lorenzo

My word !

Canonical SSW year up and coming.

Hello Hoolie ! Bit of a lively one Briefly chatting to colleagues today - realised that the naming conventions do stick from time to time, Arwen was referenced.. albeit completely different evolution. But - it's then a double edged sword - folks may think - named storm ( equal in severity to Arwen), and, if it doesn't work out as severe - then, loss of confidence in naming.. ( Sunday should have been named anyway too). What to do !

Insane

Impressive !

Oaft..

Things fairly popping off now..

Aberdeenshire looking best placed, although could end up just offshore.

Incoming...

There are a couple of hardcore definitions of Potential Vorticity Units if you the maths, the other way to look at is is just - don't look at it, feel it. 1.5PVU is the beauty of fluid dynamics in the atmosphere, like a wave rolling on a beach we see this in our atmosphere, and playing through the run let's you see how that wave crashes.. For there marry up to the H5.

NWP on the cusp of pattern changes now.. some better viewing ahead for those of a cold dissuasion hopefully, i had thought that the November damage to the vortex would have proven to be more 'harmful' and disrupted the internal vacillation, each winter looking at what it does is new, and the rebound from the blocking was rapid, hence the junk charts ( from a cold perspective) since the end of the cold December period. Each year you look at the base and think this wave break could do this and I guess bias creeps in, but the VI period is like death, taxes and Haaland. VI periods as known - the last few years has seen Nov HLB aggresively impinge on how these unfold - leading to eyes on trop kicks. The MJO of course is a trop kick - the AAM / MT cycles are of course a trop kick - however and this is crucial this season and well demarcated, so much depends on the wave guides in existence when these teleconnections play through the RWTs. We had a disruptive cycle move from lively to flat very , very very quickly - it was not that the MJO was not true it was more that the RWBs were not conducive. And in that there are fine margins and some proper academia is needed to map this stuff, the latest from Tomer showing WAFz at 100hPa is brilliant and will let us see the real time evol. of these wave trains and where the wave guides move in response to pattern changes. For now this is a watching brief on what the W1 does and it's a decent W1 to test stuff. Re Vortex Internal Vacillation http://www.homepages.ucl.ac.uk/~ucahjge/paps/matthewman-esler-JAS-2011.pdf Original post: https://community.netweather.tv/topic/98196-model-output-discussion-new-year-and-beyond/?do=findComment&comment=4784926

From tonight's GFS 18 z, image three is WAFz Heat Flux projected..

NWP on the cusp of pattern changes now.. some better viewing ahead for those of a cold dissuasion hopefully, i had thought that the November damage to the vortex would have proven to be more 'harmful' and disrupted the internal vacillation, each winter looking at what it does is new, and the rebound from the blocking was rapid, hence the junk charts ( from a cold perspective) since the end of the cold December period. Each year you look at the base and think this wave break could do this and I guess bias creeps in, but the VI period is like death, taxes and Haaland. VI periods as known - the last few years has seen Nov HLB aggresively impinge on how these unfold - leading to eyes on trop kicks. The MJO of course is a trop kick - the AAM / MT cycles are of course a trop kick - however and this is crucial this season and well demarcated, so much depends on the wave guides in existence when these teleconnections play through the RWTs. We had a disruptive cycle move from lively to flat very , very very quickly - it was not that the MJO was not true it was more that the RWBs were not conducive. And in that there are fine margins and some proper academia is needed to map this stuff, the latest from Tomer showing WAFz at 100hPa is brilliant and will let us see the real time evol. of these wave trains and where the wave guides move in response to pattern changes. For now this is a watching brief on what the W1 does and it's a decent W1 to test stuff. Re Vortex Internal Vacillation http://www.homepages.ucl.ac.uk/~ucahjge/paps/matthewman-esler-JAS-2011.pdf

Really some awful modelling to endure post start Dec and then the New Year provides peak vortex action driving stuff until mid - month. For folks of a cold persuasion - the worst modelling going, on the other side... This winter was so damn close.. and it's a learning winter the Nov /Dec patterns are exceptional, again, this revisit to early 80s NWs CWs is in a cycle - each cycle disrupting the classic VI period. But critical this year is the initiation wave guide - without chapter and verse and charts - the Pacific has not behaved. Beyond not behaved which is light, the pattern of normal 'modelling' which then affects us has moved erratically. A great case of upstream impacts. But not the usual ones and not the ones you see on RMM plots. Simply put - MJO RMMs are wrong, the composites are wrong, the regimes predicted by them are not wrong, their are canonical works creating reference, the framework and baseline needs adapting to shorter analog windows. Original post: https://community.netweather.tv/topic/98196-model-output-discussion-new-year-and-beyond/?do=findComment&comment=4783932

Above anyone else Dr Butler is who to read, trust it.

Really some awful modelling to endure post start Dec and then the New Year provides peak vortex action driving stuff until mid - month. For folks of a cold persuasion - the worst modelling going, on the other side... This winter was so damn close.. and it's a learning winter the Nov /Dec patterns are exceptional, again, this revisit to early 80s NWs CWs is in a cycle - each cycle disrupting the classic VI period. But critical this year is the initiation wave guide - without chapter and verse and charts - the Pacific has not behaved. Beyond not behaved which is light, the pattern of normal 'modelling' which then affects us has moved erratically. A great case of upstream impacts. But not the usual ones and not the ones you see on RMM plots. Simply put - MJO RMMs are wrong, the composites are wrong, the regimes predicted by them are not wrong, their are canonical works creating reference, the framework and baseline needs adapting to shorter analog windows.

Sleet trying it's very best to turn to snow here with the heavier bursts of precip. passing through, some decent 'blobs' tracking in now..

Why wouldn't you be interested in an SSW when the vortex currently looks like this... And, FTs are doing this... Gonna be a fun slingshot out of this NAO+ pain.. Original post: https://community.netweather.tv/topic/98132-model-output-discussion-the-run-up-to-christmas/?do=findComment&comment=4777415

Oh go on then..

Why wouldn't you be interested in an SSW when the vortex currently looks like this... And, FTs are doing this... Gonna be a fun slingshot out of this NAO+ pain..

Merry Xmas all - have an amazing day. Rotten spell of modelling which was inevitable is easing off, some real-time watch into late Xmas Day & Boxing Day - and some January fun ahead.

A direct hit Almost a carbon copy of similar flow from 15 Dec 2018.

Central Belt is going to need help from the weather gods to adjust this one unfortunately..

Hmmm...