SMU

My initial post was at a time when everything was alligning great - the flow ahead of the front was easterly & the allignment of the winds into the front were South- then in snap of a fingers the models removed the easterly flow & moved the winds back from south to SW - hence all rain since then the middle ground is being modelled- tonights aperge modelled snow all the way places North of the region - cambridgeshire etc- south of london sleet - SW rain ECM very similar with back edge snow GFS all rain pretty much- evaporational cooling could be a saviour but its light PPN when it gets to kent s

Moderate snow - greenhithe

a few flurries & a couple of moderate flurries in those no settling here maybe up higher s

Light snow Greenhithe ! shiver me timbers....

You lived a charmed life at your location in the SE at heights & slightly rural is worth 1c below most we are moving this summer for one more rental before buying another house in kent its got to be istead rise / meopham / vigo ! latest radar return consolidates just a slight weakened but importantly the continued protracted track is SSW... temp here at sea level est 1c

The progression of 'the blob' is making steady progress SSW - at about 30-40 miles per hour ETA Nw kent / SE london around 730-8 still gaining intensity ....

Just want it to slow down a bit temps dropping fast need a couple of hours really

Great to hear 50p flakes are about a 6 on the murr scale

Morning all definate mid Kent (& east suffolk ) streamer setting up!! unsure of PPn type - heavy showers incoming s

Im in ive got the sledges whos got the wine ?

Scrat can we come & stay at your house ?

Supreme consistency from the GFS 06z if we compare the 00z 126 v the 06z 120 theta E charts the location of the 8c line has a variation of about 15 miles - that is hard to beat at day 5 00z 126 06z 120 What it means is the front line of PPN WILL be all snow let see of the 144-168 chart can muster a -10c over the UK s

Morning all significant upgrades from the GFS overnight - swinging towards the JMA solution highlighted last night - My historic experience of the GFS in eastlerly situations- similar to the GEM ( but not as bad ) is 3 fold in terms of detail * the block always edges west with time * the depth of low 500 heights is always underestimated - usually progged on meteociel as darkish blue around 528 DAM even 524, however as we get nearer we often see smaller deeper pockets of lower heights around 518 even 512 DAM - although often hard to distinguish on the european charts because of colour distinction. * finally in the continental flows GFS often like above underestmates the depth of the cold air ( & depth contours of cold ) coming from the east / North east - so at 144 a wedge of say -6c air often upgrade to the same wedge of -6 air @ 120 but another contour of cold -8c is added ( or layered ) in the centre of the wedge- then last minute - often sub 96 that wedge of -6c & -8c core air gets layered again with a pocket of -10c air. * The ENS because of their course gridding & lower resolution will take at least 24 - 48 more hours to capture the cold pool developing & associated layers / depth so the mean will go from -6 to -8 then to -10 maybe even -11 ! ( if that high nibbles further west ) - this happened in the Easterly of 2009 & If i recall the easterly of 2013 where the initial prog of -10c bottomed out with -13c scraping by the SE. - in saying all that above I believe the JMA layering on the 850s is a tad over optimistic sometimes, but certainly more realistic than the GFS. In my books GEM sits around +4 to +6 to warm in its layers out at 120-144. Anyway to digress, the JMA last night on the 12z between 120 & 168 progged a more stable Scandi high & if we assume a bit of forecasting model history - in developing scandi high scenarios the model that sees the most stable high is often top dog while others play catch up at 144 & 120. What the JMA did last night is block the continental cold & park it at 120 just over the border in NW france, then over 48 hours due to lowering of heights & descending air created a cold pool over 48 hours - this expanded into the UK westwards via Kent & EA into most of Britain. It alligned nicely with the timing of the atlantic front & ensured that the band turned fully to snow stalled out somewhere 'in the spine' At the same time as the cold pool expanded the depth increased from a -5c starting point to -10c in 48 hours - this remained in situ over the UK due to the stationary winds & would have produced an ever increasing surface cold pool - leading to 1 or 2 ice days. The 00z GFS has now followed suit - the cold pool though at the moment is about 100 miles further east. But where its located is just enough to hold the stalled front as snow in the SE. These 5 12 hour timeframes show it perfect Looking for snow on these charts I often refer to the Theta e charts to see if the air is cold enough the rough snow line is 10c although 8 is better - the same 5 timelines show we just need a nudge west - The theta charts show the mild wedge also getting squeezed out so as a result of this upgrade ( lower heights / stable high = growing cold pool ) the snow cover = this & as mentioned a developing cold surface pool & ice day.... so thats what the next 24 hours is all about getting that tiny continental kink from the East at about 144 here just a dab further west please... Also anyone saying the NAVGEM is poor - its already being modelles last night ( as was JMA ) PS STUNNING GFS ENS SUITE P5 the pick of many stunners

Well the GFS almost follows the JMA but loses tge scandi high just to quickly - however this is a real sight to behold totally stationary air over the UK- very cold in any clear skies with snowcover it rarely lasts in the UK s

Evening last one from me - The JMA as i hinted at earlier - also alligned to the JMA 132 V UKMO 144 identical & goes on to produce a great run with snow & probable ice days in England... also a nice wedge of -10c air developing in situ.... S

So here is the JMA 84 i believe if I was challenged to make a forecast in terms of 500 heights & where the 850s are this would be my best punt for Monday- Sleet & snow flurries penetrating a way in land - more persistent in the E/NE & SE the flow is a classic kent streamer ( not thames ) so places like bluebell may get a covering the -6c@ 850 is clearing the south coast.. also the wave of high pressure in atlantic is subsiding away from the high over iceland which is great as we dont want them linked notice the energy seperation of that deep low in the atlantic signalling a split flow i would hazard a guess tonight JMA may well be the top run.... S

& this is why the METo have tweeted about snow UKMO 144 at first glance it looks a bit ropey however England is under around -6/-7c air in situ & with a slight continental drag from the east The atlantic front straddles the UK & the cold polar air has caught the mild wedge up & mixed it out so as the heights become lower & lower again the rain & snow band becomes even more to snow .... S

A much improved 06z run in short - medium term The flow allignment between 60 & 84 is more Easterly - with less mixing & the slider low at 48 on a more southerly route- a very good run for wales as potentially a bit of snow sat - Perhaps even some wintry / snow flurries in the ESE sun- all setting up to be a very cold run- T84 s

Excellent overnight runs - consolidating on the GFS theme of the last 24 hours - the ECM had followed into line, the proof again being the drop of 850s from 144 @-4/-5c over england back down to -9c from the continent at 168- snow for many on that sliding low if it ever gets that far east- I would say across the piste the next 6-8 days gradually get colder daily.... even at 192 now -8c uppers over england- s PS the cherry on the icing on the cake is the heatwave over greece..

GFS ensembles out to T96 the control is near identical to the operational the Mean - showing much better heights to the north - expectation is there will be more support for the op this time around .... S

Interesting stuff .... The undercut significantly increases the UK cold pool at t150 England has uppers of -4c at t156 England has uppers of -8c - a very good run - as posted earlier this eve the GFS seeing more & more heights over scandi fair play... the rate the cold air is decending it will be sub -10c for Eng by 168 S

Huge undercut coming with -8c air draped over the UK like kaligulas grapes... s

18z out to 102 a big inprovement- heights to the north stronger - also a better all round curvature of flow towards the UK out of southern Norway Azores high better alligned - could this be a stella run ! S PS Mucka the JMA 192 is quite rare in having atlantic cold air in situ over the UK to the west of the the low & cold continental air to the East of the low both at -6c @ 850S

Just looking at the ECM - whilst at first glance it isnt go great in terms of cold & there is no pronounced upper high over scandi after 168- there is a shift towards the GFS solution- -again referring to the 240 charts then the 216 of yesterday - now the 192- through 240 today the easterly vector of that huge low has been replaced with a southerly component -& as a result that low that was progged to blast all tge way to Norway is now progges to sink south.... expect more swings to cold in the mid term - & some more refinement over the sliders for Sat my best punt has moved away from central wales to the staffordshire morelands.... s

Evening all - well the continued backtrack in the models ( mainly the GFS ) so far has gathered some momentum today with both the 00z & 12z GFS slowly correcting west as the model begins to 'see' the not so zonal train continue to be derailed remember just 2 days ago the GFS & ECM punched the atlantic through blasting the cold away east - now as some of us have commented the energy dropping SE has been favoured here for comparison is the 240 chart 2 days ago & then todays 00z & 12z 192 charts- 240 if you look cafefully the block is wayyyyy east towards russia Now just 48 hours later the block is signalled to be over scandi You will also note the 12z is further amplified to the 00z what does it all mean - well we are at the point now where orginally a deep fast area of SW winds would sweep across the UK at around day 8/9 with a big mild wedge & no snow however now that area of PPn is coming in at a sharper angle & sliding SSE with a small wedge of mild air in the SW part- allowing for snow over a swathe of the UK- its literally moved that way in 12 hours- in terms of future runs - with this high pressure over scandi just being 'seen' late in the day then theres a high likleyhood that as we reach 144 over the next 48 hours then the high could be even stronger modelled & the CAA over europe could well be deeper & colder with the net result meaning colder for longer over the UK with more snow it may also save us from the Mildest Winter on record.... we also have the messy siders to contend with over the weekend first! lets see how the models develop over the next 24 hours- this scenario of a scandi high suddenly being robust & lows dropping in from the NW has happened in recent years - im just trying to recall when it did ! S