Models, teleconnections and nowcasting

[knocker]

Between t144 > 192 the ecm creates the cut off upper low to the south but the attempted amplification north east of the subtropical high is thwarted by the energy distribution and a surface low descends on the UK

Edited May 25, 2020 by knocker

[knocker]

The EPS this evening gives much more traction to the tpv ext east over Greenland which effectively limits the NE expansion of the subtropical high The GEFs not so bold so the ridge does retain some influence with NOAA perhaps straddling the two. There needs to be more agreement between the three main elements in this area before any detailed surface analysis can be viewed with confidence

[knocker]

The North Atlantic 300mb wind field and surface analysis for midnight

The cloud and very light intermittent rain associated with the front(s) will slowly move south east through the day and slowly dissipate. Clear and sunny north and south of this and warm in the south east (usual caveats vis model max temps)

Still a fair bit of cloud in parts of the south/east tonight but clear elsewhere and quite cool

The aforementioned cloud should clear Wednesday morning leaving a fine sunny day for all, but some cloud and light rain may well effect the far NW later as a warm front slips past

Over Wednesday night through Thursday the centre of the high cell moves east into the North Sea as the Atlantic trough swings around it's axis west of northern Greenland. But another sunny day for most with just cloud and patchy rain in the far NW for a time

The pressure on the ridge continues on Friday but again another sunny day

And by Saturday the ridge is stretched, linking to high pressure to the NW and NE as it is flanked on either side by the troughs But still another dry and sunny day, usual caveats eastern coastal regions, with perhaps the odd shower in the west

 

[knocker]

To continue briefly with the gfs.

Things get a tad  complicated over the next few days as further amplification of the subtropical zones disrupt the Atlantic trough forming a cut off low to the south, but another trough develops within the tpv and swings south east around the Atlantic high down across Ireland to phase with the trough to the east. Thus some more unsettled weather on the cards and perhaps quite windy but the detail of this is a long way from settled

[knocker]

The ecm also disrupts the trough and creates the cut off upper low but stronger ridging from the Atlantic subtropical high prevents further developments from the tpv to the NW and thus a easterly regime is initiated with low pressure to the SW/S If this is going to be the direction of travel then precisely how it develops is crucial to any possible  thundery outbreaks

[knocker]

The medium term GEFS and EPS mean anomalies this morning encapsulate the det run differences starting early next week with the GEFS leaving the back door ajar

Edited May 26, 2020 by knocker

[knocker]

A glance at the EC weeklies update for the last two weeks of June

15 > 22

A fairly quiescent tpv centred over northern Canada and relatively benign westerly upper flow across a positively anomalous atlantic which abates approaching the UK courtesy of the perennial trough west of Iberia. Ergo portending a relatively quiet spell with little precipitation and temp above average

23 > 30

No significant change

[knocker]

Midday sat image showing the frontal cloud and current SST anomalies

 

[knocker]

Some nice orographic waves today

[knocker]

Difference between the 00run and now,,,,, back door now shut....well nearly

Edited May 26, 2020 by knocker

[knocker]

The ext anomalies this evening are further developing the pattern that they have been hinting at of late which is the tpv extending east and in particular the associated trough aligning south adjacent to the UK and phasing with the trough to the south west. This of course curtails further amplification of the subtropical high north east whilst at the same tine introducing cooler air (relatively) as the upper flow veers NW around the ridge

Edited May 26, 2020 by knocker

[knocker]

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

C

A cloudy start to the day for N. Ireland and Scotland which probably will linger with the odd spot of drizzle and then thickening later as a small frontal system tracks north east. Elsewhere quite a lot of Stratus and fog around (quite thick here at the moment) but this will clear resulting in another sunny and warm day.

Rain and drizzle continuing for N. Ireland and Scotland overnight, elsewhere clear.

The frontal system still hanging around on Thursday thus still cloudy with rain/drizzle for Scotland bu it should clear later. Elsewhere another fine day

There have been developments in the west by Friday as the he Atlantic trough swings around it's Canadian axis under pressure from the amplifying subtropical high zones. This results in the centre of the  UK high cell mover shifting east towards Denmark so although another sunny and warm day the usual caveat vis coastal regions applies

By Saturday energy exiting Canada has suppressed the Bermuda ridge whilst the trough and UK ridge are squeezed between this and the European trough resulting in the former deconstructing and the latter stretching further north. All resulting in light winds over the UK and another and warm sunny apart....well you know the rest

No huge change on Sunday but perhaps approaching the critical stage of the pattern evolution

Edited May 27, 2020 by knocker

[knocker]

To continue with the gfs over the tricky next couple of days,

The Atlantic subtropical high amplifies NE once more at the beginning of next week but the residual trough west of Ireland is still active, and connected to the tpv to the NW, and another trough develops here and slips south to phase with the trough west of Iberia Thus a large low pressure area develops to the SW/S of the UK with the ridge once again being squeezes by the energy distribution

[knocker]

As can be seen the ecm does not develop a separate trough to run south and phase with in situ one to the south west, thus a completely different surface analysis

 

Edited May 27, 2020 by knocker

[knocker]

Early St/fog quickly lifting down here

[knocker]

The ext mean anomalies this morning appear to be consolidating the direction of travel that has been indicated of late

Ridging over central North America adjacent to the tpv with apex northern Canada and associated troughs south east into the NW Atlantic and in the east, aligned south over the UK and phasing with the trough west of Iberia. In between the Atlantic subtropical high ridges quite strongly north east around which the strong upper flow swings and abates to become north westerly over the UK. This would suggest more changeable and cooler weather but no, as yet, any sign of any significant precipitation

Edited May 27, 2020 by knocker

[knocker]

Looking at the clusters t144 > 168 I can't  see any strong reasons to disagree with the det run. Obviously the detail will change

Edited May 27, 2020 by knocker

[knocker]

For what they are worth max temps Thursday > Saturday and today at 1200 with the 06 ecm. Best avoid Margate

Edited May 27, 2020 by knocker

[knocker]

Bertha has formed near the coast of South Carolina - the 2nd named storm of the 2020 Atlantic hurricane season to date has formed near the coast of South Carolina - the 2nd named storm of the 2020 Atlantic #hurricane season to date.

[knocker]

Current radar Charleston

 

[knocker]

No trough ducking south on this run

Until later

 

Edited May 27, 2020 by knocker

[knocker]

Pretty warm in Ontario at the moment

[knocker]

The key time span on this evening's ecm is between t120-168 when another trough develops south of Iceland with linkage to the cut off low west of Iberia and develops rapidly as it slides down the eastern flank of the ridge. And thus a broad area of low pressure develops under the ridge

Edited May 27, 2020 by knocker

[knocker]

Given recent indicators the ext mean anomalies this evening are no surprise

Fairly amplified upstream with the tpv pretty much centred NW Greenland with associated troughs aligned to the NW Atlantic and down the UK where it phases with the trough west of Iberia. Between the troughs the Atlantic subtropical high amplifies in mid Atlantic and the upper flow swings around this the so that by the time it reaches the UK it is from the NW and abating.Thus the percentage play is for more changeable weather cooler than of late but still near average and the precipitation estimates still very low

[knocker]

The ecm has a brief flirtation with phasing the troughs t96. 120 but further amplification puts an end to that for the time being

But then further trough movements south east across Greenland have another go