Short range model discussion - into 2018

[knocker]

Outlook - Becoming more settled and warmer as the period progresses, albeit still tending to a NW/SE divide

The 500mb and surface analysis for midnight and the WV image for 0300

With the low slowly filling close to N. Ireland the UK is still in a brisk south westerly wind and currently there are showers down north west and western regions. With a trough hanging around to the west these will pep up during the day and spread further inland in the north whilst the south east remains dry and temps generally a little above average.

Still quite blustery with squally showers during the evening but then becoming more prevalent in the north but generally a clear, but quite chilly night.

Though Tuesday the showers will quickly dissipate as a ridge builds from the south east so plenty of sunshine with temps a tad above normal and certainly feeling warmer as the wind abates

But out to the west the Atlantic is still very active with a with a lot of energy exiting the eastern seaboard and and this pushes a frontal system north east across the UK on Wednesday, bringing some rain and strengthening winds to NW regions as the ridge is suppressed somewhat. A warm day with temps significantly above average in some areas

This continues to be the theme through Thursday with a cold front close to N. Ireland and Scotland bringing some patchy rain in these areas. But in the Atlantic the major upper trough (spoken about in previous posts) has entered the fray and this initiates amplification in the eastern Atlantic and western Europe that advects some very warm air north over the UK

By Friday the intense trough is in mid Atlantic with the high pressure established to the east so another very warm day, albeit quite cloudy in many areas with some dying fronts around.

And the NH profile at T120

 

[knocker]

Modis image at 1300

[knocker]

There are a lot of showers around over western regions at the moment, just had a pretty violent rain shower here. and these will spread east this evening. But tending to dissipate during the early hours, on the still fresh south westerly wind which will veer as the ridge builds in the west

[knocker]

In hemispheric terms there is pretty good agreement between the GEFS, EPS and NOAA mean anomalies this evening. The only major difference , even if one can call it that, is the treatment of the ridge/high cell adjacent to the UK. Otherwise twin vortex lobes with the main one over N. Russia and associated trough eastern Europe and with the other relevant trough aligned south east from the Canadian lobe into the north Atlantic

There is a lot of energy exiting North America, probably connected to the two jets, which diverge in mid Atlantic, one running around the ridge/high pressure and the other south east with a conduit to the European trough. The tricky detail vis the weather for the UK is down to the det. runs but the percentage play at the moment is for the UK to remain under the auspices of high pressure with little or no rain and temps a tad below average.

[knocker]

If the MODS have got five could they remove the above post, wrong thread

Outlook - becoming drier and warmer with exception of the north west vis the former

The 500mb and surface analysis for midnight and the WV for 0300

Any residual showers, including the odd thunderstorm in the SE, will quickly dissipate resulting a sunny day with temps a tad above average and feeling warmer as the winds abate as the ridge builds from the south east

But as can be seen there is a major trough in the Atlantic and during this evening and overnight a frontal system associated with this will bring rain, and a strengthening wind, into all areas north of the Midlands, including west Wales

During Wednesday the rain will clear most areas, but rather belatedly the further north you go, leaving a generally sunny and breezy day with temps above average and on the up

Overnight Wednesday and through Thursday the frequently mentioned amplification is occurring restricting longitudinal movement and thus we have a stationary trailing front from western Scotland away to the south. This will bring rain and quite strong winds to the north west whilst everywhere else will be dry and very mild in the WAA that this scenario has initiated. The main issue here will be cloud amounts.

On Friday probably drier in the north west otherwise little change with the WAA well established. I've omitted the fax as this chart hasn;t been updated on the site I use

Saturday the influence of the high pressure is well established so remaining dry with temps still above but cloud amounts still the issue.

And so on to the NH profile at T20 which in many ways is a great indicator of the forthcoming evolution

Edited November 13, 2018 by knocker

[knocker]

That's some Atlantic trough on fridy

[knocker]

There is currently a great wodge of cloud to the west associated with the next frontal system that is rapidly arriving, We have Cs and Ac here that is indicated on the midday sounding

The wind will strengthen this evening and the rain will arrive over N. Ireland and western regions by 2300. It will the track north east during the night only missing southern parts of England

[knocker]

Outlook - becoming drier and warmer apart from the NW which will tend to be subject to more wind and rain. But a major pattern change is underway which speaks for itself after a glance at last evening's EPS. But it's worth noting the intensity of the anomalies vis the Canadian trough and Scandinavian high cell which are a tad unusual.

The 500mb and surface analysis for midnight and the WV image for 0300

There is a lot of cloud around this morning but the main belt of rain and strong winds, associated with the developing low and associated fronts to the west, are currently over N. Ireland, north west England and south west Scotland. The rain will spread over the rest of Scotland during the morning after clearing N. Ireland, and by late afternoon Scotland as well although some light patchy stuff may linger in the north. Drier and mild in the south

This evening and overnight the cold front is still very adjacent to north west regions so breezy and patchy rain persisting  And becoming increasingly cloudy again further south with a weakening warm front tracking slowly north, mild and frost free

A similar story on Thursday with the now waving front still in situ and the warm front a tad further north. It will be another mild day, particularly in areas where the cloud breaks.

The two frontal areas have decided to coalesce over Thursday night and through Friday but they are now just weak features so just cloudy by now. So still a very cloudy scenario generally but very mild in the southerly drift, particularly where the cloud breaks.

Over Saturday and Sunday the pattern change mentioned at the beginning is well underway with amplification taking place, both upstream and downstream, with the trough digging south in the Atlantic and the high pressure established over Scandinavia. Thus remaining dry over the UK with probably more sunshine as the wind is backing to the easterly quadrant which also dips the temp from mild to around average

And so on to the NH profile at T120 which is poised for the next ramifications of the pattern change

 

[knocker]

The MODIS image at 1243

[knocker]

Outlook - A pattern change during the period which, put simplistically, results in a switch from mild southerlies to much cooler easterlies.

The NH profile and surface analysis for midnight

The front associated with the deep low to the NW of Scotland is currently bringing some patchy rain to the western Scotland. This will tend to fizzle out during the morning but return later pepped up somewhat. Further south over central and southern England low cloud which may well persist through the day leaving the clearer weather in between the two  Very mild in the southerly drift

The rain will quite quickly fizzle out during the evening as the front decays leaving clearer and cooler weather in it's wake and remaining very mild further south under a blanket of low cloud.

Friday will be a very mild day in the southerly drift but cloud will be the problem with some patchy drizzle with perhaps north Wales, n. England and north east Scotland the best bet for any sunshine

Through Friday night and Saturday the aforementioned pattern change is well underway with some quite intense amplification

resulting in the surface wind backing and increasing and thus a much clearer day with temps returning to around average, matbe a tad above

The pattern change continues though Sunday and Monday

resulting in the surface wind continuing to back and strengthen  so remaining dry on Sunday but showers more prevalent in the east by Monday in the now quite strong easterly wind. Temps still hovering around the average, perhaps a tad below on Monday, but feeling cooler courtesy of the wind.

The NH profile at T120.A marked difference from the beginning and the energy flows are of interest

 

 

 

 

[knocker]

Just to illustrate the airmass change Friday > Tuesday with colder air being advected into the lower levels

[knocker]

Once the St had cleared broken Ci and Ac this morning with colour infrared filter

 

Edited November 15, 2018 by knocker

[knocker]

outlook - the transition to much colder and potentially unstable regime continues over the weekend to become established next week

The NH profile  and surface analysis for midnight.

There is currently some cloud associated with the weakening front in the north but further south more extensive low cloud in the mild southerly drift with plenty of mist and patchy drizzle around as can be seen on the 0300 surface chart.

This will hang around much of the day perhaps clearing on the leeward side of higher ground. Very mild.

And this will very much the same story through this evening and overnight and the only possibility of frost will be in the glens

Saturday starts in similar vein but a decaying cold front is tracking north west from Kent as the surface wind backs and it will be clearer behind it with temps returning to average but still remaining above to the north west.

The wind continues to back a tad though Saturday night and Sunday which starts to bring the North sea into play  Thus although temps continue around average with many areas being sunny, eastern coastal areas, particularly the north, east will be a lot cloudier.

Over Monday and Tuesday the pattern continues to evolve and the easterly wind becomes established with showers of rain along eastern regions and temps continuing to slide below average. albeit apart from the east, very sunny. But this is far from a completely static scenario and the energy flows that are evident on the 500mb vorticity chart  are bringing the low pressure areas to the SW/SE into play and some much colder air over France and Germany.

And the NH profile at T120

 

[knocker]

Mild and widespread mist over England at 9700. The st. broken here

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[knocker]

Still extensive mist/drizzle over England at 1100 and the 1230 MODIS says it all

This morning's updated fax charts for 1200 Sat > Monday and the 06 MODIS says it all

Edited November 16, 2018 by knocker

[knocker]

That second line should obviously read the 0600 gfs

[knocker]

Just some minor adjustments by the gfs in the latter stages of the short range almost certainly down to the energy flows around the UK. Still low pressure tracking north west putting pressure on the high cell and backing the easterly flow over the a tad. But equally the flow to west cannot be ignored in shaping the analysis which thus slides the colder air into France. Still plenty of showers in eastern regions of the UK and a widespread morning frost on Wednesday morning

 

[knocker]

At T96 the ecm has low pressure area over western Europe centred over France This tends to strengthen the easterly over the UK and generates many rain showers particularly in the east which do penetrate away inland. Thus feeling very cold, especially in the south which is on the fringe of the colder air over France and any preipitation sneaking up from the Channel could be of sleet or snow as dew points are around freezing.

ByT120 the low has moved west and is positively tilted over the UK thus veering the surface wind. Still plenty of rain showers but the temps a shade warmer but still a fair below average

[knocker]

Outlook - A transition to much colder weather next week as an easterly regime becomes established

The NH profile and the surface analysis for midnight and the o300 surface chart

As can be seen plenty of mist/fog around in England and Wales in this still warm airmass but as the days wears on the weak cold front will track north east, and although there is no weather on it it does clear the low clag out of the way and introduce clearer air behind. Thus many areas becoming increasing;y sunny. temps still around average or a tad above.

tonight clear for most away from the north east coasts with maybe a touch of frost in places

After the chilly start a sunny for just about everyone as the wind backs a tad with temps still around average

Becoming cloudier overnight Sunday and through Monday as a weak cold front traverses the country east > west from the north Sea giving some patchy rain/light showers in eastern coastal regions. temps still around average, perhaps a tad below

Further changes so occur through Tuesday/Weds as upper upper troughs track into the western Atlantic and eastern Europe triggering some amplification of the subtropical high in the Atlantic and it's European counterpart. All of which activates the low pressure area to the SW > SE of the UK which, acting in concert, move north.This increases the easterly flow across the UK and showers become more frequent and widespread  And feeling much colder, particularly in the south where colder air may sneak north from France. The showers will be of rain but possible some sleet/snow on the higher ground

And the NH profile at T120 which illustrates the change over the period and some tricky energy flows

 

 

 

[knocker]

Low cloud cleared in many places by 1130 but not down here. Broken St all morning

[knocker]

The 1400 surface chart/ The St finally cleared, now a classy afternoon with just a smidgen of small Cu

 

Edited November 17, 2018 by knocker

[knocker]

After wall to wall sunshine tomorrow strengthening easterly winds backing a tad with showers down eastern coastal regions according to this evening's gfs.

This becomes more accentuated on Tuesday as the contrasting energy flows merge the low pressure areas to the south

And more unsettled on Wednesday as the low pressure becomes more organized and the surface wind veering to the southerly quadrant

Edited November 17, 2018 by knocker

[knocker]

Outlook - unsettled, colder and cloudier

The NH profile and surface analysis for midnight

After a clear night some frost and fog patches around in some places but once that clears basically wall to wall sunshine with temps around average but feeling a little cooler in the fresh south easterly breeze in the south.

Through this evening and overnight it will stay clear in western regions but a weakening front moving in from the North Sea will bring cloud and patchy rain to the east.

During Monday the clearer weather will still be in the west as the cloud becomes more extensive and showers may well become more frequent as a cold front traverses the country which, although temps are still around average, is the gateway to the colder air in the now fresh easterly.

Over Monday night through Tuesday the two energy flows (much discussed previously) begin to merge the low pressure areas to the SW > SE of the UK and push it north which backs and strengthens the easterly with frequent squally showers, aided and abetted by a couple of convergence zones, in the east and south but also introduces colder air into France which does filter across the Channel. Feeling much colder generally

During the next couple of days, acting in concert, quite intense upper troughs track into the western Atlantic and down Eastern Europe whilst the Atlantic and European high pressure zones amplify either side of the low pressure adjacent to the UK which now broadly covers the whole of the latter

All of this results in a couple of days of unsettled weather with patchy rain/showers, perhaps more so in the south and west, and temps a tad below average but more so in the south

And the NH profile at T120

Edited November 18, 2018 by knocker

[knocker]

The 0800 surface chart. A lot of cloud here, including some Cu, drifting in off the Channel

[knocker]

The sat. image at 1220, Finally got rid of much of the cloud here and the wind easing at tad from  gusting 40mph earlier