UK meteorology

BM's snow is from the weakening front moving intermittently from the west on the FAX chart below. With the Met Office video I posted a few days ago and that PDF document, you should now be able to understand these FAX charts fairly well:

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More analysis:
A cold start tomorrow with a widespread quite severe frost followed by a cold bright day in most places but cloud and rain, snow on the high ground will spread into the north west around lunchtime. This associated with the front from the deep depression over Iceland which is trailing a long way to the south west along the flank of the ridge.



The movement of the front, cloud and rain south east is quite slow through Wednesday and overnight thanks in no small measure to the upper trough becoming positively tilted to the south propping up the ridge. But It appears to become activated with waves forming along it and by midnight Friday is across central England with leaving frequent wintry showers in it's wake.



The front finally clears by 1200 Friday leaving all of the UK in a colder Pm airstream with wintry showers in the north and west. But this is short lived as the next fronts are already impacting N/.Ireland and western Scotland by 12 Saturday with rain and gales.

 
Severe frost and cold bright day sounds about right so far. Proper nesh. Love these sort of Winter days though, bright and crisp.
We had a dusting of snow on the ground first thing but it's thawed now. Rather cloudy and drab here thanks to moisture from the North Sea. Here's Malcolm's post:

Today and tonight

A cold frosty start to the day and throughout England and Wales it will remain cold, dry and quite sunny through the day, the exceptions being the south east where wintry showers may persist as a dieing front lingers and the south west of Wales and Cornwall where the Pembroke Dangler may persist for a while. But cloud and rain, snow on the high ground, will encroach N. Ireland and western Scotland during the morning but as this moves slowly south east the front will weaken against the ridge leaving most of England and Wales dry.



Thus by morning another widespread frost in most parts of England and Wales but the warmer (relatively speaking) air behind the front is already affecting N.Ireland and Scotland Where there may also be some wintry showers.



Thursday through Friday

By 1200 Thursday the original front has fizzled out but the next system follows closely behind and by 1200 the triple point is over NW England with cloud and rain into central parts whilst N. Ireland and Scotland continue to get some blustery wintry showers,



The fronts continue to track south east through the rest of Thursday bringing patchy rain to central and southern England with the warm sector straddling the south by midnight. Clearly to be seen on the 850mb temp anomaly chart



The fronts eventually clear the south east by 1200 Friday leaving the UK in a strong and cold north westerly with frequent wintry showers in the north and west. But to the west in mid Atlantic a deep depression is en route for Iceland with an associated complex system of fronts north east bound for the UK with the added complication of a wave depression forming as well. The cloud and rain from the first set of fronts are approaching N. Ireland and western Scotland by 00 Saturday.



Over the next 24 hours the fronts track south east accompanied by rain and gales and the aforementioned wave has developed into an intense little depression and is 986mb over northern Scotland at same time which could well produce a fair whack of snow there


The ecm has a similar take for this weekend and one has to say it's not looking great with gales and rain.

 
More from Malcolm, who is concerned regarding the weekend:
Keeping an eye on this weekend

At Saturday 00 there is a deep low 963mb off south west Iceland with the associated warm front just to the west of N.Ireland and Scotland with the cold front trailing south west in mid ocean with a wave beginning to form.



By 1800 the warm front has tracked south east accompanied by rain and strong winds, perhaps gale force in northern and western areas, and the wave over N.Ireland and just about to develop into a nifty little low.



As can be seen over the next 24 hours it tracks east across southern Scotland into the North sea, deepening as it goes, Leaving the UK in a very cold north westerly airstream in it's wake and plenty of wintry showers, particularly in Scotland, N. Ireland and western regions with, I imagine, accumulations of snow in many areas in the north. It would not be a major surprise if the ecm varies in detail

 
Meanwhile, the ECM...
The ecm develops the wave a little quicker. At 1200 Saturday the warm front is lying down central England (not unusually the fax is a tad more complicated) with rain and strong winds affecting the western half of Britain.The developing wave on the cold front is west of Ireland. By midnight the warm front has cleared and the wave has developed into an enclosed low 980mb over Edinburgh and is accompanied by heavy rain in central Scotland and strong winds gusting 55kts in N. Ireland and north west England,. By 1200 Sunday it's off the coast of southern Norway 974mb and the UK is in a showery NW airstream.

 
Apologies for the delay:
Currently most of central southern, south east and eastern England are waking up to quite a hard frost, -5C in places, but warmer air is on it's way as a weakening warm front currently lying across Wales western parts of England brings cloud and patch drizzle/rain further east.before the precipitation dies out. But there is another frontal system lurking close behind which occludes as it crosses the country. This will bring heavier rain with it as it crosses the country west-east through the afternoon and evening. Leaving frequent wintry showers in the NW in it's wake.





The front and rain continuing south east during the night finally clearing during the morning whilst in the meantime a belt of snow is affecting the NW before that too finally clears in the morning. From there after Friday will be cold with frequent squally showers in the NW and W.



But by Saturday 00 (as discussed last night) there is a deep low adjacent to southwest Iceland with the associated warm front orientated N/S just west of N. Ireland and western Scotland with a wave forming on the cold front to the south west in mid Atlantic (the fax is a tad more complicated than this but best leave that aside)



By 1200 saturday the warm front has brought rain and strong winds to the western half of the UK whilst the little wave has developed and is 999mb west of Ireland. Over the next 12 hours it deepens as it crosses southern Scotland into the North Sea where it is 987mb at Sunday 00. This could bring snow on the high ground in the north whilst the front proceeds south east across England and Wales so a pretty wet and windy saturday.



Once all of this has cleared on Sunday the UK is in a cold NW airstream with frequent wintry showers in the west and north, many of snow before on Monday the next low and fronts are lined up to the west of Ireland but this must be left here.



Keeping in mind last night's anomalies the GEFS 2-7 this morning



The ecm treats the wave on Saturday a little differently. At 1800 Saturday it has it over a fairly broad area around the Irish sea 994mb but then takes it east to be over the Humber 985mb by Sunday 00. Thus the rain belt, as against snow. is further south

 
Current FAX output - decaying occlusion over East Anglia and the south-east, triple point (where the occlusion stops at present) far south-west Scotland, warm front north-west England and Wales, cold front Irish Sea, with another cold front and showery upper trough behind in the colder air over the Atlantic.
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Warning from Malcolm that the ECM is showing possible explosive cyclogenesis (at least 24mB drop for a low pressure in 24 hours):

According to the ecm there could be some quite strong winds across Wales and central southern Britain in the early hours of Sunday as the low deepens and moves into the North Sea gusting 50-55kts and a fair whack of rain.

It is also going in for some 'bombing'. A small wave depression is WNW of N. Ireland at T96 that tracks NE and NW as it rapidly deepens to be over Iceland 960mb at T120. the associated cold front with rain impacts Scotland, west Wales and Cornwall 0600 Tuesday having cleared N. Ireland with more strong winds, possible gale force

 
Today's post from Malcolm:
Today is pretty much of a mixed bag but essentially the main front and moderate rain is currently affecting south eastern regions but will clear during the morning to clearer colder conditions. But there is another band of patchy rain, sleet and possibly snow on the higher ground following on behind that will affect the SW, Wales, the Midlands and the north. Behind all of this squally wintry showers in N. Ireland, NW England and Scotland will be more widespread for a while and quite windy in places but later the showers will die out leaving a quiet night. Quite a cold day with a widespread frost overnight.





But as can be seen on the last fax the next set of fronts with cloud and rain are just about infringing on western Ireland by 00 and by 06 this has reached N. Ireland, NW England and Scotland where there may well be snow on the higher ground. But as can be seen a wave is forming on the front west of Ireland.



The fronts track south east across the country during saturday bringing rain to most parts accompanied by strong winds, possibly gale force in western areas whilst the wave deepens and tracks north east to be over N. Ireland 986mb by 1800.and then into the North Sea by 00 Sunday. If this turns out to be the precise track then perhaps blizzard conditions for a while in N. Scotland.



By 1200 Sunday the low is over south west Norway, having brought with it some very nasty conditions in the northern North Sea on it's travels, leaving the UK in a cold north westerly airstream with frequent wintry showers of just about everything in western and northern areas, This continues over the next 24 hours to 1200 Monday although the wind will gradually back westerly



As can be seen on the last chart there is a deep low 975mb south of Iceland with associated fronts trailing south west. The low deepens rapidly to be 955mb east of Iceland by 00 Tuesday with the front already impacting Scotland (where the precipitation could fall as snow) and N. Ireland and again bringing strong winds, possible gale force. But it's quite a complicated scenario with the colder air sweeping east behind the front which actually trails a long way south west along the interface between the colder air ( upper trough) and the high pressure to the south. And along this intyerface, as can be seen, lows are forming.



What happens next as the front tracks south east across the UK is not without interest but there we must leave it.


And the ecm charts for T24,48 7 72

Certainly not looking great tomorrow,

 
This evening's view:
After a quiet and cold night we arrive at this analysis at 06 tomorrow. A deep low Iceland with associated fronts already impacting western Scotland and Ireland with rain and a wave forming on further fronts west of southern Ireland.



During the next 12 hours the fronts and rain, heavy at times, track south east across the UK accompanied by strong winds in the west, perhaps reaching gale force whilst the wave becomes more organized and nips NE to be over N. Ireland 992mb at 1800.



This will bring more heavy rain, and strong winds, as it tracks across in to the North Sea still deepening, and perhaps snow in the north, Leaving behind in it's wake frequent wintry showers as the cold Pm air, that can be readily seen on the earlier chart, encroaches.

 
Today's post:
The band of rain (perhaps some snow on high ground in the north) associated with the frontal system expected today is currently lying south west Scotland, N. Ireland, NW England, Wales and the south west whilst there is a widespread frost to the east. And the wave expected later is currently getting organized away the south west. During the day the band of patchy rain will move SE with clearer weather behind but by 1600 the wave has arrived over N. Ireland bringing more heavy rain in the north and snow on the higher ground in Scotland and the north of England



The wave continues to deepen as it tracks into the North sea whilst the front tracks SE bringing more patchy rain in England and Wales. The rain more persistent in the north and much of it could be of snow over the higher ground in Scotland and the north of England and accompanied by high winds, perhaps gale force, across N. Wales and the central belt of England. Once the low has moved further east the UK will be in cold north westerly airstream with frequent wintry showers of just about everything concentrated in Scotland and western coastal areas.



The showery and cold north westerly continues overnight but by 1200 Monday the wind has backed westerly as a front associated with another deep low is approaching from the west Over the next 12 hours the low deepens to 960mb and tracks north over Iceland at Tuesday 00 whilst the front brings rain, snow in the north, and strong winds to the UK



The front clears by 1200 on Tuesday but during it's travels it develops a wave which impacts the north and could well bring a fair amount of snow to Scotland and the north of England, particularly on the high ground.



Stepping back a little now to get a quick overview, there is a complex cold upper trough dominating the Atlantic with a strong thermal gradient and thus an ideal breeding ground for some very active cyclogenesis and this is what we get. At Wednesday 00 there is a very deep low in mid Atlantic with the warm front SW Ireland to Cornwall.



Twelve hours later the low has deepened to 947mb south of Iceland and the front has brought rain, snow in the north, and gales to the UK




Some spot charts from the ecm essentially in support of the above post



 
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