Joe Levy

I am not criticising the discussion of cold, but just promoting talk of rainfall totals as an equal part of the discussion. I am keen for cold and snow too, but also keen for the rain to stop as well, so my model interests are diverse!

Actually, it's quite useful to be reminded that before the chance of snow, there is a significant risk of flooding. For me, though I am very interested in snow prospects, the timing of rainfall, amounts and longevity of rainfall that are being weighed up by the different models is both interesting and useful.

I love snow as much as any coldie on here, but living in Exeter, where travel in and out of the city depends on several main riverside routes being accessible, my primary immediate concern is rain totals! It is deeply troubling the totals that are being forecast and I think many on here greatly appreciate the updates you give us on such matters Ian. There have been numerous times when the main reason I was able to warn relatives of flooding long in advance was because of your updates here.

I never said it meant anything of certainty! But if we don't look at them at all, what is the point of this forum? It is part of the model output and should be counted equally with other output. Also, models don't lead us up the garden path! They're mathematical equations, they have no personality tonight's output is displaying things as they currently stand, which will change no doubt. We lead ourselves up the garden path by implanting emotions into an emotionless situation! The current GEFS is pretty good for cold, noone can deny, but that does not guarantee it will stay that way. If it keeps being good for cold, then something is being calculated that won't go away, so it is then where we can have more certainty. Currently, anything can happen really!

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=187&y=174 (South West England) http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=307&y=138 (South East England) http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=269&y=0 (Northern England) As several have pointed out, the 12z ENS are much better for blocking and, as a consequence, better for cold and snow, reflected in the 850 temps. One thing that is worth pointing out is that you don't need deep cold for snow so many of these members could provide snow quite widely on account of low thicknesses and/or low dewpoints, depending on where the surface flow is coming from and the upper air profile. No certainty yet, but nothing can be ruled out!

That depends. I'd imagine that for settling snow, yes. But with low thicknesses and unusually cold uppers for a westerly, falling snow is certainly feasible. It's a long way away though and much could change in either direction.

IF posted this in the mod discussion: "By Monday, UKMO-GM has snow showers advecting well inland on westerly flow across e.g. W Country, M4 corridor, Wales etc. As I mentioned yesterday, the unusually chilly characteristics of the westerly flow - at least, as currently progged - looks more likely to bear wintry ppn than otherwise might be the norm for late Jan. One to watch...."

I fear nothing! I shall take on the PV and the Azores High by myself! Wish me luck...

You do know reverse psychology doesn't work with models right? also, no point using probability on something which we don't know the precise chances of happening, even if it is a ridiculous number like quintillion there are so many variables we cannot account for. I reckon that the chances of it happening exactly this way are extremely slim, but then we don't need it to happen precisely like this to get snow! Actually, the chances of colder weather are relatively high, just not the most likely. In any case, dabbling with probability is dangerous as it can lead to false hope and false pessimism! A 90% chance of snow leaves a 10% chance of no snow! The same works in reverse!

But battleground situations can either be soggy or snowy (more often the first) for the South-West, as we're often on the battleground!

First chart of low resolution and the Scandi block has moved westwards thanks to some help from the Arctic and the Azores high, which ridged northwards to slow down the pv injections into the Atlantic and support the Arctic high Leaving us with this lovely chart further in the future and the uppers are pretty cold too

Based on the GFS 18z at 168 hours, there is a chance, and I say a chance because I don't like to preempt what runs will show, that the azores high will link up better with the Arctic high here, because the Arctic High is further south. So far that seems to be what is happening EDIT and here at 186 hours we have this, which has a lot of potential to say the least

The Day After Tomorrow anyone? http://www.earthcam.com/usa/newyork/midtown/skyline/

It's interesting you say that, because when I tried to have a look at the environment agency website for river levels in that area, several of them came up as 'station not active' http://www.environment-agency.gov.uk/homeandleisure/floods/riverlevels/120716.aspx?stationId=3066 is this an error? or is the water so deep that they cannot record anymore! (if that's possible) I noticed how high the water was on the levels whilst on the train from London to Exeter

Living in Devon, it is always mild and soggy here! We got very little snow at all in 2013, except over high ground. So actually I think you'll find that some of us would just like to see a flake or two! The northwesterly setup showing on the models is pretty good as far as I am concerned, especially with the jet pointing nw/se. Also, any corrections westward and we get quite a different setup! I was born in the mid 90s in concrete and brick London so any snow is frankly amazing for me!

I've sent it to a lot of my family, who are now bearing the brunt of my weather obsession it's amazing how many of my friends have been forced to understand who James Madden is and what the MJO is!

I would imagine that many of us in this region would see at least a few flakes from this, as cold northwesterlies often bring very heavy showers which can turn wintry with increasing intensity and over high ground. Anyone on Dartmoor and Exmoor should be particularly interested

I couldn't agree more! In 2012, late October or early November I think, a front moved across the South of England and, with evaporative cooling and cold northerly surface flow, caused very heavy snow over parts of Somerset and Dorset! If that can happen in Autumn, when conditions are not normally favourable for wintry weather, then the persistent tendency for the models to show cold north-westerlies appearing in the next week or so is even more promising! Sometimes the best winters are about the surprises!

I laughed so much reading that, thank you for sharing! It seems like Exacta spends more time attacking other forecasters than actually forecasting!

I know it's become my automatic comment for everything this winter, but I definitely agree about the stratospheric warmings. The vortex has been very slowly weakening for weeks now, thanks to a series of smaller warmings. The GFS has not let go of the signal for a warming on the 31st Jan/1st Feb onwards for several days now, hence charts like this.

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=307&y=139 (South East England) http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=188&y=176 (South West England) http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=265&y=1 (Northern England) Another very good set of ENS. There are some good trends developing in the output at the moment, both in the troposphere and in the stratosphere! Let's see if we can get the trends in place properly and then that's where the specifics start to become relevant. Already we've observed how tiny corrections westwards and eastwards can drastically alter the sort of weather we will see. That's what we get for living on an island next to a vast landmass and a vast ocean!

I would say it is certainly possibly that such a westward trend would continue, however I wouldn't bet on it. Blocking is often underestimated, but there are no guarantees with the weather. It's something look out for, and if the westward corrections continue throughout the next couple of days, then I'd be inclined to agree. However, it may well go the other way, as is the nature of such complex patterns!

It's not the favoured model, at least not in my view, and it never was. The GFS showing a colder outlook, rather than drastically increasing the chances for cold, highlights the high levels of uncertainty in the models at the moment, as IF was pointing out last night.

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=189&y=176 (South West England) http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=309&y=141 (South East England) http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=272&y=0 (Northern England) Nice short ENS from the GFS 0z - pretty decent chances of snow around midweek and still a lot of members bringing -4/-5 uppers across the country at the end of the period

Good morning to you too! Or good evening from my perspective... I haven't yet gone to bed... yes it is interesting how much difference 6 hours can make! The GFS and UKMO have shifted significantly. The disclaimer is that this doesn't guarantee cold, but rather the uncertainty has increased even more, since such dramatic changes in a short time frame have big consequences on our ability to forecast! It's why I joined this forum, because it's so damn exciting!