Model Output Discussions 12z 01/09/2016

[knocker]

After a fine and warm Tues.-Thurs.a low tracks NE effecting northern Britain by Friday 00z followed quickly by a new low whose associated fronts traverse the UK on Saturday. The notable feature thereafter is a deep depression that tracks NE between Scotland and Iceland bringing strong winds and rain to the UK on Monday.

[Summer Sun]

ECM shows a steady improvement as we go into WC 12th with high pressure edging up from the south temperatures close to average in the north but remaining warm in the south possibly very warm at times

 

Edited September 4, 2016 by Summer Sun

[Singularity]

The models can't even come together on the timing of the breakdown later this week (any time Thu afternoon to Sat noon for the leading rain band still looks feasible).

So little wonder there are some major differences Sunday onward. Intriguing what ECM achieves in spite of the GLAAM behaviour as discussed in Tamara's (typically epic) post earlier.

[ANYWEATHER]

Evening folks!  Looks like a late summer taste for southeastern Britain in picticular  this week , although the Atlantic has a say and showing its hand by Thursday. Southeastern England the best place to be by then if you want warmth.

[knocker]

The 6-10 anomalies this evening are in pretty good agreement, all with a negatively tilted trough to the NW with perhaps the ecm being slightly more bold. This would portend Atlantic systems tracking NE and could easily bring some wet and windy weather to the north with the south/south east gaining any advantage from HP ridging from the south west. It should perhaps be noted that towards the end of the period the pattern does become less amplified and with the trough weakening the Azores HP becomes more influential. This doesn't essentially alter the N/S split scenario although the weather should become less unsettled with perhaps the HP influence spreading a tad further north.

The greater influence of the Azores lasts a couple of days into the ext period before we settle into a familiar pattern of LP to the NW and HP to the SW. This still indicates a north/south split but the day to day weather variations dependent of the phasing of the cold and warm air in the westerly flow.

 

Edited September 4, 2016 by knocker

[knocker]

Today

With a weak front crossing from the west and fizzling out a mainly cloudy, humid,  day in England and Wales with patchy drizzle but quite warm where the sun breaks through. N. Ireland and Scotland a bit brighter.

The GFS this morning

On Thursday a depression tracks NE bringing unsettled weather to N. Ireland and western Scotland with England remaining dry. This heralds the introduction of more unsettled weather generally and by Saturday the fronts associated with the next system have arrived. Thereafter with the west-east mobility becoming established a probability of the usual N/S split with initially the HP apparently more influential but this will no doubt vary from run considering the time scale and interpretation of the phasing of the contrasting air masses

.

[Summer Sun]

GFS this morning shows plenty of dry weather around next week the best of the temps would be in the south with the mid 20's on most day's always closer to average further north

The week ends on a fresher note for all

 

 

[Summer Sun]

ECM shows a north-south split to start next week some very warm temperatures are possible early next week for the south around mid week the high edges a bit further north so more parts should improve for a time with any unsettled weather becoming restricted to the far north

Edited September 5, 2016 by Summer Sun

[knocker]

The ecm making a little more of the low next Monday

Sidney is quite phlegmatic about the outlook

[knocker]

One thing about today is there is some pretty warm (tropical) air aloft. Only -6C at 500mb and the tropopause at 150mb.

[Newberryone]

14 hours ago, Summer Sun said:

ECM shows a steady improvement as we go into WC 12th with high pressure edging up from the south temperatures close to average in the north but remaining warm in the south possibly very warm at times

 

 

2 hours ago, Summer Sun said:

ECM shows a north-south split to start next week some very warm temperatures are possible early next week for the south around mid week the high edges a bit further north so more parts should improve for a time with any unsettled weather becoming restricted to the far north

 

2 hours ago, knocker said:

The ecm making a little more of the low next Monday

Sidney is quite phlegmatic about the outlook

While it has to be said and acknowledged that considerable uncertainty continues to prevail with regards to Fi, the Ecm00z op can only really be best described as somewhat of a downgrade on yesterdays 12z output for w/c the 12th Sept. Yes, it does show ridging but this only seems transient in nature compared to the already described "vast improvement" that was originally been indicated for this same period. Wouldn't be at all surprised to see further adjustments of a downward nature for next week closer to that time frame. All highly speculative I admit at this early stage however.

[mb018538]

6z looks pretty decent in the mid term - there is a very nasty looking deep Icelandic low (960mb) at 168 hours - pretty vigorous for this early in autumn, but with all these tropical storms being thrown around it's hardly a surprise. Looking like another classic NW/SE split - though definitely remaining above average for the time being. Looks like it could end up quite a warm month CET wise.

[Ian Francis]

I'm surprised nobody has commented on the high rainfall totals for the NW being modelled on the 12Z GFS.  We could be seeing flood warning in force for Cumbria and SW Scotland by the end of next weekend.

[Summer Sun]

Warm to very warm temps returning next week for the south initially then further north at the end of the run

 

[markyo]

6 minutes ago, Summer Sun said:

Warm to very warm temps returning next week for the south initially then further north at the end of the run

 

Very much doubt that will come off. Way way to far out to be taken with any credence at all,sorry.

[knocker]

You can see where the ecm is coming from towards the end of the run, out old friend the cut off low. In the meantime a pretty grotty Saturday on the cards.

[phil nw.]

1 hour ago, Ian Francis said:

I'm surprised nobody has commented on the high rainfall totals for the NW being modelled on the 12Z GFS.  We could be seeing flood warning in force for Cumbria and SW Scotland by the end of next weekend.

Perhaps you would put your location into your profile Ian? 

Welcome to the forum by the way.

[Man With Beard]

Been watching quietly the last few days ... the mid term output, to me, has shifted from continuing summer to pre-autumn. The Atlantic has regained some of its oooff and I'd be surprised if we got through another 10 days without a mini-autumnal storm. I'd also be surprised to see another heat attack from the south - the ECM has suggested it a few times but the set-up looks weak.

Edited September 5, 2016 by Man With Beard

[cheese]

8 hours ago, markyo said:

Very much doubt that will come off. Way way to far out to be taken with any credence at all,sorry.

Probably not, but you seem to think all charts showing warm or hot weather in FI won't 'come off' - I presume this is because of your preferences and disliking of such weather. If it was showing a cold, stormy outlook I doubt you'd say anything.

Sorry, I just don't see the point of making such remarks.

Edited September 6, 2016 by cheese

[markyo]

34 minutes ago, cheese said:

Probably not, but you seem to think all charts showing warm or hot weather in FI won't 'come off' - I presume this is because of your preferences and disliking of such weather. If it was showing a cold, stormy outlook I doubt you'd say anything.

Sorry, I just don't see the point of making such remarks.

Thats fine,fully understand. Just i find those types of charts rarely come off. I'd be saying the same in regard to cold weather setups also. I get frustrated with these FI charts,hot or cold,they promise so much but so rarely do they come off! Thats the main reason for my remarks,not that dislike i have for the heat bit,honest!

[knocker]

Today

Very warm humid air over much of the country. With this of course comes much cloud and if and when this clears temps could reach the upper 20sC in places. The big question is of course if. N. Ireland and southern Scotland may well be the exception with some rain or drizzle.

Regarding cloud clearance I'm not that optimistic in these parts. A quick glance at the Camborne 00z sounding shows shows some very warm air and a tonking 7.5C inversion at 900mb At the moment we have a layer of Sc under this which will take some shifting.

This morning's GFS for the next ten days. As an overview the general pattern is for depressions to travel N/NE with associated fronts impacting the UK with the SE being the least effected.

The first low scoots up to the NW of Ireland early Thursday with associated fronts bringing rain to the NW. This is quickly followed by the next low tracking NE to be 984mb NW of Scotland by Saturday 00z with fronts orientated down western Britain. These quickly traverse the country  After this some brief ridging as a deep slow moving Atlantic depression meanders north to Iceland with the fronts associated with this tracking east across the UK and fizzling out at the same time. Then a repetition of brief ridging until the next system arrives. Essentially with all of this unsettled weather the SE will continue to remain pretty dry.

Edited September 6, 2016 by knocker

[mb018538]

ECM is nice this morning - reloading the warmth with 850s back over 15c. As knocker says above, if you live the NW, it could be quite wet at times. If you are in the SE, it's going to be pretty dry, and a continuation of late summer probably into next week. No signs of anything cool and autumnal in the short to mid term as of yet.

[A.J]

3 hours ago, cheese said:

Probably not, but you seem to think all charts showing warm or hot weather in FI won't 'come off' - I presume this is because of your preferences and disliking of such weather. If it was showing a cold, stormy outlook I doubt you'd say anything.

Sorry, I just don't see the point of making such remarks.

it's more likely that due to the extremely low verification percentages in deep FI that said charts rarely 'come off'........trends, yes......any form of accurate prediction, no.......I've always gone with the philosophy of looking at day 12-16 charts and then expecting the exact opposite to materialise 

[knocker]

The ecm is still playing with trough disruption () and a cut off upper low with HP building over the UK before normal service is resumed. This could, if it in anyway near verified, lead to a brief thundery outbreak from the south but really best left as noted.

[Summer Sun]

As you were from ECM with some warm to very warm temps for the south for most of next week, later on, there is a chance of a thundery breakdown the warmer air could move further north for a time later in the week

UKMO shows an NW-SE split to start next week

Edited September 6, 2016 by Summer Sun