Model Output Discussion 31/07/14 onwards.

[Cloud 10]

...don't bother.....!

 

Is that what you meant?

 

Very difficult at that range.

 

I simply meant that the gfs seems to have picked up on the idea of low pressure over Scandinavia on its last few operational runs in FI,so maybe it has spotted a new trend?

[Polar Maritime]

Yes Gav, That little Low continues on tonight's ECMWF run to sink South over Ireland, Drawing in a slack Easterly off the North sea. I'm sure we will see further developments with this over future runs. 

 

Edited August 30, 2014 by Polar Maritime

[draztik]

Day 6, msl anom ecm

I dare say tonight's ecm won't be fluttering many hearts. Esp for southern England through days 6-10.

Edited August 30, 2014 by draztik

[knocker]

The GFS is sticking with the upper ridge centred to the NW for the weekend and similarly for the surface bringing a slack NE to the UK with slightly above average temps.

 

Edited August 30, 2014 by knocker

[ANYWEATHER]

Gfs , my favourite model is hintng on a late summers dream,  Ecm is just the opposite! Just in line with the latest metoffice update     

[Polar Maritime]

Aye, It looks like the transient affair, Picked up very well by the GFS, Is going to be just just that.. Transient.

Edited August 30, 2014 by Polar Maritime

[knocker]

NOAA is fairly unequivocal.

 

[Frosty.]

The week ahead looks pretty good to me apart from monday when a band of patchy rain spreads southeastwards, thereafter it will fine up with high pressure taking control bringing scattered clouds and sunny periods with temperatures into the low 20's celsius. Looking further ahead, turning more changeable, especially across the north west of the uk with the south & east having the best of the dry, bright and warm weather. Looking even further ahead, typical september weather with warm sunny spells but increasingly chilly nights, the most unsettled weather generally across the north / north west.

Edited August 30, 2014 by Frosty.

[knocker]

The ECM ens still sticking with the low to the SW pushing the HP further north allowing warmer air to drift in from the south within a slack pressure area giving slightly above average temps. The jet is way to the north circumventing the upper ridge in mid Atlantic.

Edited August 30, 2014 by knocker

[knocker]

Looking at the GEM and GFS surface analysis for next weekend it's difficult to find two more contrasting interpretations. All times 12Z

 

GEM

 

Saturday: Area of low pressure NW France/ western Channel with front west country to Normandy with rain in south west England and showers elsewhere on the easterly flow.

 

Sunday: Low now defined 1003mb west of Brest with the front lying across the Midlands. SE flow in north and Scotland but variable southerly in south.

 

GFS

 

Saturday: HP, centred over Scotland dominating the UK with a light easterly and no precipitation.

 

Sunday: HP centre 1028mb NW of Stornaway otherwise similar scenario to Saturday.

 

Obviously one has to await some agreement between the models before any confidence can be bestowed.

[Frosty.]

Looking at the week ahead, today will be fine and pleasantly warm for many with sunny periods but clouds will be thickening across the far northwest of the uk followed by outbreaks of rain and drizzle, this area of precipitation will push southeastwards through tonight and tomorrow with drier, brighter weather following from the north west, however, although the southeastern corner may have a bright start tomorrow, the cloud and rain which soon follows may not clear until very late on monday, really dragging it's heels across the SE corner. Most of the week then looks largely fine with temperatures on the up, especially where there are decent sunny spells, low 20's celsius could be yours..BUT..whilst some areas will have a fair amount of sunshine, others will be rather cloudier and temperatures will be somewhat lower as a result.

[IDO]

GFS hi-res still not going for the surface low for late next week that GEM and ECM have been keen on for many runs. This morning the GFS op for next weekend: 

 

 

 

GEM still bringing in the surface low:    

 

Only 2 members of the GEFS now have a similar setup. GEM keeps that LP system over the UK till D10 whilst the GFS op continues with HP till D16:

 

GEM D10:   GFS D16: 

 

So it would appear early September may partly hinge on the evolution for later next week. It has to be said that GFS do have embedded areas of lower pressure within the upper ridge but they currently do not model these to form areas of surface lows. I do think that GFS has again got this right and ECM will backtrack. Interestingly GFS continues to top the verification stats on the 0z for heights at D10:

 

All of late are struggling so the current setup is causing problems.

 

NAVGEM was going with GEM on yesterday's 0z but switched allegiance on the 12z and have stayed loyal to GFS this morning:

 

UKMO moving towards GFS on the 0z: 

 

This morning's ECM takes a step towards the GFS at D7 with the cut off upper low not translating to a surface low so the dominant feature remains HP:

 

and at D8: 

 

Although GFS op is settled in week 2, it is not warm, with uppers mostly 4-6c and the wind a N'Ely. So cool nights and below average temps countrywide though feeling warm in the sunshine.

 

So a shift this morning towards a more settled HP dominated week 2 as the GFS has been suggesting for some days.

 

 

 

 

[knocker]

The ECM 500mb anomaly still plugging the low to the south west. The surface analysis still has the HP to the NW of the UK mainly dominate but the circulation in the southern half is rather complicated by the low as can be seen on the 850mb charts. The result of this is the possibility of temps around 23C on Sunday in the south. But this is a knife edge situation and as there is certainly not a consensus with the models so to be viewed with much caution.

Edited August 31, 2014 by knocker

[mushymanrob]

NOAA is fairly unequivocal.

 

indeed, its quite firmly supporting the building of the azores high to our west allowing a cool/cold airmass from a northerly scource for week 2 of september.

 

 

edit... just viewed the ecm 00z.... sorry but i dont buy those uppers later in the run, they dont look like a plausable evolution to me... if this happens within 48 odd hours then i might believe it.

 

 

 

Edited August 31, 2014 by mushymanrob

[knocker]

 

edit... just viewed the ecm 00z.... sorry but i dont buy those uppers later in the run, they dont look like a plausable evolution to me... if this happens within 48 odd hours then i might believe it.

 

 

 

I tend to agree. Looking at the 850mb circulation the question is why would the temp be that high?

[mushymanrob]

I tend to agree. Looking at the 850mb circulation the question is why would the temp be that high?

 

there doesnt appear to be an upper southerly (scorced), so how those high uppers can form over the uk in september is something i dont understand.  but its fi anyway and is unlikely to become the final solution.

[Man With Beard]

A warm and settled week ahead after a weak front fades in the next two days. Mid-term, ECM moves towards the other models - it had been determined to bring some sort of breakdown for next weekend but it now shows a far weakened trough which may do no more than increase the thunderstorm risk. Still looking at 25C tops by the end of the week.

Into week 2, well the anomaly charts now being reflected more consistently in the ops, so probably still settled but the risk of a more northerly input - by no means certain and a southerly input could happen locally if the ECM trough hangs around to the SW.

[Summer Sun]

UKMO shows pressure starting to fall in the south towards the end of its run increasing the risk of some showers developing the driest weather by this time would be for the north where pressure remains high

 

 

 

[johnholmes]

Currently with what seen since back I would say anomaly charts are not totally consistent as to how much ridging and ec has once shown a marked trough to sw of uk but other show no more than a weakness in the upper flow

ec-gfs

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

Sun 31aug

Ec-gfs

Today and ec has mostly got rid of the cut off low, only a suggestion of a minor trough beneath the ridge/+ve heights(actual high shown over uk

Gfs is quite similar to its last issue and has a suggestion of a ‘weakness’ beneath the marked upper dige/+ve heights

NOAA

Noaa

6-10 = not sure, it is something of a change from the last issue, ridging/+ve area and position but will take closer look in morning.

More pronounced +ve heights in similar area and ridge is back that it showed previously

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

[mushymanrob]

well the anomaly charts might not be in full agreement, and have shifted sharpish from one picture to another (ive noiticed this happens quite alot). but they all suggest that in week 2 of september some sort of high pressure will likely be centred to our west or northwest. thus adding fuel to the notion of a cool second week.

 

[johnholmes]

well the anomaly charts might not be in full agreement, and have shifted sharpish from one picture to another (ive noiticed this happens quite alot). but they all suggest that in week 2 of september some sort of high pressure will likely be centred to our west or northwest. thus adding fuel to the notion of a cool second week.

 

test8.gif

 

I have not seen many suggestions other than that mushy, so why highlight this?

You are correct in that the 500mb anomaly charts, and both the predicted contour values/directions etc, along with a highish anomaly for heights within a similar area, do you suggest that a surface high is most likely to the W/NW of the UK.

As to what temperatures may be experienced then a close look at the visual sat piccs, the skew-t relevant diagrams for the part of the country any of us live in and dropping the predicted 925mb wind direction/speed for about 12 h ahead should help see how close the synoptic model is likely to be. No point in looking for that detail until much closer than the 6-10 day overall pattern suggestion from the 500mb charts.

[Milhouse]

10c upper temperatures lurking off the south coast on the ECM mean at day 10.

 

[Summer Sun]

UKMO maintains the settled theme into next weekend

 

 

850's for t120 are not available at the time of posting

 

[mushymanrob]

I have not seen many suggestions other than that mushy, so why highlight this?

You are correct in that the 500mb anomaly charts, and both the predicted contour values/directions etc, along with a highish anomaly for heights within a similar area, do you suggest that a surface high is most likely to the W/NW of the UK.

As to what temperatures may be experienced then a close look at the visual sat piccs, the skew-t relevant diagrams for the part of the country any of us live in and dropping the predicted 925mb wind direction/speed for about 12 h ahead should help see how close the synoptic model is likely to be. No point in looking for that detail until much closer than the 6-10 day overall pattern suggestion from the 500mb charts.

 

hi john

 

i highlight this because i think they (anom charts) give credence to those fi runs which suggest high pressure situated somewhere to our west/northwest into week 2 of september, so yes, the runs suggesting a surface high somewhere in that region is likely IF these anomaly charts are correct. 

 

im not guessing temps this far out (other then to suggest 'cool' or 'warm'), obviously the exact position an orientation of any high will have a marked impact on temps, so no real handle on the detail as you say.

 

of course im no expert, if any of my assumptions are inaccurate please feel free to correct me!

[Milhouse]

The GFS12z really wants to keep summer going with the fine and warm conditions persisting out to the 2nd week of September. The best of the warmth, as usual, will be for southern England with winds coming from an easterly direction for much of the upcoming 7-10 days. Upper temperatures ranging between 6c and 12c, temps peaking in the low to mid 20s on most days.