Short range model discussion - into 2018

[knocker]

Not a brilliant outlook for today and tonight. The northeast will be under leaden skies with the occasional drizzle with the winds off the North Sea, Cloudy in many other areas as well with patchy rain tracking east > west across central England and Wales. The best of the weather will belong the extreme south of England, the north west and western Scotland and this is reflected in the temps.

By 1200 Thursday the easterly regime is well established with high pressure to the north east and low pressure to the south so low cloud, drizzle and suppressed temps for the north east and east coasts and central areas of England remains he order of the day. A bit brighter further south with some showers but the best of the weather will again be north west Scotland.

But changes are afoot courtesy of the upstream energy and the associated negatively tilted trough stretching from Greenland to Iberia exerting more pressure on the block to the north east and facilitating movement of small lows within the complex low pressure area to the west and south of the UK. Thus Friday sees one such low track north west across England and Scotland bringing some wet, and very windy weather in the north, with it. Again the best of the weather and temps in the  south.

As the front and rain move north and clear overnight Friday they do at the same time remove the easterly regime so that by Saturday the UK is in a very slack pressure gradient and a pleasant and warm day for most is likely with just the odd shower around. But as can be seen out to west some quite intense upper lows have been riding east on the 160kt jet and there quite a deep surface low 975mb south west of Ireland.

So by Sunday a familiar story is unfolding, east bound energy against the block, and the surface front is just about making inroads in the west of the UK but elsewhere anther fine and warm day portends. But another twist is around the corner but that's outside the remit of the thread.

 

[knocker]

Further to the above this morning's fax charts with a bit more detail vis Tomorrow and Friday.

The waving front cross the Midlands tomorrow, and the little system tracking NW on Friday terminating the easterlies.

Sunrise 0600 UTC

[johnholmes]

tracking NW on Friday terminating the easterlies.

Music to my ears, double figures will seem like the Med!

[knocker]

The high res MODIS at 1100 UTC( courtesy DSRS) and the 1200 surface chart. Poor temps across the NE as expected and plenty of poor vis around.

Edited April 11, 2018 by knocker

[knocker]

As it's a quiet day a quick saunter into the medium term with a glance at last night's NOAA and this morning's GEFS and EPS anomalies.

All pretty much on the same page with, upstream, high pressure over the Pole. a vortex lobe in the region of Ellesmere Islands adjacent to a ridge/trough combination in NW North America around which twin upper flows exit into the Atlantic of which the stronger is of that leaving the eastern seaboard.

But these flows hit the buffers downstream because some quite intense amplification is underway involving the Mid Atlantic trough and the European high pressure, with the main N.Russian vortex lobe and trough an interesting on looker.

Thus west > east movement is curtailed (almost) and an upper flow from the southerly quadrant is the order of the day. So certainly temps above average but the precise position of the surface ridge/high cell and the trough (keeping in mind still a lot of energy trying to push east) is critical to how far east any surface frontal intrusions, with some rain and increasing wind,  will reach. Something for the det runs to sort but certainly a definite improvement on this week is on the cards and some quite warm temps in some areas and equally welcome pretty dry except possible in the west.

[knocker]

Another pretty dour and dank day tomorrow in the north east and central areas with drizzle and poor vis,a brighter elsewhere particularly the north of Scotland.

During the late late afternoon and evening a more organized belt of rain will move north west across southern England into Wales.

[knocker]

The setting sun highlights frontal cloud

[knocker]

For much of north eastern and central England today it will be a pretty bleak day with low cloud, poor vis and intermittent drizzle. But by mid afternoon, and through this evening, a more concentrated band of rain will swing across the UK from  the south east affecting most areas. The best of the weather in far western areas  Temps very poor in the gloom, particularly in the eastern coastal regions, and a fair way inland, and Scotland

Overnight and through tomorrow morning, as the rain above swings across the south west, another more consolidated band of quite heavy rain tracks north west from the North Sea across Scotland clearing by midday. Still cloudy in the north east and maybe some central and eastern areas but the temps are starting to pick up as the passage of the front curtails the easterly. .

By 1200 Saturday, with the front well out of the way to the north, the UK is in a col with an Atlantic low to the west and the blocking high to the north east leading to a quite balmy and welcome scenario, albeit a few showers around, with temps above average everywhere

Twenty four hours later the Atlantic is dominated by an upper trough orientated west > east with a deep surface low west of Ireland and associated front already bringing rain and fairly strong winds into western parts of the UK leading to a W/E temp split across the latter. But perhaps the key issue here is the burgeoning of the Bermuda high pressure to the west and the continuing intensity of the block to east and the impact this has on the orientation and intensity of the Atlantic trough and forthcoming evolution.

So continuing this point on Monday the Atlantic is now dominated by the restructured upper low flanked by amplified ridges which severely curtails west to east movement and initiates some pretty intense WAA into Europe. Thus the above mentioned front fizzles out leaving a warm showery day on Monday

Edited April 12, 2018 by knocker

[knocker]

Satellite 0500 UTC

[knocker]

Sunrise with the 0600 geostationary (courtesy DSRS)

[knocker]

One key aspect over the weekend and next week will be how far east any Atlantic systems will progress against the block. This morning's fax updates with the progress of the occlusion over the weekend.

 

Edited April 12, 2018 by knocker

[knocker]

The 0600 Atlantic analysis and forecast for 00 Saturday

[knocker]

The high res. MODIS at 1145 UTC (courtesy DSRS)

And the 1200 surface chart and looking at it obviously the only place to be is down here with Sidney

Edited April 12, 2018 by knocker

[johnholmes]

stop rubbing it in k, Ill get the east coast lynch mob organised if you're not careful!

[knocker]

A but John as I was just about to post

As previously discussed the transition into the new pattern gets underway tomorrow as a shallow low tracks NW and although it will be accompanied by a belt of rain it will remove the North Sea influence and the current dross and another world dawns on Saturday.

[knocker]

The 1800 UTC geostationary

[knocker]

At any time of year that would be an impressive Atlantic low

[knocker]

As everyone will be aware today marks the end of the cold and dismal weather many have endured over the last few days. Currently a shallow area of low pressure is moving north west over England with a band of rain over the Midlands and the north  This will clear most areas by mid afternoon leaving brighter conditions with a few showers in it's wake and temps recovering from the south.

Tonight will be dry but probably cloudy in the north

Tomorrow finds the UK in a col so after some early morning mist has cleared a quiet, partly cloudy, and warm day for most but to the west the Atlantic is going through the gears with a lot of energy exiting North America and with a fragment of the Canadian vortex starting it's journey to phase with upper low west of Ireland.

By early Sunday the surface low associated with the aforementioned upper low west of Ireland is 978mb with associated fronts already bringing bringing patchy rain to N. Ireland, south west Wales and Cornwall along with a strengthening wind, This patchy rain will track east during the day but probably not reaching the far east of the country. Meanwhile the vortex fragment/lobe has intensified into a deep upper low as it slips further into the Atlantic as the Bermuda high amplifies to the west.

By 1200 Monday the intense upper low is dominating the central Atlantic flanked by the amplifying ridges over NE North America and Europe which curtails any significant west > east movement thus the fronts, and any perturbations in the flow of the massive surface low. are struggling to make inroads across the UK. So much so that by 00 Tuesday any frontal rain is confined to N. Ireland and the north west. Still quite warm in the strengthening south west surface wind.

The frontal rain makes little progress overnight and into Tuesday as the European high amplifies again and in the process positively tilts the upper trough in the west and strengthens the south westerly flow but temps still above average.

Edited April 13, 2018 by knocker

[knocker]

The GEFS anomaly for an overview of the above

[knocker]

Satellite at 0445 UTC

The 0600 surface analysis, albeit a tad sparse

 

[knocker]

The 12 UTC geostationary and surface chart Quite cloudy

[knocker]

Dear oh dear, spoiling those in the north east yet again tomorrow!

[knocker]

Our intense mid Atlantic low connected well into the lower Stratosphere.

[knocker]

The counter punch, but will it succeed?

[knocker]

The 1800 geostationary (courtesy DSRS) highlighting the major low to the west which will track slowly east and bring patchy rain to the UK on Sunday. Also the connected system aligned Greenland to the west of Ireland/