Winter Model Discussion - 11/01/13 00z Onwards

[Paul T]

When comparing the 48hrs GFS and the 48hrs High resoluation NAE there is very little difference. The positioning of the pressure systems are pretty much the same. Other GFS runs have been up to 750miles out, but this run seems more 'accurate'. @ 48hrs.

I have high confidence that this GFS run is illistrating a pretty accurate picture up to around 96hrs based on this.

Attached below for ref.

[craigore]

Steve M's slider at 120 perfectly illustrated on the UKMO run

But arent we losing the cold uppers at this point.?

[kold weather]

Yep BA I have mentioned that, with that being said under fairly heavy precip, and dews/850hpa profiles only a little too high, I'd think most would get away with it, esp above say 50M.

GFS shows the PV running out of gas somewhat again by 180hrs and starts to withdraw northwards again which means our block can hold itself where it is. Great run, real cold run as well, esp the further Se you go.

[john mac]

Just for fun.

Atlantic hits a brick wall next Saturday.

2 hopes, no hope and bob hope, look how extensive the cold is!!

p.s. good luck in the southern area final your going to need it!!!! lol

[cooling climate]

The UKMO chart at t144 is Awesome and although the GFS is different at this

timeframe it is as Steve said small steps at a time. So if the ECM is similar

to the UKMO and I think it will be expect the GFS to play catch up during

tomorrow.

Would love to see the UKMO t168 chart although I think we will get an idea

how good it would look from the ECM run.

[Tim Bland]

Just for fun.

Atlantic hits a brick wall next Saturday.

Looks like the energy will go over it and allow the atlantic in. We need the Jet to play ball.. Yet again the milder interlude is pushed back. IMO we will keep seeing this from the models until what we end up with is a short thawing out period before a renewed surge of cold from the NE.. Happy days

[Paul T]

I expect this is how many of us would like the charts to look next week! CFS keeping the dream alive

I tell you what, it isnt far away from the GFS now!

[mulzy]

But arent we losing the cold uppers at this point.?

Linked wrong chart - corrected now.

[weather eater]

Lord knows where this is all going every run is different, FI is so close I can stick my tongue out and taste it. Fantastic UKMO especially for the longer term, great GFS, no need to worry about its FI because every run seems to produce a different evolution from 72hrs so it’s anybody’s guess.

[ITSY]

GEM nowhere as snowy as GFS or UKMO - with the bulk of the country getting nothing on Monday. Just worth mentionning, we have no idea of amounts yet, just possibilities that are on the table.

Rumours on TWO of data issues circling from Canada which is making these runs 'better' than they should be. No idea of how true that is.

Basically, don't pin flags to the mast yet.

[ChartViewer]

GEM T84

[Mark Bayley]

GEM's take on Monday, precipitation struggling to progress east, although good for the west, especially Wales. The NOGAPS similar to the GFS and UKMO. Monday into Tuesday is firming up to be a very interesting day for something more significant (UK wide). Beforehand snow showers in eastern counties seems likely.

[John Cox]

Pressure building fast over Scandi in the mid-range as well on the GFS. Interesting.

UKMO @ 144 can I just say...... "WTF"

Very similar to the most major snow event in my lifetime in Dublin 9th Jan 1982.

http://www.wetterzentrale.de/pics/archive/ra/1982/Rrea00119820109.gif

[Lynxus]

Just for fun.

Atlantic hits a brick wall next Saturday.

.... And being the GFS it will be over doing the atlantic somewhat, So I would expect this model to look almost 90% different with the Atlantic not getting so far east..

[Zenarcher]

Models on their 12z runs today are much better I'm happy to see this, just goes to show they are still changing big things even at 60 hours.

[Geordiesnow]

Lord knows where this is all going every run is different, FI is so close I can stick my tongue out and taste it. Fantastic UKMO especially for the longer term, great GFS, no need to worry about its FI because every run seems to produce a different evolution from 72hrs so it’s anybody’s guess.

Indeed and its what you expect in the medium range, especially dealing with a complex set up with many factors for the models to factor in so it'll be foolish to be sucked into the UKMO/GFS charts after 96-120 hours or so.

What I'm pleased about is that the big 3 models do hint at some sort of easterly flow for Tuesday maybe into Wednesday which will no doubt will bring snowfall for many members, the models also seem to agree on Monday's low coming into cold air, how much PPN there will be and what it falls as is still open to debate but no doubt some areas will see some snowfall for sure. Admittedly we still await the ECM run regarding the potential easterly flow around 96-120 hours but it last few outputs have picked up on this I notice so its one to keep an eye on especially if this afternoon ECM run carries on it trend.

[EML Network]

Each day that goes by, the cold seems to extend another day with it (Good sign) , the way things stand, if the GFS were to come to pass, we'd still see the cold entrenched over the country by Mid Day Thursday, the UKMO would certainly keep the cold entrenched until Thursday too, where it would go there after is open to debate.

So as long as this trend continues, we really can't complain.

We know that FI sits somewhere around + 96, and all respected models keep us in the cold until then...for once lady luck (for now) is on our side, the main snow threat for most won't be until Monday / Monday night, in between now and then is another 10 GFS runs, so those in the West, the time to be disheartened is not now, but If I were living either in the extreme SE tip of England , or the Midlands / East Midlands I would be getting very excited right about now.

steady as she goes ...we're another run closer to something special

[kold weather]

Yes the GEM doesn't do anything because it just keeps the LP heading eastwards and doesn't drop it at all. Its of course still possible that this does happen, but I'd stake alot on the GFS in this case, say what you like about it but once it gets an idea with these sorts of little lows between 72-96hrs, it doesn't often let it go, especially when other models are going down the same route.

[alexisj9]

To sum up, this run gives widespread 5-10cms (locally 15cms) Monday/Monday night. Follows on with 5-10cms for Northern, NE, central and Eastern parts on Tuesday/Tuesday night and then will likely produce showers off the North Sea on a stiff ENE/NNE wind - totals for which can't yet be forecasted.

But most places will be unlucky at some point not to see 10cms and indeed central/northern/eastern areas perhaps 15cms or more between Monday and Wednesday.

Lots to play for then, but REMEMBER, this is only one run and is therefore no more likely at this stage than the run we saw earlier which gave Eastern and central areas far far less.

Awaiting UKMO with much interest now.

I agree this is only one run, and I am trying not to get over excited but this is not the first run like this, this patern and similar has been showing for days on most models. It's starting to look like something like this may happen.

[Isolated Frost]

Superb synoptics again.

Saturday seems very cold, with some light snow shrs possible, especially in the east and south-east under a E flow.

The low should provide some snow for high ground in southern areas as well.

Sunday then looks very cold, but relatively dry.

Monday then looks either prolonged mod snow with the EC/UKMO or snappy, heavy snow with the GFS.

After Monday we have the GFS bringing in a showery E regime, the UKMO brings in what would turn into a prolonged cold spell, and the EC eventually topples over- though it has not updated to the 12z yet.

Signs are for a very fun next 7 days at the least... the crux may even come later on the month which makes this SO exciting.

Anyone else notice the agreement from ALL 3 major models for a unstable, showery E flow with heavy snow shrs on eastern coasts from Tuesday to Wednesday (potentially even longer... a la UKMO)

[The Eagle]

NOGAPS pretty similar to UKMO at 96 hrs (big change from 00z)

[Buzz]

GEM nowhere as snowy as GFS or UKMO - with the bulk of the country getting nothing on Monday. Just worth mentionning, we have no idea of amounts yet, just possibilities that are on the table.

Rumours on TWO of data issues circling from Canada which is making these runs 'better' than they should be. No idea of how true that is.

Basically, don't pin flags to the mast yet.

Not exactly, the original post on TWO was as follows:

"There is a serious model point here.

As far as I can tell over the last 3 days at least, every morning run has been a downgrade on the day before (from a coldie point of view), and every subsequent run through the day a steady upgrade until we're all drunk on tales of frozen derring-do and snowfests at the end of the day. This has happened at least the last three days, regular as you like. So it must surely be a data input issue? Are the later runs fed with more information and so are more accurate than the morning runs, or vice versa?"

and there was a response to that as follows:

"Paul Blight (meteorologist on UKWW) reckons it is a data issue related to difference in available data over NE Canada / Greenland. Be prepared for another downgrade in the morning then!"

In other words the exchange was related to something discussed earlier in this thread regarding 00z and 06z runs Vs 12z and 18z runs, namely the latter often looking better than the former. In short, I wouldn't worry about it.

Edited January 11, 2013 by Buzz

[Frosty.]

It's great to have the gfs onboard but I think it's still too progressive in shunting the coldest uppers further southeast and it's nothing like the meto update today so I would go with the ukmo 12z which has an undercut and would keep the very cold spell going on and on. We can now relax and just enjoy the unfolding drama because the very cold and snowy spell is now set in stone. Looking into next week, heathrow airport will finally be able to use their new equipment following the dec 2010 fiasco, plenty of snow clearing next week for them and plenty of snow for everyone else too but I don't think the cold block will be eroded like the gfs 12z shows.

The beast is yet to come

[Summer Sun]

Some significant snowfalls likely next week nearly 40cm for high ground in SE Scotland! 10cm to 20cm widely or 3 to 7 inches in old money and upto 15 inches (1.3ft) in SE Scotland

Edited January 11, 2013 by Gavin.

[Bolton67]

Anyone else notice the agreement from ALL 3 major models for a unstable, showery E flow with heavy snow shrs on eastern coasts from Tuesday to Wednesday (potentially even longer... a la UKMO)

Perfect flow for wash streamers...