lorenzo

Not sure Buried, good question, Need Chiono to provide a clearer answer than one I can, still find the whole definition of them pretty vague to say the least.. Canadian Warmings often happen in early winter. They take place when the Aleutian stratospheric high intensifies and moves poleward. The Canadian warmings can reverse the meridional temperature gradient and sometimes briefly change the zonal wind direction over the polar cap, but nevertheless they do not lead to a breakdown of the cyclonic polar vortex. http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/figs/ecmwf1/fluxes.gif Still the whole puzzle around these events is of interest and here are some some analogs of Canadian warming years to try and get a clearer idea.A Sunday puzzle to work through these and make some deductions... 10mb / 30mb / 50mb - November Canadian Warming Years 10mb / 30mb / 50mb - October Canadian Warming Years 10mb / 30mb / 50mb - October 2013 October 500mb Analog vs October 2013

Another precarious winter countdown begins.. hard frost up here this morning, feeling like Winter already,look forward to when everyone else can join the fun. ECM @ Day 10 ECM vs GFS, GFS much sharper. GFS GEM - really ramps that low and provides that west based solution. GEFS for same time frame Maybe am getting chart fatigue, I always thought the 12z runs were more bullish for cold solutions, seems the 00z is the new 12z !

JJ Frost has been on the rampage overnight, feeling like proper Winter oot there this morning. Didn't quite make it to the 3am Ice skating session though. Charts to match too ! GFS determined to deliver a Greenland high, will it still be the same at 12z....?? Mixed solutions across this theme from GEFS, GEM and the ECM out at day 10, so plenty of model watching between now and the 20th to see how the strength of this ridging and warm air advection turns out.

Some quality model output around for cold lovers this morning, just added a bunch of charts to the model thread. Here are the best ones.. ECM wanting to slam Scotland into the freezer after mid month.. Go on verify ECM, you know you want to... this one will jog a few memories..

CH, Canadian warming events are very rare, whilst one is overdue they are a bit of an anomaly in themselves and cannot be really categorised until after the fact with re-analysis. Last one 13 yrs ago ! Evn without the CW there is plenty of other interest. Here are a few of the latest TC's for PNA / AO / NAO, the positive regimes of the AO and NAO heading toward a more neutral > negative position. With the PNA being an upstream pattern that is not often referred to on here, this image neatly shows how the hemispheric pattern is set up. The ECM earlier this week very bullish about the cold plunge but has backed off a little. Onto the ECM which is pretty amazing looking and let's hope it maintains the theme.. 144 is a point of interest as this is where that MA ridge really cranks up. Then some fantastic cold looking charts thereafter. Great to see, will we have a game of ECM picks up a trend, drops it, GFS picks up the trend, drops it, then both verify and annoy the hell out of everyone with GFS getting the blame..

Could anybody help me please?, there was a post on here last year listing the date and type of every SSW since strat monitoring began, I was wondering if someone would be kind enough to post it again please. Thanks in advance. Aside from the Berlin page, here are another couple of frequently used lists of SSW, one matching to ENSO and the other displays displacement and splits. Couple of charts from this morning GFS 00z, peak of warming activity at 30 mb by 72 hrs before this subsides. Out to t+192 at 10mb a very Cold looking compact vortex approaching -80 degrees, with 2 distinctive areas of vorticity.

Further footage from Tacloban City. Debris visible and wind audible. http://instagram.com/p/gboELfKWyn/ Really not looking forward to seeing the human side of this as opposed to the pure meteorology in the build up to landfall.

Strongest Landfalling storm in World History. http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2573

Unreal.. Further Instagram vids http://instagram.com/p/gbhv7SwhgB/

Sunrise beginning now. Going to be some unreal imagery and footage of this monster. Video from Tacloban City http://instagram.com/p/gbfcM6KW1x/ Unconfirmed that Satellite reports of 858mb...

Congrats Edo ! No idea how you will find the time with 4 of them on the go, I struggle to keep track with 3. It's great having a boy though to even out all the Girly stuff ! From further afield on Netwx, thought I would share this from the Super Typhoon thread, a totally stunning image of Haiyan / Yolanda. Frightening.

Some crazy imagery on Twitter right now. This loop is spell binding a real jaw dropper. http://cimss.ssec.wisc.edu/goes/blog/wp-content/uploads/2013/11/131107_coms1_ir_haiyan_anim.gif

Steve, I get what you are trying to say, the strat thread is popular and people take what they want from it in a linear fashion. i.e Raging Vortex - no Cold. Broken Vortex - Easterlies galore. In reality it is trickier than that and not a guaranteed route to cold. You are right to say it is a guide, but I don't think we rely on the strat alone. This winter the GWO and ENSO are arguably more interesting as trying to understand and fill the void in information left since GP departed. Some images below that confirm the research being done regarding loading patterns for SSW events, which means we can look for these patterns in the model output and look ahead to attempt to predict the evolution of the strat, of course reliant on model information. Meanwhile, the CFS view of the blocking for week 3 and week 4, teasing output into December.

I trust NL better than the GFS for the Winter is here.. The Pacific Rim is struggling away to amplify sufficiently to make inroads in the Arctic. The peak around +72 hrs for the wave activity created from the Kaijus. Week 3 and 4 CFS shows the mid Atlantic ridging, then some high latitude blocking into December. http://origin.cpc.ncep.noaa.gov/products/people/sweaver/cfs_fcst/images1/wk3.wk4_20131105.z500.gif Overall a positive AO outlook, but this isn't hard and fast for Winter. The AO after peaking is trending negative for a period, and the NAO weakly negative, so some blocking across either Greenland > Scandi > Russia potentially on the cards.

An overall positive trending AO for winter has in previous winters also included periods of negative AO. So all is certainly not lost. That said we could do with an SSW again this/early next year after a period of staring at a rampant vortex.

OPI is October Pattern Index devised by some Italian Meteorologists, it is an extension of the SAI work by Cohen and claims high correlation with the predicted winter AO. Link is here. http://www.centrometeotoscana.it/forum/index.php?topic=7473.0 Correlation Interesting reading

Right, will leave this ugly looking analog here, based in particular on the OPI and predicted AO and ENSO neutral range depicted on plot. Here is your DJF analog for all dates. Quite a limited dataset. ENOP.txt

Yesterday it was the crystal clear skies, today it is the hazy sunshine through the low Autumn fog. Lovely crisp morning and also enjoyed scraping the car ! Enjoy fireworks night. Got to love Scotland... http://www.youtube.com/watch?v=sSJ5PgUx0Zg

Great analysis by Ethan in that blog post, from the Mitchell presentation on the publications page, see link in Teleconnection paper thread by Interitus. This chart has a longer term look at the trend. January is the month to watch.. Edit - correcting typo.

Interesting read Sebastiaan, thanks for the link. One wonders if these guys are really onto something, I guess the million dollar question is what computation is being used in their 'Telemappa' software to create the 'axis' line, the one visible Labrador > Siberia on the October composite. Approfondiemento means deepening if anyone is wondering about the lines on the GPH plot. Indicating the vortex strengthening. Google translate doesn't translate the images ! A very specific forecast on what the expect the vortex to do, well worth a read, I suspect this forecast will be under close inspection as it takes the Cohen SAI work onto the next level. re: earlier, Regards to NAO, would definitely keep a look out for that and put it in the mix.

Certainly a repeat of the period into the second third of October, also saw that trough wanting to dive bomb the continent. Here is the composite for October, the September one shows the main feature being the Scandi High.

Great read, all the factors in the mix covered here, best of luck with the forecast. If this verifies then January looks great

Great work LS, well done !

Hopefully this loop will open, shows exactly the point you make, into the output period the recurve is evident and the ridge holds steady. http://www.atmos.albany.edu/student/kgriffin/maps/mslp/mslp_npac_loop.html Edit - add image.

Some mighty ridging present on the output today, as highlighted earlier by BA the Pacific really ramping up, catching up so these lifted from the 00z. That Aleutian High anomaly chart is literally off the scale and the mean itself looks quite handy ! Anomaly / Mean Met Office builds that Siberian High also picked up on this morning ECM run, the NH plot signals the Atlantic ridging also. Very interesting picture with respect to disrupting the PV with Wave Activity. Another MJO plot built from Velocity potential anomalies highlights potential for the mid Atlantic Ridge, where will it go after that... GLAAM has gone through the floor, so it will be interesting to see just how outrageous these predicted blocks can get.. You can almost sense the loopy GFS 18z runs are just around the corner..