Partholon
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Posts posted by Partholon
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Generally when the N hemisphere is HP dominated we see HP bouncing between Scandi and Greenland, this is a common occurence during prolonged cold spells. December 10 was very similar but I think it started with a greenie high as far as I can remember. Meto outlook was promising with only a smaller mild blip mid month.
Unfortunately, I think they've changed their longer term outlook again today, though): December 2011 was indeed a greenie high. I remember it fondly, because the amount of snow that accumulated was more than I'd ever seen before in Ireland.
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All change after the SSW.
Well played C, hats off Sir...
So a technical SSW has now actually occurred? Whatever the case it's a very good sign when all eyes are off this thread, and there are a thousand-odd eyes on the model thread:)
With this in mind, I hope chino' and others who provided all the info in this thread are rewarded with some of white stuff in the days ahead.
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Interestingly HP moving to Greenland is what GP indicated might happen. Since he has got the overall picture correct, hopefully he'll be right about this little piece of the jigsaw. If those of us further west are to see any snow we need this to happen.
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Quite a noticeable rise in mean zonal winds and drop in stratospheric temperatures is expected in a few days time! I hope it's only a temporary affair before another warming takes place.
http://wekuw.met.fu-...ww/wdiag/ts.php
Karyo
Well even if that's the case, surely it will take a while before it begins to take effect? Would this have anything to do with the impact from the solar storm?
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I think it's safe to say it's going to get colder in Ireland, it's just a question of how cold it will get, and how long will it last. The uk met office is confident of cold air persisting for at least the first week or two of February(the longer it persists the better chances of snow coming from some direction eventually), but of course these met office forecasts do not have Ireland in mind specifically, so it could well get milder here, while the cold air persists in much of England. If this is how it plays out, at least let us have some snow before the change.
After the winter so far, it'll be a real sickner if we don't get anything out of this.
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Simon Keeling's forecast is useless.
So his forecast haven't been accurate this year? Or is that more of a desire for him to be wrong rather than a statement of fact .
Anyway I shouldn't be worrying about a cold spell ending, that hasn't even happened yet. Even if he were to be right, better to have brief cold conditions than none at all!
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Simon Keeling's forecast posted earlier in the thread is disappointing. The Atlantic is back in after no length of time according to him. He obviously doesn't think a Greenland high will develop to help prolong any cold spell.
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I see Met Eireann in their latest update are not even mentioning the possibility of wintry showers for the weekend. I think the chances of a good upgrade are low at this stage. Looking to the longer term, some of the models do show opportunities for a decent cold spell.
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Matt Hugo's latest ECM 32 day update was as he put it the best he's seen for northern
blocking since December 2010 with a clear indication from the model of easterlies from
23rd to 29th then Greenland blocking and north/northeasterlies 6th to 12th Feb.
The dates are unimportant its the fact their sounds of though their was a strong signal
for northern blocking.
Considering how accurate the ECM 32 dayer has been I find it strange that given the strong
indications of a cold outlook (this is the second update to show this) he has downplayed
this with no blogs on netweather and only a couple of references on (TWO) and now he is
talking of a stronger signal for a +NAO.
Could the GFS profiling of the stratosphere with a much more +NAO and stronger Vortex
be proving correct I wonder.
The UKMO in their extended outlook yesterday made no mention of blocking. That may suggest they are backing the GFS on what happens in the stratosphere and its effects lower down.
If so maybe that's why he's downplaying the ecm 32 day update?
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not looking too good according to this guy:
Matthew Hugo @MattHugo81 1h Reply Retweet
...mean zonal wind set to increase above 20 to 30hPa now longer term from the ECM = renewed support for +NAO/Atlantic weather..
I guess a positive slant on this might be that it takes a few weeks for the effects of this to show up on the models
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I can't help but think, that that despite the fact that a cold outbreak is v.likely within the next 5-15 days, and potentially a severe one, with some potent blocking high synoptics as the aleutian ridge moves into siberia.. but then the pv builds again, regardless of the probable surface high o/greenland.. I think one or two more warmings are needed before january closes, most favourable quite strong and n.pole orientated.
We have slowly doused the fire that is the pv, as proven by the prominent blocking high over alaska currently, and the projected shift west of the pv into baffin/nunavut soon... but we need more water (strat warming) as the fire is contagious. Just a couple buckets more, but we need it soon...
with this post in mind:
Sorry if this is in the wrong forum, but what was the state of the stratosphere back in the winters of 1947 and 1962/63? Was the stratosphere warm throughout those prolonged cold spells, or was it a case that the initial warming created such huge blocking highs, that they couldn't be dislodged despite the stratosphere cooling down? Last year, according to the experts, it seems once the stratosphere started to cooled down in December, our chances of cold returning were low. So i suppose my question is can blocking highs sometimes be sustained, even if the stratosphere cools down significantly?
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So what you're really saying is it's beginning to look fairly bleak now for sustained blocking. If there is no further warming the vortex will probably quickly reorgainse itself and move back over Greenland. One positive is the CFS temperature chart for February, but those can change frequently.
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Well that's my December forecast and White Xmas thrown out the window.
However, RJS is so far having a great forecast!
As I said earlier, right up till the 15th December he was spot on. Then, his forecast got even better with the promised cold spell between the 15th and 22nd happening with many areas seeing their first snow of the winter with some distruption. He expected snow on the ground before Christmas which has happened (3cm out there right now). And he also expected it to get milder at Christmas which looks set to be correct. And at the moment, developments in the Stratosphere is looking favourable too for his forecast. The models after Christmas Eve will change a lot so at the moment I expect the events correctly predicted to happen (by the models) for beyond Xmas is unlikely to be accurate.
So all in all, RJS's December forecast looks set to be spot on. Let's hope that January and February are accurate too (except that little bit better).
His lrf forecast for December 2010 was spot on too. Unfortunately there after his forecast was not very accurate. I really hope it doesn't turn out to be the same this year. An important thing to remember is his forecast for January seemingly hinges on a strat' warming occurring. The experts over in the Stratospheric warming thread have cautioned that despite promising signs one may not take place at all. It'll be really disappointing if we don't get out of this current dreadful pattern to something far better, as it would indicate solar activity has increased enough to bring our weather back to normal.
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any ssw in december was always going to be unlikely though.
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I thought Roger J Smith's and GP's winter forecasts were mainly based on the idea of a SSW event happening before the end of December?
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Monitoring tells us that the cooling is most pronounced around 60N, which is further south than under most strong vortex events. What is really striking at the moment is the modelling of the tropospheric vortex; the primary centre west of Greenland; the second forming in the Bering Straights - totally out of kilter with Ninas and likely to cause no end of problems with NWP as they will be preconditioned to programme a ridge where troughing is developing. Slowly, slowly, starting to develop as a hemispheric pattern but going to take a long while to blossom.
Monitoring tells us that the cooling is most pronounced around 60N, which is further south than under most strong vortex events. What is really striking at the moment is the modelling of the tropospheric vortex; the primary centre west of Greenland; the second forming in the Bering Straights - totally out of kilter with Ninas and likely to cause no end of problems with NWP as they will be preconditioned to programme a ridge where troughing is developing. Slowly, slowly, starting to develop as a hemispheric pattern but going to take a long while to blossom.
Are you saying that signals are emerging to support what you expect to unfold in 6 or 7 weeks time?
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Its interesting, the broad picture was suggestive of a Euro high but it looks like the P{V might pull just far enough west to allow the HP to build close to the UK. It makes a big difference to the practical outcome of the weather.
Will have to wait and see how that evolves, but a HP close to the UK, maybe just centered to the east/south-east of the UK is IMO the most likely solution now.
Do you think it will eventually move towards Scandinavia or sink...?
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Plenty of time for things to change. For example I'm pretty certain most people wouldn't care if we had a mild December and first half of Jan if we were to have a late Jan/Feb like both 47 and 56.
Very true. It would be good to have the cold to come, rather than it being all over by January. Retailers might appreciate it being later this year too.
So I hope we get a hugh siberian high tracking westwards towards Scotland in January, which holds firm against incursions from the Atlantic for a solid month or more
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sorry I was only able to watch to his predictions of heavy snowfalls with dates.
Now, whatever one uses to predict the weather, it really is utterly impossible to do that sort of thing-utterly impossible. One could say that it would appear to be the coldest over a certain period up to a month ahead over a period of dates and that snowfall would seem probable sometime between those dates but to be as insistent as he sounded on actual dates is simply not possible to give that kind of detail.
IF it turns out correct, + or - a week he can and will claim a correct prediction, outside that time frame and his forecast will be flawed but I do not doubt if we get cold let along extreme cold (by the way what does he mean by extreme cold?) or no severe snowfalls (causing severe transport disruption over large areas) he will still claim he is right.
No professional organisation is going to get mixed up with pointing out his errors so he will get away with it again even if he is wrong. And so the saga of his forecasts and accuracy will continue.
I really should stop responding to these outputs from him. I've said it many times and its true, get the forecast right=keep quiet, get it wrong and be quick to apologise and explain what you think went wrong. To me that seems the honest way to go about being a forecaster, be it for 1 day ahead, 1 month ahead, or a season ahead.
end of another jh rant.
not everyone is full of humility , these kinds of people will always be quick to self-praise if they get it right, but not forthcoming about when they get things wrong. you're wasting your time expecting them to change.
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Interesting read Partholon. What's the geomagnetic ap index right now?
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What do people make of this:
Let’s take a look at some select years in the past few decades, and examine the states of both the QBO and geomagnetic ap index, and their corresponding impact on the NAO phase.
1972-73
1973-74
1974-75
1979-80
1983-84
1988-89
1989-90
1991-92
1993-94
2000-01
All of the above years featured a -QBO (easterly), yet all winters (DJF) had a +NAO average. If we look at the geomagnetic ap index for those winters, they all featured either high or rising values.
1977-78
1978-79
2008-09
All of these years featured a +QBO (westerly), yet the winters had a –NAO average. The geomagnetic ap index was either low or decreasing during those seasons.
Thus, in 13/40 years since 1970 the QBO and NAO were inversely correlated and did not follow the expected signal (+QBO/+NAO, -QBO/-NAO). So 67.5% of years followed the expected QBO/NAO combination. However, the geomagnetic ap index-NAO correlation since 1970 was quite a bit higher.
The QBO and geomagnetic ap index appear to have a relationship, which is not surprising; solar activity impacts stratospheric circulations/patterns. With that being said, geomagnetic activity appears to be more important than the QBO in terms of connection to NAO modality. In times of lower geomagnetic activity and –QBO, the –NAO potential is likely enhanced significantly.
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In the september I said cold and snowy
http://null.co...=238418#p238418
that was where I said that post.
actually its quite scarey how close I got...lol
http://null.co...=237479#p237479
On Friday sept 10th 2010 I posted this
Im going for middle of november, once the sun sets on the polar regions for the winter, it will cool down very very quickly.
bloomin heck I wasnt wrong...lol
I have to sign up to see those. I was hoping you were going to say you predicted a mild winter that year ):
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Absolutely Isolated Frost, its early in thge mroning and Ive been up through the night with the babies, what I am saying is dont expect any significant cold weather before January, thats when winter will start proper and yes the early start to winter last year was very unusual and I cant see a repeat performance as the atlantic is pushing all the time.
What was your thinking in 2009 at this time?
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Perhaps he is over-egging it. Roger J smith does predict a cold end to November, but nothing as severe and sustained as last year. It would be great if Corbyn is right, but he always seems to predict very cold weather.
It's interesting to note that Stuart Rampling and Roger J Smith seem to have similar ideas for later on in the winter, just a difference in timing.
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This is quoted from The In Depth Model output discussion, posted by TWS in the second week of Sept 2010. Considering this was about 9 weeks in advance it's not actually that far away from how winter actually turned out, cold and snowy Nov/Dec with average/mild second half to winter.
I get the impression of a cold and possibly snowy start to the season in November/December due to frequent northerly winds. After that perhaps becoming near average to fairly mild into January/February.
So we did get signals quite early on, which were perhaps ignored as it was to early for much interest. Unfortunately we haven't had any hints of a signal or guidance which would point towards any severe prolonged cold weather like last year which I'm sure would have been picked up on.
I wasn't aware of this. That is a fairly worrying piece of information alright. What about the prolonged cold spell of the previous winter? Was there any signal in advance about that by anyone?
Ireland Regional Discussion - January
in Regional
Posted
The lastest met eireann update is as follows:
Wednesday, Thursday and Friday will each be very cold a largely dry days with sunny spells. Temperatures will only range from 3 to 6 degrees by day and will fall as low as -5 degrees in places at night. Winds will be mostly light to moderate and east to southeast in direction. Current indication suggest that next weekend will continue very cold with a risk of wintry showers on east and south coasts.
Although that could have all changed again by tomorrow!