Winter 2009 / 2010 in Western Europe?

[martinastro]

Me too Mark. I bet the thaw will be a very messy affair

Accident on Coleraine Road not far from my estate, there's a car on its roof, it must have slide on the snow/ice, the road sign was struck hard before it rolled. Don't know of any injuries, Police and Ambulance are not at the scene yet.

[paulster78]

By all accounts an exciting week ahead then weatherwise, a reliable long term forecast is hard to pin down at the minute with so many variables in the picture- but snow definitely looks on the cards over the next 48hrs .  Had another dusting of snow here this afternoon and today was another ice day.

Excellent shot of the sunset by the river Martin, it looks sooooo cold!

Jez hope everyone ok there, really bad smash outside Omagh this week 2 young lads killed-there was bad fog at the time, very sad.

[martinastro]

UKww Weather Warning – Ice, heavy snow spreading to many areas

Valid from: 0800z Saturday 9th - 00z Tuesday 12th January 2010

Areas affected: Ice - all areas. Snow - Scotland at first; England, Wales, Northern Ireland later.

General evolution: Currently, an anticyclone centered 1042mb over Norway has an extension westwards with another centre of 1033mb over Ireland. A large area of low pressure with a centre, 997mb, just west of Italy, ensures a strong pressure-gradient and Easterly airflow across N Europe. Associated fronts move slowly north and west to affect the UK.

The high drifts off northwards and the Mediterranean low begins to fill and drift off eastwards towards the end of the forecast period, as a major Atlantic low starts to extend its strong winds and fronts eastwards towards the UK.

Forecast:

Again, sheet-ice will continue to present a severe hazard on all untreated surfaces, underfoot and to drivers.

Snow showers continue to bring new accumulations of snow to the northern half of Scotland on Saturday, these dying out tonight. More showers pushing into Eastern parts of England, extending towards the Midlands.  At the same time, outbreaks of snow move into the south-east of England, where 5-10 (locally 15+)cm of snow will fall and the strong winds will cause drifting, with blizzard conditions giving poor visibility possible.

The snowfall will then work its way north and west. By Sunday afternoon and throughout Monday, it will be affecting other areas of England, Wales and eventually Northern Ireland. Again, heavy falls and blizzard conditions in strong winds are expected, the latter especially over hill country. Given the already cold and icy conditions, further disruption may reasonably be expected.

Although this Warning expires at 00z on Tuesday, attention should be drawn to the frontal systems approaching from the SW by then. These pose yet another threat of strong winds and snowfall from Tuesday onwards. Why not check out the detailed discussions as the situation evolves by reading UKww's synoptic discussions here ?

If you need to travel then please check the latest advisories and keep a winter travel kit in your vehicle.

For checking out where there is rain, sleet or snow the following link may be useful:

UKww will monitor this Warning and update it if necessary.

Issued by JSM for UKww, 0900Z 09/01/2010

[markt]

What a difference overnight makes!

Woke up this morning to overcast skies and snow - even though it isn't showing on the rainfall radar!  However there is a thaw taking place, in between the snow flurries everywhere is starting to take on a damp appearance as the lying snow and ice starts to melt.  What I need is heavier snow!  Fortunately more is predicted for later - my only concern at this stage is that it could well be sleet or even rain...  Temperature at the moment is 0c.

Gonna keep a close eye on this! 

[martinastro]

11Z Update

Bit of a Mess frankly !  Rather complicated upper and surface features affecting the UK with confidence growing on a slow return to less cold weather as we go through the week. But More snow for many - esp in the north.

12Z Sat Models have not done a good job in the precip detail, The NAE really was doing well, but developments overnight have meant a poor precip forecast from yesterday.  The 00Z Models were not much better in misplacing all sorts of detail.  I.E The Sleet/Snow over the SW was not well handled, was better handled by the ECMWF 2 days ago than last night ! The Precip in the SE did not organise as much as the NAE expected, GFS was better here, and the precip coming into Eastern PArts was delayed.... All in all rather poor precip forecasting from all the models, except in parts of CS England where nothing much was expected and nothing much fell !

WV Imagery showsd two upper areas of mid level forcing, one over the SW approaches - this driving the Rain/Sleet and Snow into SE IReland, and the 2nd over Belgium drifting WNW and is helping to produce the Rain/Sleet and Snow over the North Sea, Lincs and that leaving the Dutch Coast.  Elsewhere its cold, grey and breezy, infact windy across parts of Northern England with gusts between 30 and 45Knts.   Warm Advection has taken place overnight aloft, but Air aloft is still quite cold.  00Z Ascents from Herstmonceux show that the warm advection is well aloft at 600/700mbs and that the airmass below is cold.  The warming at the surface is simply the result of mixing and the less cold air from the North Sea being modified and essentially producing a less cold b/l over most parts of England and Wales.  (De Bilt also shows similar)  It is therefore meaning a rise in WBFL's slighly across Eastern Coastal Areas up to 200m now which means a sleety mix is more likely nr the coasts - but still snow inland, and increasingly so as the area of precip over Lincs comes WNW into N England, it becoming increasingly of Snow.  Sleet /Snow across the SW dying out during the day , but odd flurries blowing around in the wind today.

Its fine and Sunny but very cold across Scotland and staying that way today. Snow moving WNW into N England into N Ireland later this evening.

Tomorrow similar to today, but winds becoming light further south with Showers running into Southern Devon and Cornwall with time as the wind veers, Snow Inland, Sleet on Coasts. 

WBFL's are creeping up - still largely nr the surface inland but 100-200m increasingly nr coasts.

The week ahead  - well there are still model problems. Even by T+60 the UKMO GM (06Z) vs the GFS (06Z) has the low in different places coming into the SW.  The UKMO has the low digging more SE, whereas the GFS allows it to run west of IReland. This is important as it affects the about of "backing" of the WInd and means it comes from the ESE as opposed to SSE meaning a difference in the B/L structure of the lowest 150mbs which affects the Rain.Sleet.Snow distribution.  ECM was similar to UKMO, but either solution is possible and the ENS supports both so your guess is as good as mine at this point...!!

General idea is for rain to spread into the far SW on Tues and move slowly NE turning to Snow inland but at the same time slowing and weakening and really not making it further than say Wales, to Bath to Poole before dying out.  The next system will have another go at pushing further north, now UKMO GM and GFS suggest this one will be more successfull at pushing less cold air into the SW and South but more snow across the Midlands into N England, however the ECMWF doesnt suggest this one will get as far north as the model consensus. Infact the ECMWF is somewhat on its own this morning with most other model guidance suggesting by the weekend most parts except the far north will be in less cold air, but a slow and painful transition with certainly more snow to come in the north this week. 

The biggest question marks in the short term are

Snow depths today and tonight - Well 1-3cm over most parts - though locally 4-10cm over the Upslopes of the Pennines and the Mourne Mountains in N IReland elsehwere just a dusting.

SNow coming into the SW on Tues, this is much harder, Rain/Sleet likely in Cornwall, Southern Coasts, but Inland N Devon, Somersety, Bathm Bristol and Inland S Wales could see 5-10cm of Snow before it fizzles out...

Temps - Staying cold in Scotland, elsewhere cloud, low level mixing has brought some weak warm advection across most central and southern parts -esp SE parts where the wind off the sea is bringing less cold air in ... Its not exactly warm though.. Cromer for example still only 1.4C right on the coast... 

TOI 12.05

PJB

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

[markt]

Thanks for the update Martin!

Curious setup for me so far today - snow is falling, settling and accumulating on snow / ice surfaces, however surfaces that are free of ice / snow are soaking wet, the snow just melting as it lands.  To get a whiteout all over the intensity of the snow needs to pick up significantly... 

[brianb]

snow is falling, settling and accumulating on snow / ice surfaces, however surfaces that are free of ice / snow are soaking wet, the snow just melting as it lands.

I've got the opposite - dry, easterly breeze force 5, air temp has been above freezing for 12 hours & is now 3.8C (thermometer pretty accurate) yet the ground remains frozen with patches of sheet ice on the road just about starting to thaw (the worst possible conditions for driving!)

[martinastro]

Wow, made it down to Lough Neagh at Ballyronan Marina, it was a spectacular experience, a huge area of the Lough is frozen solid with boats frozen in the water and people walking on it, it looks like a scene from 'The Day After Tomorow'. Will post video and images later. What a rare sight this was, I wonder if I will ever experience that again. Lots of families there recording the event, met some wonderful people.

[JohnC]

I see the Atlantic low will push and split north and south on Wednesday when we, here in Gloucestershire may get some snow then the high will  dominate again. The worst two months of a year are January and February so plenty of time for more cold periods and snow.

[JohnC]

 Sunday: It's 10.45pm and it's snowing moderately here.with large flakes .Raintoday shows a band of (red) heavy to moderate snow moving SE >NW, We weren't expecting any according to the forecast, not till Wednesday.

[paulster78]

On the topic of raintoday- it was showing sleet/snow mix in my location from 9.45pm and there was nothing falling from the sky As I write this the sleet has started. Bit of a thaw here today although mostly from roofs and trees/hedges.

[martinastro]

Light rain/sleet here so far, looks like a snow non-event here so far, will see what Mon/Tues brings, although I'm not optimistic.

[martinastro]

22Z

Brief Update tonight.  Rather a messy day ! Precip waxing and waning deom time to time with varying levels of Intensity meaning a mix of rain/sleet and snow for most. The B/L was perhaps a fraction warmer than expected, and this meant the difference between Rain.Snow given the marginal precip intensities.   A Lot has been said about the fact this airmass is so warm in an East Wind.  Well the wind has actually been NE for most the weekend, and even though it originates further east, two sets of modifications have happened to it as confirmed by 12Z Ascents.  a) It was modified air that originally crossed the Alps from the Med - hence there is a large warm nose at 600-800mbs, characteristic of an "upper warm front" and 2nd the airmass entering most of England and Wales originated nr the Skagerrak off Denmark, meaning it crossed the largest portion of the sea before arriving in the UK, hence many places saw this lowest level airmass (lowest 50mbs) warm a little even though 950mb temps well still well below freezing across the whole area.  When the North Sea is still between 5-7C it makes a substantial difference having a long sea track vs a short sea track.

Over the coming 48hrs the airmass will and winds will veer more SE'ly and hence the airmass arriving in the UK will be a continental type and with lower DPs, and surface Wetbulbs, WBFL will lower in the south , but remain similar in NE England where the lengthy sea track will persist in delivering rain.sleet to coasts and snow inland.

Precip has actually increased this evening, this large assoc with the weak forcing evident on Mid Level WV Imagery and is providing enough ascent to deepen the boundary layer to produce some outbreaks of Sleet/Snow, A dusting in places inland and up to 5cm on some exposed upslopes well away from Coastal influences.

Looking further ahead there continues to be problems later on Tuesday and Into Weds.  The Met OFfice have now issued an Early Warning for Snow.  The 12Z GFS, UKMO GM was more progressive than the 12z ECMWF, which has to be said whilst has been at odds with other models in some respects has been rock solid with its less progressive solution both in the short term and then longer term, though even with the ECM there is better agreement at most places becoming less cold (at least for a time) late in the week and the weekend. 

The 18Z GFS has moved towards the ECMWF with respect to Tuesday's low into Weds.  The driving trough which deepens the low to the SW of the UK spins up the low and then the Jet Energy forces SE into Biscay and Iberia which means the trough disrupts to the SW of the UK.  This trough first becomes negatively tilted, extends then disrupts as it cannot break down the block to its NE.  There is better agreement from the ECMWF 12Z, NAE 18Z and GFS 18Z of Rain turning to Snow inland across the SW (likely rain/sleet in Cornwall, but turning to Snow in Devon away from the immidiete SE Coasts (onshore flow) Significant falls occuring 5-10cm in places and up to 15-20cm over the Moors. Strong winds generating blizzards in places for a time before the winds ease off. 

The front makes inroads then into S Wales and into Somerset and CS England, at the same time a breakaway low forms in the trough disruptiuon and moves east - now this development becomes inportant as its this low which heads ESE and extends the snow risk into CS England, The positioning of this low is crucial in how far east the snow gets it also has the added effect of Backing the wind off the land instead of the Sea. The ECMWF has 2-5cm extending about as far as the ISle of Wight before fizzling. The 18Z GFS takes it a little further and has greater precip intensity (has 14cm over SOmerset by 06Z Weds)

I need to stress even though we are talking only 48-60hrs away - there is as much uncertainty in what ive written above as a normal 5 day forecast... Its very complex and 50miles movement in one direction or another makes a lot of difference.

TOI 22.50

PJB

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

[brianb]

Light rain/sleet here so far, looks like a snow non-event here so far

Just rain here. Temp has fallen from +4 during the day to +1.6 but this is normal winter weather not "cold snap" - still some frost in the ground though.

[markt]

Well i've just woken up to another 2" covering of snow.  Checked the local 'hotline' to see if school / work is open and it's only open to year 10 & 11 (15 / 16 year olds), open to staff as usual - curious move this, will be intersting to see the reasoning behind it.  We're not exclusive as a school either doing this, there's quite a few in the borough that are doing it...  Not been outside but it looks quite breezy this morning...