WINTER FORECAST 2010-11
OK well I've had a crack at winter forecasting for the last three winters, with varying degrees of success.
My success for the last two winters particularly has been really encouraging, and has made me keen to have another crack this year.
I will begin (as always) with a basic summary of how I expect each of the three winter months to pan out, followed by a more dedicated month-by-month forecast.
** Please note that the forecast is based on my own methods, including pattern matching from previous years and also a study of solar activity. I've also taken into account the development of La Nina in the Pacific. Feel free to comment on my forecast, but please don't rip me to shreds, because this is just something I do as a hobby, and I have enjoyed compiling this forecast as always***
OK, so starting with a basic summary of how I expect the winter to pan out.
I believe that once again we are in for a colder than average winter, and in fact possibly the coldest winter since 1962/63.
I do not believe it will as cold as that famous year, but I believe there will be many significant cold outbreaks – with much of the coldest weather affecting the north and north east of the UK.
Conversely, areas in the south and west will experience closer to average conditions at times.
I do expect a couple of brief milder interludes, particularly in the south and west, with temperatures rising to above average here at times, particularly later in the winter.
DECEMBER 2010
December will start on a bitterly cold note with strong north to north-easterly winds predominating.
The first week of the month will see areas of low pressure undercutting a block to our north east, bringing spells of rain/sleet and snow to many areas of the south.
Further north, closer to a large cell of high pressure over Scandinavia, it will be exceptionally cold at times, though more settled with snowfall more in the way of showers rather than prolonged snow.
I feel that the first seven days will see maximum temperatures range from -5 in the north to around freezing in the south – perhaps a little milder in the extreme south west.
During the second week, a deep area of low pressure in the south west will attempt to push north and east into the block of cold air.
This has the potential to bring blizzard-like conditions at times with the chance of significant snowfall in many areas.
In the north, more settled with sunshine and snow showers at times, and remaining bitterly cold here.
Temperatures will range between -6 in the north to +4 in the extreme south west.
Overnight, we could easily see temperatures plummet to exceptionally low values, particularly across the snowfields – possibly as low as -25 in the highlands of Scotland – so close to record-breaking low temperatures.
The third week will, I believe, see a change to slightly milder weather for a time as more areas of low pressure and frontal systems affect much of the UK.
December (13th-17th), The north of the UK will never really escape the cold conditions, although it will get slightly milder here with spells of sleet and snow at times as the frontal systems make inroads.
Temperatures will be in the range of 2 or 3 degrees in the north to perhaps double figures briefly (10 degrees) in the south west, so at least it will be mild here.
In the week running up to Christmas (20-24th) I believe we will see a gradual settling down of the weather as an area of high pressure builds across France and the Low Countries.
This will bring cooler, drier and more settled weather, though with a fair amount of fog and frost.
Some of this fog could linger all day in prone areas (such as the Vale of York), leading to quite depressed temperatures in these areas.
However, there will also be some spells of winter sunshine, making for a crisp and seasonal feeling in the run-up to Christmas.
Temperatures will range between 2 degrees in the north to 8 in the far south, though maybe struggling to rise above freezing where fog lingers.
Temperatures overnight will plummet well below freezing in many areas, with sharp frosts likely nationwide.
At present, I think that Christmas will remain relatively settled, although the area of high pressure may begin to retrogress into the north Atlantic.
This will result in winds turning more northerly, particularly across the north.
Instability in this pattern could lead to the outbreak of wintry showers across northern areas, possibly with some snow on the highest ground of Scotland and Northern England.
But generally, I expect Christmas Day to be bright and dry, if rather on the cold side. Temperatures ranging from 3 degrees in the extreme north to 6 or 7 in the south.
Night-time temperatures will drop below freezing nationwide, ranging from -6 to -3 degrees.
The final week of December sees the high continue to retrogress out into the Atlantic, leading to a northerly interlude.
Showers will become more widespread, with the continued possibility of snow in some areas, particularly on northern and eastern facing coasts.
Much of the south will remain dry, with showers few and far between here.
Temperatures will be in the range of 3-7 degrees nationwide.
Overall, I expect December to come out with a below average CET and average rainfall.
JANUARY 2011
I expect the New Year to dawn on a fairly settled note in the south, though with further showers of rain, sleet or snow across northern most areas. However, the area of high pressure in the Atlantic will topple back into the UK, leading to a run of westerly winds and a more unsettled and mild regime briefly.
However, a strong build of higher pressure over Scandinavia will start showing its influence in the second week, which will bring, I believe, bring the chance of a UK-wide cold event once again.
So the first week of January will see north or north westerly winds continuing, feeding showers into the northwest. These showers will continue to have a somewhat wintry flavour, particularly over higher ground.
As the area of high pressure in the Atlantic topples back over the UK, this will cut off the showers briefly during the second half of the first week and temperatures will recover slightly.
I believe temperatures will range between 4 degrees in the north to 8 in the south, possibly rising to above-average values of 10-12 during the latter part of the first week.
At this point, I anticipate a large anticyclone over Scandinavia to begin to exert an influence, as areas of lower pressure skirt along the south of the country with a southerly-tracking jet.
Initially these areas of low pressure will deliver more wind and rain, particularly from the midlands southwards.
Winds will be south westerly to westerly at first with temperatures around or just above average.
Further north under more of a high pressure influence, conditions will settle down and become quite cold as the Scandinavian High takes control.
Temperatures during the second week will range from around 1-3 degrees in the north to above-average 9-12 in the south.
I believe the Scandi block will start to really exert its influence in the third week as areas of low pressure begin to undercut the high.
Winds will be more from an easterly quarter and temperatures will become below average to perhaps well below average in many areas.
As areas of low pressure bump into the colder air, precipitation will turn more wintry in nature, even across low ground in the south.
Bitterly cold easterly winds will see maximum temperatures range from around freezing point in the north, to perhaps 2-3 degrees in the south.
With the active jet being diverted south of the UK, there is the chance of formation of channel low pressures, which will have the potential of delivery quite a significant snow event from the midlands southwards.
During the fourth week of January, I expect the Scandi High to continue to block the Atlantic to a certain extent, although it will perhaps sink slightly towards the Balkans area, leading to a change of wind direction into the south east.
This will, in turn, lead to drier conditions across the south, though still rather on the cold side.
With the air being drier though, significant spells of sunshine will make it feel quite pleasant out of the wind at times.
Across the north, there will be showers of sleet or snow at times, interspersed by spells of sunshine, but staying cold.
Maximum temperatures during the last week of January will range from around 2 degrees in the north to around 4 or 5 in the south.
Overall, I expect January to come out with a slightly below average CET and average rainfall.
FEBRUARY 2011
**Lower confidence for this month, and so I make no apologies for being a little more vague as the month goes on**
The last month of winter 2010-11 will start as January finished, with showers of rain/sleet or snow across the north and drier/brighter weather from the midlands southwards.
A deep area of low pressure will zip across northern-most areas during the end of the first week, leading to a brief, but potent northerly spell in its wake.
This northerly spell will not last too long as heights rise again to the south, bringing a spell of more zonal and mild weather towards the middle and end of the month and possibly an early end to winter here.
So the first week of February will begin quite unsettled across Scotland and northern England. Showers of rain or sleet (snow on the hills) will make it feel quite miserable here, although in the south with sunnier skies, it will be rather pleasant in lighter winds from the south or south east as a mid-latitude high continues to block weather systems coming in from the west.
But it will be all change as a potent Atlantic storm does its best to smash the block.
A deep area of low pressure will zip across northern most areas.
Bumping into our cold air, this will bring heavy spells of snow in Scotland and high ground in northern England. Coupled with gale-force winds, there will be blizzard-like conditions at times, especially on exposed northern and western facing coasts and hills.
Some of this rain will fall as snow across the highest ground further south.
It will also be very windy in the rest of England and Wales, with gale force north-westerly’s and spells of rain or snow from frontal systems.
Temperatures will range from between 2 or 3 degrees in the north to 8-10 degrees in the extreme south during this period.
With a strong jet more directly affecting the UK, this area of low pressure will move fairly swiftly, and in its wake, we will see this brief northerly outbreak.
Strong to gale-force northerly winds will penetrate nationwide, and it will feel bitterly cold at times.
Showers of sleet or snow, initially affecting northern areas, will also begin to penetrate further south on increasing northerly winds.
Some of these snow showers will reach as far south as the Midlands, blown along on strong northerlies.
As is always possible in an unstable airstream, this may lead to the formation of small polar low pressure areas, which could serve to pep up the wintry precipitation.
Temperatures will range from around freezing in the north to 3 or 4 degrees in the south, but feeling much colder than this with the addition of the wind-chill factor.
Overnight we will see sharp and penetrating frosts with temperatures ranging from -5 to -2 degrees.
Height rises to the south will begin to cut off the northerly outbreak during the third week of February as winds turn more westerly again.
This will, I believe, lead to a much milder and settled third week, with some areas in the south beginning to feel particularly mild for the time of year.
In the north, however, you will still be influenced by north-westerly’s, so colder and more unsettled here.
Areas from the north of England southwards will become quite settled, though rather cloudy, but temperatures will rise markedly, perhaps getting back into the very mild category at times.
I believe these will range from around 4 or 5 degrees in the extreme north, to perhaps as high as 13 or 14 in the south west.
The final week of February will see a continuation of milder weather across the south; though will spells of rain likely at times.
The height rises to the south will continue, with an area of high pressure from the Azores bringing much milder weather in across the whole country.
There will be frontal systems crossing the country at times, bringing showers or longer spells of rain, but also some drier and brighter interludes.
I believe we will see an early start to spring-like conditions in the south of the UK as winds from the south west push temperatures into the mild to warm category towards the end of the month.
In any sunnier spells, temperatures in the south could reach 12 to 14 degrees quite easily, possibly higher in places.
Even in the north, the weather turns much milder, heralding a taste of spring across northern England and southern Scotland.
Showers or longer spells of rain here at times also, but daytime temperatures ranging from 6-10 degrees.
Overall I expect February to come out with average temperatures and average to above average rainfall.
That's all folks. I hope you enjoyed reading this. I've taken many, many weeks compiling this forecast. It may be right, it may be wrong (or it may be something in between).
I've had a decent success rate over the last three years, and so hopefully it will continue this year too.
My overall summary is a winter that will prove memorable in its severity and longevity.
There will be one or two mild spells, but generally a bitterly cold winter will predominate, with overall precipitation being around about the average for winter nationwide.
The overall CET for this winter will be (in my opinion) below to well-below average, but not withstanding a couple of mild spells along the way.
I believe we are in a new era – a “post-modern” winter if you like. The continued solar minima has made a big impact on our climate, and I feel that more winters like this are on the cards.
At times, what we may see this winter will make last winter seem fairly benign, particularly in the north and east, which has the POTENTIAL to see the coldest winter in decades.
For what it’s worth, I expect to see a quick recovery towards the end of February, with possibly an early start to spring, with March being warmer and drier than average, possibly heralding a warmer spring in general.
Hope you enjoyed reading this as much as I enjoyed compiling it.
Cheers guys.
Moomin.
Witney, Oxfordshire
100m ASL