Models, teleconnections and nowcasting

[johnholmes]

Happy Christmas, especially knocker for doing the detailed weather commentaries, much appreciated mate.

 

[knocker]

Medium and upper cloud has been encroaching down here since late morning from the warm fronts associated with the low WSW of Ireland. Both the Atlantic lows are depicted very well on the 1399 sat imane

Some rain from the upper and surface warm fronts will effect N. Ireland by 2000 and then northern, central and eastern England by 0300 to be followed by the cold front, with the heaviest rain tending to be over Ireland

Edited December 25, 2019 by knocker

[knocker]

According to the gfs a little wave develops on the front Sunday/Monday but doesn't amount to much

as the high cell is too resilient but not for long as the energy from the west is pretty relentless

[knocker]

Little to add to previous comments on the GEFS anomalies

[knocker]

The ext EPS stll not in total agreement with the GEFS with the subtropical high retaining more influence although the suggestion is of the pattern retrogressing a tad. We shall see

 

[knocker]

The North Atlantic 500mb and surface analysis for midnight

The band(s) of rain associated with the, now, weakening occlusion will continue to track north east through the day with heavy pulses in places. But little respite to follow as the low to the west fills rapidly as to tracks east bringing more heavy rain to Wales and southern central regions during the afternoon and evening

Much of the rain will clear away during the evening but another frontal system with a developing wave is tracking NNE and the warm front will bring further rain into western regions through the night which will be heavy over western Scotland by morning. A cloudy night elsewhere

By Friday the low is south east of Iceland with much of the country in a mild, cloudy, warm sector but heavy rain and strong winds will continue over Scotland bfore clearing in the afternoon

On Saturday most of the country will be dry and in a mild south westerly but frontal rain will continue to effect N. Ireland and northern Scotland at times

A not dissimilar story on Sunday

By Monday the cold front that has been causing the rain in the far north is moving south so the rain becomes more widespread

[knocker]

According to the gfs the next five days are about an intense tpv. a strong westerly upper flow across the Atlantic and the influence, or not, of the subtropical; high in the east

[knocker]

The ext GEFS this morning is suggesting a minor resurgence of the subtropical high in the vicinity of the UK

[knocker]

One way or 'tother the ecm has a lot of energy swanning around in the Atlantic next week which results in unsettled and quite windy, particularly in the north, for the UK

[knocker]

Moderate rain here at the moment on this complex frontal set up

 

Edited December 26, 2019 by knocker

[knocker]

Equally the ext EPS is retaining  certain amount of influence from the European subtropical high this morning, with an east European trough, which is rather indicative of a N/S split

Edited December 26, 2019 by knocker

[knocker]

The rain has stopped here I can actually see a patch of blue sky, and the wind has eased considerably

[knocker]

A quick glance at th 06 ecm over the next couple of days

Now

and then

[knocker]

The ext GEFS continues to indicate a tad more influence from the subtropical high in the vicinity of the UK as the structure of the tpv/trough adjusts

[knocker]

Interesting 850mb temps in the NE on Sunday. Unfortunately I don't have access to any ecm forecast soundings

.

[knocker]

There are significant downstream differences between the ext GEFs and EPS. involving the tpv/trough and the position and intensity of the subtropical high. This needs to be resolved before one can have confidence in the direction of travel

[knocker]

A quick glance at the EC weeklies update for the last two weeks of January. I appreciate that many of the 'experts' in the other thread dismiss these but that is no reason why I shouldn't post them here

16th Jan > 23rd

Aleutian ridge/trough west North America with tpv northern Canada

But the trough extension from the latter is south east into the NW Atlantic, and not east which facilitates the some ridging, with positive anomalies, of the European subtropical high. Probably indicating a NW /SE split and the precipitation chart is indicative of this

24th > 31st

If anything in this period the Atlantic trough has retrogressed a tad facilitating more influence from the subtropical high over the UK

 

Edited December 27, 2019 by knocker

[knocker]

Might sneak some rain into the south west Tuesday morning. Certainly a broad temp spread

[knocker]

Foehn Effect tomorrow?

And Sunday

Edited December 27, 2019 by knocker

[knocker]

I'm aware that precipitation totals and spread over ten and fifteen days need to be treated with caution but given the predicted less volatile period coming up, and indicated pattern, these look reasonable. Most places should be quite dry which will be good news after recent experiences but the bad news is over western Scotland which is in the firing line of this type of pattern.

Edited December 27, 2019 by knocker

[knocker]

Perhaps the most significant movement in  the ext GEFS is that of the tpv towards the Pole as it becomes less intense. This drags the some of the cold Arctic air east over Greenland whilst the subtropical high retains a fair amount of influence over the UK

 

 

[knocker]

After the trials and tribulations of the last dew weeks it looks likely that the next couple of weeks, at least, will be relatively tranquil and dry except, unfortunately, western Scotland

 

Edited December 27, 2019 by knocker

[knocker]

Foehn this weekend, particularly tomorrow

Some rain creeping into the south west Tuesday morning and a mix of temps across the front

[knocker]

And little change with the ext GEFS this morning with weakening vortex over the Pole, extension to Alaska and trough eastern Europe

[knocker]

As previously mentioned the tpv is starting to relocate to NW Greenland with trough extension eastern Europe whilst retaining subtropical high influence over the UK. So continuing quite a reasonable outlook but still indicating a N/S split