Members Winter Forecasts 2012 - 2013

[Zenarcher]

Last year we had a thread that allowed members to forecast the winter ahead so please use this thread to post up your winter forecasts and feel free to discuss as well. There's already a few winter forecasts in the blog section if you haven't checked them out I would recommend that you do so.

Here's my forecast my first attempt at something like this. I look forward to reading other peoples forecasts for winter

2012 - 2013 Winter Forecast

Written By Sean Macdonald aka on NW weathermaster

How the forecast has been made

I've used the CFS monthly mean maps that pick up long range trends for the upcoming months. But I have also used a program called ''Climate Simulator'' to help back up my forecast in certain area's. I used the program several times last year and it proved pretty accurate and for this winter it has some interesting thoughts. I have gone through a lot of data from the year 2012 to get the mean temps from different parts of the world to build up a realistic picture for the simulator. I ran the model several times in it's highest resolution and checked the data over for trends each time. It took about 5 minutes to complete it's calculations each time, it takes all sorts of technical information from solar activity to the current state of our global climate.

December

Temperature

The CFS monthly average shows warmer temperaure's in Greenland. Meanwhile down at the UK we are a few degrees colder than normal. This is something the climate simulation agree's on both that Greenland should be warmer and the UK colder.

Rainfall

The monthly mean is showing it to be below average thanks to the blocking.

Pressure

High pressure is expected to be strong over Greenland and Iceland meanwhile over Europe is where the low pressure

is likely to be.

Overall - I expect December to be the coldest month of the winter. We have good agreement from both the simulations and the CFS mean that Greenland is expected to be warmer and the UK colder. We also have the pressure patterns showing things to be blocked.

January

Temperature

The simulator still gives below average temperatures here however the CFS does disagree and shows mostly average temperatures and maybe even slightly higher than normal for England.

I've made up this image below to explain why January is still expected to be okay and the difference to last years January. Also yes the simulation agrees on above average temperatures in the Svalbard region as well.

Rainfall

The CFS goes for above average rainfall for most of the UK for January.

Pressure

Low pressure is expected to sit over the UK and in the Atlantic this is the reason for the near to average temperatures and rainfall. However over the Svalbard area pressure is expected to stay high there.

Overall - While I expect most of January to have near to average temperatures but mostly slightly lower than normal the signals to me are clear that with blocking likely we will see some cold spells occur through this month.

February

Temperature

Once again the simulator goes for temperatures to still be below average but the CFS still disagree's and goes for mostly average temperatures and above average in England once again.

Just like January I explain why the temperatures are still a good thing for us. (Sorry about the images being different they've updated them to look better this year.)

Rainfall

After a wet January I expect things to go back to normal by Febuary in fact England may recieve lower than

average.

Pressure

Very strong over our North and East,

Overall thoughts - I believe February will be similar to January but current trends suggest blocking may be even stronger, also the month may be drier than normal.

The climate simulation graphs,

Once it has completed it's calculations it allows you to check graphs for each area of the world they aren't fancy or anything but I'll explain,

Greenland temp,

So the green line is the average temperature you get in Greenland and then the pink one is the simulated temperature. The other two lines which are blue meaning daily minimum average and red daiy highest average, interestingly even the daily high average is much higher than average so this gives support to the CFS on it's temperature forecast.

UK temp,

The first part the few blocks are 3 months December, January and February and they show the pink line the simulation to be below average compared to the green line. The last few blocks when the lines start to rise shows early spring where things go slightly back to normal, anyway this is also good news for us.

Svalbard temp,

Just like on the UK one first few blocks where the line is flat is our winter months and the simulation went for above average temperatures once again supporting the CFS. The lines going up are is just spring when the average temps rise.

I didn't expect to use the climate simulator in my forecast because I've only used it briefly last year. This year I read more into it and when I ran a few simulations and compared it to the CFS I was surprised to see agreement between them and thought it would be great to use it as back up.

[A Winter's Tale]

AWT'S WINTER FORECAST 2012/2013

DECEMBER...quite cold, changeable with periods strongly influenced by low pressure but there should be some quiet and settled spells at times. Some periods of partciulary wet weather and at times quite windy and there could be a few storms. Temperatures 0.5 below to 0.25 above the average. CET 4.3C. Rainfall 90% in the north and west and 70-80% in the south and east. A good deal of hill snow in the highlands and some wintry weather at times . Sunshine 0-5% above average.

JANUARY...cold with a sustained period of below average temperatures, wintry precipitation and dry conditions - in the north, and some cool, changeable and unsettled weather during the month with some wet and windy weather and possibly wintry in the north. Temperatures -1.25 to 0.25C below avergae. CET 2.8C. Rainfall 85%. Some widespread snowfall in cold spells and a risk of hill snow in the highlands throughout the month. Sunshine 5% above average.

FEBRUARY...average with some cold, wintry spells but generally more unsettled and changeable with temperatures in general close to the average. Temperatures 0.25 below average to 0.5C above average. CET 3.8C. Rainfall 85 to 100%. Some wintry precipitation in cold spells. Sunshine 5% above average.

[Bristawl Si]

I think it'll be an average winter across all components that make up our weather in the UK.

A bit of everything i suppose.

Cold at times but no really prolonged cold spells.

I think there'll be a north/south split, with coldest, snowiest in the north. The South experiencing fleeting glimpses of snow - maybe 2/3 days at a time.

I just wonder whether it will be one of those 'so nearly winters' in terms of v cold and snow.

Only a hunch from me.

[UV-RAY]

Much ado about nothing will probably best sum up the coming winter.

[Zenarcher]

Most members forecasts seem to go for a cold blocked December and if the charts the models are currently showing come off then it's a good start to our winter forecasts.

[Zenarcher]

My short updates based on CFS trends,

December: Rainfall still close to average and slightly below in the North. Temperature's still going for below average. Pressure still expected to be strong to our North.

January: Rainfall average for all of the UK. Temperatures still expected to be above average. Pressure indicates the Azores high to take charge giving us a settled but mild January.

February: Rainfall average but below in the North. Temperatures below average. Pressure still showing to be very strong and good for blocking patterns.

Overall nothing much has changed with December and February still looking good for blocking patterns and cold meanwhile January slightly more mild and pretty average.