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Winter 2009 / 2010 in Western Europe?

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Author Topic: Winter 2009 / 2010 in Western Europe?  (Read 18268 times)
paulster78
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« Reply #405 on: February 17, 2010, 10:13:58 pm »

They even admitted on bbc newsline this evening that the snow today had caught them out, lol thats why i love the weather so much-its unpredictability!  Traffic chaos here with the morning rushhour a nightmare, I heard of a 4-5 mile queue of traffic on the Dromore to Irvinestown road that was simply going nowhere and the police were stopping traffic on other roads and telling them to turn around and go home!   Back to normal now with a good thaw during the day but freezing fog has formed now with ice a danger.     
          Impressive amount of lightning out in the Atlantic alright with a few recent strikes off the coast of mayo-will definitely be monitoring the weather over the next few days Smiley
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« Reply #406 on: February 17, 2010, 11:49:20 pm »

Looked like a great show Paul, when I was watching it on the radar I wished I was there incase there was lightning.

fri, Sat, Sun has unstable air over Ireland/N. Ireland, certainly looks interesting at this range. Heavy showers of rain, hail, or snow with a risk of thunderstorms in W, NW and SW areas. Time will tell though. Maybe time to start the first convective thread of 2010. Netweather have a forecast out for far W Ireland shore regions and S Britain Thurs.

http://www.netweather.tv/index.cgi?action=convective;sess=
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« Reply #407 on: February 18, 2010, 01:29:07 pm »

Good convection going up here today. Fantastic tall, crisp/solid updraught towers, in fact the best I have ever seen in Feb.
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« Reply #408 on: February 18, 2010, 01:56:55 pm »

The frost and fog has only just cleared here in the last hour, very hard frost last night. I think I can just make out the top of some convective clouds to my N-N/E.
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« Reply #409 on: February 19, 2010, 09:03:03 pm »

Just seen a bright blue flash of lightning tonight among the stars, must have been very distant though because there was barely a cloud in the sky, possibly from the NE or E direction.

Earlier today we had some pretty decent cold air convection with impressive large cbs with good anvils to the N, NE, and S, SE. The two cells S of Slieve Gallion, in the Cookstown and Lough Neagh region, looked the best of the day with tall anvils and an overshooting top, all of which looked impressive for this time of year this far inland.

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« Reply #410 on: February 20, 2010, 10:23:32 am »

Getting really fed up of this .... solid cloud with intermittent hail (yesterday) / snow (overnight) despite forcast for "clear sky". In the gaps between the showers the sky is filled with a solid mass of high cloud, probably overgrown CuNim anvils.

About an inch of snow on the ground this morning.
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« Reply #411 on: February 20, 2010, 12:40:04 pm »

hi from weathor!!! Smiley Smiley Cheesy

Will it snow tomorrow??
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« Reply #412 on: February 20, 2010, 06:00:50 pm »

Where are you from Weathor?

There's still snow on Glenshane today and ice in the forest. Forecast for next week is VERY interesting for parts of UK and Ireland. There could be a major/severe snow event for some!
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« Reply #413 on: February 20, 2010, 06:05:29 pm »

Cyclonic cold weather continues over the British Isles.  Positive contour heights continue to stretch from Eastern Canada to the Greenland Plateau whilst a deep longwave trough extends from Novaya Zemlya to west of the British Isles.  This is pushing a continued cold feed of air SW just to the NW of the UK whilst Atlantic Mobility is being driven east by a strong Jet stream unusually far south nr 35N - with an effective combining of both the Subtropical and Polar Front Jets to create a highly unsettled Zonal flow from the Azores to Italy.  Postive rising of contour heights is then seen over SE Europe with rather warm conditions persisting over SE Europe and the Middle East.  Little change in the overall pattern is expected in the short term.

Detail:

Snow showers are running into parts of the UK at present, morning snow showers have given a covering in parts of the SW, but are largely fading as they move into dry air over CS England.   WBFL in the far SW are between 200-400m (365M on Camborne 00Z Ascent) but fall off as you move NE .   Snow showers are persistent and heavy around the West and NE of Scotland this morning giving several CMs of Snow. Elsewhere Snow Showers are running down the north sea, perhaps clipping Norfolk, and there are lots of rain/hail showers in the English Channel affecting the Channel Islands.

Elswhere largely fine and sunny. HRV imagery confirming where the snow is lying, coastal fringes of NE & E England, Central and North Scotlan, a good part of Wales and parts still of Central England and the SW.

The evolution over the coming few days is highly complex, as the longwave, various shortwaves embedded in the Longwave and the Atlantic all combine to produce some very unsettled and for some very snowy/wet weather, Atlantic systems being diverted a little further NW than last week as heights build over N Africa, causing the Jet to buckle a little.

WV Imagery over the Atlantic, shows a highly complex duplex of systems, which does not inspire confidence, given the rather data coverage in the area, which is born out by the rather scattergun solutions seen by models of low centres over the coming days.  Whilst there is good agreement on the overall synoptic pattern, detail in the individual low centres is moderate at best and for most of time rather low.

The first of these developments takes place tonight as a shortwave rounds the base of the longwave trough and heads towards the UK, at the same time a W Jet develops over the S of the UK and this enduces pressre falls and increased baroclinicty over the Central and Southern parts of the UK.  There is scope for error on which areas are affected.  The mini low develops over SE Ireland this evening and transfers east on the north (cold) side of the developing Jet over the South, increased forced ascent develops both convective and stratiform elements and an area of rain/sleet and snow develops and moves east.  The GFS and now 06 NAE take the main thrust of the precip 50-100miles further north than the 00Z NAE or the 00Z ECWMF, which were preferring a route through Central areas of Wales into the Midlands.  The 06Z GFS and 06Z NAE both prefer to keep the main snow threat across Mid and N Wales and into N England into the Peak District.  Areas further south are in slightly less cold air and therefore see rain and not snow.  Though it has to be pointed out that the system crosses at night and that WBFL's could be dragged down in any heavier precip cores, so that anywhere north of the M4 corridor is at risk of seeing some snow overnight, though your chances are higher if you live further north.  Both models target Lincs into Yorks and across the Pennines as higher risk areas.  Though with the ECM running it further south and highest accumulations from MidWales across Midlands to Lincs - clearly confidence is not high.  2-5cm the main order of any accumulations

The front moving into the SE stalls later tomorrow through the English Channel and then returns north on Monday in assoc with the complex low moving NE from the Azores, there have been a multitude of solutions for this low.  Its a very complex affair as a subtropical airmass combines with a much colder one - there is considerable uncertainty as to what lows form when. There is now reasonable agreement on the track of Monday's low - roughly following the same path as Thursday's low. (from South DEvon across CS England to the East Anglian Coast), Rain returns to southern england during the morning and turns to snow across SE Wales, the Midlands and Eastern England during the day.  Rather less heavy than previously mean WBFLs up a bit and Sleet/Snow will be mainly above 100-150m, but occasionally penetrating to lower levels.  Hills of SE Wales and the Midlands look most at risk - generally 2-5cm.

BEyond Monday - models now seem keener on the idea of running a 2nd low across the UK (effectively the back low in the complex west of the Azores) , this low deepens and fills a little at least twice in the coming period as various jets and shortwaves engage it.   There is therefore considerable disagreement on its exact location and depth when it arrives over the UK, though there now appears at least moderate confidence of it coming into the SW and moving ENE to emerge from the coast of Eastern England by midweek.  However Ensembles give locations from NW ireland to NE france as positions of this low. Again on its N Flank Sleet and Snow will fall as colder air in place will be dragged into the circulation. Both the 00z GM and 00Z ECMWF were deep - the ECM having a 965mb low over PEmbrokeshire by T+90 with a wide arc of Snow spreading into N England and S Scotland.   The threat of widespread snow in the SE appears to have receded on the 00Z and 06Z Solutions... with N England the targetted area on both the 00 & o6 models.  All models slow the low as it emerges from the East Coast meaning 10-20cm is possible across hilly parts of the north midweek and heavy rain further SE.  (ECM has 60Knt Gusts moving into the English Channel Midweek)

BEyond that there are yet more lows which cross the UK bringing more rain and snow to the UK, and whilst the detail is changing run to run - the overall theme remains consistent and for which there is reasonably high confidence in that the cold cyclonic spell continues for some time yet.

Paul Blight
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« Reply #414 on: February 20, 2010, 06:06:20 pm »

FORECAST FOR Monday 22nd February- Sunday 29th February 2010

ISSUED 20th February 1230Z

POTENTIALLY SEVERE WEATHER OVER THE PERIOD- Heavy snow across parts of N Wales & the N Midlands and N England (and possibly S Scotland) from Monday right through to Friday 

--------------------------------------------------------------------------------

WEEKLY SUMMARY
A complex low moves north on Monday across southern parts with rain here and snow further north with a further deep low pressure area moving into the SW on Tuesday and running ENE. On its northern flank more sleet and snow is likely with the risk of gales in the far SW. After midweek yet more low pressure areas seem likely to cross the UK bringing more rain with some further snow over hills, keeping us in a highly changeable cyclonic period right through until Friday though a short break may occur early next weekend as a weak ridge develops before more unsettled weather pushes into the SW & west later.

Monday 22nd looks likely to see rather deep low pressure slowly fill as it runs across the south. Wet to start then here with some heavy rain in places at first. A cold start further north with an early frost at first, localised freezing fog and icy patches almost anywhere away from coasts.  Scottish glens will again be especially cold. Anywhere north of the M4 into the central Midland may see either sleet and snow by dawn with moderate accumulations in places, esp over hills along with icy patches and poor visibilities. Mainly cloudy by day across N England and N Wales with some light sleet or snow at times away from coasts. The fog mist and cloud clearing slowly further north to give some sunny periods. Another frost with a few freezing mist or fog patches reforming by evening in much of inland Scotland with icy patches also, when any cloud clears away, generally though staying cloudier for most further south with some light rain or sleet at times, this only very slowly clearing away eastwards, and it will likely persist across the far south, south east and east Anglia. Temperatures near average at 5-6C in most southern areas today, may be up to 8C in the far SW, but only 1-2C in the north and 0C across upland areas of the UK such as the Highlands.

Tuesday 23rd will probably see the low near to southern England along with a slow moving frontal band of rain. Wales & central & Northern England & S Scotland still cloudy with light rain or sleet at times though central & N Scotland will likely see a moderate frost with some freezing fog to start in a weak easterly flow before sunny periods develop. By day the front pepping up a bit as another low in the SW moves NE, giving further rain here as well as across the south of England and S Wales with sleet and some hill snow in places north of the M4 corridor. A slight or moderate frost with some freezing fog patches returning to central and N Scotland later. Further south the sleet -or in places snow -band pushing slowly north still, giving locally heavy snow at times across N England with some accumulations along with icy patches and poor visibilities. Temperatures generally staying below average in central and northern parts along with Wales at 1 to 4C but only -1C in the Highlands but up to 5-6C in the south east and east Anglia and 9C along the SW & southern coasts.

Wednesday 24th looks likely to see the low centred across southern parts slowly moving away into the N Sea leaving most parts of the north in a weak N’ly or NE’ly flow, but a stronger W-NW’ly further south. Some shower bands of wintry pptn may occur throughout the period over N  Scotland along with N Ireland esp close to coasts. A very frosty start for many here too with icy patches about. Mainly though a dull cloudy day with periods of rain across the S Midlands and S Wales dying out only  slowly with some sunny periods developing in the west. Always cloudier in the east & south east with some persistent rain or sleet about, perhaps heaviest in eastern coastal counties, esp for a time later. By evening a slight-moderate frost setting in again after dusk in many inland northern areas, esp the Scottish highlands with some freezing fog patches too but staying cloudier in the south, SE and SW so no frost here. Temperatures feeling quite raw at 1-3C in most northern & central parts though in the south, SE & SW more like 5-7C though only -1C over the Scottish Highlands.

Thursday 25th looks likely to see low pressure to east and a col across the Uk for a time as further low pressure moves towards the SW later. A moderate frost possible at first away from coasts in the north, possibly some freezing mist or fog patches about but cloudy with rain sleet or snow generally at times in the east until the early afternoon with a few showery outbreaks, in north western areas too. By day through most northern, central & western parts quite dry with sunny periods. Another moderate or severe frost setting in, with some localised freezing mist & fog patches, for many northern areas inland after dusk. More rain working into the SW by late afternoon as fronts move NE, heavy in places, with further wintry showers about in the far north. As the rain reaches areas north of the M4 corridor by evening it may well turn to sleet & snow from Wales east towards Berkshire, giving moderate falls in places, esp over hills, in a rather strong E-SE’ly wind. Max temperatures about 1-4C generally but up to 5C in the south and 8C in the far SW but only -2C across the higher ground of Scotland

Friday 26th seems likely to see the area of low pressure move across the southern UK or Midlands but the detail is very unclear . An early frost and freezing mist patches inland in the north especially severe over some Highland glens. A lot of cloud about in central areas with some sleet and l snow giving accumulations in places. Generally drier and bright in Scotland and N Ireland by day but the south and SE of England a bit drier but cloudy and milder. Another frost by evening in the far north but mainly too cloudy for this elsewhere as the outbreaks of rain sleet & snow  continue in central parts especially with a risk of continuing accumulations in places.  Temperatures generally 5-7C by day in the south though up to 9C around the SW coastal counties but more like 1-4C in central and northern parts and -1C over the Highlands.

Saturday 27th and Sunday 28th seem likely to initially see low pressure move away east taking its rain, sleet and snow away too and there’s a suggestion a weak ridge of high pressure may affect many areas on Saturday. So quite cold by night as cloud clears with slight-moderate frosts & freezing mist & fog patches inland in places away from coasts, mins generally as low as -4C to -2C but the Highlands and prone areas esp valleys inland across Northern England may see as low as -8C. Generally bright by day after early low cloud and freezing fog clears away but the risk of some wintry showers at times on Saturday in the far north and the far SW though these more likely to be of rain & hail here. Sunday may see the weak ridge push away east across to the eastern UK after an early frost and freezing fog patches quite widely inland before more rain pushes into the SW & west later possibly turning to sleet or snow in places as it pushes NE later on but leaves many parts in the east with a reasonably dry, fairly sunny day.  Temperatures over the weekend by day will likely be rather cold for most northern areas at 2C to 4C, possibly only -1C in the Highlands but more like 4-7C in the south, SW, S & W Wales & N Ireland. 

FEATURES TO MONITOR THIS WEEK

*Some fog or freezing fog patches, mist and low cloud inland through the week & weekend esp in northern & western parts
*Some moderate-severe frosts overnight more esp in northern parts with icy patches at times if there’s any standing water
*Wintry outbreaks with some snow about from the M4 north more esp over hills and more generally in central and N Wales, N Midlands & N England, with some moderate accumulations in places likely along with drifting at times in strong winds

FORECAST CONFIDENCE is strong for the patterning but moderate becoming moderate-poor for detail by Thursday onwards

Dave Wiseman
UKww Executive/C & M Manager/Warnings team
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markt
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« Reply #415 on: February 20, 2010, 11:25:52 pm »

Thanks for the overviews Martin - I enjoy reading them!

Well there's been more snow here at home than there has in Iceland this winter (just cold and dry there) - will be interesting to see what pans out for the week ahead!
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« Reply #416 on: February 21, 2010, 04:33:24 pm »

10Z Update -21Feb

Developments overnight planned out much as expected, though with slightly more Snow over N Ireland and far SW Scotland than expected, though accumulations are quite small in general.  Overnight a 110Knt Jet has developed over Southern Britain, this has created increased surface and upper baroclinicity across the UK.  At the jets left exit diffluence zone a small surface depression has developed.  This currently over N Wales and will move ENE and slowly fll as the Jet moves away.  The increased ascent has occured at night with a cold airmass firmly in place over the Northern half of the UK, hence we have seen heavy Snow developing.  2-5cm generally, but reports of 6-9cm in a few places.  At 09Z both the 12KM NAE and 16KM ECWMF have a good grasp of the precip zone which stretches from E N Ireland to Morcambe Bay acrtoss through Leeds to Hull and down to tCambridge and Suffolk.  Its largely rain south of 52N. Heavy Rain has moved across the more southern Counties overnight.

The Snow will continue to push E and NE through today, tending to become lighter and turning to rain over lower levels with time, though several CMS to come across N England. Rain hanging on close to the SE and infact ECM is not keen to clear from far SE at all today, hinting at a return of some precip to Hants, Sussex and Kent later today. NAE is similar and hints at outbreaks of showery rain returning from Portland Eastwards this afternoon.

Tonight most places become dry and clear with another cold night across Scotland and N England under Clear Skies and Snowcover (ECM has temps below -12C again across Scotland and below -8C across N England)

However cloud persists further south as another depression approaches. This one again has the potential to bring more snow to Wales, Midlands and Eastern England.  The 00Z GM, NAE, GFS all bring the low through the English Channel nr the English Side, However the 16KM ECMWF brings it ENE closer to the FRench side effectively shunting the precip further SE away from the Midlands and confining it to SE England with Snow threat reduced and confined to the Chilterns largely.   The Hirlam is similar to the ECMWF (though this not surprising as it gets its boundary data from that model)

I do not like going against the ECMWF, but given the available evidence from just about every other model has the precip further NE and as the NAE has done a superb job with the Snow overnight, its hard not to do anything else, but with lower confidence than normal for a 36hr forecast.

So rain comes back into the south later tonight and spreads ENE tomorrow, and turns to snow from SE Wales, across the Midlands into E England.  NAE quite bullish about a period of Mod Snow developing giving generally 2-5cm on low ground and 4-10cm on ground above 150m. Heavy rain in the south for a time.  It should be noted the huge discrepancies between Models (GFS has precip reaching Manchester and ECM barely has it north of London, though the NCEP experimental FIM has it more like the NAE)

Another low comes towards the SW on Tuesday (this one the 2nd low currently north of the Azores).  All models return north the frontal band on Tues. However because the ECM has not dragged as much milder air north (for reasons above on Monday) it is quicker to turn it to snow on Tues.  The GFS which has the greatest incurson of milder air is slower to turn to snow *(an example of where early errors in a forecast can lead to further problems down the line) The ECM turn the rain to snow more bullishly on Tues across Inland Southern England, S Wales, Midlands to produce a snowy afternoon indeed across Central areas. Another 3-6cm possible as it pushes north. 

The Snow pushes on North into N England and N Ireland with less cold air moving norht for a time and lots of heavy rain/showers across the south as a deep low moves through the Channel Hail and Thunder possible into Weds across the South.

Beyond that, another strenthening Jet Core comes across the Atlantic and develops another low close to the AZores in the highly embryonic area of the north Atlantic, this low turns NE and heads towards the South of England.  There is perhaps not surprisingly another mirrad of solutions for this low, from winding up to the West of the UK to running across N FRance. 

The UKMO GM, ECMWF and NCEP experimental FIM run the low through the Channel (Operational GFS has it further NW), which engages cold air again and sucks it into the Depression.  More rain moving into the South and turning to Snow across Wales, Midlands and East Anglia (and Southern England if ECM is correct)

However given we have problems with the detail 24hrs ahead - we can have very little confidence in the forecast for 120Hrs, except to say it looks like staying very unsettled and cyclonic with a good deal of Snow for many - esp northern parts.

EDit - 06Z GFS is more like 00Z NAE and increases the Snow signal over the Midlands tomorrow. However NAE has moved SE too and is moving closer to ECM ( only has 5mm North of Oxford vs 19mm in 00Z)  Clearly there is scope for sig errors in the forecast, but the trend is clearly SE, but it may be the SOuth Midlands & Northern parts of Southern England are at risk of Snow.

P Blight 09:53
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Martin Mc Kenna
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« Reply #417 on: February 21, 2010, 04:34:07 pm »

SE parts of N. Ireland had 4" of snow this morning, that caught the forecasters off guard.
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« Reply #418 on: February 21, 2010, 08:55:27 pm »

Wednesday looks interesting Martin.
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« Reply #419 on: February 22, 2010, 08:21:39 pm »

19Z Update - 22 Feb 2010

General Situation

Synoptically nothing is changing fast. Aloft, a large high is located over Greenland and the Davis Straights into Eastern Canada. A deep trough is extending SW from the Barents Sea to West of the UK and a very strong combined Polar Front and Subtropical Jet covers the Atlantic and European Sectors (140Knts West of Maderia at 12z)

Over the coming days, little changes to the NW of the UK, but 300  &500mb heights rise over N Africa and the Med over the coming days forcing the Jet to veer towards the UK, this means it becomes less cold across the South of the UK, but with low level cold ever never too far away we can expect further snow - esp mid week over Northern parts of the UK.

The 500mbn pattern becomes less zonal with time over the Atlantic sector as more meridionality is returned.

Possible Severe Weather

Heavy Snow for Northern Parts on Weds / Thurs and Heavy Rain for the South

Discussion

Today's snow was quite extensive this morning - but weakened this afternoon. Still some heavy rain cl.ose to the Sussex and Kent coasts thisd evening, but largely clear and cold tonight across the north , this colder air advecting south again overnight and getting as far as about the M4. Another very cold night across Scotland. Still Snow showers around the North and NE of Scotland.

Main next event is the next frontal system coming into the South and moving north.  The frontal timing has continued to slow on succussive, GFS, NAE and ECM runs, but confidence is reasonably high for a fairly snowy spell of weather on Weds/Thurs across first Northern England and then Scotland. 

Tomorrow rain comes back into the South with WBFL, largely above 600m, however this falls into increasingly cold air which will be in place across Wales, Midlands and N England, it turns to snow over the Welsh Hills above 150m-200m and then expands NE as the thermal divide across the front increases.  Precip intensitiies pick up and both the GFS and NAE and inferred precip amounts in the ECM generate a fairly extensive spell of Snow later tomorrow into the evening across the Midlands, Wales and N England, most accumulations above 200m, and turning to rain from the south with time.   2-5cm in places, and up to 10cm over 200m or so esp N Wales, Peaks and PEnnines.

Much less cold - WBFL above 1000m move into the South on Weds, but it still stays very unsettled as the deep convective low (nr 20W) moves east along the SOuth Coast.  Models in agreement for some very heavy rain, hail and Thunder to move east giving local flooding in places.  At the same The snow pushes North into N Ireland, S Scotland giving several cms in places and the front actually slows down and the warmer air occludes out to the east, hence we keep cold air in the north maintaining the risk of Sleet and Snow right into Thursday. (though by then largely Scotland only)

Another deep depression with origins well south of 40N comes NE on Thursday and moves close to the South Coast again Around 975mbs overnight into Friday , another very heavy band of Rain comes NE (another 20mm possible) and this band then pushes N to rejuvenate the oclcusion by then almost stationary across Scotland giving more snow.  On Friday , the cold air spills back South again and the rain turns to Snow again across parts of N England and N Ireland

Windy at times in the South, though the strongest winds occuring over the Channel Islands and N France .

Beyond the end of the week, there has been discrepancies in the handling of an extremely low latitude low which moves ENE, then NE towards Western Europe.  Various models have deepened/ Not deepened this low depending on its speed NW at the same time as an active shortwave runs SE towards Iberia.  This low develops NE of Puerto Rico in the relatively deep tropics and moves ENE towards Maderia and the Canary Islands before turning NE, and deepening as it engages both an active shortwave and two Jets.  The low on the 12Z Models interacts with the LEft exit of a propogating NW;'ly Jet diving south of the Azores and the right entrance of a SW'ly Jet over the SW Approaches and English Channel.  This combination allows for massive amounts of upper level diflfuence and allows large scale ascent to take place forcing the low to deepen potentially explosively.  It will also have PVA and a large thermal divide(  Deep layer PM air diving SE and warm Subtropical air riding NE) (Theta W across the low goes from sub 6C to > 12C creating a huge amount of precipitation. 

12Z Models are in actual good agreement over the low, with it coming NE west of Iberia.  GFS has it furthest NW (earlier deepening) and pushes it across the SE of England, whereas the ECM and UKMO GM keep it over NE France (both have a deep low coming NE across NC France at T+144, ECM then moves it into Holland slowly filling) IN the GFS solution the low is closer to the cold air over Scotland and sucks it SE into the Low and the precip turns to Snow, however the more eastern movement in the ECM and the faster movement, means this struggles to occur.  Anyway - lots will change before thisd occurs - however the development needs watching

Paul Blight
UKww Manager - Education/Warnings
Associate Fellow Royal Meteorological Society
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