Jump to content

The Seasonal Forecast Thread


Recommended Posts

Ok

December

After we see HP to N/NW with trough S to SE UK with NE'ly flow we are likely come December see this get sheered away and THE COLD SET UP get quickly dissipated as quickly as it has developed. HP to our S/SW and a very active deep LP over Iceland bringing a westerly flow will set in. The LP could be quite vigorous and bring gale to severe gales to N and western areas backend of 1 st week. The HP to our SW/S/SE format will dominate December with 'normal' service resumed and a general W flow mild in south and N getting mix of cold and mild. It may be that HP ridges further north midmonth to bring a colder frosty period but will give way to more disturbed pattern over Christmas. Signs of Scandi trough possibly being the lead as we go into New Year. CET 6.3c

Jan

To have a cold start but stormy pattern will take over after 1st week through to middle part. I then anticipate the signs of the huge blocking to come in Feb to be showing its hand with Atlantic heights ridging to Greenland and a trough forming over, just west of UK with arctic Russian block to east. Similar set up we see as approaching now. CET 3.5 to 4c

Feb

To hold this pattern unlike early Dec and indeed strengthen with a strong E to NE flow which will persist as blocking varies from Scandi to Iceland and Greenland. The pattern will repeat/re-impose throughout the month. CET 1.5c [max]

Detail I will bolt on at start of each month - these are original thoughts - could get off to very bad start.!!

BFTP

Edited by BLAST FROM THE PAST
  • Like 3
Link to post
Share on other sites
  • Replies 1.2k
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

The above summer forecast verified reasonably well in most cases, the prediction implied a top ten outcome and in fact the summer was around 3rd to 5th warmest on record depending on which data you us

Detailed version -- highly variable winter pattern expected     As promised, here are some more detailed predictions based on my research. I have tried to assess all the information offered in vari

2014/15 Winter Forecast    My attempt at a winter forecast. Some of the theory is taken from a previous project i undertook at University. I have attached references that i have used/think may be of

Posted Images

Ok

December

After we see HP to N/NW with trough S to SE UK with NE'ly flow we are likely come December see this get sheered away and THE COLS SET UP get quickly dissapated as quickly as it has developed. HP to our S/SW and a very active deep LP over Iceland bringing a westerly flow will set in. The LP could be quite vigorous and bring gale to severe gales to N and western areas backend of 1 st week. The HP to our SW/S/SE format will dominate December with 'normal' service resumed and a general W flow mild in south and N getting mix of cold and mild. It may be that HP ridges further north midmonth to bring a colder frosty period but will give way to more disturbed pattern over Christmas. Signs of Scandi torugh possibly being lead as we go into New Year. CET 6.3c

Jan

To have a cold start but stormy pattern will take over after 1st week through to middle part. I then anticipate the signs of the huge blocking to come in Feb to be showing its hand with Atlantic heights ridging to Greenland and a trough forming over, just west of UK with arctic Russian block to east. Similar set up we see as approaching now. CET 3.5 to 4c

Feb

To hold this pattern unlike early Dec and indeed strengthen with a strong E to NE flow which will persist as blocking varies from Scandi to Iceland and Greenland. The pattern will repeat/re-impose throughout the month. CET 1.5c [max]

Detail will bolt on at start of each month - these are original thoughts - coukld get of to very bad start.

BFTP

Brave call BFTP, for December anyway......maybe.

I'm just wondering if the cold forecast for first few days could easily hang around for a couple of weeks or even end up with

reload after reload of cold.

What do i know but it just seems we're in new phase of colder winters started in 2009 (bit like what we saw 78-87). I know last year wasnt cold but generally in a colder cycle.

Fair play though for a LRF.

Edited by Bristle boy
Link to post
Share on other sites

A very brave call with regards to December Fred, I admire that as it would have been easy to change your views now after seeing stellar charts for next month. Good luck with the forecast, I just hope December is wrong though.Posted Image

Link to post
Share on other sites

I hope I'm wrong too, getting prolonged cold instead would be great, but I have to stay with the signals I have despite model output. I await forecasts from GP etc and C re stratos and see where we go from there. Thanks for kind words guys, it would be a touch ingenuous of me to call cold now as that wouldn't be my LRF. Here's to being WRONG ! As I well maybe Posted Image

BFTP

Edited by BLAST FROM THE PAST
  • Like 3
Link to post
Share on other sites

I hope I'm wrong too, getting prolonged cold instead would be great, but I have to stay with the signals I have despite model output. I await forecasts from GP etc and C re stratos and see where we go from there. Thanks for kind words guys, it would be a touch ingenuous of me to call cold now as that wouldn't be my LRF. Here's to being WRONG ! Asry well maybe Posted Image

BFTP

Just a hunch - nothing more as i havent got skills to produce a LRF - but just wondering whether this Dec could be similar to '81?

Link to post
Share on other sites

I hope I'm wrong too, getting prolonged cold instead would be great, but I have to stay with the signals I have despite model output. I await forecasts from GP etc and C re stratos and see where we go from there. Thanks for kind words guys, it would be a touch ingenuous of me to call cold now as that wouldn't be my LRF. Here's to being WRONG ! Asry well maybe Posted Image

BFTP

Good luck with your prediction Fred. Posted Image

Just wondering what signals are you using to suggest that the upcoming cold spell will be shot lived?

Chino updated his thoughts over on the strat thread this evening and it looks quite promising for cold loversPosted Image

Link to post
Share on other sites

Good luck with your prediction Fred. Posted Image

Just wondering what signals are you using to suggest that the upcoming cold spell will be shot lived?

Chino updated his thoughts over on the strat thread this evening and it looks quite promising for cold loversPosted Image

Its my original thoughts using soalr/lunar cyclic effects. I'm not convinced its saying early end to cold now and Dec has been hard to call, just posted original thoughts and see how they pan out. Its looking a very interesting start to winter

regards

BFTP

  • Like 1
Link to post
Share on other sites

Hello. Posted Image

This year I decided to make a seasonal "outlook" of my own. I guess its a statistical forecast, because it is based on reanalysis. This is basically just a composite or a blend of the winters in the past. I used certain winters and blended them together. I have chosen the years and months, based on the overall global setup and similarities in the oceanic and atmospheric features. The graphics were made on October 29, when I finished my analysis process and first published on November 1st on a weather forum in my country. So lets say I have 1 month "lead time" before the start of the forecasted period. This is my first attempt of "statistical" forecasting, so I don't really expect much success to be honest, but I need to test it, so i decided to make a "public test", by posting it on different weather forums.

Some interpretation is required. This is basically an average picture, like an ensemble mean, so it has its respected deviation and variance. But just the average or "middle" picture will suffice for my first attempt. I posted this on a forum in my country, so the text on the graphic is in my language (Slovenian). But some words, like the names of the months are similar, so I think you will understand what period is represented on the graphic. Posted Image

I am only aiming at the DJF 500mb geopotential height anomaly for the verification in March, when the forecasted period is over.

Now the graphics. Keep in mind that this is unaltered in any way. And it was made in the end of October, when none of these features were present in the seasonal models. At least not in this magnitude.

Posted Image

Corresponding precipitation anomaly:

Posted Image

And temperature anomaly:

Posted Image

And I will also add the December 500mb height anomaly, made on the same date with the same system.

Posted Image

And this was CFSv2 when I made these graphics.

Posted Image

I first posted these images on a weather forum in my country, on November 1st. And all the graphics were made before that. Here is the link to that topic to prove it. Basically so no one can say that I "cheated", by looking at current models (which differ anyway) and intentionally making a similar picture. Posted Image

Best regards.

  • Like 7
Link to post
Share on other sites

Just want to add in here whilst its quiet.....even though I thought Dec was a tough call....my alternative view still would have been well short of the mark of what looks likely to come. Its way colder and blocking far more robust and widespread, as my other view was cold zoneality being prevalent. So a spectacular bust looking probable for early part of forecast......and as it looks mighty cold....so pleased Posted Image

BFTP

  • Like 5
Link to post
Share on other sites

Just want to add in here whilst its quiet.....even though I thought Dec was a tough call....my alternative view still would have been well short of the mark of what looks likely to come. Its way colder and blocking far more robust and widespread, as my other view was cold zoneality being prevalent. So a spectacular bust looking probable for early part of forecast......and as it looks mighty cold....so pleased Posted Image

BFTP

Well admired fred.

Link to post
Share on other sites

Maybe I won't be off to a bad start after all? If I'm not the models would have performed poorly as a very cold prolonged set up looked likely. Still if they changed like they have they could change back.

BFTP

Yes u could be right after all Fred!

This has to be one of the biggest model turnarounds since NW started!

Link to post
Share on other sites

Here's my forecast for 2012/2013 with the trend added back in,

post-5986-0-51125300-1352908483_thumb.pn

or,

Nov: 8.26C (+2.11C)

Dec: 4.40C (+0.21C)

Jan: 2.74C (-0.66C)

Feb: 3.68C (-0.37C)

Mar: 7.40C (+1.87C)

Not so chilly as before, but colder than normal. Don't forget that the +/- are against the entire CET set, not the meteorological norm (1970-2000?)

It'll be interesting to see how that pans out (Nov looks to be a little on the high side)

I have decided to abandon this version of my forecast and revert back to the original, using November's CET as the guide to getting the magnitude of the prediction correct. (current CET is 7.47degC against my prediction of 7.32degC)

Hope no one minds!

I am therefore keeping with,

Nov: 7.32C (+1.17C)

Dec: 3.46C (-0.73C)

Jan: 1.80C (-1.60C)

Feb: 2.74C (-1.31C)

Mar: 6.46C (+0.93C)

- a bitterly cold winter to come for the CET zone.

Original write up, here

Edited by Boar Wrinklestorm
  • Like 1
Link to post
Share on other sites

Ok its about the right time to state what I think this winter will deliver - based on my initial hunch and other forecasts.

December - colder than normal, but not exceptionally so, think of a mish-mash of 2008 and 2009 rather than 2010. Expecting alot of cold unsettled weather thanks to low pressure being steered on a southerly track with strong heights over the arctic ridging into Greenland. Also expecting a short-lived significant cold period perhaps mid month as heights ridge down from the NW - think a tamer version of late Dec 95.

January - most likely to be below average and possibly significantly below, but perhaps not quite as cold Jan 2010. Low pressure again will be held on a southerly track thanks to stronger than normal heights over the arctic and greenland. Chance of a very bitter polar continental outbreak with easterlies - a rarity in many January's. SW England could end up notably wet with a number of snowy epsiodes as low pressure tries to move in from the SW from time to time.

February - difficult to call perhaps slightly below average as the upstream pattern changes emphasis moving the cold core away from the NE and further to the NW. Again though with a southerly jet, alot of snow may occur at the 'battleground'.

I'm not expecting the winter to be as cold overall as 09/10 but it will be quite similiar in nature albeit wetter overall with the possibility of a number of significant snowy outbreaks but milder air may make inroads into southern parts from time to time whilst the north will stay largely cold throughout.

A hybrid of winter 08/09 and 09/10.

  • Like 5
Link to post
Share on other sites

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.

DECEMBER - MORE DETAILED FORECAST

First week: Starting cold, and dry, becoming unsettled with some wet and windy weather but on the cold side with the threat of some wintry precipitation in the north.
Second week: Initially unsettled and quite cool, turning a bit colder with northerly associated with mid-atlantic high with some snow in the north.
Third week: Becoming more settled for a few days with high pressure close to/over the British Isles - cold, frosty. Return to chilly, unsettled conditions.
Final week: Cool, quite unsettled start, becoming progressively colder later with snow becoming increasingly more widespread.
  • Like 3
Link to post
Share on other sites

For those interested i have published my thoughts for December Posted Image

http://forum.netweat...cember-outlook/

All charts and analysis can be found in my blog as i do not want to clog this thread up with tons of charts! My summary is attached below

Forecast

Overall im finding it rather difficult to produce a forecast, but then isn’t it always! What’s apparent is the PV shall remain disrupted and disorganised as we progress through December. I am generally supportive of height rises to the NE given the latest runs, although feel that these will transfer nearer Greenland as we progress through the month when we see further wave breaking disrupting the vortex and leading to more movement of the PV segments. This would be supported by the GFS MJO outlook, and ensemble forecasts for the NAO from both the ECM and GFS. The CFS could also be included. Weatherwise a cold and unsettled start, with the potential for height rises to out NE, and some sort of easterly flow during the first third. As we progress into midmonth and beyond I feel higher pressure would transfer closer to Greenland, bringing a more N/NE’rly flow.

I intend to update midmonth.

Edited by Mark Bayley
  • Like 1
Link to post
Share on other sites

TWO Winter forecast: Cold early and late

Overview

Cold weather mostly early and late in the winter, with milder spells sandwiched in between.

Temperature

The winter is expected to be slightly colder than average (possibly close to average) over the 3 month period.

Precipitation

Slightly drier than average in the south east, but close to average in the north west over the 3 month period.

December

Temperature: Slightly below average (below average more likely than above average)

Precipitation: Below average

First half

The first half of the month is expected to bring colder than average conditions with an ongoing risk of overnight frosts. Precipitation amounts are likely to be lower than average, but bringing a mix of rain, sleet and snow. As usual snow will be more likely over higher ground and in the north, but much of the country could see some snow for a time.

Second half

The second half of the month may begin wintry, but less cold weather is forecast to push back across the UK, and for this to last for much of the time with temperatures trending back above average. With milder weather there is likely to be an increased tendency for wet and windy weather, particularly in the north west and later on in the period. The south east should be drier at times. Overall the frost risk is expected to reduce and become fairly low, although perhaps higher in the south eastern corner at times.

January

Temperature: Slightly above average (above average more likely than average)

Precipitation: Close to or slightly above average

First half

The first half of the month is expected to changeable weather with showers or longer spells of rain. Transient colder conditions are likely, especially in the north where hill snow is likely, but on the whole temperatures are expected to be above average during this period, with a relatively low frost risk for the first half of January. Very windy at times.

Second half

The second half of the month may see a continuation of the unsettled weather with temperatures close to average in the north and remaining slightly above average in the south. A mix of wet and windy weather, and brighter interludes is expected. Some brief colder incursions from the north west are likely to bring hill snow, and possibly snow to lower levels temporarily in the north.

February

Temperature: Slightly below average (below average more likely than average)

Precipitation: Slightly belowaverage

First half

The first half of the month is expected to bring a good deal of relatively mild and unsettled weather across the north of the country. The wettest weather is forecast to be in the north west, with the south be drier at times. Later in the period an increased frost risk is expected in the south and east.

Second half

A transition to much colder weather is expected in the middle and second half of the month, with possibly the coldest spell of the winter developing. With the colder conditions frosts are likely to become widespread, and some snow is likely. Cold conditions are expected for most of the period

Link to post
Share on other sites

TWO Winter forecast: Cold early and late

Overview

Cold weather mostly early and late in the winter, with milder spells sandwiched in between.

Temperature

The winter is expected to be slightly colder than average (possibly close to average) over the 3 month period.

Precipitation

Slightly drier than average in the south east, but close to average in the north west over the 3 month period.

December

Temperature: Slightly below average (below average more likely than above average)

Precipitation: Below average

First half

The first half of the month is expected to bring colder than average conditions with an ongoing risk of overnight frosts. Precipitation amounts are likely to be lower than average, but bringing a mix of rain, sleet and snow. As usual snow will be more likely over higher ground and in the north, but much of the country could see some snow for a time.

Second half

The second half of the month may begin wintry, but less cold weather is forecast to push back across the UK, and for this to last for much of the time with temperatures trending back above average. With milder weather there is likely to be an increased tendency for wet and windy weather, particularly in the north west and later on in the period. The south east should be drier at times. Overall the frost risk is expected to reduce and become fairly low, although perhaps higher in the south eastern corner at times.

January

Temperature: Slightly above average (above average more likely than average)

Precipitation: Close to or slightly above average

First half

The first half of the month is expected to changeable weather with showers or longer spells of rain. Transient colder conditions are likely, especially in the north where hill snow is likely, but on the whole temperatures are expected to be above average during this period, with a relatively low frost risk for the first half of January. Very windy at times.

Second half

The second half of the month may see a continuation of the unsettled weather with temperatures close to average in the north and remaining slightly above average in the south. A mix of wet and windy weather, and brighter interludes is expected. Some brief colder incursions from the north west are likely to bring hill snow, and possibly snow to lower levels temporarily in the north.

February

Temperature: Slightly below average (below average more likely than average)

Precipitation: Slightly belowaverage

First half

The first half of the month is expected to bring a good deal of relatively mild and unsettled weather across the north of the country. The wettest weather is forecast to be in the north west, with the south be drier at times. Later in the period an increased frost risk is expected in the south and east.

Second half

A transition to much colder weather is expected in the middle and second half of the month, with possibly the coldest spell of the winter developing. With the colder conditions frosts are likely to become widespread, and some snow is likely. Cold conditions are expected for most of the period

Posted this in another thread but anyone have any ideas as to how Brian came to this conclusion for his forecast?

Link to post
Share on other sites

********I am off the mark************

Morning folks, it is clear that December as whole for me is off the mark and wrong. I have no doubt abouth that. Severe cold is building to our N and E and we are at times going to get in the mix so an up and down month but cold generally being the winner and possibly only SW areas being only places that get less cold/milder interludes. I will post an attempted detailed monthly outlook later today but IMO those that have called for more cold than mild and those that see northern blocking being more of a feature......I think well done. I say that because my detailed outlook will have a wintry flavoursome look to it.......

So ok see you later and already now the best I can do is 66% on my LRF and that is if it is day perfect which is impossible so I'm realistically at best down to 50% Posted Image .....................CET is below average this month

BFTP

  • Like 6
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...