UK meteorology

I'm ready for the beast from the east, bring it on! I laugh at inclement weather, ha ha! :)
You were saying how much you hated snow the other week!:p
Anyway, here's a snow-hater (Malcolm) with his 72 hour thoughts:
As I'm sure everybody is aware the UK is in the process of moving into a colder regime so for the this period we will mainly be looking east, but not exclusively, and a general overview is gradually getting colder, becoming very cold by the end of the period with snow showers becoming more widespread in the east and south.

A tad more detail. Once early fog has cleared today will be mainly sunny with light winds as the ridge dominates and feeling colder in the south where the easterly wind is picking up. The exception being the far north west where the cold front is very adjacent where it will also a be a littler warmer (relatively) in the south westerly wind. It will even bring some patchy rain later and tonight before clearing and by morning the will be a hard frost generally.



Friday will be another clear and sunny day with temps struggling to 5-6C but the with the the ESE wind increasing the wind chill becomes a bigger factor so by 1800 we have this scenario. It is worth noting here that the front(s) and warmer air have made inroads a fair way east north of the UK reaching as far as the Norwegian coast as the gfs makes more of this later.



Saturday portends another clear and cold day but by 1800 a shallow low/wave has formed on a front over the Norwegian coast and becomes something of interest as we move into next week.



By Sunday 1800 this feature is tracking slowly SWS and the colder air in the east is moving steadily west so the wind chill factor is increasing over the UK as is also the likelihood of snow showers in the east and south which may well spread a fair way inland.



By Tuesday 00 the low is in the North Sea which does mean an easing of the easterly flow for a time but by this time it's bitterly cold over the UK



A just a note about model temps. At no time should they be taken as definitve
Regarding the shallow wave over the Norwegian coast the updated fax charts show a weakening occlusion in the area. Not to make too much of this

 
I haven't got much time this morning, but here are Malcolm's thoughts:
over the next few days the much colder weather moving across the UK from the east will become established and the general outlook relatively straightforward albeit the detail might be slightly more elusive as the days progress. Essentially most areas will be dry with plenty of sunshine but getting increasingly colder with some widespread hard to severe morning frosts and with the easterly wind picking up an increasing wind chill factor particularly in the south. Initially perhaps some isolated snow flurries in the east but becoming more frequent and heavier by the beginning of next week but mainly affecting the east and central areas.It's the detail of this that is harder to pin down and to some extent will depend on the precise wind direction.

So a little more detail.

Today and tonight dry, sunny and clear, with the wind a tad south of east, leading to a widespread frost by morning.



After the frosty start Saturday will also be dry and cold and with the wind picking up the wind chill increasing. Max temps in the 5-6C range.



Another cold night and widespread frost on Sunday morning thus heralding another dry and sunny day but getting increasingly colder with max temps in the 3-4C rage in the very brisk wind wind chill again becoming increasingly important. The wind tending to back a shade that could well impact the location, including the range inland, of snow showers as they perhaps become more frequent. This is not yet a precise science.



Similar story overnight into Monday but a more severe and widespread frost by morning and generally a much colder day with temps struggling to reach 2C and in the strong wind which is now easterly feeling bitterly cold. Some slight complication here in the north where the small disturbance over southern Norway may well influence the onshore flow in the north east. By now snow showers in the east will become more frequent and widespread and will become a radar watching issue.



Into Tuesday and a similar scenario, beginning to sound like a stuck record, and getting colder with temps in many places struggling to get above freezing so feeling bitterly cold and in the strong easterly the snow showers more frequent and probably reaching further inland and still concentrated in eastern and central areas.but not ruled out in other areas of course.Thus by Wednesday 00 the very cold air is well established



Perhaps worth a look at the 500nb pattern before we leave it and note the low to the south west


The ecm has a more pronounced wave feature just east of Newcastle at Monday 00 which it tracks SW to be over Liverpool by 06 Tuesday. It could well bring a more concentrated belt of snow with it. And actually the gfs is not dissimilar

 
Malcolm's post. Don't worry about the two forecast soundings; I don't fully understand them yet - the first one shows that the temperatures at 850hPa aren't much colder than at ground level, and the one at the end shows the tropopause (the boundary between the troposphere and stratosphere) at 450hPa pressure height where normally it would be around the 300hPa pressure height, indicating low heights, which you might recall indicates a cold airmass:
Despite a widespread hard frost this morning the UK is still in the warmer air as can readily be seen by glancing at the 00 sounding for Nottingham where the 850mb temp is a mere 2C less than the surface. From here a sunny day for most with temps rising to the 5-6C region but there may well be some cloud in the south west, N. Ireland and western Scotland. Feeling cold in the easterly wind.



A clear night leading to another widespread frost tomorrow morning and another dry and mainly sunny day but temps struggling in the east to get to 3C as the colder air now starts to encroach (the forecast sounding in East Anglia shows the much colder air aloft) and feeling very cold as the easterly wind picks up a tad with some snow flurries in the east.





From this point the UK is well and truly into the cold easterly regime and starting to feel bitterly cold with a significant wind chill factor but also with some complications over Monday and Tuesday involving the little wave tracking south west from southern Norway into Ireland that has been discussed previously.This could well bring a more concentrated area of snow showers mainly affecting the North East whilst at the same time with the easterly wind pepping up snow showers becoming heavier and more frequent in the east and spreading further inland. Snow showers may also run up the channel.







Wednesday a bitterly cold day in the strong easterly wind with temps in many places not getting above freezing with heavy snow showers in the east common place but the interface between the warmer and cold air is still apparent over southern Norway.



And just look at the temp profile now with the tropopause down around 450mb
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The ecm has the little wave feature over the Humber at 0600 Tuesday and south Wales by 1200 and then NW of Cornwall by 1800. This could be accompanied by more concentrated snow showers from the Humber through the Midlands to south Wales and a also a line of showers across the south east and up the Channel.

And prior to that over Monday according to the fax update a weakening cold front traverses the country east-west which probably accounts for the increased snow shower activity.

 
Something extra from Malcolm - from yesterday evening - the anomalies (don't worry about the charts if you're not sure how to interpret them, though they're not hard to understand if you take some time; the red areas represent higher than average pressure with higher heopotential heights, and blue represents lower than average heights):
Further movement of the upper pattern this evening vis the anomalies as it continues to evolve. Although not total agreement they are all very much in the same ball park. The intense high cell continues it's westward drift to be over the coast of north east Canada accompanied by an intensification of the vortex over northern Russia. And although the Atlantic is still dominated by the upper trough the subsiduary center that was over the UK has weakened considerably and moved west of the UK leaving a very slack gradient from the northern half of the UK west into the central Atlantic. Energy leaving the eastern seaboard runs east under this and south, or not, of the UK. How far north this will track is rather the key question because that will dictate the movement and intensity of surface lows so over to the det runs. And until that is decided temperature forecast are a bit of a lottery although remaining below average is a safe play.

 
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Usual post, though from midnight rather than 7 am:
...later today the very cold air will arrive from the east bearing gifts, wanted or unwanted depending on your inclination. Thus from tonight and through the next few days the ideal convection conditions will breed an increasing number of snow showers which will spread further afield than the eastern parts of the UK in the strong wind and at times be more concentrated as small disturbances run west in the flow. Plus it will be bitterly cold which the strong wind will exacerbate giving a very high wind chill. Snow accumulation will increase and spread during this period but will be impossible to accurately forecast so down mainly to observation. Anyway enough waffle

Today a clear cold day with maybe some patchy cloud and a cold night with a widespread hard frost by morning The GFS-WRF on the snow showers and a forecast sounding for tomorrow illustrating the much colder air.







Another very cold night and a severe frost Tuesday morning but the much mentioned wave feature tracks south west overnight and through Tuesday morning and brings more concentrated snow showers along the route as indicated with the charts.





Another very cold night with a severe frost Wednesday morning heralding a bitterly cold day with extensive snow showers but changes are afoot, The blocking high cell gears up and starts to move west which allows the Atlantic upper trough(s) to nudge in from the south west with the associated surface low west of Iberia by 1800.



Another bitterly cold day on Thursday but the surface low is now taking closer order with much warmer air entering the mix with the possibility of frontal snow and blizzard conditions for the south west. Have to leave it there



This is of course according to the gfs
The ecm take on the low and the 1-5 850mb temp contour and anomaly



 
Until Thursday, I'd suggest you might want to check the Met Office site for weather warnings related to snow coming in from the North Sea. I might not be able to post them all as there may be quite a few and because my dad is unwell at present - he has a GP appointment on Tuesday at which point we might know a touch more.
 
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