

The GFS ensembles continue to point to a rather dry outlook with below average rainfall continuing for the foreseeable

 

 

Continued Ensemble support from ECM to build pressure later next week

 

Edited April 11, 2013 by Gavin.

[chionomaniac]

It does now look like retrogression is on the cards with the HP moving NWwards towards Greenland according to the GFS 12Z. Would be interesting to hear from philnw with whether the NAEFS supports this too as that means our milder weather would be wiped out currently with northerlies. See if the ECM agrees.

 

 

I think sometimes the GFS goes OTT but there is a strong suggestion that the AO could do negative again as was mentioned Millhouse in one of the latest vids done by Gavin p. It would be very interesting to see what MJO phase 7 or 8 looks like in mid to late April. Because I think that is where we are heading.

That is one of the reasons why the atmosphere is so variable at the moment and having massive implications not just here but worldwide.

 

 

I can't see retrogression and Greenland highs being on the cards at all ,pj. Firstly there is very little suggestion from the MJO forecasts that we will be entering phases 7/8 any time soon. The forecasts - especially the ECM and UKMO suggest a quelling of tropical convection if anything:

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml

 

 

Furthermore we have seen the first downwelling of positive mean zonal wind anomalies this year from the stratosphere, which are likely to lead to an increase in the vortex strength over Greenland for the first time this year. This is most definitely borne out by the 500 hPa ensemble anomaly charts for days 11-15 - I don't think that we have seen such negative anomalies forecast there for quite a while:

 

 

And look where the greatest positive height anomalies are - towards the SW of the UK.

 

I think the suggestion last month that there would be a SE/NW split around mid April looks like holding true, though I am still unsure at this point how far north any anticyclone will exert its influence.

[Guest pjl20101]

It's when I watched Gavin p's vid ed and that is one of the things he addressed. But the AO has obviously changed since he made the video. Cheers for that, my bad.

[Panayiotis]

The CFS keeps hinting a cold spell for late April as it retrogresses the high from the south towards Greenland then a low pressure situated to the east giving us a bitter northerly, I dont know if its cold enough for snow for the south but certainly for the north snow showers may fall if it verifies:

 

http://modeles.meteociel.fr/modeles/cfs/run1m/cfs-0-294.png?12

http://modeles.meteociel.fr/modeles/cfs/run1m/cfs-0-336.png?12

http://modeles.meteociel.fr/modeles/cfs/run1m/cfs-0-348.png?12

http://modeles.meteociel.fr/modeles/cfs/run1m/cfs-0-396.png?12

http://modeles.meteociel.fr/modeles/cfs/run1m/cfs-2-396.png?12

http://modeles.meteociel.fr/modeles/cfs/run1m/cfs-0-450.png?12

http://modeles.meteociel.fr/modeles/cfs/run1m/cfs-2-450.png?12

Edited April 11, 2013 by Panayiotis

[West is Best]

Message for John (no pm possible still) Good morning!

 

You asked me to remind you about a London Marathon forecast so I'm taking the liberty of doing so! It would be fantastic if you could do one. The event is Sunday week, so 9 days off now and a number of runners have been asking the all-important question! Even if it's tentative to start with, and then updated would it be possible to do one?

 

Thank you so so much in advance.

[mushymanrob]

well.. the danger of more cold is still there, in fact this morning its greater.

 

after a cloudy, muggy, warm but with some rain this weekend the atlantic mobile regime takes over until later next week. all models suggest some sort of long ridge moving in and building over us. on the east theres a cold plunge, on the west a warm southerly, or in the middle a halfway house between the two. what we are likely to get in a weeks time obviously depends upon the exact position of the expected ridge that becomes a cell. (?...is that right? thought a ridge is a long thing and a cell a 'round' thing?...lol.. )

 

but its likely to be sunnier under the high, whether its warm or cold though is anyones guess this far out as the actual outcome is far from certain.