Winter Model Discussion 18Z 5/2/13 onwards.

[pandit-scholar]

Not really sure where all this misguided 'GFS is rubbish' twaddle emerged on here (we're discussing computer models, not football teams)... but to return to the focal point of Sunday, which we anticipate could deliver a significant snow event:

At stake here are some marked differences in the rate of E'ward frontal progression into the UK between the 12z UKMO-GM and other operational centre output, notably ECMWF. These appear correlated to the rapidity and scope at which the amplifying upper ridge over the country on Saturday cuts-off. For example, the 12z ECMWF deterministic is markedly slower with this process compared to UKMO-GM, with net result of retarding the frontal progression to a greater extent. This slower solution is favoured by Exeter, who have modified the GM accordingly (away from raw version you'll see on websites).

Clearly this has profound implications in what will prove a high-stakes forecast, should current evolution continue in similar tone. Bear in mind the frontal zone in question is only just now taking shape off E coast of N America... still a way to go on this story.

However, the slower EC (and presently modified GM) solution offers less threat of disruptive snow into London during Sunday, as opposed to raw GM, which did. Hence, this sort of issue - high stakes, as I suggest - remains a clear uncertainty.

The consensus solution follows EC's snow accumulation prognosis (sorry I'm not allowed to share that as actual mapping), which - with frontal leading edge moving into sub-300m WBFL air across much of S England & Midlands/Wales - looks a decidedly bothersome blend. EC offers as much as 10-15cm snow anywhere from approx central Somerset up through Bristol, eastwards to around Reading and north through pretty much all of Wales and West Mids (some peak totals in these areas excess of 20cm). To the SE, similar amounts (to around 10cm) across Wilts, Hants, to W Sussex. Clearly, distribution is uncertain but in broad terms, the combined weight of EPS and deterministic output is indicative of parts of W/S Scotland, eastern Northern Ireland, N England, Wales, West Country north of Taunton, West Midlands and southern-central England being most at risk of disruptive snowfall durIng Sunday and overnight into early Monday. Currently, Exeter suggest 30% chance of some snow into London itself later on Sunday, albeIt any ccumulations here in the capital are thought likely to be pretty small.

Anyway, that's some detailed thoughts for now, ahead of whatever the 00z runs might yield.

I thought the UKMO 12z showed the heaviest snow for the east and southeast on Monday Morning. Now it seems only the west will get it again. When is East Anglia going to get its big snow event. Might as well give up!

[Dunstable Snow]

Yes, it can be a great place to be (hence why the NE'erly early next week would be 'rather' nice to consolidate)

Interesting inside METO info about the latter part of the weekend and snow potential. Best and safest to be on the cold side of the low - but like January just gone by, it is possible we are again going to see another fine line with a cone snow area in the middle, with the dry and coldest weather on the eastern flank which erodes the precipitation quickly as the very dry continental air cuts into the precipitation area, then the heaviest snow area closest just ahead of the frontal zone, and then going further west a cut off zone into a marginal rain/sleet area. The whole boundary from driest cold continental air (and little or no snow) to the modified higher dewpoint airmass might be only a 150 to 200 miles wide (or less?).

Yep , fully agree , and where I live now normally does well in these situations ...far enough east to be on the cold side of the low , but far enough west to get decent precipitation , and far enough north with altitude etc .. I just hope for your neck of the woods that the convective NE kicks in and lasts for a reasonable period of time. If it does you will do far better than me out of this ( as will my son in Uni at Canterbury !). Cheers

[Bonjangle]

Shooks we are in the firing frame again .

Winter has still not done anything in my experience , we had snow cover for 8 days with all 5 inches , lets have a good blizzard like in the late 70s .

[london-snow]

I thought the UKMO 12z showed the heaviest snow for the east and southeast on Monday Morning. Now it seems only the west will get it again. When is East Anglia going to get its big snow event. Might as well give up!

Hasn't EA done very well this winter compared to other parts of the country?

It was only a few weeks ago that EA was getting frequent heavy snow showers from a easterly where other parts in the south east received not that much in the way of connective showers.

As for the weekend it is far from solved atm and at a guess we won't know the exact snow line until a couple of days at least imo.

[pandit-scholar]

Hasn't EA done very well this winter compared to other parts of the country?

It was only a few weeks ago that EA was getting frequent heavy snow showers from a easterly where other parts in the south east received not that much in the way of connective showers.

As for the weekend it is far from solved atm and at a guess we won't know the exact snow line until a couple of days at least imo.

Live in Essex. 15 miles from the coast! Snow wasn't brilliant a few weeks ago started thawing after a day

[Captain Shortwave]

I thought the UKMO 12z showed the heaviest snow for the east and southeast on Monday Morning. Now it seems only the west will get it again. When is East Anglia going to get its big snow event. Might as well give up!

Many areas in East Anglia got decent snow, yeah it was hit and miss. I live by the sea and got 2 good events. One from a large slow moving shower which got caught up in the developing low which gave Wales/Midlands there big dumping. And then then a couple of days later by a feature running up from France. The second one I thought hit most of the region. Especially as I was in discussion inside the regional thread at the time. If the low passes through like ECM and UKMO does a strong north East wind behind will give some decent snowfalls through convective showers before and beyond then if the UKMO iceland(ish) wedge forms then this area could do very well. If ECM then coastal areas will get scattered showers if the flow doesn't bring lots of murk and low cloud in a more stable flow.

Edit saw your recent reply, hmm maybe you have just been unlucky. I think the second event did hit my area pretty hard. Anyway there's still lots of potential snow events to look at with interest.

Edited February 6, 2013 by Captain shortwave

[london-snow]

Live in Essex. 15 miles from the coast! Snow wasn't brilliant a few weeks ago started thawing after a day

That's the thing with a easterly though mate. Even in quite decent easterlys the closer to the coast you are the more marginal things become.

[starstream]

I live in Essex too,am on a mobile so can't see locations.

we did get some snow in the Jan event but barely 4cm.

it wasn't as impressive as more north of the county or the west of the county,

it surprised me as generally Essex does.quite well but last time , not my bit.

sorry mods i know its IMBY but was just clarifying Essex was relatively poor compared to EA in general.

Edited February 6, 2013 by starstream

[pandit-scholar]

Many areas in East Anglia got decent snow, yeah it was hit and miss. I live by the sea and got 2 good events. One from a large slow moving shower which got caught up in the developing low which gave Wales/Midlands there big dumping. And then then a couple of days later by a feature running up from France. The second one I thought hit most of the region. Especially as I was in discussion inside the regional thread at the time. If the low passes through like ECM and UKMO does a strong north East wind behind will give some decent snowfalls through convective showers before and beyond then if the UKMO iceland(ish) wedge forms then this area could do very well. If ECM then coastal areas will get scattered showers if the flow doesn't bring lots of murk and low cloud in a more stable flow.

Edit saw your recent reply, hmm maybe you have just been unlucky. I think the second event did hit my area pretty hard. Anyway there's still lots of potential snow events to look at with interest.

Basically not much hope of a repeat of 2010. Thought the 995 low on the UKMO on th 11th February would mean significant snow. I had relatives who wanted to come over from India for a trip to see us next week. Told them to wait until Spring due to the risk of heavy snow in the East of England (one of them in their 80s). Told them to delay until Spring with a link to the UKMO 12z chart. Will be pretty frustrating & embarassing if nothing comes next week!

[pandit-scholar]

That's the thing with a easterly though mate. Even in quite decent easterlys the closer to the coast you are the more marginal things become.

My area did well in 2010 from the snow!

[Bonjangle]

Aint it strange , we never had computers and we all lampost watched in the 70s-80s , and we did have a good snow event with blizzards .

We have computer models now and its up and down and round the back and in the front , to me it dont make any scence.

Computer models to me are pants , human input is much better.

I rest my case ' but before i do its blowing a gale here and temps are still above freezing and 4c .

[Kentspur]

Not fair:-( I got brain freeze from the strong West winds and soaked in squally rain like a drowned rat at the football tonight in Dartford (England c vs turkey), the same showers go to Holland just across the sea and fall as snow! Hopefully you will be sending them to us (as snow) next week fingers crossed!:-)) come on models!

The Snow shouers did come over from Uk to me , but wat amazing to me , in 45 minutes 6 cm .Mayby some pace more.

Wile the 2 meter T is still above 0 , like 0.7,.

Ok i will join Briitain by the 00z runs.

Dont be afraid wintry people.

Tkae a deep breath everbodey inc me .

Lets look everything so simpel as it is .

We have one thing comment en thats the weather.

Don t fight each other personaly , fight with argumenst relevant to the weathermodels or ssw , or mjo , or nao , ao , bao.

For me , i dont care or it is cold or warm or snow or rain. Its al in the game.

Dont shoot the pianist.

[Ryan Dutch Weatherman]

This is unbeliveble , no any models has predicted the snow ammaunt fall in just 1 hours couple places in even west Netherland with 5 /10 cm snow.En ist not freezing yet. Ist stil above 0.0.

[Skyraker]

The Snow shouers did come over from Uk to me , but wat amazing to me , in 45 minutes 6 cm .Mayby some pace more.

Wile the 2 meter T is still above 0 , like 0.7,.

Ok i will join Briitain by the 00z runs.

Dont be afraid wintry people.

Tkae a deep breath everbodey inc me .

Lets look everything so simpel as it is .

We have one thing comment en thats the weather.

Don t fight each other personaly , fight with argumenst relevant to the weathermodels or ssw , or mjo , or nao , ao , bao.

For me , i dont care or it is cold or warm or snow or rain. Its al in the game.

Dont shoot the pianist.

heh, i'm really starting to enjoy these.

[london-snow]

This is unbeliveble , no any models has predicted the snow ammaunt fall in just 1 hours couple places in even west Netherland with 5 /10 cm snow.En ist not freezing yet. Ist stil above 0.0.

Good on you my dutch friend i hope you get what your hopes desire.

Let's also hope your western friends in us join in the action in a few days time. Dutch dreams.

Edited February 6, 2013 by london-snow

[london-snow]

So who is up for the 00z & what are your early predictions for what it holds?

Mine punts are ~

GFS ~ Finally trends into line with the ECM & UKMO solution.

UKMO ~ Solid.

ECM ~ Solid.

[Zenarcher]

At 60 hours the GFS has the low to the South of Greenland moved more North compared to the 18z it had it further South. So it moving North brings it more in line with the ECM here so GFS showing good early signs at the moment.

Edited February 6, 2013 by weathermaster

[london-snow]

At 60 hours the GFS has the low to the South of Greenland moved more North compared to the 18z it had it further South. So it moving North brings it more in line with the ECM here so GFS showing good early signs at the moment.

Glad to hear that somebody is up WM good on you mate.

Let's now hope the GFS 00'z moves towards the consistent ecm & ukmo.

[Dave Kightley]

It's better.....looks marginal the further west you are though....

[Zenarcher]

GFS 00z is better and has moved more in line with the ECM

For example here's Sunday

GFS

What's changed here from the 18z? Better heights over our North reaching into Greenland then we have shortwaves going under the block both of these changes are a step closer to the ECM.

ECM for the same time

Edited February 6, 2013 by weathermaster

[london-snow]

Good start now let's hope its finally smelt the early morning coffee & the ukmo & ecm don't decide to go off on one.

I am off now for a few hours got work to do. See you all around 7am for the 00z finish line.

[Dave Kightley]

Ukmo is very nice at 144h or not...Looks better then the GFS at that timeframe..is that a shortwave north of England ??

Edited February 6, 2013 by Dave Kightley

[Dave Kightley]

Lack of comments on the UKmo must be making me look silly but that 144h looks very snowy to me...

[snowmadchrisuk]

Well , For Sunday , the latest GFS holds the precipitation back West, Keeps it as mainly rain and then Weakens it in to virtually nothing as it arc's over the West Mids. Following this , just following Netweather's precipitation type charts , there is no big Snow chance again until deep FI . Not the best run in my eyes , but we await the ECM .

[snowmadchrisuk]

Lack of comments on the UKmo must be making me look silly but that 144h looks very snowy to me...

UKMO , +144 is a very good chart and a bit like last night's ECM , although Sunday's event would also have a massive warm sector for it to get there as the LOW drops straight across the Country ..