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Weather Masters 2012 - 2013 Winter Forecast

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Zenarcher

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[center]Updated summary below and in the comments - Last Updated 9th February 2013.[/center]

[center][size=5]2012 - 2013 Winter Forecast[/size][/center]

[center]Written By Sean Macdonald aka on NW weathermaster[/center]


[center][b]How the forecast has been made[/b][/center]

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.

[center][size=5][b]December[/b][/size][/center]
[b]Temperature[/b]

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.

[attachment=146269:cfsdecembertemp.gif]

[b]Rainfall[/b]

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

[attachment=146270:cfsdecemberrain.gif]

[b]Pressure[/b]

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

[attachment=146271:pressuredecember.png]

[b]Overall[/b] - 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.










[center][b][size=5]January[/size][/b][/center]
[b]Temperature[/b]

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.

[attachment=146272:cfsjanuarytemp.gif]

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.

[attachment=146275:Jantempsexplained.png]

[b]Rainfall[/b]

[attachment=146273:cfsjanuaryrain.gif]

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

[b]Pressure[/b]

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.

[attachment=146274:pressurejanuary.png]

[b]Overall[/b] - 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.










[center][size=5][b]February[/b][/size][/center]
[b]Temperature[/b]

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.

[attachment=146276:cfsfebuarytemp.gif]

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.)

[attachment=146277:Febtempexplained.png]

[b]Rainfall[/b]

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

[attachment=146278:cfsfebuaryrain.gif]

[b]Pressure[/b]

Very strong over our North and East,

[attachment=146279:pressurefebuary.png]

[b]Overall thoughts[/b] - 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.

[b]The climate simulation graphs,[/b]

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,

[b]Greenland temp,[/b]

[attachment=146280:greenlandtemp.png]

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.

[b]UK temp,[/b]

[attachment=146282:uktemp.png]

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.

[b]Svalbard temp,[/b]

[attachment=146281:Svalbarbtemp.png]

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.

---------------------------------------------------------------------------------

[b]9th of February 2013 Update From CFS[/b]

[color=#000000][b]February:[/b][font=helvetica, arial, sans-serif][size=3] Above average rainfall for England and Wales but elsewhere below average. Temperatures close to average but at times below average. Pressure patterns indicate low pressure to sit over Europe and high pressure over our North, the Azores high starts to gain some strength as well.[/size][/font]

[b]March: [/b][font=helvetica, arial, sans-serif][size=3]Rainfall well below average for Scotland but elsewhere above average. Temperatures below average everywhere. Azores high weakens completely and low pressure sits out in the Atlantic but high pressure sits over Iceland and Greenland giving off cold temperatures.[/size][/font]

[b]Climate Simulator February Update[/b]

[font=helvetica, arial, sans-serif][size=3]So far this winter it's done really well in my view, I last ran it in early January and now with the latest data from around the world I have ran it again to see what it says. Basically it agrees with the CFS on temperatures being slightly below average for February but shows temperatures go well below average for March interesting to see this as it hasn't done this before, it has shown only temperatures to be slightly below average so this will be interesting for March and not only that the CFS also goes for temperatures in March to go down below average.[/size][/font]

[b]Overall - [/b][font=helvetica, arial, sans-serif][size=3]Not much left of winter now I expect February to be fairly average and any cold spell not to be extreme and will be short lived as for March early signs are saying it could be a very cold and perhaps snowy end to the winter.[/size][/font][/color]
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[quote name='A Winter's Tale' timestamp='1354218706']
Very good forecast wm!
[/quote]

Thanks :)

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[b]Latest CFS trends,[/b]

[b]February:[/b] Above average rainfall for England and Wales but elsewhere below average. Temperatures close to average but at times below average. Pressure patterns indicate low pressure to sit over Europe and high pressure over our North, the Azores high starts to gain some strength as well.

[b]March: [/b]Rainfall well below average for Scotland but elsewhere above average. Temperatures below average everywhere. Azores high weakens completely and low pressure sits out in the Atlantic but high pressure sits over Iceland and Greenland giving off cold temperatures.

[b]Climate Simulator February Update[/b]

So far this winter it's done really well in my view, I last ran it in early January and now with the latest data from around the world I have ran it again to see what it says. Basically it agrees with the CFS on temperatures being slightly below average for February but shows temperatures go well below average for March interesting to see this as it hasn't done this before, it has shown only temperatures to be slightly below average so this will be interesting for March and not only that the CFS also goes for temperatures in March to go down below average.

[b]Overall - [/b]Not much left of winter now I expect February to be fairly average and any cold spell not to be extreme and will be short lived as for March early signs are saying it could be a very cold and perhaps snowy end to the winter.

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