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#1264938 - 28/05/2014 18:04 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
crikey Offline
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Registered: 01/02/2011
Posts: 2586
Loc: Tweed Heads
Noticing that 10hpa animation is about 4 days behind

Usually 'snow baby' there is significant strong surface MSLP cells in the sub polar region underneath the warm anomaly or near about.
Last year l don't remember the SSW bubble shifting from 120E ( a standing wave perhaps).
This wave has moved and appears to be oscillating between warm and colds somewhat.
Jenni' from New Zealand thread is reporting a strong cold burst
You can see the wave action evolving and creating a crest of cold air over NZ
That cold crest arrived across NZ today.

http://www.bom.gov.au/australia/charts/v...it=Refresh+View

There are some nice deep lows emerging in the surface sub- polar region currently. Hopefully lets hope this gets the wave atmospheric action going and some decent cut off cold pools and good strong fronts.
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#1265309 - 02/06/2014 18:36 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
crikey Offline
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Registered: 01/02/2011
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Loc: Tweed Heads
That warm SSW anomaly is really cranking at 120 W ( southern sub polar-pacific)
Nice strong blob currently. Different location from last year.
The sub polar Jetstream is looking dismally weak still.
The sub- tropical jet very strong across the sub tropics at 200hPa
SAM/AAO marginally negative
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#1265322 - 02/06/2014 21:24 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
CoastalStorm22 Offline
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Registered: 10/07/2006
Posts: 2701
Loc: Lane Cove, Sydney, NSW
Wow, that anomaly is really something crikey! Some of the biggest I think I've seen actually, and now we have the cool spot developing SW of oz, which has me thinking what that means for us moving forward? Thoughts?


Edited by CoastalStorm22 (02/06/2014 21:25)

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#1265326 - 02/06/2014 22:24 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
snowbaby Offline
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Registered: 05/08/2009
Posts: 295
Loc: Albany, W.A
I'm not sure I'm on the same page - I can only get the animation up to 22May. The most current thing I can get is a 10+ K positive temp anomaly about 90W@May29th from ESRL website




Edited by snowbaby (02/06/2014 22:31)

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#1265332 - 02/06/2014 23:08 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
Seira Offline
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Registered: 27/08/2003
Posts: 7163
Loc: Adelaide Hills.
Originally Posted By: snowbaby
I'm not sure I'm on the same page - I can only get the animation up to 22May.

http://www.cpc.ncep.noaa.gov/products/intraseasonal/temp10anim.gif

smile

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#1265351 - 03/06/2014 12:34 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
paulcirrus Offline
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Registered: 08/08/2011
Posts: 1455
Loc: Brisbane - Windsor
well thats intersting. To be honest out of all the weather i never follow the stratosphere stuff. But looking at Cosmics animation, does this mean a big change in our weather is on the way. That is a huge cold anomoly building to the west of oz and seeing the warm pool head east and deepen makes me think for some stupid reason, it will spell the end of the constant ridging and allow bigger cold fronts north. Well i sure hope my fantasy comes true.
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#1265359 - 03/06/2014 14:07 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
bd bucketingdown Offline
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Registered: 07/02/2008
Posts: 6033
Loc: Eastern A/Hills SA
Unfortunately Paul it does not look the same further downwards!...

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#1265366 - 03/06/2014 17:01 Re: Stratospheric sudden warmings (SSWs) [Re: bd bucketingdown]
Mad Elf #1.5 Offline
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Registered: 05/03/2012
Posts: 2904
Loc: Mt Hallen QLD
Wow, that chart shows another nasty warm bit west of WA.
Not excited by this at all, looks to me a warm winter is on with substitute water skis instead of snow. Hope it changes.

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#1265371 - 03/06/2014 17:53 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
crikey Offline
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Registered: 01/02/2011
Posts: 2586
Loc: Tweed Heads
CS22 said" which has me thinking what that means for us moving forward? Thoughts?

My thoughts CS22
Currently the sub polar jet at 200hpa( lower stratosphere)
is still incredibly benign and almost non existent
Also very zonal currently ( not wavy)
This is bad as some nice deep wavy Jetstream is needed for some deep cold fronts
and the sub -polar jet is currently contracted way south.

The current picture of the upper stratosphere that snowbaby' has posted shows air rising /expanding near sth America but contracting /shrinking /cold anomaly on the other side of the SH near Australia.

This imbalance /disturbance should crank up some wave action in the atmosphere. making the waves more meridonal ( wavy)

Will be fun to watch the effects of this upper air pattern down in the troposphere.
Great some are interested in watching these dynamics unfold

My thoughts are that if the sub polar Jetstream doesn't crank this winter. could be very mild winter.

Hoping for some favourable synoptics to emerge





Edited by crikey (03/06/2014 17:55)
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#1265374 - 03/06/2014 18:13 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
crikey Offline
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Registered: 01/02/2011
Posts: 2586
Loc: Tweed Heads
Picture of the current MSLP in the SH.
THe westerly belt has swollen/expanded in size as it should for late Autumn and in to winter
But note the zonal (west > east) flow with little wavy activity
therefore no deep fetch cold fronts clipping the mainland

An active sub -polar Jetstream with a meridonal pattern is required to stir the cold around into the more northern latitudes.


source
http://www.bom.gov.au/australia/charts/indian_ocean.shtml

I will do a pic' the Jetstream later as well to illustrate the problem
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#1265378 - 03/06/2014 18:26 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
crikey Offline
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Registered: 01/02/2011
Posts: 2586
Loc: Tweed Heads
200ha Jetstream very quiet. Both the sub -tropical and sub polar are zonal ( not wavy)
The sub-polar is exceptionally weak and contracted south and the sub tropical Jetstream has weakened in strength as well
Actually don't think l have seen the jets so inactive for 1st week of winter since l first started observing 3 yrs ago



http://www.bom.gov.au/australia/charts/v...it=Refresh+View
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#1267132 - 23/06/2014 14:12 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
crikey Offline
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Registered: 01/02/2011
Posts: 2586
Loc: Tweed Heads
Noting 23rdJune 2014..Wave pattern in the upper stratosphere at 10mb is completely zonal and lacking activity. No current SSW warm spots.

Stratosphere at 200 hpa. Sub tropical jet is strong but sub tropical jet remains weak
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#1267236 - 23/06/2014 23:01 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
snowbaby Offline
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Registered: 05/08/2009
Posts: 295
Loc: Albany, W.A
.... flux burst currently underway @ 10Mb...wonder if vortex will weaken early this year...like to think this currently extreme tight zonal mode might have to be counter balanced by extreme disintegration...


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#1267715 - 27/06/2014 16:36 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
snowbaby Offline
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Registered: 05/08/2009
Posts: 295
Loc: Albany, W.A
Interesting to see the following tropopause height (anomaly?) appearing in past little while over the pole. Haven't found a great deal about the subject as yet. Not sure if it foreshadows any unusual exchange of properties between troposphere and stratosphere. A rough gestimate on my part puts it about 70Mb(perhaps higher). This strange bump(sometimes itís more fragmented) of what presumably is much colder air sitting in a pocket in the stratosphere really intriguing - anyone any ideas? Cant say Iíve ever seen it before.





Edited by snowbaby (27/06/2014 16:37)

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#1267743 - 27/06/2014 18:24 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
crikey Offline
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Registered: 01/02/2011
Posts: 2586
Loc: Tweed Heads
Is that an older picture 'snowbaby'?. time stamp 4th July 2014?
However
( see BD's 50hpa animation above)
The 50hpa animation is showing a new warming blob 23rd June south of S/west WA Australia .
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#1268052 - 29/06/2014 08:47 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
snowbaby Offline
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Registered: 05/08/2009
Posts: 295
Loc: Albany, W.A
I wasnít very clear - itís forecast.

Found the following from ďStratosphere Troposphere Interactions: An IntroductionĒ(K Mohanakumar)
ď...the warmer temperatures associated with a blocking high cause isentropic surfaces to bend upwards......by pushing transporting tropospheric air poleward and bending the tropopause upwards, blocking highs can increase the time it takes STE processes(stratospheric-tropospheric exchange) to occur...Ē

If so, weakening of vortex may be delayed.

Like to see these warm anomalies in the surf zone extend further into the vortex itself. If itís going to happen should pick it up in daily EP flux charts first.

An early breakdown in the vortex would be exciting - w.a seems to get best cold outbreaks well into August - even later, though I have vague impression thereís a bit out there about the breakdown, in recent years, occurring later than even Iíd like....

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#1270967 - 24/07/2014 20:23 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
crikey Offline
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Registered: 01/02/2011
Posts: 2586
Loc: Tweed Heads

20th July 2014

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#1270972 - 24/07/2014 22:29 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
snowbaby Offline
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Registered: 05/08/2009
Posts: 295
Loc: Albany, W.A
Been some signs of upper vortex temp starting to rise - likely a result of increased planetary wave activity(wave 1).



Been a fairly consistent burst in recent times the graphic below is typical of that.The dashed line contours appearing throughout are indication of flux convergence - that is wave breaking - in this case inside the vortex (as well as in other areas of the troposphere)




Some deformation in the cold 10hPa temperature field away from a very singular concentric pattern vortex- like its being squeezed or displaced a little at this level to perhaps form a bipolar pattern with an area of warmer temps. Neutral or warm anomalies on the vortex at 10 hPa overall.



I cant find this pattern developing in the levels below 10 hPa (and at any level in the geopotential height fields either) - despite the strong anomalies the mean pattern is still basically a more concentric one on the continent.. Thereís some analysis I saw recently that 2002ís split in the vortex started at the base (ie:100hPa) - no sign of that at all.

In perspective - the vortex has been very strong. Whilst the 10hPa temp has lifted quite dramatically it has been bumping along at the bottom of the climatological range and is only now getting back to the mean.

While ever the wave activity continues though, an interesting watch period immediately ahead.

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#1273954 - 21/08/2014 18:05 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
snowbaby Offline
Weather Freak

Registered: 05/08/2009
Posts: 295
Loc: Albany, W.A
Wish I had more time to look into it.For a little while now thereís been periods of field distortion in the vortex (weakenings) alternating with periods of re-intensification.

I thought that early this winter the vortex was very strong. Temps were low @ 10hPa at the bottom of the climatalogical range. There was a warming (about mid to end of July) which was not major according to the established standard for these things. However itís always possible this warming and subsequent periods of wave1 activity have preconditioned the vortex for something dramatic, perhaps a little more dramatic than the typical annual disintegration .

Wave activity is pretty negligible inside the vortex at the present but there are other factors possibly at play - a process called self tuned resonance is believed to have led to the split of 2002. Cant say Iíve got handle on that one as yet....more study to do!

Interestingly though, a similar elongation in the 100hPa temp field to the one below was a precursor in the 2002 event.



Iíve noticed other distortions over the last month or so. For instance the pv distribution below moves dramtically away from the typical stable symetric distribution.





600K represents about 50 hPa unfortunately cant find any charts for higher in vortex.

In general these field distortions have up to now been followed by periods of stable, symetrical distributions as the vortex re- intensifies, seeming to re-establish itself.

In the progged gph@100mb chart for 28 August below it's possible to see a split developing - whether the height field develops in the way forecast and whether it goes as far as actually splitting will make an interesting watch in next little while...a little caution required since a similar pattern to this has emerged before this winter without that happening.


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#1273960 - 21/08/2014 18:52 Re: Stratospheric sudden warmings (SSWs) [Re: crikey]
crikey Offline
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Registered: 01/02/2011
Posts: 2586
Loc: Tweed Heads
Thanks for keeping this thread alive 'snowbaby' . There does appear to be a vertical oscillation over the winter. The max on the 28th July 2014

https://picasaweb.google.com/110600540172511797362/Stratosphere2014#6049933733184782498

and the minimum of the wave about now. 21st aug 2014
That is a period of one month. If that oscillation continued the next warming max would be about 21 st Sept. Pure speculation of course. As the SH warms the oscillations weaken


current animation
http://www.cpc.ncep.noaa.gov/products/intraseasonal/temp10anim.gif
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