Cold Spell Discussion

[weather eater]

When I got my kids to school on Friday it was -12C, but the head still had them out in the playground rather than cluttering up the inside. God for her!

Can she come and work down here. 6 more weeks of winter to go, plenty of time for more bad weather, something has to be done in this regard. We have several clients who are teachers, none of whom has made any attempt to get to work. My wife is a member of a Landrover forum, she was telling me last week about a head teacher on her forum who had shut his school so that he could go and play in the snow with his landrover, all at our expense.

[Thundery wintry showers]

Joe B from accuweather's take on the coming weeks

....

I remain partial to 02-03 which had a nasty February,

Poor English and a lot of comments about good and bad weather where it's not entirely clear what he means by it- he says February 2003 was "nasty", but as far as I remember, apart from a four day NW'ly from the 2nd to 5th with sunshine and snow showers for the north and west, it was an exceptionally dry sunny month with high pressure leading to warm days and cold nights.

[tufty]

Probably not the right forum for this,and apologies if its not.

I have ony just started taking a keen interest, so tend to take a back seat and prefer to read.

However a question if i may....i notice from the meteox satimage site that we currently have a low progressing west to east, and also an eastlerly air flow.

Now the sat image clearly shows the air space in the middle being compressed, and i understand that its the classic east west battle scenario, and that either could win, lose, or stall.

My question is what generally happens to the air/clouds as both fronts approach, and what is the most likely outcome.

Again, sorry if its not the right area to ask but as before i tend to read with a keen interest.

[drgl]

http://www.sat24.com/Region.aspx?country=gb&sat=ir&type=loop

Shows the impending East/West battle nicely, i can't remember seeing satellite pictures like this before, i have a feeling there maybe more snow about than some think.

[Thundery wintry showers]

Probably not the right forum for this,and apologies if its not.

I have ony just started taking a keen interest, so tend to take a back seat and prefer to read.

However a question if i may....i notice from the meteox satimage site that we currently have a low progressing west to east, and also an eastlerly air flow.

Now the sat image clearly shows the air space in the middle being compressed, and i understand that its the classic east west battle scenario, and that either could win, lose, or stall.

My question is what generally happens to the air/clouds as both fronts approach, and what is the most likely outcome.

Again, sorry if its not the right area to ask but as before i tend to read with a keen interest.

I think it's the classic case where as the two airmasses collide, the lighter, warmer air rises over the top of the colder, denser air, resulting in clouds and precipitation from a warm front.

[tufty]

My thoughts exactly drgl,looking at the image both east and west efforts look similar, and i think this is going to catch a few out.

Correct me if i am wrong but was 1981 a similar scenarion with an east west battle, and was this not the year that devon and cornwall got clobbered big style.

Looking at what is modelled to happen is that the low from the west wraps around the eastlerly towards the south but i have a feeling that this could develop into a stall.

I am, no expert !.....and leave it to those more experienced to comment otherwise, however i watch with interest as to the final outcome.

It would not surprise me to see the metoffice upgrade the alerts fairly soon.

[winterfreak]

I think it's the classic case where as the two airmasses collide, the lighter, warmer air rises over the top of the colder, denser air, resulting in clouds and precipitation from a warm front.

So TWS, as we saw in November, those LP's barrel across the whole of the UK no problem at all. Why is it then that only SW and possibly CS England will be in the firing line for that? is it the easterly blocking slowing it all down? I'm hopeful that LP will get far enough to me!!!

[drgl]

Haven't a clue on '81 i'm afraid, i was too young & out enjoying it!! I'm no expert either but would trust eyes over computer models this winter! Still light snow falling here, that is nearly 24 hrs now of very light snow, the point is the cold hasn't gone............yet

[Timmytour]

My thoughts exactly drgl,looking at the image both east and west efforts look similar, and i think this is going to catch a few out.

Correct me if i am wrong but was 1981 a similar scenarion with an east west battle, and was this not the year that devon and cornwall got clobbered big style.

Looking at what is modelled to happen is that the low from the west wraps around the eastlerly towards the south but i have a feeling that this could develop into a stall.

I am, no expert !.....and leave it to those more experienced to comment otherwise, however i watch with interest as to the final outcome.

It would not surprise me to see the metoffice upgrade the alerts fairly soon.

i think it will stall...but a lot further east then currently being shown. i think for those in the West country expecting snow, it's going to be disappointing except for those on the highest ground.

[tufty]

I think it's the classic case where as the two airmasses collide, the lighter, warmer air rises over the top of the colder, denser air, resulting in clouds and precipitation from a warm front.

Thanks TWS, for the reply, ....of course makes sense now, so i assume it all depends on the cold heights and the likely hood of the warmer air being able to get over the top, otherwise the stall scenario comes into play ?.

If so what are the current heights of the west approaching low, and the flow from the east.....or more to the point which chart do i need to look at to try and work it out for myself.

Thanks for the help

[Rollo]

Poor English and a lot of comments about good and bad weather where it's not entirely clear what he means by it- he says February 2003 was "nasty", but as far as I remember, apart from a four day NW'ly from the 2nd to 5th with sunshine and snow showers for the north and west, it was an exceptionally dry sunny month with high pressure leading to warm days and cold nights.

I have just checked the archives for Feb 2003 and apart from a scandi high for about 3 days it was a normal Feb re Temperatures-I think JB may have got his years mixed-up.

[Thundery wintry showers]

So TWS, as we saw in November, those LP's barrel across the whole of the UK no problem at all. Why is it then that only SW and possibly CS England will be in the firing line for that? is it the easterly blocking slowing it all down? I'm hopeful that LP will get far enough to me!!!

It's because there's a huge blocking high over Scandinavia which is halting the progress of weather systems trying to come in from the west.

Thanks TWS, for the reply, ....of course makes sense now, so i assume it all depends on the cold heights and the likely hood of the warmer air being able to get over the top, otherwise the stall scenario comes into play ?.

If so what are the current heights of the west approaching low, and the flow from the east.....or more to the point which chart do i need to look at to try and work it out for myself.

Thanks for the help

The warm air will always rise over the top of the cold air in a warm front (as distinguished from a cold front, where cold air undercuts warmer air). So what it really depends on is the wider atmospheric circulation pattern, which dictates whether the frontal zone moves eastwards or grinds to a halt as it comes up against the blocking high over Scandinavia.

A good indicator of the temperatures involved is the 850hPa charts which show the temperature at the height where the atmospheric pressure is 850 hPa where 1 hPa = 1 millibar. The other popular measure is the 1000-500mbar thickness (the thickness of the air between the heights where the pressure is 1000 & 500 millibars) but this is less reliable at determining conditions at the surface.

[stewfox]

i think it will stall...but a lot further east then currently being shown. i think for those in the West country expecting snow, it's going to be disappointing except for those on the highest ground.

Agree, there is too much mild floating around and a slow thaw going on through England (low levels)

[winterfreak]

It's because there's a huge blocking high over Scandinavia which is halting the progress of weather systems trying to come in from the west.

Ah, that makes sense. I take it it won't reach Tonbridge and stall over me giving large accumulations then? Oh well, never mind! Thanks for the reply....

[tufty]

It's because there's a huge blocking high over Scandinavia which is halting the progress of weather systems trying to come in from the west.

The warm air will always rise over the top of the cold air in a warm front (as distinguished from a cold front, where cold air undercuts warmer air). So what it really depends on is the wider atmospheric circulation pattern, which dictates whether the frontal zone moves eastwards or grinds to a halt as it comes up against the blocking high over Scandinavia.

A good indicator of the temperatures involved is the 850hPa charts which show the temperature at the height where the atmospheric pressure is 850 hPa where 1 hPa = 1 millibar. The other popular measure is the 1000-500mbar thickness (the thickness of the air between the heights where the pressure is 1000 & 500 millibars) but this is less reliable at determining conditions at the surface.

Thanks TWS, i will look at those charts.....hmmm just got to get my head around them then

[Thunder Snow]

Very icy here in carlisle this morning, and now i cant wait for some rain or milder air to move in. As its very dangourus out and about. Puddles with ice underneath, frozen slush.

And looking at the modles we may see some rain and slightly milder air soon, as what we have now is just a mess.

Roll on the next cold spell any ideas.

[Thunder Snow]

Less Cold

Well here we are after a long cold spell for all of the UK, the cold spell is loosening its grip across the UK. However there is still some rain/sleet and snow around across Central England/Northern Wales/Ireland and Northern England, however the snow is mainly falling across the hill and will be light in nature. Down to lower levels and towards the coast it is likely to be or rain, further inland it will be a wintry mixture. There still will be a cold Easterly breeze. Further North across Scotland is will be cloudy with some rain/sleet and snow moving into Southern areas, further North there will be some sunny spells, but still feeling cold. Further South it will be mostly cloudy and cold. Wherever you have snow you will see a slight thaw, this could refreeze later tonight when tempertures drop to freezing or below.

Into tonight then the rain/sleet and snow mix will continue it joureny across Scotland, turning heavy over the hills for a time. Elsewhere is will be cold with cloudy skies, so tempertures will stay towards the freezing mark or just below. Ice maybe a factor where snow has settled, so take care during the early hours.

Tuesday and its a tricky one. A weather system will try to move in from the South-West, bringing rain at first. As it moves in it will bump into the Colder air, so heavy snow is likely across the hills of the South-West, with snow possible at lower levels for a time, but i think this may turn back to rain. As the system moves into South Wales/Central England and Southern Areas there is again likely to be some heavy snow for a time, again i feel is will be border-line for low level areas but im not ruling out a covering/dusting in places. Wheres as higher routes will see snow with totals reaching 10-20cm. For Northern Ireland it will be a cold and cloudy start with some light showers across the coast, as we move towards the afternoon and evening the rain/sleet and snow mix may just reach this area, with snow favored for higher routes, but again lower levels may see something. Scotland will start cold and cloudy with some snow flurries likely, with maybe somthing heavier for a time over central hills. Eastern Scotland will be damp and cold. Towards Central England and the South East it will be cold and overcast.

I would just like to stress there is alot of uncertainty as to how far North this system will get, at the moment i think it will strech from Southampton area/ across much of Wales and turning patchy across Ireland. The snow is likely to be heavy for a time, the system is likely to begin to turn patchy and weaken towards dawn on Wednesday. Ahead of the system there is likely to be some wintry showers across Central England/Towards the South East and Northern England, but at the moment i dont think these are any cause for concern.

Wednesday the main band will weaken with snow is effecting Wales and the South of England, it may just make it into Central England.

However there is alot of uncertainty about tomorrows event and into Wednesday, but this is how it looks to me and the moment. This forecast is subject to change and i will try to update it tonight.

Weather Warning: Snow is likely to effect the hills of Northern England through-out the day, giving a covering of 10-15cm mybe 20cm locally.

Weather Warning: ICE: Where any snow has began to thaw, ice is likely to be a widespread problem as tempertures dip to freezing or just below.

Weather Watch: An Atlantic system will start to move in from the South West, this is likely to bring some heavy snow towards the South-West/Most areas of Wales and maybe Central England for a time. Snow is likely to be heavy at times, with falls of 2-5cm across low lying areas with 10-15cm (20cm locally) across higher routes. Winds are likely to be gusty at times, so blizzards condtions are likely more so over higher routes.

[Terminal Moraine]

25cm of lying snow here is the most in January since 1987 which, I feel, is more a reflection on how snowless January has been in the last 20 years than on the snowiness of this one. The sum of all the snowfalls so far this month is just over 29cm which is a long way behind the Januaries of years like 1984 or 1986 when the sum was almost 70cm.

Still, we're not even half way through the month yet and, who knows, GFS might have got the forthcoming mild spell wrong. ( He said, wildly grabbing at straw )

[Craigers]

25cm of lying snow here is the most in January since 1987 which, I feel, is more a reflection on how snowless January has been in the last 20 years than on the snowiness of this one. The sum of all the snowfalls so far this month is just over 29cm which is a long way behind the Januaries of years like 1984 or 1986 when the sum was almost 70cm.

Still, we're not even half way through the month yet and, who knows, GFS might have got the forthcoming mild spell wrong. ( He said, wildly grabbing at straw )

well the bbc arnt event sure if the mild will get through!!!

[Thunder Snow]

At the moment i dont think it will be mild, just milder and less cold. As for Tuesday and Wednesday i think there will be heavy snow for the hills of the South-West, with some snow to lower levels for a time. I think the snow will then move into wales and stall. 2-5cm across low lying areas, higher routes 10-15cm (20cm) locally.

Just my thoughts.

[MisfitDog3]

Given the ever closing Isobars over the southern and western areas of the UK forecast for the next few days I have a question about windchill. If the air temp is 2 degrees with a 30mph breeze, presumably the windchill factor does not actually effect the melt-rate of the snow and ice above zero? What I mean is snow presumably reacts to the real ambient temp rather than any 'windchill' factor?

[Thunder Snow]

Hmmmmm i spy a flood threat. :unsure:

[Osbourne One-Nil]

Horrible, nasty, dank, dismal day here, with the temperature reaching just 1.6º, but not dropping below 0.8º either.

Bleurk.

[Thunder Snow]

Very messy here, with loads of mud/slush ice and some snow still left. temp 1c

[Optimus Prime]

A February 1947 dull cold and wet day. Maximum 1.3c. Still around a foot of snow on the fields with 10cm on the paths and side roads.

BBC promising a warm up later this week. Channel 4 remaining cold.

With the BBCs constant ramming off Global Warming and Channel 4s more even less biased journalism I know who to believe.

Edited January 11, 2010 by Optimus Prime