Winter/Spring 2013 (Model Output Discussion)

Sponge Bob

Only in FI but don't let that stop anyone.

Caff Caff

Of course because it could be even colder! A snowlover can dream...mainly thanks to FI but it's better to post FI to track progression, trends and changes than not but hey, I'm no expert.

musical theatre manic

i have no idea what those charts mean ....some layman language would be nice :P

Sponge Bob

musical theatre manic wrote: »

i have no idea what those charts mean ....some layman language would be nice :P

Blue or Purple = Cold and Not Blue = Not Cold.
If = Not Cold then = No Snow!

HTH

Joe Public

Tindie wrote: »

WOW, No one posted anything for about 24 hours, what everyone doing their Xmas Shopping before we snowed in lol

The goalposts are moving so much on this thread that people are getting confused. It started as a general Winter 2012-2013 then it got more technical and lately it's gone to forecasting late Autumn weather.

Sponge Bob

Joe Public wrote: »

lately it's gone to forecasting late Autumn weather.

Thats because the next week will be warmer than much of October Joe.

Sponge Bob

NAO rapidly heading for its most positive result since our mini Heatwave in early September. Not forecast to remain there too long.

Wolfe_IRE

I can see a trailing off of temps during the final 10 days of the month but little more than that. We should see winds shift from a SW to W-NW during this period. There is little potential for wintry weather during the next two weeks and temps for the month should finish up below average (1.5c or so) if this trend continues.

Su Campu

Very negative Z500 anomaly over the northern Atlantic/Greenland area over the next 1-2 weeks typifies the very positive NAO. Note the positive anomaly over western Russia. Watch that space this winter is my advice.

BLIZZARD7

I think there are signs of a change in the last third of the month- Latest ECM shows heights building to our north east over scandi/svalbard and possibly migrating westwards, Polar vortex also splitting- charts very similiar to this time in 2010.

Obviously its not likely at all that we will have a repeat of that epic cold spell and all these charts are still firmly in FI, but things are setup alot better than this time last year and despite a cold strat the outlook is promising imo.

ECM 12z +240hrs




Vs November 2010





Dan

Wolfe_IRE

The extended period of mild weather this week we will be replaced by cooler conditions next week (a degree or so below average). No sign of any wintry outbreak into the final week of November. It is going to remain unsettled for the coming 10-14 days, at least.




UK Met Office outlook


Monday 26 November—Sunday 9 December
Drier and colder conditions to start December?

November looks like ending on a rather unsettled note, with temperatures remaining around or perhaps a little below average.

However, a new month may bring about a change in the weather pattern.

Although there is inevitably a lot of uncertainty, the start of December may see drier and colder conditions affecting the United Kingdom, with pressure possibly building out to the east. If this happens, things may turn drier and brighter, but considerably cooler than of late for many of us, particularly in the south.
Next week

The unsettled theme looks like continuing for a while yet, but a new month may bring about a marked change to our weather. Could winter be on its way?
http://www.bbc.co.uk/weather/2635167

Loughc

Is it just me or did it feel much milder last night and this morning?

Tom Cruises Left Nut

lockie1983 wrote: »

Is it just me or did it feel much milder last night and this morning?

Its not just you !

Up to 13 degrees in my neck of the woods

Wolfe_IRE

LATEST FROM UKMO:



It seems that it is the time of year for colourful headlines about an impending big freeze. We had them at this time last year, which prompted our Chief Executive to write an opinion piece in The Times.


Now we have very similar stories again, with the front page of the Daily Express declaring ‘Coldest winter freeze on way’ and warning that temperatures are set to plunge as low as -15C. There have been other stories elsewhere along similar lines, with some saying that the Met Office is briefing the Government about a cold winter ahead.


So what are the facts behind the headlines?


Some of the stories have taken a cue from parts of our current 30-day forecast. Today’s forecast for 26 November to 10 December reads as follows: As is usual, there are uncertainties in the forecast for this period, but there are signs that the changeable conditions will continue through the start of this forecast period. There is also a signal for temperatures to be close to or just below the seasonal average. Into December, although there are no strong indications that any particular weather type is going to dominate, on balance colder, drier conditions than at present are favoured, rather than milder, wetter weather, especially across the southern half of the UK.

However, perhaps what the newspapers have failed to pick up on and report to their readers is that there is still a great deal of uncertainty about exactly what weather we will see – as there often is when looking at timescales of over five days ahead.


The science does not exist to make detailed forecasts for temperature and snowfall for the end of this month, let alone for December or even the winter as a whole.


With regards to us ‘briefing the Government on a cold winter’, this is related to our three monthly outlook for contingency planners.


This is a complex product designed to help contingency planners making long-term strategic decisions based on risk exposure. However, it’s not useful for most other people as it doesn’t give one forecast for what’s ahead – rather it outlines potential scenarios and their associated probabilities.


It’s worth noting that while contingency planners use our three month outlook to inform long-term decisions, they make their operational decisions on our five day forecasts and warnings.


These will always provide the best possible guidance on any periods of cold weather, frost or the likelihood of snow, giving detailed local information across the UK.


Ultimately, we’re heading into winter and we expect winter to be colder than the rest of the year – but it’s too early to say exactly what temperatures we can expect or where and when we might see snow.

Wolfe_IRE

Above average mean sea level pressure suggested in the Global long-range model probability maps i.e. adds to this blocking theory being mooted

Wolfe_IRE

As we head into the winter season, it is important that everyone here on the boards.ie weather forum puts the widely reported prospects of severe wintry weather affecting western Europe, including Ireland and Britain, at the end of the month into context.

As many members here have been saying for the past few weeks, it is highly likely that temperatures as a whole this month (November) will finish at least 0.5c to 1.0c below the 1981-2011 average. This follows a cooler than average September and October.

This week will be relatively mild but unsettled. I can see a trailing off of temps during the final 10 days of the month but little more than that. We should see winds shift from a SW to W-NW direction during this period resulting in a dip in temperatures. There is little potential for “significant” wintry weather during the next two weeks. However, wintry showers are likely, particularly in the western half of the country and on high ground, during brief cold incursions from the northwest during the final days of the month.

The Daily Express (Scottish edition) today published an article stating: “SCOTLAND can expect the first big winter freeze by the end of the month, with temperatures plunging to as low as -15C, forecasters predicted last night. Experts warned the UK is set to shiver with bitterly cold winds, harsh frosts and snow likely to last into December.”

There is little or sign that such a severe wintry blast is likely to happen. Of course it could happen, pending a dramatic change over the coming days in relation to what computer models are presently saying i.e. a cool SW-W jetstream influenced weather setup interspersed with brief colder incursions from the NW.

The UK Met Office has also been setting the record straight in relation to media reports of “two months of snowfall” and temperatures hitting “-20c”. http://metofficenews.wordpress.com/2012/11/12/whats-in-store-this-winter-responding-to-the-headlines/

So, will Ireland experience snowfall this winter? Ultimately, it is impossible to tell with any certainty when and where it will snow other than to say that there are increasing signs that that our winter will be colder than winter 2011-12. It is important to point out that a colder than average September, October and November does not necessarily mean that December will follow suit. It should also not be regarded as a precursor to a severe winter. The bottom line is that there are signs that blocking will be more of a feature in our weather during the early part of winter. Should this trend continue to show up on the main computer models, then our weather will turn colder with the airmass over Ireland originating from our east or northeast. This trend is something that we all will be watching very closely. Please note that the first signs of the late November 2010 wintry outbreak did not appear until about 10-14 days in advance.

Wolfe

derekon

Just read on Mark Vogan's twitter page that he is now allowing people to subscribe to his website by direct debit if they don't have a debit or credit card.

How helpful is that ?

You can now pay by direct debit for complete sh*te!!! :D:D

D

Blizzard 2010

GUYS just check out GFS18z in F1 from t288 - t384 :eek: I know its only F1 but certainly good eyecandy:D

BLIZZARD7

18z GFS is beautiful tonight! What a run! Perfect example of what I was saying could happen- small chance but the trend continues!


Only going one way from here!



Then BOOM!



Take above with a pinch of salt unless it becomes more common in the models over the next few days.





Dan

Caff Caff

The end of the month is still trending towards a drop in temps and an Eastern Promise! Not extreme FI but FI nonetheless. I would still keep a close eye on the models for this continuing trend. See 18z above. This would bring with it a 850hpa of -8°c. Looks beautiful!!

Su Campu

While we're on the subject of the crazy 18Z, here's the GFS forecast sounding for Dublin Airport for the 28th. Cold but clear. SLP (not shown) is 1032. T2m 1.3 C, DP -3 C.

Lucreto

I can't remember who said it here but the charts didn't have the 2010 cold weather until 72 hours before it happened.

Wolfe_IRE

Lucreto wrote: »

I can't remember who said it here but the charts didn't have the 20 10 cold weather until 72 hours before it happened.

hi lucreto. they were showing cold a good 10 days at least before late Nov cold. regarding tonight's gfs run, we need to see a continuation of the blocking trend in the next few runs. morning time could present a downgrade on the extent.of the cold shown tonight but it's the trend we need to watch.

Lucreto

Wolfe_IRE wrote: »

hi lucreto. they were showing cold a good 10 days at least before late Nov cold. regarding tonight's gfs run, we need to see a continuation of the blocking trend in the next few runs. morning time could present a downgrade on the extent.of the cold shown tonight but it's the trend we need to watch.

I don't have my hopes up for anything this side of Christmas. But I do like the trend.
Just finished the major bulk of my Christmas shopping just in case..:D

Redsunset

Accuweather winter forecast in line with M.T late Jan into Feb cold.



Meteorologists expect Siberian cold to reach portions of western and northern mainland Europe, especially during the middle to latter part of winter. Much of the United Kingdom, Denmark, the Netherlands, Belgium, Poland, Germany, Switzerland, France, Spain and Portugal will have below-normal temperatures for the season."January to February will be the best chance for cold air coming out of Siberia," AccuWeather.com Senior Meteorologist Alan Reppert said.




Well to the north of the active storm track expected this winter, near- to slightly below-normal precipitation is in store for the U.K., Ireland and Scandinavia."London will be mild to start [this winter]. Then it will be turning colder for the end of the winter. That could be there best chance for any snowfall late January and February," Reppert said.

Blizzard 2010

Redsunset wrote: »

Accuweather winter forecast in line with M.T late Jan into Feb cold.



Meteorologists expect Siberian cold to reach portions of western and northern mainland Europe, especially during the middle to latter part of winter. Much of the United Kingdom, Denmark, the Netherlands, Belgium, Poland, Germany, Switzerland, France, Spain and Portugal will have below-normal temperatures for the season."January to February will be the best chance for cold air coming out of Siberia," AccuWeather.com Senior Meteorologist Alan Reppert said.




Well to the north of the active storm track expected this winter, near- to slightly below-normal precipitation is in store for the U.K., Ireland and Scandinavia."London will be mild to start [this winter]. Then it will be turning colder for the end of the winter. That could be there best chance for any snowfall late January and February," Reppert said.

Might suggest a north - northwesterly airflow

BLIZZARD7

Not much change today- Blocking still to our north on the GFS 00z-



00z ECM looking much better too-

+192hrs



+240hrs



So while its all still in FI- The trend is still most definitley there, High latitude blocking and fragmented vortex that is.

Matt Hugo has also said ECM 32 dayer is still showing blocking to our north.

Interesting models at the moment.





Dan

BLIZZARD7

General Theme still there on the 06z GFS.






Dan

Strangegravy

musical theatre manic wrote: »

i have no idea what those charts mean ....some layman language would be nice :P

Have a look at this thread, a bit of reading in it but it will make the winter months on here a lot more fun if you go over it!

http://touch.boards.ie/thread/2056447334?page=1

BEASTERLY

Lucreto wrote: »

I can't remember who said it here but the charts didn't have the 2010 cold weather until 72 hours before it happened.

Not true. The models were picking the trend up as far as 15 days before the cold actually hit us proper. As usually happens in this situation they got pushed back bit by bit eventually "verifying" about 72 hours after they were forecast to on the original charts. For example here's a chart from the 13th of November showing a situation which verified(Obviously the particulars are different) exactly 2 weeks later. Here it is modeled to happen about 3 days before it actually did.



What couldn't be nailed down until 72 hours as is always the case, was how cold, how much snow, and where, accurate wind direction etc. But the charts were saying there was going to be a cold blocked scenario of some sort up to 2 weeks before the event.