lorenzo

At the end of a stormy December and Into 2014 and the storm track story continues... GEM / GFS / UKMO for next Monday another vigorous Atlantic beastie inbound. This one should get named 'Anne' by the Adopt-a-vortex team, hopefully the UK will get it's own naming of storms at some point in 2014 ! Hopefully the atmosphere decides it's time to even up the balance and serves us all a sustained period of reverse zonality ( whole of February would do just fine thanks !!).

Interesting blog post from the Capitol Weather Gang on SSWs, contains a couple of good links to previous entries re January 2013. http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2013/12/31/sudden-stratospheric-warming-could-it-lead-to-a-very-cold-january-in-d-c/ With reference to the 12z GFS run - whilst not as stunning as last night the split vortex remains forecast. 10mb split 372 16/01/201420mb split 360 15/01/201430mb split 384 16/01/201450mb split 348 15/01/201470mb split 336 14/01/2014100mb split 324 14/01/2014 Thought I would share this link I stumbled across this week good explanations of what we are looking for on the Berlin plots.http://www4.ncsu.edu/~jmlheure/Previous_forecasts.html

EC32 goes blocktastic at the end of the run c25th onwards, however the temp anomaly looks very strange with Russia in particular looking toasty. Meanwhile the wave 2 plot on CPC beginning to look spectacular.

Initial response still some time away, should 30mb split occur. As chiono wrote earlier improved chances of easterly setting up some 7 days later, then lagged effect of cold filtering down. This of course depends on down welling. SSWs Not easy to predict, after effects even more so.

Was just looking through the 18z re YET ANOTHER Atlantic Storm fleeing in, so many variances on positioning of these lows that I think even the pub run can't cope ! Heights and Temps for GFS are on Instantweather maps http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2013123018&var=HGT&lev=10mb&hour=360

Fantastic work Recretos glad you got your Internet fixed, the GFS side animation reminds me of this from NASA. http://gmao.gsfc.nasa.gov/researchhighlights/SSW/fig_8_epv_01142013_obs_fcst.png http://gmao.gsfc.nasa.gov/researchhighlights/SSW/ Impressive charts this evening on Instantweather.

Find a wider range image BUS - it's hexagonal...!!

Learner area is packed with information - http://forum.netweather.tv/forum/5-the-netweather-guides/ From there this link on Ensemble forecasting - https://docs.google.com/document/d/1ClkAme7CLzViv51_1r8KQINHoendcxYbHJh2Ya2zQzI/edit?hl=en&pli=1 RE: Meteociel - couple of images may help. When you select GEFS - Global Ensemble Forecasting System, the 'control' run opens, from here and highlighted you can see the mean and also spread charts. If you click panel, this opens up all the different variances created by each of the 'perturbations' or ensemble members. If you click diagramme you can see the ensembles plotted as a graph, click Carte Europe presents a map on whcih you can click to bring up the ensembles for that location. http://www.meteociel.fr/modeles/gefs.php?carte=1 Where the operational run deviates from the cluster of ensembles this can be considered an 'outlier' solution, you read this a lot specifically where a model produces a very warm run or a very cold run.

The Nukes have arrived

Potentially January 17th - for a 3rd year in row ??!!

Re: Ed mentioning the VI period ending, that brown blob at the top of this chart is receding.. Think the MJO is the guilty party in relation to the GEFS Control Run, high amplitude phase 6. Out of kilter with the other projections. GWO cycles round to frictional > Mountain Torque after 10 days... Will we get the EAMT ?

Different posters have put up the 500hPa anomaly plots for the last 5 years then also compared with the previous decade and there are clear differences in the established patterns. Whether these can directly be attributed to increased SSW I really don't know, I guess we will need to look back at that once there is a larger dataset. I was really just thinking about what I had saw in these plots combined with the fact that we are having colder and snowier winters of late. The following post has some more reading re: links into Arctic Sea Ice as does the most recent Cohen paper on Warm Ocean / Cold Continents. http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2013/12/24/arctic-warming-jet-stream-coupling-may-portend-another-winter-of-extreme-storms-and-cold-air-outbreaks/

Here is some re-analysis of previous SSWs - the central dates are from the Martineau site for convenience, also where you can view the linked animations, rather than go back to historic years have just picked from 2006 onwards wrt thoughts that this is where climatology shifts and recent winters have been 'different'. The Idea for the zonal wind time latitude series came from GP post in last years thread where he compared the zonal wind profile against 1968, the heights to look at pre-cursors. The date display on the zonal wind is a little weird to read, starts with year / month / then days are in chunks of 10. i.e 00 / 10 / 20 / 30. December 2013 for comparison with this season vs. previous. 17/01/2013 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2013_01_17.gif 17/01/2012 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2012_01_17.gif 30/01/2010 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2010_01_30.gif 28/01/2009 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2009_01_28.gif 24/02/2008 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2008_02_24.gif 26/02/2007 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2007_02_26.gif 24/01/2006 http://curriculum.pmartineau.webfactional.com/wp-content/svw_gallery/test/gif/2006_01_24.gif

I agree John, clicked like on the original post after deciphering it. More of these things I think, where a picture sums up the post.

Duff moisture code? To be fair there are heaps of acronyms knocking about just now and the original post contained a 'stramash' of them. SEPA warning as of 20:00 re the drookit. http://www.sepa.org.uk/about_us/news/2013/flooding_update_-_2000.aspx

That's a monster cold run within that set Nick, worth posting image.

From the twitter feed of @romartinezfranc Helluva Pic !

Never realised this thread was on NetWx until earlier this week - appreciate the updates John, great stuff.

Looks like on balance we are going to have to endure the massively tricky model watch involving - how much of the vortex remains in it's Greenland home fuelling the Atlantic train of depressions. Just as within the ensembles there are zonal, varying degrees of interaction with the Arctic high, Azores lingering about - as for nothing at all showing signs of cold, yes it's one of the ensembles, but it's there.

ECM control run is a block party this morning.

Fair to say the GFS is ramping up the interest.. this looks significant. Couple of things - if the vortex does go , what an extreme amount of cold is bottled up there ready to spill to lower latitudes considering the nearly off the grid JMA plot this morning cranking in at -87 degrees. Regarding where it spills, 2 locations come to mind as figuring throughout this season - 1 the core of the CONUS and 2 to our East with that repeat hit of troughing deep into the continent. I reckon it would be about impossible to guess where a 'fallout' would occur from any immediate down-welling but these have certainly been this years favourite locations. Also,wrt to the Glosea 4 this model has ran in winter seasons where there has been something of an inevitability about the SSW event happening, solid Wave activity existed throughout the seasons leaving the vortex open to a final hit. The Kamchatkan ridge bossed the NH profile and no surprises it gets noticed on the output. This season the vortex is in a different category of strength to the last couple of years, so you wonder if the model, if indeed that is what the longer outlook is based on, is reacting to the very strong wave activity and interpreting as a SSW whereas perhaps this wave activity against this season vortex isn't going to deliver the same result. What a start to 2014 coming up for watching the developments.

With GEFS plotting this as an AO, wonder if we are going to see some ensemble members to rival that outrageous control run at the end of November...

Couple of charts from the Berlin site from the latest run to illustrate the wave activity. Getting warmer at both 10hPa and 30hPa. Max Temp on this run for 10hPa spans from -36C at analysis to -8C For 30hPa analysis max temp. begins at -46C to -29C. Leading to a strong change in the zonal wind strength, down from 220 mph to 134mph, so whilst reduced by nearly 100mph, still ramping away.. Wave 1 - above 2000 at day 10 now. Wave 2 Peaks at day 6. A decent attack on the vortex however it remains solid as shown by the lack of red arrows pointing right i.e poleward on the trop and strat EP flux charts. From 4th Jan just into negative AO territory, ECM control run more negative, where you could argue that if using -1 to 1 as neutral then the mean remains as a neutral AO. Considering the giant wave activity to achieve just a neutral > slightly negative AO, really underlines the vortex strength. More wave action needed, however GEFS sees this differently, looking at the range in green around the mean, solid negative. Some model divergence to pick through which makes both the assault on the vortex and the resulting fallout all the more interesting, another meaningful Wave 1 later in January and goodnight vortex would be my guess at this stage. Sources - as per request above to add links to posting http://models.weatherbell.com/ http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/northpole/index.html http://ds.data.jma.go.jp/tcc/tcc/products/clisys/STRAT/index.html#monit_nh http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/diag.php?lng=eng

RE SSW - rather than provide the huge technical explanation ( stratosphere thread is the home for that). This 57 second vid sums it all up neatly.

Good Luck ! GWO and GLAAM has broken my brain for about 4/5 years, still not got it nailed.