Models, teleconnections and nowcasting

[knocker]

Possibility of some storms in the S/SE Thursday as the trough and cold front cross the country whilst the low to the south west continues to develop

And by midday Friday it is 977mn NW of Ireland and associated cold  front has cleared the east coast. Thus beaming very windy in the NW for a time and quite wet, mainly over northern regions

 

[knocker]

Over the next three days a another trough drops into the Atlantic to phase with the one in situ whilst the subtropical high pushes north towards the UK resulting in a N/S split and becoming warmer

[knocker]

Amphan

[knocker]

[knocker]

Frontal cloud layers over northern UK and orographic waves

 

Edited May 19, 2020 by knocker

[knocker]

A positively tilted trough can be a tad annoying

[knocker]

Not that it's worth considering at this range but the gfs develops a low at the base of the Atlantic trough next week

[knocker]

And the GEFS medium term mean anomaly is not adverse to developing an Atlantic trough which has been the direction of travel in the ext area recently

Edited May 19, 2020 by knocker

[knocker]

And further to that

[knocker]

The North Atlantic 500mb and surface analysis for midnight

Some cloud and patchy rain/drizzle over northern Scotland at the moment that will only effect Orkney and the Shetlands today whilst elsewhere patch cloud and getting quite warm in the SE of England (usual caveats model max temps)

Mainly clear tonight but the cold front is edging east bringing some rain to N. Ireland and possibly the odd storm in the south west. Not the low at the base of the Atlantic trough is getting organized

The showers/storms will move into the SE/E during the day on Thursday whilst more persistent rain effects Scotland courtesy of the waving front. And the low to the south west is now deepening rapidly near the left exit of the jet

The low will continue to track north through Thursday night/Friday to be NW of Ireland by midday and the associated fronts will bring heavy rain to the north before giving way to frequent showers  The winds will strengthen reaching gale force in the NW

By Saturday the low is north west of Scotland so still wet and windy here whilst some showers over the rest of the country but less windy. But note another trough tracking into the western Atlantic

And by Sunday a new positively tilted trough in mid Atlantic has evolved flanked ob either side by the amplifying subtropical zones Apart from some rain still over northern Scotland not a bad day

Edited May 20, 2020 by knocker

[knocker]

Continuing through next week with the gfs

The Atlantic trough does exert some pressure on Monday with the man centre moving north towards Iceland so still a tad windy with showers for Scotland

The next couple of days are a tad unusual in the sense there is a swathe of high pressure underpinning the trough to the north,which has tendrils running south, resulting in the ridge trying to extend north east into the UK. Of course none of this is a done deal

Edited May 20, 2020 by knocker

[knocker]

Storm 'potential' tomorrow

[knocker]

The ecm a tad more robust with the ridge

[knocker]

This morning's GEFS and EPS  anomalies more or less mirror the det outputs with the trough to the NW gaining more traction but the latter not being so keen to relinquish high pressure influence

[knocker]

Tomorrow

Friday

[knocker]

It's beginning to look as if the development of the trough in the Greenland/Iceland area could play a key role in the direction of travel

[knocker]

How the trough over Iceland develops in relation to the underlying high pressure is pretty critical regarding the detail for the UK

[knocker]

Some interesting and thickening Ci encroaching from the west

[knocker]

The ext anomalies continue to evolve in the direction that has been indicated of late. Ridge NW North America adjacent to the tpv over northern Canada which extends south east towards the UK. Quite a strong westerly upper flow exiting the eastern seaboard, courtesy of the Bermuda high  pushing north a tad,. which abates somewhat in the east This would portend nothing drastic, perhaps trending towards a N/S split , with temps around average, perhaps a little above

[knocker]

The North Atlantic 300mb wind profile and surface analysis for midnight and sat image

A couple of bands of showery rain. already effecting western regions, will track NE across the country today with some thundery outbreaks possible, particularly in the east/south east later this morning. And still quite warm in these regions And notable the low is now 966mb at 20W

Overnight the fronts and rain associated with this will sweep across the country, particularly effecting the NW where it will also become very windy. Some heavy showers may also effect the south east

The rain will clear northern regions by late Friday morning to be replaced by heavy squally showers, mainly concentrated in the NW, and generally a much cooler day than of late/

Over Friday night and through Saturday the low continues to fill and track north east to be 984mb NW of Scotland by midday. thus still windy here with rain courtesy of the trailing back occlusion. Some showers further south

By Sunday there have been further developments in the Atlantic as the subtropical high zones amplify and thus generally not a bad day but rain will effect Scotland courtesy of a waving front

The high zones continue to amplify on Monday as the main centre of the Atlantic trough moves north to be south of Iceland. All of which results in a mainly sunny and dry day with light winds

Edited May 21, 2020 by knocker

[knocker]

Moving through the rest of the week with the gfs and it's essentially a story of the energy tracking east across the Atlantic south of the Greenland/Iceland trough being diverted by the strongly amplifying west Russian ridge which facilitates ridging north east of the Atlantic subtropical high around the western flank of the cut off upper low in eastern Europe. Fine margins

Edited May 21, 2020 by knocker

[knocker]

The ecm differs greatly from the above by amplifying the Bermuda high and interrupting the east bound energy and creating a weak trough in mid Atlantic. Which facilitates stronger ridging in the east and advection of warmer air in the south and then much of England and Wales, with the complication of the aforementioned trough in the north/ Quite obviously there are still issues to be resolved

 

Edited May 21, 2020 by knocker

[knocker]

An update of the ext anomalies this morning without comment except to say the outlook very favourable

Edited May 21, 2020 by knocker

[knocker]

As can be seen front though and very pleasant

[johnholmes]

Front clearing through here, blue skies just west of here. I 'think' there may have been half a dozen spots of rain! Prior to the front some Ac Castellanus was briefly visible.

Just looking at the Fax chart k has put up. Perhaps not the front but the prelim one (upper cold front).

Edited May 21, 2020 by johnholmes