SMU

Cheers yes I saw them in the gym- The execution of the 12z & its total coverage of the pole in high pressure with 3 main areas of low pressure around mid lattitudes means that for November 1st which coincides with the optimum low point of the next phase of the negative AO means that the 1st day reading could be -5 AO i will whizz through & check the records...

Evening - Well just a minor update - After a bit of a rollercoaster for the models last week the prospects of more 'unseasonal' blocking continues to tease us like one of the old 1p ' look what the butler saw reels' - lets hope our money doesnt run out when we get to December !!! We have seen a very sedated vortex early doors this year & as highlighted before October is knocking on the door of a 66 year record - IE the -AO. Whilst perhaps its not a significant record for the UK - in the bigger picture, especially Up past 60N - This is a significant record. It shows a very disjointed & fragmented Vortex. The record for the month is -1.5 & he were are at the 22nd - http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index_ensm.shtml I would say -2 by the 25th is a realistic figure & with a significant trend across today from the 00z ( used for the AO ) to the 12z has been all 1 way..- building a bigger block. So based on this I think the landing zone will be around -2.25. A record breaker & the only October in history sub -2. As said - 1 swallow doesnt make a Summer, however today we have seen that potentially for the opener to November the AO/NAO is ramped ! The models are reacting to the overall ensemble mean around that all important 60N zonal wind - This is basically the end result of all the feedbacks fed upwards & downwards into the atmosphere. I need to go a check what constitutes what speed represents a negative zonal wind however we may be close after todays modelling - http://www.atmos.albany.edu/student/hattard/realtime/u_65N_10hpa.png This is significant dropping below 1 standard deviation from Climotology - & with a double dip - the possibility of dropping past 2. The strat is also reflecting a split now at day 7 - which is very very different to the October mean http://www.atmos.albany.edu/student/hattard/realtime/nh_strat/nh_stanom.php Anyway, more strat features come online for November - from the Berlin site. Which will give us a clearer picture- So - in a nutshell we are in the best possible place we could ever be on the entry to November. Also PS - as regards svalbard snowcover,I agree with a post above- the recent october Blocking tendancies have put Svalbard in almost exactly the wrong position for October snow with all the cold going to the East & south of that locale ... for them the Oct snow has almost been wiped off the map in a matter if years ! Cheers

Yes a steady overall drop around 1 point...

Yes at T180 we nearly have the first boom chart of the season ! S

Nice day 7 Strat update from GFS - I would take that as a starter for 10 S

Morning - Spectacular ECM again this morning, with what appears again to be a full reversal of the zonal train at day 10 with a solid 2 wave pattern- clearly seen here the vortex is very displaced - miles off centre from the pole, & if you look there are 3 low pressures moving clockwise around ~ 60N - a true sign of reverse zonality- of course this is day 10, however its where the transition sits being the crucial timeline- & this is around 168 where you see the cross polar ridging on the models- even the UKMO has some signature at 144- The timing of the this next bout of -AO probably arriving past day 8 ushers the end of the month & the keenly awaited 2016 November - from a cold perspective it would feel like there has never been so much anticipation of the -AO/NAO being so negative at such an early point in Winter - the last -1.5 november was 16 years ago! Could we beat -2? October is also on course to beat the record of negativity - beating the hyper winter ( -AO) of 2009- here are yesterdays ensembles - watch for a move to better clustering on low values on todays updated ones around 4pm- - All this is in response to the overwhelming model ensemble drop off in the midrange of the 60N zonal wind - which could drop into record breaking negative territory .... S

hi now look at the ECM 168 12z & see the difference already - notice the sliding low- a shift towards the hunch but not fully yet-

hi we often see ( with scandi blocks ) the models in the 168 area want to move energy over the block ^^ as posted above- with that you then get a very elongated high pressure from scandi to the SW of the UK like this ( below )with all the action of the jet on the north however if the Scandi block is stronger than the model 'sees' it often disrupts the jet enough to amplify it & suddenly instead of everything going SW> NE it bends NW > SE all of a sudden the models then start putting more energy underneath & hey presto a different outcome something like this -but with more going SE This is the only GFS ensemble really showing more SE energy - notice it trying to close off a low over scotland Something to keep an eye on S

Afternoon all- 24 hours of change in the models hasnt worked to favourably for those enjoying the runs with a lot of polar blocking- However again I believe we *MAY* be on the edge of another change over the next 24 hours - all models have moved )at around 144 to take this low OVER the block flattening it See the 990 low in the central / Northern atlantic moving ENE on the GFS that flattens the high- so this is what the model is predicting past that notice its a small 985 low north of scandi at day 7 ive a feeling by tomorrow that will going under the block instead of over - forcing more atlantic ridging that forecast at the moment.... it will also sustain the eastery continental flow for longer & also remove that huge fat high pressure to the SW thats been modelled.. JUST A HUNCH S

Hi Ruben yes this fits in with the global ensemble mean for the Zonal wind rapidly decreasing All - ^^^ This is why the models keep going for a lot of northerly blocking ! S

The easiest summary of the 12z suite... 'Something for everyone' a bit of late warmth + some early season cold at the end- no sign of a sustained vortex building.. Gonna be another 6 - 7 days before any change so - enjoy the quiet 'continental' weather

Afternoon Well a topsy turvy 24 hours sees the GHs removed- interestingly the UKMO 12z has us in chilly Easterlies out to 144 with no sign of a breakdown- infact it looks very similar to the GEM 00z - an interesting day- & from a coldie POV id rather the prospect of cold just holding off until the start of Nov - just so there is a more substantial cold pool to tap into

Awsome ECM however unusual split - UKMO + JMA v GFS / ECM & GEM on the fence for this eve....

Yes look for the deep Scandi trough diving south around 26-28 th OCT

Another 10 days & that big gap in western russia should be filled - look out for the deep eastern Scandi trough

As with Scandi High pressures & those even more rare retrograde Highs - The GFS has always been the last model to come ln board - always taking pidgeon steps to the euros - If you take it on a sliding scale what I have noticed is the ECM picks the over amplified solution & the GFS is always to flat, however generally in these scenarios the ECM slides back maybe 20/30 % & the GFS moves 70/80% so theres a meeting point & thats whats happening today- The UKMO has a very good track record in these scenarios & looks excellent at 144- As we now stand all ensemble Means at 192 have higher pressure development around the pole with slightly different levels of depth, however importantly the core of the cortex is dropping into Scandi East / western Russia- Its all good news so far this October....

Remarkable inter-run consistency from the ECM - with mouthwatering charts developing post 192 - However the transition is 144-168 This is the first real model test into 2016 - the GFS not 100% keen but coming on board - The ECM goes the whole hog - If it does verify then on the 26th oct we will be heading into Nov with a sub -3 AO & - sub -2 NAO.. Also should it land the October -AO will be smashed - Poss sub -2 ( only sub -2 in 66 years ) So much to contemplate.....

Yeah ^^ im not convinced yet - The mecca ECM has let us down over the last 3 years so Im waiting for the signal to reach 120 however UKMO GEM onboard as well if so -AO ensembles will tank tomorrow S

As above the GFS now backing the ECM - the 228 charts onwards could tease us with early thoughts of snow for halloween...

a couple of cherrypickers from the 18z

spectacular GFS & GEM ( not to mention ECM was similar at 240 ) **IF** this varifies we are looking at a tanked -AO at around the 28th of October just days before the curtains raise for November AO stats... the key period is 168- 216 getting enough greenland heights up against that low to reverse the 60N circultation- goodbye zonal wind !

7pm -745 at the moment - then 1 hour earlier as the clocks roll back

Yes its not about the UK yet- the expanse of cold air is still growing- so ideally the second week in November is really the main starting point- anything in the run up to that is a Brucey Bonus- ATM - its all about the AO

The end of October is traditionally when the vortex is cranking up- however this year- its gone on holiday- This is not normal- its so far from normal the polar height field is almost inversed !

Hi I think its more cause & effect - that then helps become self perpetuating- Significantly low ice > Tamar region high geopotential heights > Southward & westward SAI development > Winter feedbacks supporting -AO This feedback isnt the MAIN driver of the weather - ENSO / Strat profiles can overule this - however when the strat is condusive & the ENSO isnt super + it certainly helps- S