ArHu3
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Posts posted by ArHu3
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3 hours ago, Catacol said:
Have you got a link? Never heard of this before....
So strange, only a wiki article in dutch and german... Hellmann number for a certain period is the modulus of the sum of the below 0 degrees centigrade days. eg a week with average temperatures of -10,-10,10,10,10,10,10 will have quite a remarkable hellmann number of 20 but a very unremarkable 7.1 degrees for an average
Koudegetal - Wikipedia
NL.WIKIPEDIA.ORG -
2 hours ago, Don said:
Well, that’s it folks. Cold/snow lovers are doomed for at least another season......
Most of these minima years were actually pretty cold eg 81 ( = winter 81/82 ), 85, 86, 2010
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2 hours ago, Catacol said:
If the usual approx 14 month cycle is maintained then peak eQBO would in in the sweet spot next year. Just past solar minimum too. Statistically it is easy to prove that not every eQBO winter is cold and not every solar minimum winter is cold but it is also the case that the memorable cold spells in the UK over the last 35 years or so have tended to feature eQBO context with a vague link to solar too. Since 1985 we have had 12 January/February/March months with a CET of 3 or below (Jan 85, Feb 85, Feb 86, Jan 87, Feb 91, Feb 96, Jan 97, Jan 09, Jan 10, Feb 10, Mar 13, Feb 18) and all were preceded by a December where an eQBO was in place apart from Feb 86 and Feb 91 when the winter was wQBO throughout. That’s 10 winters in the last 35 with a cold sub 3 winter month in the period beyond vortex peak and 8 match to eQBO in December. My eyes also see a vague solar connection here though I know others will disagree.
If we raise the bar a bit to mid/late winter months with a CET of between 3 and 3.5 then we add in Jan 86, Jan 91, Feb 94, Jan 01, Jan/Feb 13. From the info above we know already that Dec 85 and Dec 90 were wQBO but the other 3 winters had eQBO in December. That makes a grand total of 14 out of 18 cool to cold Jan/Feb/March CET months (defined as CET 3.5 or less) linked to an eQBO in December. Converting this into years we have had 13 winters in the last 35 with at least one cool/cold winter month and 11 had an eQBO December.
We can also analyse in reverse. How many mild Jan/Feb months have been preceded by a wQBO in December? I’ll take anything above 5.5 as mild....and we see Jan/Feb 89, Jan/Feb 90, Jan 93, Feb 95, Feb 98, Jan 99, Feb 00, Jan/Feb 02, Jan 05, Jan/Feb 07, Jan 08, Feb 11, Jan/Feb 14, Feb 19 - and of these 14 winters with a mild mid/late winter profile 10 featured a wQBO in the preceding December.
My take on this has always been that eQBO on its own is not a guarantee of anything (eg the deepest eQBO December on record was Dec 14 but the super Nino overrode everything...) but without an eQBO cold spells are few and far between. Equally not every mild winter month is preceded by a vortex pumped up in December by a wQBO - but the majority are.
This is a simple tool and I think it has value. Dec 2019....where are we? Right on the cusp. Another reason perhaps why things are so hard to call this year. Winter 2020/21 does indeed look better.
If you look at averages alone you miss possible cold spells followed by warm spells, it's better to look at the Hellmann cold number
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I will remember 2019 as the year of the hottest day ever in the Netherlands, with temperatures reaching 40 degrees in my neighborhood. I don't remember any other memorable event but those 40 degrees were damn hot
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8 hours ago, ALL ABOARD said:
Nope that's definetly not how it works
I've looked through all the known major warmings, many were preceded by a marked cold period (in my location, ie. The Netherlands) if the event was a displacement it was never followed by a marked cold period and in case of a split it was some of the times but not all of the time. Like we saw last year when a 3rd fragment ended up right over Greenland .
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1 hour ago, bobbydog said:
All is not lost...
Getting toasty up there...
If the trop vortex follows these purples we're screwed , southwesterlies until spring
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1 hour ago, carinthian said:
Horrible conditions today in the Eastern Alps. Full Fohn affect. Temps nearly 10c at 1500m. Snow melting away very quickly at the moment. Just have to sit back and wait. All very frustrating in the resorts. Cancellations coming in now.
C
How's the snow in Tirol and higher up?
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1 hour ago, Paul_1978 said:
But will be the vortex be displaced where we want it or where we don't want it!
EC has it moving towards Scandinavia and then probably to Siberia, which probably won't be too bad for us since it leaves Greenland open for building heights
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8 minutes ago, Iceaxecrampon said:
For the past 2-3 weeks the different members ensembles of the various models each went in their own direction and there was no clear signal at all but it appears the MJO will emerge somewhere in sector 6(with a few members in sectors 5 or 7) with a bit of amplitude. We want the MJO in sectors 7,8 and 1 as they favour blocking in our region
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7 minutes ago, Kirkcaldy Weather said:
The models seem to have great difficulty with the Indian Ocean Ocean dipole but once the MJO leaves the pick up the correct signal again
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Mjo seems to be gaining even some more amplitude today and I think it will increase more and more in the next few days when the models finally figure out where exactly it will emerge
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4 hours ago, Crepuscular Ray said:
Still no record-breaking snowfalls and minimum temperatures, though.
It's usually not coldest at midnight but right after dawn, there is still a lot of retained heat from many many intense solar cycles
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6 hours ago, feb1991blizzard said:
Not sure that it will materialise this early, i have looked back at a few analogues - not many i must admit so small sample size but looks to me like Indian Ocean Sector and then continuation around into phase 7 and 8 is the best MJO analogue for SSW's , ECM not looking very high amplitude MJO at all at the moment.
6 hours ago, feb1991blizzard said:Not sure that it will materialise this early, i have looked back at a few analogues - not many i must admit so small sample size but looks to me like Indian Ocean Sector and then continuation around into phase 7 and 8 is the best MJO analogue for SSW's , ECM not looking very high amplitude MJO at all at the moment.
this is yesterday's plot but the same problem is still current, because the different members of the ensemble go to such different sectors the average amplitude is low
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Finally EC is getting some grip on the MJO and I think the amplitude for week 2 will be bigger than what the average shows because it still hasn't figured the sector out completely
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7 minutes ago, Dennis said:
MJO looks better -into phase 8 over the next period - wintersetup with NNE Highpressure
The bias corrected looks even better with more amplitude into phase 7 and it looks much better than yesterday's outlook too
Today
Yesterday
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@Midlands Ice Age could cosmic radiation affect ozone levels? There is of course plenty of cosmic radiation at the poles even during their winters
(Edit yes it can and these particles then can aid cloud formation as demonstrated by Svensmark)
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Finally after almost 2 weeks of a mild ensemble in unison for the entire 2 weeks out we see some discord and colder solutions from Christmas eve onwards.
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After a forecasted rebound the 1 hPa winds are forecast to decrease again, let's hope this trend now continues (although in previous years it usually oscillated downwards)
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1 hour ago, Catacol said:
And just to illustrate the truth of current huge model volatility the long range EC clusters are genuinely all over the place. The 6 groupings here represents virtually the entire spectrum of possible options. Right now FI NWP output is even more useless than normal...
probably because it doesn't know what to do with the mjo, I guess we just have to wait until the mjo leaves the indian ocean and hope for the best
but for the first 10-12 days the EC is actually very certain and I have seldom seen so little spread in the wind direction in the ensemble so far out
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4 hours ago, Surrey said:
I know it's the true depths of FI on the GFS but I don't think I have ever seen charts like it towards the end when it starts to pull in upper air temps like it is showing from Africa.. Silly charts.. Will look totally different on the 06z but can you imagine that.. How many all time high temps would probably be broken in December..
I know it's a period best forgotten but you don't remember mid December 2015 anymore?
WWW.METEOCIEL.FRArchives NCEP de 1851 à maintenant-
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4 minutes ago, s4lancia said:
OK, this is going to get interesting. General concensus on a rapidly growing SPV. Wave and flux activity looking very promising.
Intrigued how this is going to play out.
A huge Wave 1, sprawling wave 2, coinciding with the vortex winding up...
EC has 1 hPa dropping very sharply back to mid November strength with 10 and 30 hPa following, to me that does not seem that we will get a strong vortex, strong vortices always seem to gain strength in the upper levels first
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EC control evolved to a bitter cold Christmas in the Netherlands but it's just a fi outlier of course
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Now only if we got a slight modification of that EC +216h chart
so that it would look a bit more like this
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Winter 2019/20 | Moans, Ramps & Chat
in Spring Weather Discussion
Posted
Cold dry conditions aren't good at all but what happens in winter is that people cram together with the heating on and just all infect each other