Model Output Discussions 12z 08/03/17

[knocker]

The last two or three runs have not been without interest and this morning's GFS is no exception. It does appear that a pattern change may be underway, or at least indicated, It involves a strengthening of the Franz Joseph lobe of the Vortex and trough (which also involves a very cold plunge into Eurasia) and with another chunk breaking off from Greenland/Canada into the Atlantic which will loosen the hold of the high pressure in the vicinity of the UK, albeit perhaps only for a short time. And it's worth a look at the cold plunge.

Meanwhile back on the farm all is well with the high pressure becoming established tomorrow and sitting over the UK for the weekend so that bodes well. some quite large diurnal fluctuations, and hopefully cloud kept to a minimum. From here through the middle of next week it essentially becomes a battle between the three protagonists, the Eurasian and Atlantic troughs with the high pressure in the middle.

The Atlantic wins out and by the weekend a depression 989mb is into N. Ireland with associated fronts traversing the UK. What next? A possible repeat surge of the Azores as has been hinted at elsewhere?

So whichever way you hack this it looks very much like a week of dry, quite pleasant weather before, perhaps, a mini break.

 

 

Edited March 23, 2017 by knocker

[knocker]

Although of course varying in detail the ecm is pretty much on the same page as the GFS. Worth noting the Eurasian cold plunge reaches as far south as Libya, and even Niger. And last but not least day 10 has huge potential. BANK!.

Edited March 23, 2017 by knocker

[Frosty.]

Nice ukmo 00z, once the current vile trough is out of the picture it's high pressure and warm fine days with long sunny spells..weekend looks very good, especially saturday..perhaps a bit more cloud from the east later in the weekend.

Edited March 23, 2017 by Frosty.

[knocker]

After the pattern blip the EPS mean anomaly is looking at a return of the status Quo with twin vortex lobes Franz Joseph/Canada/Greenland with associated troughs with the Azores once more ridging in the vicinity of the UK. Thus indications of a WSW upper flow with temps a tad above average and weather tending towards a N/S split.

Edited March 23, 2017 by knocker

[Frosty.]

19 minutes ago, knocker said:

After the pattern blip the EPS mean anomaly is looking at a return of the status Quo with twin vortex lobes Franz Joseph/Canada/Greenland with associated troughs with the Azores once more ridging in the vicinity of the UK. Thus indications of a WSW upper flow with temps a tad above average and weather tending towards a N/S split.

That's good news, and looking at the GEFS 00z mean, the azores high and high pressure generally looks like being our friend during the next few weeks, especially further south, bar the occasional atlantic intrusion..pleasantly warm at times with temps into the 60's F..

Edited March 23, 2017 by Frosty.

[johnholmes]

Using the anomaly charts for the 5-14 day period.

The EC-GFS version continues to flip from ione thing to another. NOAA ploughs on with its insistence of blocking to our NW in the 6-10 day time scale with this less obvious after day 10.

Which is correct?

We will know in 6 days time I suppose. My experience suggests that NOAA is more often correct than the other two. Not had chance/time to check how the upper air pattern today fits what any of the 3 suggested 6-10 days ago. Can anyone oblige please?

anyway the e anomaly charts below.

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

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

Just done a check on NOAA 6-10 last Tuesday to Thursday and very much like the 00z 500mb chart shows on Net Wx Extra this morning. Upper dige NW and marked troughing over and s/se of UK. Not to mean the current one will be correct but it certainly got the last prediction very close. If I get time I will drop them in as a pdf for anyone interested to look at.

 

noaa for net wx 23 march 2017.docnoaa for net wx 23 march 2017.doc

Edited March 23, 2017 by johnholmes

[Frosty.]

I will be glad to see the back of this cool unsettled weather, looking forward to a spell of high pressure and pleasantly warm sunshine.

[mb018538]

Agreed!

IT appears that as that low anchors out west, eastern areas especially could see some pretty mild to warm days as the winds veer more southerly.




15-16c Monday,17-18c Tuesday, 15-16c Wednesday, 13-14c Thursday, 14-15c Friday.

Bearing in mind the average for this part of the month is only around 10-11c, we're well above average. Some chilly nights to come along with these warm days too.

[Frosty.]

It's a cracking outlook, really quite warm for the time of year next week..who wants cool unsettled dross?. .not me!

[frosty ground]

The GFS 06z Run is still showing plenty of cloud for the day light hours of Saturday and Sunday especially north of the M4.



Sunday shows a bit more promise for Wales, again in this set up west is usually best.

The UKM raw data as presented by their online apps shows Saturday to be a better day than Sunday.

Next weeks warm temps ara again Cloud fests with the usual light rain.



Monday is the best  day but you can see the atlantic coming in.



Mild and Damp is not really that great.

[Frosty.]

7 minutes ago, frosty ground said:

The GFS 06z Run is still showing plenty of cloud for the day light hours of Saturday and Sunday especially north of the M4.



Sunday shows a bit more promise for Wales, again in this set up west is usually best.

The UKM raw data as presented by their online apps shows Saturday to be a better day than Sunday.

Next weeks warm temps ara again Cloud fests with the usual light rain.



Monday is the best  day but you can see the atlantic coming in.



Mild and Damp is not really that great.

It's a beautiful outlook, tomorrow and saturday look dry, mainly sunny and much warmer.

[johnholmes]

It is quite amusing to see the different slants on what a weather model is showing, the half full glass from frosty and the half empty view from frosty ground.

Tae your pick

 

[Frosty.]

6 minutes ago, johnholmes said:

It is quite amusing to see the different slants on what a weather model is showing, the half full glass from frosty and the half empty view from frosty ground.

Tae your pick

 

Things certainly look more positive after today's cool miserable damp day, tonight becomes clear and frosty, apart from the far south and then Friday and the weekend look very pleasant under high pressure with long sunny spells..big improvement IMO.

Edited March 23, 2017 by Frosty.

[Chris.R]

15 minutes ago, Frosty. said:

Things certainly look more positive after today's cool miserable damp day, tonight becomes clear and frosty, apart from the far south and then Friday and the weekend look very pleasant under high pressure with long sunny spells..big improvement IMO.

 It's already beautiful here; 11°C, dry and very sunny.  Bring it on! 

[Frosty.]

Just now, Chris.R said:

 It's already beautiful here; 11°C, dry and very sunny.  Bring it on! 

Good to hear, that will be spreading to most of the uk from tomorrow.

[frosty ground]

30 minutes ago, Frosty. said:

It's a beautiful outlook, tomorrow and saturday look dry, mainly sunny and much warmer.

If you ignore the cloud amounts and just look at temperatures then yeah you are right.

 

[Frosty.]

12 minutes ago, frosty ground said:

If you ignore the cloud amounts and just look at temperatures then yeah you are right.

 

I'm ignoring the cloud amounts because cloud predictions, especially from the gfs are useless even a few days ahead..with my half full glass I expect there will be some very pleasant weather with sunny spells and light winds, feeling much warmer by day.

Edited March 23, 2017 by Frosty.

[johnholmes]

With High Pressure mainly in charge, and its position, see Met Fax charts into the weekend, then following visual sat piccs and the 950 mb winds from any ascents east of or over the east coast of England, should give a fairly reliable idea of how much cloud and where. Obviously temperature will be dependent on that cover. Wind strength will also be a factor for some areas, chiefly for southernmost counties. One worrying aspect, looking at the Fax charts is that Exeter feel the need to keep a warm front on their charts. Admittedly decaying but from experience many years ago I would be careful of too much optimism for counties over and east of high ground.

A quick look through skew-t diagrams suggests that Friday, possibly Saturday, many areas even in eastern districts should see reasonable amounts of sunshine, but tending to cloud amounts increasing into Sunday. That is of course IF the model has this correct, and more than 24 hours ahead is far from easy to predict, so look at the visual satellite imagery Saturday and Sunday morning, add the 950 mb winds to it so get an idea for where low cloud is likely to move. This is perhaps the most accurate feel for what to expect.

Edited March 23, 2017 by johnholmes

[frosty ground]

24 minutes ago, Frosty. said:

I'm ignoring the cloud amounts because cloud predictions, especially from the gfs are useless even a few days ahead..with my half full glass I expect there will be some very pleasant weather with sunny spells and light winds, feeling much warmer by day.

So you are ignoring data that is against what you want. 

The temp Data is interconnected to the Cloud data, not sure how you can ignore one without the other. 

You are the same frosty that posts dozens of Snow prediction charts 7+ days away all winter...... Any reason why you don't ignore those charts?

[Methuselah]

36 minutes ago, johnholmes said:

With High Pressure mainly in charge, and its position, see Met Fax charts into the weekend, then following visual sat piccs and the 950 mb winds from any ascents east of or over the east coast of England, should give a fairly reliable idea of how much cloud and where. Obviously temperature will be dependent on that cover. Wind strength will also be a factor for some areas, chiefly for southernmost counties. One worrying aspect, looking at the Fax charts is that Exeter feel the need to keep a warm front on their charts. Admittedly decaying but from experience many years ago I would be careful of too much optimism for counties over and east of high ground.

A quick look through skew-t diagrams suggests that Friday, possibly Saturday, many areas even in eastern districts should see reasonable amounts of sunshine, but tending to cloud amounts increasing into Sunday. That is of course IF the model has this correct, and more than 24 hours ahead is far from easy to predict, so look at the visual satellite imagery Saturday and Sunday morning, add the 950 mb winds to it so get an idea for where low cloud is likely to move. This is perhaps the most accurate feel for what to expect.

Thanks for that, John...As an aside, I wonder how cloud cover will depend upon the current SSTs in the North Sea? Intuition tells me that they ought to be warmer than usual...

[Frosty.]

Well a nice settled spell with high pressure starts tomorrow with plenty of sunshine and light winds and temperatures responding in the sun but nights look chilly. Into next week and it starts largely fine and warm but then the high declines by midweek as the atlantic fires up a little but from there it looks like a typical nw / se split will become established with more in the way of azores high / ridge influence across the s / se of the uk and only occasional rain with the northwest seeing the lions share of the unsettled atlantic weather but still with some fine spells there too. Temps look generally above average to rather warm further s /e with less risk of night frosts as time goes on and closer to average across the n / nw of the uk due to the eventual increasing frequency of wet and windy weather.

Edited March 23, 2017 by Frosty.

[knocker]

Just the ticket. Channel the cold air down to Timbuktu and waft the warmer stuff over the UK

[mb018538]

Yep, looks like from midweek onwards things will start to gradually break down from the west, with the east holding on to the driest and warmest weather. That said, it isn't wet anywhere until Wednesday at least:



Even the W/NW isn't showing much in the way of rain. Thursday could be the last of the very mild days, with 16/17c in places:



It remains slightly above average until the weekend, though with the chance of rain at times.

[Frosty.]

No complaints about these temperatures next week from the Gfs 12z, very pleasant. Think I will have to stop calling myself frosty though, doesn't seem appropriate to enjoy these charts being called Frosty.

[Sky Full]

On 21 March 2017 at 09:10, Sky Full said:

(Edited).  Images from the 21st March showing the 31st March:

 GFS:                                                                   ECM:

       

 

 Oh those models!  How they tease us with their chopping and changing.  Compare the images above dated 21st March showing projections for the 31st March with the following from today.....

GFS:                                                                          ECM:

           

 Two days ago both models thought that our late March burst of Spring would still be there or thereabouts at the end of the month but now they both agree that the incoming Atlantic low will be more dominant and will in fact have put the high pressure right back in its box over the Azores.  A wet and windy start to April is now their preferred plan - but not mine!  Hopefully there is still time for all this to swap around but either way we will soon see which of the predictions was the right one......