Model Output Discussion 06Z, 13 Sep. 2013 ---->

[ANYWEATHER]

Yes but the met office update sounds great as does most of the output with just a few exceptions, potential heatwave next week for the south I reckon, by late september definition, 19c is the average temp in the south at this time of year, could be 6,7,8 degrees celsius higher than that early to mid next week

Look Frosty, I respect your posts. But the models scream unsettled by late next  week,

[Captain Shortwave]

Look Frosty, I respect your posts. But the models scream unsettled by late next  week,

Except the UKMO and GEM don't and the GFS isn't exactly that unsettled.

Whilst the ECM is usually top dog, it hasn't exactly been on form over the past week

Edited September 19, 2013 by Captain shortwave

[Frosty.]

528 dam line approaching northwest scotland....BOOM   

[Frosty.]

Look Frosty, I respect your posts. But the models scream unsettled by late next  week,

Cheers mate I respect yours too, let's wait and see, there are mixed signals..as always

[Man With Beard]

A warm period still on course from Sunday but by Tuesday there are a number of things going on which make forecasting beyond midweek a real challenge. Firstly, we have a cut-off low developing to our west. Anyone watching the charts over the summer will know just how much difficulty the models had in predicting what these cut-off lows would do - would they "cut-off" fully or not, how far south/north would they move - questions which never seemed to be settled until the final 72 hours. We're in a similar position next week - perhaps it hasn't been considered as much because the low is not directly over us, but it's near enough to influence our weather for much of next week - for example, with the GFS (below), the low doesn't cut-off that much and so the north turns more unsettled more quickly - and warm air, rather than being dragged into the Atlantic, keeps on coming for the south of the UK. However, with the UKMO, the cut-off is far more pronounced and the low serves to prop-up the high in our region. Given recent experience, neither outcome can be discounted and the consequential differences in wind direction have big impacts on temperatures Wednesday-Friday next week. So best to sit on the fence atm for Wednesday onwards, it's just a bit too complicated to forecast.

Edited September 19, 2013 by rjbw

[Captain Shortwave]

^ Add to that the ECM still wants that trough to stick over Scandinavia, something all the other models have dropped from the output. Which I find rather odd. Safe to say I didn't see that ECM op coming because I thought it would drop that trough as well. I guess we should look at the ECM ens and see whether they back the operational.

Edited September 19, 2013 by Captain shortwave

[No Balls Like Snow Balls]

Look at all that lovely cold over Greenland. 

 

 

Latest NOAA 8-14 day 500mb shows LP to East of UK and HP to West of UK, pretty much ala ECM

 

 

Still no real concrete evidence of a prolonged warm / very warm spell. Ensembles still show it cooling down after midweek.

 

ECM and UKMO really not that different at T120, they both then go off on there own path at T144.

 

 

 

Have I really seen posts about July type weather Next week or is it all a dream!!. Seriously pull the other one.

 

 

 

 

 

 

 

 

 

Edited September 19, 2013 by No balls like Snow Balls

[SMU]

Evening -

That cold air is beginning to appear again in the models for the last part of sept!

Maybe make the most of those BBQ's this wkend

S

[AWD]

Not in full agreement yet so use with caution, but the anomaly output is starting to take the look of an increasingly unsettled nature with a trough somewhere to our north/north east;

NAEFS also suggestive of a drop back in temperatures, for the north and south, although nothing to abnormal either side of average;

[johnholmes]

Not in full agreement yet so use with caution, but the anomaly output is starting to take the look of an increasingly unsettled nature with a trough somewhere to our north/north east;

image.jpg

NAEFS also suggestive of a drop back in temperatures, for the north and south, although nothing to abnormal either side of average;

image.jpgimage.jpg

 

 

They certainly should be viewed with caution, they have both ECMWF especially, chopped and changed by unusually large amounts over the past few days, (something that does happen around this time of the year as I explained in earlier posts). Not only do they not agree with one another today or over the last 2-3 days, they are also fairly different from the NOAA outputs (see below) for 6-10 or 8-14, which themselves have not been totally consistent over the last few days.

In my view, for the time being, do not use the anomaly charts to support one or other synoptic model. If 3 days from now all 3 are pretty similar then we can begin to have some confidence in their predictions-not at the moment.

http://www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php

Edited September 19, 2013 by johnholmes

[legritter]

Evening all ,lets enjoy some warm weather ,im pretty sure even some of us coldies can squeeze in some bbq days before the nights become colder and darker . looking at current charts i think i will pack some rain gear for our holiday in mijorca next week for 12 nights ,got caught out about 20 or so yrs ago in late september warm but plenty of thundery days ,please keep the very interesting data coming from regular contributers that makes our Net Weather site so interesting , ill be back with a tan i hope in october ready for our autumn and winter ,lets hope its a memoriable one ,

[damianslaw]

Short term - some very pleasant weather as we see a strong ridge develop from the SW turning things much milder and drier for all and hopefully sunnier - low 20 maxima very possible by Sunday in the south and perhaps widespread come Monday.

 

As others have stated the models today have moved away from the sustained dry warm spell they have been suggesting for much of next week - as we see a cut off low pressure develop to our SW - this is often a classic sign of a negative AO/NAO pattern developing as heights build strongly over our side of the Pole. How this phases with the trough development shown to form over scandinavia during the next week will determine he prospects for the end of the month.

 

If it merges with this feature watch heights build rapidly to our NW forcing trough formation over the country and most likely a very cool plunge of air from a northerly-easterly quadrant.

 

This is late September - it is much more difficult to sustain a dry settled spell now than at any stage between say mid Feb and mid August, we are firmly in what is on average the more unsettled half of the year.

[johnholmes]

re this

Latest NOAA 8-14 day 500mb shows LP to East of UK and HP to West of UK, pretty much ala ECM

 

 

It does not show low pressure east of the UK, what it shows is a very small -ve height anomaly east of the UK-a very different thing.

Edited September 19, 2013 by johnholmes

[Frosty.]

^ Add to that the ECM still wants that trough to stick over Scandinavia, something all the other models have dropped from the output. Which I find rather odd. Safe to say I didn't see that ECM op coming because I thought it would drop that trough as well. I guess we should look at the ECM ens and see whether they back the operational.

It's a stunning turnaround because the ecm 00z ensemble mean was as warm and anticyclonic as you could dream of in late september, maybe the gfs deserves some credit for that wintry looking 6z control run after all.

[No Balls Like Snow Balls]

re this

Latest NOAA 8-14 day 500mb shows LP to East of UK and HP to West of UK, pretty much ala ECM

 

 

It does not show low pressure east of the UK, what it shows is a very small -ve height anomaly east of the UK-a very different thing.

Yeah i know what i meant but you word it better and correctly.

Edited September 19, 2013 by No balls like Snow Balls

[Captain Shortwave]

It's a stunning turnaround because the ecm 00z ensemble mean was as warm and anticyclonic as you could dream of in late september, maybe the gfs deserves some credit for that wintry looking 6z control run after all.

I think it's best to leave any conclusions until tomorrow, if the ECM keeps the same output and others back it then fair enough. But until then with a lot of uncertainty about the Atlantic pattern it's best to keep an open mind and not assume warm and dry weather or cool and wet. The models don't agree with each other or themselves run to run so what confidence can we have in the end?

[Tamara]

In terms of some of the summaries given in the last couple of days or so it shouldn't be a surprise that some indication is coming that the pattern might recycle with cooler (and also more unsettled once again) conditions taking hold as we head towards the latter part of the month. Most will welcome some further warm weather and hope that it can last a reasonable time, but also in the nature of the thread it is about deciphering realistically how long this may last

 

However, as of this evening, we are losing the distinctly (too early) autumnal conditions and about to start some very welcome pleasant and warm weather. So first and foremost lets enjoy that

Edited September 19, 2013 by Tamara Road

[SMU]

where did my post go?

[joggs]

where did my post go?

Probably in the winter thread Steve lol,nice to have you back!.

[Captain Shortwave]

where did my post go?

It's still there, unless it's another post

 

Evening -That cold air is beginning to appear again in the models for the last part of sept!Maybe make the most of those BBQ's this wkendS

[Mark Neal.]

GFS 18z shows the settled weather through the weekend and warmer conditions, continuing into start of next week.

              

 

GFS 18Z at 114hrs, has the high starting to move southwards still settled at this stage ,but the warm uppers move southwards again. 

 

 

Edited September 19, 2013 by Mark Neal.

[Mark Neal.]

132hrs on GFS 18Z has High Pressure over country but now 1020mb, Losing its grip but settled to midweek. Look at Cold air to the NE, Russia looks like it will see first real cold of the season. Iceland seeing a deep low. 

[Captain Shortwave]

132hrs on GFS 18Z has High Pressure over country but now 1020mb, Losing its grip but settled to midweek. Look at Cold air to the NE, Russia looks like it will see first real cold of the season. Iceland seeing a deep low. 

Lol give the GFS a pat on the back, that's another completely different set up at day 6 which doesn't agree with any other models.

Oh well might wake up with the models saying it will be 80F by the end of the week, or 10C at the same time. Who knows.

After the cool blip there might be a renewed push of warmth northwards

Edited September 19, 2013 by Captain shortwave

[Mark Neal.]

156HRS, we have a low pressure to the NW, looks like the high is moving away and low pressure about to make its return, thats Thursday onwards on this model run. 

[Cheshire Freeze]

156HRS, we have a low pressure to the NW, looks like the high is moving away and low pressure about to make its return, thats Thursday onwards on this model run. 

 

Aye, will the greeny show up in FI again I wonder??