Model Output Discussions 12z 08/03/17

[mb018538]

Anyone notice the GEM sneak in some quite hot air this morning??



On face value this chart doesn't look too warm..



But it's actually very warm and humid. Albeit very temporary!

[Man With Beard]

3 hours ago, Summer Sun said:

Something a bit drier and warmer returning to the south and SE next week?

Indeed - it's not far away from that SS.

I'd advise anyone against forecasting specifics after D5 at the moment. The small size of the depressions coming out of the Atlantic mean hot/sunny weather or cold/very wet weather could be available within a drive of a few hours. One only has to look at the incredible difference between where I am today (very wet) and just 80 miles to my east in Hastings (already over 22C and climbing).

[northwestsnow]

Main theme remains extensive northern blocking and a southerly tracking jet, until this Greeny high goes and gets itself a life its hard to imagine the UK avoiding godforsaken troughs.

[Summer Sun]

Sunday might be a decent day for most with high pressure over the UK temps likely to range from the mid to upper teens

Becoming more unsettled again into next week with a mix of sunshine and showers and some longer spells of rain now and then

[I remember Atlantic 252]

Sunday chart, SS looks like proper summer!, southerly continental air, 21st May bit early, so yes, as you say, likely upper teens

[knocker]

The ecm this evening has Sunday being quite a reasonable with the high pressure to the east being the main influence. The exception may be the south west, Wales the NW. N. Ireland and Scotland where showery conditions may still pertain.  Monday sees the Atlantic low with associated fronts traversing the south west and by 12z Tuesday the low is over the Irish Sea with some pretty inclement conditions affecting N.I., Wales and England in the form of frequent showers and longer outbreaks of rain. thereafter the Azores ridges north, forcing the low south east, and hangs on in there until the end of the run with the UK under a very slack pressure gradient. This could lead to a rather pleasant end to next week and weekend but it's very early days to going down that route, albeit the earlier anomalies were hinting along these lines.

 

Edited May 17, 2017 by knocker

[Matthew.]

Always nice to see high pressure to the Se and low pressure to the Nw even if it is in a local way 

[Fourty Point Three Degrees]

Awful looking blue blob on the GFS with compressed isobars on the 2nd day of June? Don't tell me its autumn already .

Edited May 17, 2017 by 40*C

[Cheshire Freeze]

30 minutes ago, 40*C said:

Awful looking blue blob on the GFS with compressed isobars on the 2nd day of June? Don't tell me its autumn already .

HP straight through the pole too. Tallies with low sea ice extent aswell so I believe.

None of the long range forecasting tools seem to be showing anything particularly unsettled for the coming summer- however you have to wonder whether there is an overriding factor (which the modelling is not taking into account) which also accounted for the disaster at forecasting the winter just gone?

Edited May 18, 2017 by CreweCold

[knocker]

A quick look at last nights anomalies for the 6-10 day period.. Again they are all in the same ball park, albeit differing in detail. The key elements as far as the UK is concerned are the vigorous low and associated trough N. Russia, The upper low to the south west (which isn't cut off) and the positive anomalies in the Iceland area with associated ridge from the vicinity of the UK If this is anywhere near correct it may provide a window of quiescent weather as the weekend looms One obvious complication is the timing of any movement east of the Atlantic trough

Back to the here and now. Saturday sees a shallow low pressure area centred NW of Scotland and the UK in light, showery, westerly streamlines. But this low is about to be joined by another low courtesy of the upper trough to the south west and by 12z Sunday there is a double centred low to the west with HP to the south east that has pushed up from the south west. This tends to divide the UK /NW/SE with showery condition still pertaining in the former and drier and warmer in the latter,

The depressions to the west soon become one and it's the movement and configuration of this low that is the key to the next few days. It slowly fills and tracks east across the UK bringing on a showery regime, interspersed with longer periods of rain as front moves west to east on Monday, By 12z Thursday this has become a very weak feature over the Netherlands with the UK slipping into a very slack pressure  gradient and some very quiet weather with any intrusion from the west slipping quietly by to the south. This I'm sure will be open to different interpretations over the next few runs, and probably by the ecm later but it is not at odds to the beginning of tis post.

So in a nutshell some fairly unsettled weather over the next week but not that unpleasant with a fair amount of sunny intervals and although the temps are not any great shakes it will feel quite warm in these.

Edited May 18, 2017 by knocker

[knocker]

Although varying in detail on the handling of the low vis direction of travel and intensity the overall theme is similar.

[Summer Sun]

UKMO shows a northwesterly flow setting up by mid next week some of the best weather could well be in the south-west where you'd be closer to the high

On the other hand, we have ECM which prefers to have low pressure

More runs needed

[Man With Beard]

While that heights anomaly sits in the N Atlantic, we're always going to be at risk of something more unsettled. But that's not to say it will be unsettled. This morning's ECM takes a new route to divert the Atlantic lows away from our shores - eventually:

[mb018538]

The 00z ensembles are interesting:



There seems to be a divide occurring at day 5/6, depending on where the low heads. The warmer runs appearing clear the low away and allow high pressure to pull some very warm air up behind, the cooler runs keep the low hanging around (the more favoured outcome).



P4/P15 show the warmer solution winning out, but there are more with low pressure winning out. An area to keep an eye on for now.

[knocker]

A very acceptable scenario with some support from the GEFS

 

[Summer Sun]

UKMO brings the high back into play next week

[northwestsnow]

9 minutes ago, Summer Sun said:

UKMO brings the high back into play next week

UKMO looks ok, not great by any means but GFs is, in comparison, absolutely hideous, think its suggesting NINE degrees at noon on the 26th of May imby, there are no words if thats near the mark.

[mb018538]

Looks like west is best....if the high can build with the low pushing east, we could be in business.



Comparing with GFS though, and they couldn't be much different really. Lots to sort out!

[Matthew.]

At least it's encouraging from the UKMO that the ridges, when they come, are not straying too far west. With a bit of energy from the western Atlantic and we could be in the money

[Man With Beard]

Sorry this is only slightly on topic ... I've never seen anything so weird. Does that little blob in the English Channel represent 128mm of rain in 3 hours?

Smallest storm ever!

[knocker]

A little further west and it top up a few buckets

[knocker]

The ecm is a much better run this evening. The Azores is much more influential vis pushing in from the SW next week, thus the main low to the NW fills and tracks east further north. So we end up with low pressure to the east and HP over the UK which then becomes an area with a very slack pressure gradient. Depending what the EPS comes up with later I'm beginning to feel more optimistic regarding the holiday weekend.

Edited May 18, 2017 by knocker

[ANYWEATHER]

Evening All. Models are still in disagreement  next week , but the overall pattern is for more settled and warmer conditions to develop, but we are talking about the ecm and gfs in a boxing ring!!!

[Singularity]

Biggest development in a while there as ECM drops the disrupting trough idea in favour of it 'hurdling over the UK' as it very much appears to do. It'd still bring some rain right up north - but then they have not had much of that lately in many parts of Scotland I gather - but much of E&W may get a good chance to dry out should this prove to be the correct path (and if so, kudos to GEM and UKMO for resolving the low in that way several runs ahead of ECM).

While GFS keeps the disrupting trough though, nerves remain strung tight.

[knocker]

NOAA and the EPS are looking okay this evening but the GEFS continues to promote the trough rather than any ridging but I'll take two out of three at this stage.

Edited May 18, 2017 by knocker