TEITS

Looks like 06Z GFS is picking up a wash streamer late sun/monday morning. Extending all the way into Wales!

I think some models are having a laugh when it comes to the precip predictions. Take for example tomorrow , the Euro4 suggests little in the way of convection across much of E England. However I firmly believe snow showers will be widespread and not restricted to only streamers.

Whilst some are looking W at the low pressure for a possible snowy breakdown. Im looking in the other direction. Could it be that no fronts will get anywhere near at the end of the week (except SW) and the Scandi HP will extend further W than currently modelled? Also could it be the following week sees even colder upper temps -15C.

Here we go Paul. http://old.wetterzentrale.de/archive/ra/1991/Rrea00119910207.gifhttp://old.wetterzentrale.de/archive/ra/1991/Rrea00219910207.gif

Whilst I am looking forward to what snowfall occurs this week I do have concerns with the impact on the current pandemic. I am due to have my vaccine in the next few weeks and if this cold spell becomes extended this may delay the vaccine roll out. Obviously other factors come into play i.e food supplies, online deliveries, and even more importantly the ability of ambulances to respond to emergencies. A week of sub zero temps and lying snow of 10cm shouldn't cause too many problems. However a 2 week cold spell and/or snowfall in excess of 30cm would cause chaos!

Sometimes you need to use instinct and experience rather than simulated models. I have a very good idea of snowfall distribution across my area under the conditions suggested by the models for next week. Never forget how in the 80s an E,ly brought 1ft of snow in Peterborough in under 2hrs from a band of snow showers. At times we can become too dependant on computer models. For example I just knew the GFS was way off with its handling of the low for this weekend. At one stage it even had the low move NW to Iceland against the huge block to our N. Instantly I knew this was wrong.

We should all sit back and forget about snowfall, breakdown of cold spell and marvel at the N Hemisphere chart at only +48. I have lost count how many times I have drooled at +384 charts but even those didn't match what we are seeing at +48.

Well it seems upgrades have occured since I last posted. Finally we can look into some detail because I need to make sure I have plenty of supplies. My mobility scooter is rubbish in the snow! The transition period is between sat night/sun. A band of rain will turn to snow affecting from N lincs to SE. This continues throughout sunday and although the snow will be light/moderate, due to temps, dewpoints the amounts will build up. Probably a little break on Monday from snowfall before the snow showers begin flooding in. Main areas affected is Lincs, E Midlands, E Anglia. Obviously the NE of England/Scotland will be hit hard by the snow shower activity. Difficult to predict for Wales, NW England, W Midlands, SW England. More reliant on low pressure from the atlantic bringing a blizzard for its snowfall.

Just forgetting about snowfall for a min. I cannot put into words how special this N Hemisphere chart is. This could not be more opposite to the norm if you tried.

I recommend using this model which only goes to +54 with regards to the low. As you can see further SE than GFS and supported by the ECM. I know I sound like broken record but a trend SE is more likely with an E,ly arriving across all of the UK sooner.

Just a quickie and shall explain later but the low at +48 is too far NW by the 18Z GFS. Much more likely to be further SE. This is a positive because it would allow the E,ly to arrive earlier.

Much better 06Z GFS P compared to its 0Z run. http://modeles16.meteociel.fr/modeles/gfsp/runs/2021020206/gfs-0-174.png?6 All evidence points to the GFS op being wrong and so does my instincts. However I would still refraIn from telling anyone that a big freeze is on its way. Finally I don't wish to be rude but some need to realise that in this situation a small synoptic change can have a massive impact on the actual weather. What I mean by this is does a shortwave become detached from the parent low or become absorbed. If it becomes detached what track does it take. What about the track of the parent low, could this be forced further S by the blocking than currently modelled. So please lets try and keep our emotions in check.

This output is so incredible I am not even sure I want the 12Z GFS to come off due to the current situation. The forecast would be like those in the classic 1980 E,lys i.e snow showers becoming heavier and more prolonged merging into periods of snow. Many a time I read that sort of forecast back in the old teletext days! Still think we could see the E,ly sooner than the 7th Feb, possibly this friday!

Normally I would agree if it wasn't for this mornings UKMO. Very complicated set up really. The midweek low has one shortwave moving E, another S and the main low remains in situ and then tries to move N!! I shall stick with what I said earlier and that is this low will move S along with the shortwave at a much faster pace than what the ECM/GFS is suggesting. The ECM can be wrong with the predicted snowfall for this weekend and early next week being dreadfully way off from its predictions a few days ago. I said as much at the time because its forecasts never made any sense to me. On a positive note you could argue that whilst the 06 GFS is poor early on, the latter stages are far better than a few days ago. So its swings and roundabouts really as I do not expect this to be our last chance. Seems N blocking will continue to be a feature for a while yet.

If this low is going to take ages to move S then locations to the N of this within the cold zone could recieve a right dumping. For example the end of the week could be very tasty for the far N of N England/S Scotland. These Arctic highs are a bloody nightmare. The link with the high in the Atlantic and the Arctic high is causing mayhem. If the Arctic high edges further S then the low will be forced to move S much faster. The influence the Arctic high has on the UK can clearly be seen on the models when viewed from the N Hemisphere. Remember me mentioning the cross polar flow?. If you look at the ECM this doesn't really become established (nearly at +144) but then look what happens at +168! Lack of forcing prevents low from moving S much faster. End result is opportunity for spoilers to occur and ruin our chances. My motto has always been get it in as fast as possible to enjoy the rewards!

No concern from me with regards to todays output. The key thing to remember is the atmosphere seems primed towards blocking around the Greenland/Iceland/Scandi region for the forseeable future. This combined with the time of year as Feb is generally the month when blocking is more likely to occur. You will always see swings and roundabouts in the model output with regards to these situations. Im still going for the cold E,ly to arrive sooner than the output suggests as I feel the low pressure will sink S faster than currently modelled. Just remember Dec 2009, 2010, Feb 2018 all had the ups and downs in the output with similiar posts to what I have read this evening!

I haven't much time but I thought I would make a few points. 1. Unconvinced of snow risk this weekend. The area condusive to see snow rather than rain will see little or no precip at all in my opinion. Im thinking my location, midlands etc. Snowfalls mainly reserved for higher ground in Wales, possibly SW England. A shift S is likely to continue with this low. 2. The milder spell next week is more likely to become shorter. The 18Z GFS has the low at+144 way too far N as its underestimating the forcing from the blocking to the N. The result being a faster E,ly setting in than currently modelled. 3. Some of these runs have been mindblowing i.e -17C upper temps. I am not sure I wish to see such an extreme cold spell. This will delay vaccinations and probably extend lockdown!

If the ECM continued then the colder airmass would move S as the flow veers more towards a NE,ly than E,ly.

GEM is heading in the direction I was expecting with this incredible cross polar flow.

Fasinating watching the output over the past few days. Whilst next weekend is interesting I am more interested in beyond (around 3th/4th Feb) when we could see a cross polar flow with an incredibly cold airmass on the S flank of the high pressure extending from the arctic. Already seen more snow than the past few winters but that wasn't difficult to achieve!

Just an observation of trends in winter when blocking is involved be that in Greenland/Scandi or both. I know some disagree but I still believe these models have a historical bias programmed into them and always try and return to default weather pattern. This is when models come unstuck when blocking over higher than normal lattitudes occurs. For example the Arctic high has always been a nightmare to forecast for these models. I do not expect a sudden flip but a slow move towards what I describe.

Based on what I have seen of the model output these past few days I would like to make a few points. 1. Do not be surprised to see a slow shift to the south of the overall pattern over the next few days. 2. Keep an eye on any future snow events as low pressure moves across the UK. Very often we see these move S on successive runs. I have lost count of many snow events modelled for the N of England only to move that far S the precip does not even reach the S coast. 3. Even if the above does not occur in the reliable timeframe the overall trend from the models is to slowly push the PFJ further S.

Wow at this mornings output although again I hope a cold spell as severe, prolonged does not occur. Any other winter then bring it on. Just to show how extreme the 0z GFS is look at the predicted temps for sicily. My family members in Palermo would be surprised with these temps.

Almost impossible to figure out what the outlook is going to be. I feel the usual scenario will occur around 12/13th Jan as we see a shift W of the high pressure to our NE and less progress from the Atlantic. Whilst I wouldn't expect this to change to sudden cold E,lys the effects of which have a knock on effect later on. We then have the added complication of the Arctic high and polar vortex bringing a bitterly cold airmass to NE Europe. The effects on the UK could be a bitterly cold, convective cold spell or a moderately cold spell but with battleground blizzards or even both. l haven't included the milder option because as I said in the covid thread, I do not want to see a severe cold spell this winter. I bet it will be sods law we get one when this is the last thing the country needs!

Looking at the Euro4 im not convinced GFS is right even at +48! Note the N,lys over the far N of Scotland and Shetland islands. Ridge of high pressure extending further S in this model compared to others.