East Anglia & South East Cold Spell Discussion Part 19

[yamkin]

A cold rainy day at 4.5c

[loveletter]

Raining quite heavy here and 2.3

[Ben_Cambs]

The rain will be a benefit for us in the Longer term, as the low heads off south and the colder air takes charge, so as the front leaves our region tomorrow it may turn to snow on its back edge. A possible widespread snow event next week on Wednesday, needs to be kept an eye on. Raining moderately here at the moment

Met O outlook very good aswell:

There will be a good deal of fine, dry and bright but cold weather across the UK from Sunday and through next week. Sleet and snow showers will affect many northern and eastern parts at times, perhaps becoming more persistent and spreading into some other regions from the middle of next week. Nights will be frosty, with frost locally severe in some areas, and overnight freezing fog will be slow to clear from some inland parts. There is uncertainty from next weekend onwards through the rest of the period with the strongest signal for the weather to remain generally cold with occasional wintry showers, though some western and southwestern parts may become less cold for a time

Edited December 30, 2009 by Snowman0697

[VillagePlank]

Interesting times weather watchers in Kent ...

First the 6z ensembles:

Clearly, a little on the mild side from the 1st Jan, going to the very mild side from about the 3rd Jan to 7 Jan. A mild outlier, for sure, so, for now, I will stay with the 00z since it follows the ensemble mean from 6z - ie bin the 6z; it's highly unlikely to occur this way.

Overall synoptics show a Greenland high linking up with a rather northerly Scandinavian high, leaving the UK in the grip of Northerly/North Easterly. This is exacerbated by the bifurcated jet stream, with the main arm over the Mediterranean. This is likely to induce cyclogenesis over Southern Europe and keep high pressure formation to a minimum for the timebeing.

Breakdown scenario is probably related to the weaker arm of the jet stream just south of Greenland, and covering Iceland. If this strengthens, and given that polar temperatures are pretty much average, rather than high, this is the 60% side of 60/40 bet. This will result in a weakening Greenland high - however, this shouldn't spell the end of the cold-spell, since the high over Scandinavia will likely hold, and, potentially, move south as the low pressure over Europe fills giving the UK a direct arctic maritime feed - one of those classic northerlies from times long since gone, perhaps?

The North to North-Easterly aspect of our source airmass is almost dead-set to bring in cold to very cold air. And this is air all the way up, one might say. 500hPa level is below 5280m, and 850hPa level is below 1300m - both are the boundaries, in my opinion, for a 50/50 chance of rain/snow. I know that's a little pessimistic, but, hey, we all have to draw lines in the sand somewhere. This cold air is forecast to stay, widely, over the British Isles for a week, if not more - however, the very far South of England may see these levels notch North a bit from time to time as the week progresses, and hard to predict low pressure brings with it some warmth:

Of course, this all depends on the track of the low pressure which amounts to some disagreement between models and people; I think this is fruitless, and will, more or less, be a now casting problem.

Anyway, the question is, I suppose, regardless of the sheer length of this cold spell, is it going to bloody-well snow? Well, first you need to look at the thickness charts and they need to be inside the lines already mentioned, but, my favourite marker of snow is Theta-W (wet-bulb) temperature charts. If it is less than 2C and the thickness's are the right side of the 50/50 lines, then it will snow at sea-level. You'll be happy to know, that apart from modification occurring associated with that LP system, the levels all seem to be the right side of marginal.

So, the key is that LP system. It needs to travel about 80 miles further south - entirely possible - to keep the cold feed in Southern, hence South-Eastern Britain. East-Anglia will remain cold for the period, I think.

Any precipitation that occurs is likely to be convective based drifting in from the North-Sea, so is wholly unpredictable - therefore it is not a question that can be answered, today, rather, a much more vague Easterly facing counties are most at risk during the period, and look to the radar during the day (most days, actually) and hunt out showers heading for your location.

Edited December 30, 2009 by VillagePlank

[Neilsouth]

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=ukuk&MODELL=nae&MODELLTYP=1&BASE=-&VAR=prty&HH=42&ZOOM=0&ARCHIV=0&WMO=

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=ukuk&MODELL=nae&MODELLTYP=1&BASE=-&VAR=prty&HH=48&ZOOM=0&ARCHIV=0&WMO=

Not much snow for ea and se end of the week , shows mostly rain

[VillagePlank]

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=ukuk&MODELL=nae&MODELLTYP=1&BASE=-&VAR=prty&HH=42&ZOOM=0&ARCHIV=0&WMO=

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=ukuk&MODELL=nae&MODELLTYP=1&BASE=-&VAR=prty&HH=48&ZOOM=0&ARCHIV=0&WMO=

Not much snow for ea and se end of the week , shows mostly rain

6z is a mild outlier - see my post above.

[Neilsouth]

6z is a mild outlier - see my post above.

Ah so thats based on the gfs? , thought it was the ukmo

[VillagePlank]

Ah so thats based on the gfs? , thought it was the ukmo :wacko:

Whoops - yup, me wrong

[Guest North Sea Snow Convection]

Definitely a chance of some snow showers from the north easterly on late Thur/Friday

All we need is some snow cover, then plenty of frost to keep it there for days and days, with toppings up of course!

Edit: Have stolen this line from Ian Fergusson's eagle eye BBC weather/METO insight view regarding the outlook into the New Year from the SW thread

Beyond that, most of the week looks effectively dry, often clear and very cold, with inland fog a problem for some. Bulk of the snow signal is restricted to eastern England and the SE, with a weaker signal for SW at times.

That will do nicely muchly ta!!

Edited December 30, 2009 by North Sea Snow Convection

[Ben_Cambs]

Definitely a chance of some snow showers from the north easterly on late Thur/Friday

All we need is some snow cover, then plenty of frost to keep it there for days and days, with toppings up of course!

Edit: Have stolen this line from Ian Fergusson's eagle eye BBC weather/METO insight view regarding the outlook into the New Year

Beyond that, most of the week looks effectively dry, often clear and very cold, with inland fog a problem for some. Bulk of the snow signal is restricted to eastern England and the SE, with a weaker signal for SW at times.

That will do nicely muchly ta!!

Yep! All we need is a covering and the cold will let the snow stay!

[simon65]

starting to get a lot of snow in the rain here in Leighton buzzard

pressure 992 and falling

temp 2.8

dewpoint 1.6

[Ben_Cambs]

Thursday :smiliz46:

East of England: Bedfordshire Cambridgeshire Essex Hertfordshire Luton Norfolk Peterborough Southend-on-Sea Suffolk Heavy Snow & Widespread Icy Roads Thu 31 Dec Snow showers are expected to affect many areas but especially coasts and hills exposed to the north. The showers may be heavy and give fresh accumulations of 2-5cm in some places and locally 10cm.

Icy patches on untreated surfaces may become widespread.

Issued at: 1458 Wed 30 Dec

[tinybill]

i see bbc news weather is saying snow for the east coast for the weekend

[saint]

Thursday

East of England: Bedfordshire Cambridgeshire Essex Hertfordshire Luton Norfolk Peterborough Southend-on-Sea Suffolk Heavy Snow & Widespread Icy Roads Thu 31 Dec Snow showers are expected to affect many areas but especially coasts and hills exposed to the north. The showers may be heavy and give fresh accumulations of 2-5cm in some places and locally 10cm.

Icy patches on untreated surfaces may become widespread.

Issued at: 1458 Wed 30 Dec

Snow showers? Surely it will be from the front?

[Ben_Cambs]

Snow showers? Surely it will be from the front?

That's what I was thinking too! Maybe a cluster of showers on the back edge of the front?

[nwales]

It's trying its best to snow here.. there are big wet flakes mixed with the rain. Temp has fallen from 3.4c to 2c

[Ben_Cambs]

This could potentially give a decent covering to a lot of areas:

[tinybill]

well i just looked on the French site which not far off on their its saying the east cost can expect snow from new years eve and if you go deep in to F1 on there its cold all the way with snow at times

http://www.meteociel.com/modeles/gfs/precipitations/30h.htm

Edited December 30, 2009 by tinybill

[Ben_Cambs]

Ive noticed a feature on GFS on Friday afternoon, could give a good covering of snow?

[jetwife]

Just raining in Luton at the moment, anyone know when we will get some???

[tinybill]

http://www.netweather.tv/index.cgi?action=snow;sess=

if this happens in jan we will be digging ourselves out lol

Edited December 30, 2009 by tinybill

[Michael Fishermans Friend]

BBC at 1.55pm mentioned very little about any snow for tomorrow or New Years day just saying there could just be a little wintryness on the back edge as it clears the east coast - so are we getting to optimistic on here?

[The Giant Daddy Jackpot]

A very cold and snow free weekend awaits us. Looks interesting on Tue\Wed though with a LOW moving in from SW.

[nwales]

Sleet continues here, 1.6c

[rmc1987]

BBC at 1.55pm mentioned very little about any snow for tomorrow or New Years day just saying there could just be a little wintryness on the back edge as it clears the east coast - so are we getting to optimistic on here?

Yes, you are.