Short range model discussion - into 2018

[knocker]

An update on my earlier post. Since going to post another band of thundery showers has pushed north across the Channel and is currently affecting south west counties but just skirting Cornwall. It can be seen on the geo. This sort of set up can frequently make mugs of us all.

[knocker]

High res. MODIS at 1116 UTC Clearly indicates the SE > NW movement of the convection. the Haar and the extensive Algal bloom in the North sea

Edited May 27, 2018 by knocker

[knocker]

A fair range of temps across the board on the 12 UTC observations. Not bad at Aviemoor 24.5C

http://www.met.reading.ac.uk/~brugge/12.html

[knocker]

The showers/storms that have still been affecting parts of the Midlands and N. Wales today will gradually fizzle out this evening but for many areas it will be quite cloudy as the low cloud and mist ventures further inland along the eastern fringes of Scotland and England where it may well cover most of the Midlands. It will draw back tomorrow portending a very warm day in most places which may well trigger the odd storm in central areas But still 'cooler' along.eastern, and some south western, coasts.

[knocker]

The 1500 UTC obs

http://www.met.reading.ac.uk/~brugge/15.html

[knocker]

The 1800 UTC geostationary and the storms still impacting the west Midlands

[knocker]

A look at last night’s short term anomalies to get an idea of the NH background pattern as the next transition gets underway. Essentially we have three vortex lobes but the two that interest the UK are over northern Canada, with an upper low in the north west Atlantic and northern Russia with associated trough eastern Europe.

Although there is a divergent flow out of north east N, America courtesy of the ridge and aforementioned low there is a strong section running east across southern Greenland en route to the east European trough around the  Atlantic and European high pressure. This restricts northward movement of the Atlantic ridge and effectively ‘seals’ of the eastern Atlantic, the UK and Europe leaving them with just internal movement.

Ergo, portending temps remaining above average but the synoptic detail for the UK difficult vis cloud and extent and intensity of any instability.

A bit more detail

Yesterday's storms have now passed and today dawns with a fair bit of low cloud and mist that has ingressed from the North sea quite a way inland, particularly in central areas of England. This should soon burn off and recede to the coast but will depress the temps here whilst the just about everywhere else enjoys a warm/hot day.. But this may well trigger some quite intense storms later in Wales, the midlands and south west areas with some localized heavy falls of rain.( note convergence line on the 1800 fax) By late evening any storms should have fizzled out but extensive low cloud and mist will return.

The low cloud and mist will pull back to some extent on Tuesday but it will tend to be a cloudier day, sunnier in the west, with temps lower than today and likely some showery rain will impinge on the south west/south coasts

There appears to be a problem with the gfs this morning, at least I'm having a problem, so I'll leave it there for the moment and hopefully continue later.

 

 

Edited May 28, 2018 by knocker

[knocker]

I'll carry on using the 1800 output as it will not change significantly.

By Wednesday the ridging Atlantic high pressure has created another cut off upper low which has facilitated the extension of the low pressure influencing the UK and France westward, Temps still above average but cloud may be an issue in places and showery/storm activity will affect northern Scotland late on.

A not dissimilar story on Thursday and Friday with temps remaining above average, particularly in western Scotland, and with the usual caveat vis north east/east coast regions, again storm activity could crop up more or less anywhere whilst the UK remains under the auspices of the moist and potentially unstable low pressure whilst at the same time the high pressure builds once more to the west.

 

 

 

 

Edited May 28, 2018 by knocker

[knocker]

The ecm take for Weds with a fair temp range as it's much cooler under the precipitation.

The 0600 UTC geostationary (courtesy DSRS)

[knocker]

With reference to my opening comments this morning the ecm has the 100kt jet tracking across southern Greenland and the cut off low, for the moment, keeping the low pressure interested in the UK. and a continuation of some instability

I'm off down to see Sidney

[carinthian]

On ‎24‎/‎05‎/‎2018 at 07:35, johnholmes said:

The 12Z Fax chart above is ludicrous. Why on earth so many trough lines, and at this range no one, can have the faintest idea where any, if there are any, will actually be.

Senior man must have been on something last night in my view.

ignore it.

Now then JH get to grips with this latest fax chart from HQ. Looks like a weather forecasters air traffic control visual with those lines waiting in the queue and all heading to Blighty. There must be some reasoning to these prog (fronts ) / lines of activity or is it guess work. I know we always looked for buckles in the isobar charts in the early days but this chart takes it to another level. Watched over the past week and not far off the mark by the head man/girl. Great stuff.

C

[johnholmes]

57 minutes ago, carinthian said:

Now then JH get to grips with this latest fax chart from HQ. Looks like a weather forecasters air traffic control visual with those lines waiting in the queue and all heading to Blighty. There must be some reasoning to these prog (fronts ) / lines of activity or is it guess work. I know we always looked for buckles in the isobar charts in the early days but this chart takes it to another level. Watched over the past week and not far off the mark by the head man/girl. Great stuff.

C

Great Stuff!

Have you forgot all you were taught Paul?

To produce a chart like that seems non professional to me. However, the model, now King and must be obeyed, perhaps shows such things. They are not fronts but perhaps predicted bands of ppn, trough lines showing on the model.

The probability of all 7 being in the right place at the time of the Fax are pretty minimal in my view, but hey ho, times are a changing and I'm just a bloody old ex senior forecaster.

 

[carinthian]

3 minutes ago, johnholmes said:

Great Stuff!

Have you forgot all you were taught Paul?

To produce a chart like that seems non professional to me. However, the model, now King and must be obeyed, perhaps shows such things. They are not fronts but perhaps predicted bands of ppn, trough lines showing on the model.

The probability of all 7 being in the right place at the time of the Fax are pretty minimal in my view, but hey ho, times are a changing and I'm just a bloody old ex senior forecaster.

 

Yep John, things have moved on a bit !I remember those fax charts out to 72 hours and looked in wonderment as how far they could forecast. Nowadays out to 120 hours pretty spot on.  I will save that fax chart at 60t and just see how accurate those lines of precipitation are . Bet they are not far off the mark!

Cheers,

PS Had a pint at The Ye Olde Bells of Peover the other night on my visit the Cheshire. Think you know of it from your days at Ringway/MAN !

C

[knocker]

Still some cloud, haze and mist over the south west Midlands and east Wales on the 1200 geo. And of course the north east coast. And the 1100 UTC chart

[knocker]

The 1200 UTC obs

Boulmer 14.7C and 25C on the south coast Quite a few stations are reporting vis reduced by smoke!

http://www.met.reading.ac.uk/~brugge/12.html

Edited May 28, 2018 by knocker

[A.J]

6 hours ago, knocker said:

The ecm take for Weds with a fair temp range as it's much cooler under the precipitation.

The 0600 UTC geostationary (courtesy DSRS)

Malcolm, re, wednesday ppn charts, is that inferring more along the lines of dynamic rainfal along that trough or convective?.....I haven't had a chance to look at any charts re. forcing, instability etc....cheers

[knocker]

6 minutes ago, ajpoolshark said:

Malcolm, re, wednesday ppn charts, is that inferring more along the lines of dynamic rainfal along that trough or convective?.....I haven't had a chance to look at any charts re. forcing, instability etc....cheers

In a sense I suspect a bit of both as these troughs appear to be areas of concentrated showers/convection sliding north west across the Channel/North Sea

Edited May 28, 2018 by knocker

[knocker]

The high res. MODIS at 1345 UTC (courtesy DSRS)

[knocker]

A line of convection west of London on the 1500 UTC geo?

[knocker]

Any showers that are triggered in the south this evenig will eventually die out leaving a clear night in the west but the return of the low cloud and mist in the east which will extend a long way inland across much of central England and the south west. It will withdraw again to morrow but probably not completely so on another warm day again the east coast 'cooler'. But thundery outbreaks will start affecting the south quite earle and will continue through the day and there could be some intense localized rainfall in areas unlucky to catch a storm..

[knocker]

When the gfs creates the cut off upper low in the eastern Atlantic it also creates a more intense one in the west. I just mention this en passant because it seems to think it may play a vital role further down the line.

Edited May 28, 2018 by knocker

[knocker]

The odd storm on this convection line on the 1800 UTC geo.

 

[knocker]

The ecm is creating a new surface low around 45N 20W by 1200 Friday courtesy of the two cut off lows  It then tracks it east towards Coruna by 1200 Saturday which boosts the general area of low pressure and initiates some unsettled weather over the UK Friday and Saturday. Of course where is a roll of the dice 

[knocker]

For this period the UK will essentially stay withing the circulation of the low pressure to the SW/S and thus a moist, unstable, airstream from an easterly quadrant. Temps remaining above average but cooler in the east with a fair amount of sunshine with a westerly bias but but showers and storms, sometime in concentrated bands, will affect many areas at times.

Today.

After a generally mild night the low cloud and mist affecting many areas will gradually retreat to the eastern coasts (hopefully) leaving a sunny but a tad cooler day than of late, But storms currently over Holland will swing west along the south during the day with possible some intense localized rainfall if you are unlucky to catch one. This evening the low cloud and mist will start to return inland as another band of showers starts tracking north east across the SE and the North Sea.

The murk may well hang around a bit in eastern regions as the line of showers and the odd storm cross eastern and central areas during another warm day so sporadic sunshine unless you in western areas, particularly western Scotland.

By Thursday the next phase in the evolution is underway with the cut off upper low to our south west boosting and re-orientating the surface low which will increase shower activity in general, with the odd storm, but may also negate the east coast malaise on another warm day.

On Friday the slack area of low pressure covers the UK with again a fair bit of showery activity whilst out to the west the Azores high is ridging north quite strongly between the cut off lows.

Not a lot of change on Saturday but the high pressure transition continues apace with, something I've touched on previously, a strong westerly jet in the tight thermal gradient north of the high pressure.

Edited May 29, 2018 by knocker

[knocker]

The 0400 UTC chart. A lot of haze, mist around and the odd drizzle