Short range model discussion - into 2018

[knocker]

The 0900 surface chart and overview of surface wind

https://earth.nullschool.net/#current/wind/surface/level/orthographic=-2.88,53.70,3000

[knocker]

Either side of the front on Wednesday.

Precipitation

[johnholmes]

Oh goody it's raining again. Much more and my fish will have a very large pond to swim around in!

At least it will be warmer rain?

[knocker]

You are under there somewhere. The high res. MODIS at 1300 UTC. It's stopped raining here

[knocker]

The 1500 geostationary and 1200 analysis

[knocker]

I think the most significant aspect of the weather over the next 24 hours will be the persistence of the band of heavy rain and snow over N. Ireland and Scotland and the associated temp differences.

[knocker]

Wednesday has the makings of a pretty foul day with a low centered over Wales and fronts across the border area thus a band of rain with heavy showers elsewhere. Temps ranging  from 4C in northern Scotland to 10-11C in England/.

Thursday a much better day with a transient ridge as the low moves east, apart maybe for Scotland and the far north of England. Still a marked variation with the temps 4-8C in the north and 10-11C further south

Friday starts okay but rain soon pushes in from the west as the next low approaches but the eastern half of England and Scotland should remain dry. Temps 12-15C south of Carlisle but only 4-10C N.Ireland and Scotland

Edited April 2, 2018 by knocker

[knocker]

A quick overview. Today and for the rest of the week the UK will remain under the influence of low pressure, apart from a very brief transient ridge on Thursday. Thus also remaining unsettled but temps much milder in the south than of late although there will be a sharp latitudinal temp gradient at times

So today we have a complex area of low pressure with low centres to the west with associated fronts trailing across the north of the UK. Thus N. Ireland, Scotland, and the very north of England will stay cloudy with a continuation of the rain, sleet and snow saga and still quite windy whilst further south there will be sunny intervals with probably some heavy rain showers thrown in.

but overnight and trough Wednesday one of the aforementioned low centers tracks north east over Wales and England bringing a more concentrated area of showery rain and quite likely hail and thunder in places whilst further north the belt of very inclement , windy, weather persists.  All in all a quite unpleasant day likely, particularly in Scotland with a marked temp contrast.

Overnight Weds the low moves away east leaving the UK in the transient ridge on Thursday but away in mid Atlantic the next deep upper trough has arrived on the scene and the complex large surface area of low and fronts associated with this are edging into western Ireland by Friday 00.

But during Friday the Bermuda and Azores highs amplify and the subsequent block drastically slows down any west > east trough movement whilst at the same time reorienting the upper trough to a more N/S structure and thus backing the upper flow over the UK and initiating some WAA, much of which will slide to the east and just deliver the UK a glancing blow.

It all gets a bit messy on saturday as the trough just to west starts to deconstruct under renewed pressure from the west leading to a sunshine and showers day but pleasantly warm in most areas.

 

Edited April 3, 2018 by knocker

[knocker]

Satellite 0500 UTC

[knocker]

The 0900 geostationary UTC That patch of cloud spoiled a cracking morning in these parts

Edited April 3, 2018 by knocker

[knocker]

The high res. MODIS at 1200 UTC (courtesy the Dundee Satellite Reception Station)

[knocker]

The interesting developments this evening with the GFS run, start quite early. By 1200 Friday the upper trough is just to the west of the UK with surface fronts just staring to affect western regions.

But the trough is coming under massive pressure from the block to the east and energy exiting North America which is splitting the Bermuda ridge, Consequently a messy showery scenario over the UK, albeit relatively warm.

The consequences of splitting the ridge and the continuing block o the east are quickly apparent and lead to an interesting N/S temp reversal on Sunday.

And where is all of this leading?

 

[knocker]

The 1800 geostationary (courtesy DSRS) showing the deep Atlantic low at 30w with associated fronts and the forthcoming transient ridge tomorrow,

The ecm going for a generally warm day on Saturday particularly in the SE where temps may reach 18-20C Not quite so warm on Sunday and in fact quite cool in Scotland where temps may only reach 6C. Temps specifics over these, and future days, all rather depend on the precise surface analysis as this pattern evolves over the weekend and the beginning of next week

 

Edited April 4, 2018 by knocker

[knocker]

Ecm 850mb temp anomaly and contours and GFS rainfal

[knocker]

A quick look at this evening's anomalies to get an idea where the short term may be heading.

Not bad agreement with high pressure over the Pole , low pressure in the NE Pacific and an active Canadian vortex.with a lot of energy leaving North America  But this energy hits a major block in mid Atlantic in the form of a positively tilted European ridge stretching NE to Iceland and an an Atlantic trough that has deconstructed into an upper low over Franc/Iberia.(more or less a Rex block) Thus the westerly upper flow diverges leaving the UK in a slack low pressure area. This portends a relatively calm period but the detail may be tricky for the det runs to sort.

 

Edited April 4, 2018 by knocker

[knocker]

That should of course read stretching NW to Iceland

Edited April 4, 2018 by knocker

[knocker]

Today will be dry and fairly sunny for most areas as yesterday's low moves east into the north Sea and a transient ridge moves in.  So, although the day will will start with quite a widespread frost, with little wind it will be quite pleasant, Particularly in comparison with recent days.

The weather remains quiescent overnight but the pattern change alluded too in last evening's post is already underway. there is a large complex area of low pressure just to the west of the UK, courtesy of the upper trough, with surface front(s) affecting western regions by1200 Friday.with rain edging into N. Ireland, western Scotland and Cornwall. But already the European high is beginning to amplify whilst simultaneously energy exiting North America is breaking down the Atlantic ridge all of which puts the trough to our west under severe pressure. And it starts to deconstruct.

The deconstruction process continues over the next 24 hours leaving a pretty messy surface analysis with low centers littered about and the front struggling to cross the country giving a fairly benign unsettled day with showers. But the trough being forced south has backed the upper flow and parts of the UK  do benefit from the resulting WAA albeit most passes to the east.

By 1200 on Sunday, with the block to the east still in place and assisted by high pressure in the Iceland area courtesy of the earlier assault on the Atlantic ridge, the energy  exiting North America is tracking south east and 'topping' up our trough to the south. All of this leaves the eastern Atlantic and the UK in a very slack pressure area with showers and, according to the GFS interpretation of the pressure/temp distribution (a weak front?), a reversed temp gradient

.

Not a dissimilar pattern on Monday but more significant changes are afoot with the Atlantic high pressure once more beginning to amplify and about to connect to the ridging European high, but that for another day.

 

Edited April 5, 2018 by knocker

[knocker]

Satellite at 0436 UTC

[knocker]

To put the above post in an NH context this morning's GEFS T120 Anomaly.

[knocker]

The 0600 surface charts

The 0600 geostationary WV (courtesy Dundee Satellite Receiving Station)

 

Edited April 5, 2018 by knocker

[knocker]

Regarding Sunday evening the ecm also has a weak front across the south with a belt of slightly lower temps but then on Monday temps in the 13-15C range south east of a line Weston to the Wash and 7-9C north of it

[knocker]

Would you adam and eve it. Nice clear morning quickly gave way to Ci and Ac as can seen on the 0900 geostationary (courtesy DSRS)

[knocker]

The high res. Modis at 1140UTC. (courtesy Dundee Satellite Receiving Station).

 

[knocker]

Apropos nothing really but classic signature of upcoming atmospheric River on this mornig's GFS

http://www.atmos.albany.edu/student/abentley/realtime/pacific_pw.php

Edited April 5, 2018 by knocker

[knocker]

Most areas will stay clear and dry this evening and through the night. And in fact central and eastern areas probably through tomorrow bur further west patchy frontal rain will move east from the morning albeit very slowly, Temps pretty good in the southerly drift.

 

Edited April 5, 2018 by knocker