Short range model discussion - into 2018

[knocker]

Quite interesting that about the same time as this 1200 UTC sat image a clearance of some quite large Cu and the medium and high cloud, that has been around all morning, is approaching from the north west with, and apparently, much drier air. The midday sounding will presumably still show the cloud

Edited August 30, 2018 by knocker

[knocker]

Well the midday sounding is still in thick cloud as expected and the front must be in close proximity. Plenty of sunshine here now with the thick cloud to the south.

 

[knocker]

Well I got that wrong as there is no front on  the 1200 analysis

[johnholmes]

Not to worry k, happens to all of us

[knocker]

1 hour ago, johnholmes said:

Not to worry k, happens to all of us

Indeed John. So to fall back on the alternative theory and as there was some large Cu/Cb around at the time I suspect the midday sonde was launched into one.

[knocker]

Tracking the wave as it swings north east between Iceland and Scotland and the weakening front as it meanders south east down the country on Monday

[knocker]

This evening's fax at T72 has a very complex area of low pressure to the north west of the UK with the block to the east connected south west to the Azores HP via the south of the UK. Thus the fronts associated with the former track NNE just to the west of Ireland.

the cold front then tracks south east down the UK through Monday introducing some cooler air before ridging stretches north east on Tuesday

Edited August 30, 2018 by knocker

[knocker]

Essentially the next five days can be summed up as a battle between the trough to the north west and the energy tracking north east south of it and the blocking high pressure ridging from the south west into north west Europe which the latter eventually wins after a skirmish at the coal face over the UK.Illustrated quite well by the upper air charts and surface analysis at midnight.

Some detail.

After a clear night in many places, still some cloud around in the south and south east

A chilly start with some mist and fog around in some areas which will quickly clear giving a generally sunny and warm day with cloud popping up in central and southern areas. But more general cloud and patchy rain will arrive in the MW and SW areas during the afternoon as the fronts associated with the deep low in the Denmark Straits push slowly east.

Overnight and through Saturday the fronts continue to push slowly against the block so western areas continue to be cloudy with patchy rain/drizzle whilst the east and south have a clear night with mist and fog in places by morning which again quickly give way to another sunny and warm day

The weakening fronts tend to linger in the west on Sunday thus remaining cloudy whilst again the east will be sunnier and quite warm although generally the temps are a tad above average. But to the west another frontal wavy is tracking quickly NNE and the band of rain on the front will effect N. Ireland and western Scotland by early afternoon.and start tracking south east.

The front and patchy rain continue to move south east on Monday leaving slightly cooler air in it's wake as the ridge starts to get the upper hand

Generally a sunny day on Tuesday and although temps will only be around average feeling quite warm as there is virtually no wind.

And the NH profile indicates high pressure gaining the ascendancy and is a pretty good illustration of NH ridging in general. A point made by MV in a tweet yesterday evening.

 

Edited August 31, 2018 by knocker

[knocker]

This morning's fax for Monday and the ecm

"Cooler' air after passage of front

The 0600 sat image with the front orientated NW/SE to the south west and the 0500 surface chart. A bit nippy up north

[knocker]

The disagreement between the ecm and gfs det runs thus morning starts immediately after T120 and it appears to be with the handling of the upper trough over Iceland after that time. The ecm develops it over Scandinavia which has the effect of amplifying the high pressure just to the west of the UK resulting in a completely different orientation of the surface high cell.and a 'cooler' next week. Supported to some ext by the ens. Complicated further by the developing trough in the western Atlantic. We shall see

Edited August 31, 2018 by knocker

[knocker]

This evening's fax has the cold front/occlusion duo tracking south on Monday and they leave 'cooler' air in their wake/

This morning the ecm introduced the idea of dropping the upper trough south to the east of the UK whilst pushing the European ridge further east and thus temporarily (?) interrupting the Euro > Azores axis resulting  in the surface high cell being established further west. It continues with this idea this evening. But this still portends dry and quite pleasant weather and maybe chuck some fog into the mix in the chilly mornings.

Nice cloud boundary with the fronts just to the west on the 1800 sat image

Edited August 31, 2018 by knocker

[knocker]

[knocker]

Strong indications over the last 24-48 hours of a change of pattern, much of which is later than the short range, although the seeds are sown within it. The seeds that are apparent in our neck of the woods involves the upper trough dropping down to the east, severing the Euro < Azores HP axis and promoting intensification of the ridge over the UK. In a NH context this also involves a strong Aleutian ridge and a cross polar trough Russia to Canada, This establishes the surface high cell in the vicinity of the UK  Much along these lines.

Anyway back to here and now and the battle between the Atlantic and the ridge with the upper air and surface analysis for midnight;

The proximity of those surface fronts means that northern and western areas will be cloudy with patchy rain/drizzle today with the sunny and warmer conditions concentrated in the south and east. There might be clearer interludes late on in N. Ireland and south west Scotland.

The cloud and drizzle will hang around in western and northern areas overnight and through Sunday morning whilst elsewhere there will be clear spells leading to fog patches by morning which will quickly clear leading to another warm and sunny day. The cloud may thin in some south western regions but during the day the next wave and associated fronts will track NE over Ireland bringing more concentrated rain and freshening winds to the north west.

Overnight and through Monday the wave continues to track rapidly NNE

whilst the cold front moves south east down the UK introducing cooler air in it's wake

As the ridge becomes ore influential a couple of bright sunny days are on the cards for Tuesday and Wednesday with perhaps some showery rain on the weakening front in the south east and some patchy rain in northern Scotland from another front close by.

And at T120 the scenario mentioned at the beginning of the post is unfolding in the NH

Edited September 1, 2018 by knocker

[knocker]

This morning's fax charts for Mon/Tues and the ecm

And the NH profile at T120

The 0600 sat image and 0500 surface chart.  Plenty of fog around in the south. Currently St and mist here

 

[knocker]

Midday sat image and surface chart

And

Edited September 1, 2018 by knocker

[knocker]

 

Edited September 1, 2018 by knocker

[knocker]

An active Atlantic

[knocker]

Interesting take on the transition by the gfs det. this evening

[knocker]

21 minutes ago, knocker said:

Interesting take on the transition by the gfs det. this evening

 

[knocker]

And on the same wavelength

[knocker]

And the ecm not to be outdone by the renewed amplification

And the 1800 geostationary. St and fog back here

[knocker]

The NH profile at midnight

And the surface analysis

Pretty much a west > east split regarding cloud on a generally fairly warm day today with maybe bits and bobs of rain/drizzle in the some western and northern areas. But during the afternoon the complex wave/fronts structure to the west develops and runs quickly NNE with rain on the cold front impacting N. Ireland and western Scotland and then moving south east

Overnight and through Monday the front and band of rain ( doubled up with the occlusion on the fax charts) continue to track south east but tending to fizzle out as high pressure ridges north east. Another warm day to the south east of the front but cooler air behind with the odd shower on the cards towards the far north west.

The weakening front(s) still lingering across England and Wales on Tuesday so generally a dry day but with variable cloud with perhaps the odd spot of rain

But by Wednesday changes are afoot with renewed amplification in the Atlantic as an upper low arrives in the west accompanied by strong ridging in central areas resulting in another low dipping south east into the North Sea.

On the surface this drags fronts down from the north west with sporadic rain effecting N. Ireland and Scotland and introducing cooler air whilst the rest of the UK remains dry with temps around average.

Thursday quite a cool day in the northerly breeze after a decidedly chilly start but generally sunny with the likelihood of some showers in northern areas.

And by T120 we are looking at a very different NH profile from when we came and a developing Omega Block

 

Edited September 2, 2018 by knocker

[knocker]

A forecast sounding illustrates the much cooler air on Thursday

[knocker]

The ecm has the upper low dropping down a tad further west

The 0600 sat image

 

[BlueHedgehog074]

2 hours ago, knocker said:

The ecm has the upper low dropping down a tad further west

A little bit dissapointing, that. Still a few days away, so enough time for some possible changes to be made.