Short range model discussion - into 2018

[knocker]

The front and band of rain will continue the slow eastward progress through this evening and tonight with some heavy bursts in places before clearing into the North sea in the morning leaving cooler air in it's wake. Tomorrow will be a generally clear sunny day with some showers which will be more frequent in the north. And temps down on recently, particularly in the south east.

[knocker]

Amplification and the block disrupt the upper trough over the weekend isolating an upper low in the vicinity of the UK and in the process distorting the jet and slowing lateral movement. Thus quite a messy picture over the weekend with frontal rain clearing east on Saturday and then generally sunny with showers over the weekend, perhaps more frequent and heavy in the south west on Sunday with the trough in close proximity.

[knocker]

The front and rain belt has continued to track east across the country overnight giving some heavy bursts of rain in places and it will be slow to cleat East Anglia and the south east this morning and probably wont until early afternoon. Behind the front a much cooler airmass for all but probably plenty of sunshine albeit interspersed with showers, particularly in Scotland where they could be quite heavy, and possibly thundery in the east later. The showers will tend to subside overnight thus a clear night, on the cool side in places, before the front and next belt of rain  arrives over Ireland by 1200.

The front will stagger east across the country during the rest of Friday decaying as it goes bringing patchy rain in western areas and freshening winds in the north but again not too bad in the east

The general analysis at 1200 Saturday finds that the Atlantic trough has been split by the burgeoning Bermuda high pressure and the continuing resilience of the block to the east creating a cut off upper low just to the west of the UK. All of this results in a surface low north west of Ireland with the UK in a very slack gradient and rather cool changeable conditions with heavy showers, perhaps thundery, in the south west and south.

A not dissimilar scenario on Sunday but the filling low to the west has slipped over Ireland and the associated occlusion will  continue to bring showery rain to the south west.and generally temps around average.

Monday finds the block continuing to be resilient to the energy from the west so once again a rather diffuse analysis with the UK in a very slack gradient which portends another sunny day with some showers with temps around average, perhaps a little above.

Edited May 10, 2018 by knocker

[knocker]

The GEFS 3-8 anomaly this morning gives a pretty good overview of the above.

The key players, the Hudson Bay vortex/lobe, the Scandinavian block ridging north west, low pressure over Europe and the Atlantic trying to ridge north east. Thus the westerly upper flow diverging west of the UK leaving the latter virtually in a col.

 

Edited May 10, 2018 by knocker

[knocker]

This morning's 0600 geostationary (courtesy DSRS) illustrates the current state of play well. Front still around in the south east and showers elsewhere, particularly western Scotland.

 

[knocker]

The ecm quite similar for Saturday and the beginning of next week with slack gradient over the UK portending sunny intervals and showers, perhaps heavy and thundery in places, with temps around average.

 

[knocker]

The high res. MODIS at 1210 UTC.

A showery regime in some places.

 

[knocker]

Today's showers will tend to fizzle out later today and overnight leaving a clear but quite chilly night in some areas. So a generally clear start to tomorrow but the front and rain associated with the deep low south of Iceland is over Ireland at 0900 and will track slowly ENE, with the wind becoming fresh in the north west,  through the day but the east/south east of the country remaining dry and relatively pleasant. By 00 Saturday showery rain associated with a trough to the south west is approaching Cornwall

 

Edited May 10, 2018 by knocker

[knocker]

The gfs is still keen to develop a wave along the tight thermal gradient at the base of the Atlantic trough and develop it as it tracks north east. The ecm this morning was not overly keen on the idea so await this evening's

[knocker]

The 1800 geostationary showing the system to the west that is going to influence out weather over the  next two or three days.

[knocker]

The ecm is still not in agreement with the gfs at the beginning of next week vis the wave development

I've just noticed that I've posted the 00 gfs charts. these are the correct ones.

Edited May 10, 2018 by knocker

[knocker]

UKMO trending towards the ecm

[knocker]

At midnight a diffuse area of low is situated north west of Ireland with associated front orientated just west of same. The influence of the front can be seen on both the Valentia and Camborne 00 soundings.

During today the low will become more organized and the front will very slowly track east across the UK. Thus by 1200 rain will have arrived over N. Ireland, the Western Isles and the south west. There will be some heavy bursts down the western half of the country as it moves east and the wind will freshen but central and eastern areas will stay dry for much of the day with temps in the high teens although high cloud may well ingress later. The front will tend to stall as it reaches the eastern fringes of the country

Over the weekend the low is almost stationary north west of Ireland and is slowly filling but it will influence the weather over the UK for the two days bringing sunny intervals and showers and some more concentrated periods of rain. Perhaps more on Saturday with a trough in the vicinity of the south west and today's front still lingering around the east coast thus the showers and rain more concentrated in these areas. Temps around average

By 1200 Monday the low has lost it's identity but a slack pressure area still exists over the UK so another relatively cool showery day with showers and sunny intervals. But out to the west a wave is forming on the front at the base of the upper trough.

The wave tracks north east to be north west of Ireland by 1200 Tuesday with the UK remaining in a slack pressure gradient but dryer and temps picking up a bit to be a shade above average.

Edited May 11, 2018 by knocker

[knocker]

Satellite at 0430 UTC

[knocker]

UKMO Monday/Tuesday

 

[knocker]

Excellent 0600 geostationary (Courtesy DSRS)

[knocker]

The EPS 3-7 mean anomaly this morning broadly speaking supports the det run. After that it wants to displace the vortex lobe towards Greenland which would not be good

 

Edited May 11, 2018 by knocker

[knocker]

The jet stream at 0900 UTC

https://earth.nullschool.net/#current/wind/isobaric/250hPa/orthographic=-0.76,58.94,497

[knocker]

The high res. MODIS at 1110 UTC (courtesy DSRS)

[knocker]

A clearance as the front went through just now

[knocker]

The 1500 UTC geostationary

[Pennine Ten Foot Drifts]

So according to GFS virtually no rain around Sunday afternoon, and yet BBC continuing to show heavy rain for much of eastern/northern England pretty much all day (which models haven't been showing for a number of runs now). Do they know something the models don't, or are they as usual just 12 hours behind the curve?

[knocker]

33 minutes ago, Pennine Ten Foot Drifts said:

So according to GFS virtually no rain around Sunday afternoon, and yet BBC continuing to show heavy rain for much of eastern/northern England pretty much all day (which models haven't been showing for a number of runs now). Do they know something the models don't, or are they as usual just 12 hours behind the curve?

Well this is my understanding of the likely weather for the weekend in simple terms

After a clear night tonight tomorrow will dawn clear and bright in most places but a trough to the south west will bring heavy showers, perhaps thundery, to that area that will spread a tad north and east during the day. But in addition a wriggling front moving slowly north will bring rain to the south and east during the afternoon which will spread up the eastern half of the country during the rest of the day and overnight.

It will continue to affect eastern areas during Sunday,, more likely the north east, but how far west and for how long rather depends on the precise position and movement of the front. Elsewhere should be bright with the odd shower

 

 

Edited May 11, 2018 by knocker

[knocker]

Once the front clears away on Sunday it will be clear with the odd showers on Monday apart from the south east which is under the influence of the developing low pressure over Europe. West of Ireland the frontal wave is developing but doesn't amount to much as it tracks north east.

A generally dry and quite pleasant day on Tuesday with light winds as the low to the south east subsides and the weakening Atlantic front brushes N. Ireland and the Western Isles.

[Pennine Ten Foot Drifts]

Great stuff, thanks Knocker