Model Output Discussion 19th January 2014-18z onwards.

[mackerel sky]

I was just looking through the chart archive for early February 2009. If you can't remember the first two weeks of February 2009 then at face value they don't look that remarkable. Up until then it was a snow free winter for the bulk of lowland UK. But under what can only be described as ;marginal' conditions we had 2 weeks continuous snow cover, despite no -10 uppers ever covering the UK. Once we had a dump of 8 inches, it was thawing temporarily, but then another dump came etc (one came despite uppers of -2C!). If there had been no thawing, I worked out we would have had 22 inches of snow in that fortnight. At the most we had 11 inches level, and quite a history of freeze-thaw in the snow, when we digged out on the Sunday and thought we should go back to work (all the schools closed on the thursday and friday - infact I worked from home half arsed, and it was a delight to see parents having the most amount of fun possible with their kids, before retiring to pubs in the afternoon - I also think my son was conceived then, and he is four now...). At the bottom of the layer was basically 2 inches of sheet ice, like window panes, then a heavily compacted layer of 4 inches, plus 5 of nice snow on top, when the digging out commenced. 

 

Back to the models... someone mentioned that the 528 DAM line on the FAX charts was down to the south coast, and we have low thickness values pretty much all next week. I can't contribute a lot to serious model discussion, though I used to - i've just watched things play out from 12 years of model watching here and look for analogues and what was actually born out in terms of the real weather (and 12 years is as good as it gets, check out my member number). We can talk about percentages, but I would say the ensemble support is such that with 75% confidence we should be rather excited. It isn't going to be classical cold, but with opportunities for surprise dumpings for anywhere, and that review of the early February 2009 charts fills me with glee in relation to what might come. 

 

Mods - please feel to remove elsewhere if you don't think suitable for serious discussion. 

[shaky]

Good news!!latest euro4 very similar to jma at 48 hours!!also -7 uppers incoming sunday evening with low thicknesses!

[Snowman.]

I wouldn't take any mean chart past T144 when working with things like this as its fine details that are the difference here and pulling up a mean at T240 proves nothing other than the wide range of a scatter.

[Panayiotis]

So just to back up my post from earlier, here is the expected temps from the high res EURO4 and the GFS @48hrs:

EURO4 much colder @850hPa compared to the GFS 18z, with -7C uppers over Ireland compared to -4C/-5C on the GFS.

Edited January 25, 2014 by Panayiotis

[Timmytour]

Let's face it there are some good opportunities brewing for next week and personally I think the way the GFS has been slowly progressing, albeit erratically towards colder solutions in the relatively short time frame makes me think wednesday's going to give the first snowfall of the winter in my locale anyway.

But of course caution is the key....hell even the Express don't have the S word in their headline for Saturday (just 80mph gales!)

[Snowman.]

Let's face it there are some good opportunities brewing for next week and personally I think the way the GFS has been slowly progressing, albeit erratically towards colder solutions in the relatively short time frame makes me think wednesday's going to give the first snowfall of the winter in my locale anyway.But of course caution is the key....hell even the Express don't have the S word in their headline for Saturday (just 80mph gales!)

 

'progressing'

 

It's been thrown around and dragged screaming and kickin'!

 

Lets hope the GFS revamp in the coming months will make me want view it as a reliable source for when it comes to these situations.

[Panayiotis]

The NAVGEM possibly picking up the signal for a stronger block, with the 18z looking a lot like the UKMO @144hrs:

Just to compare here's the 12z:

Edited January 25, 2014 by Panayiotis

[Just Below Zero]

'progressing'

 

It's been thrown around and dragged screaming and kickin'!

 

Lets hope the GFS revamp in the coming months will make me want view it as a reliable source for when it comes to these situations.

Lets face it.  No rescource is reliable in these instances. Not now or not even the next generation of super computers.

Upto 5 days we may expect to go from say 79.1% accurate to maybe 80.2%. But even if it were 90% we could never rely on it.

This is the sheer beauty of temperate climate. No need to ever get hung up because there is always something different around the next corner.

Even 30 minutes out on radar things change daramatically!

That said someone somewhere in the BI will be very happy with their cotton wool landscape this week.  And for those doubters there is less than 5 months to go before the nights start drawing in for the next round on the NW forum.

 

 

God that red wine was good tonight!!!

[Yarmy]

Without wanting to make a prediction, the one consistent theme is how cold the 850s are coming from the WEST despite the Atlantic modification. The SSTs off labrador are miles below average and there is a below average SST corridor all the way to Blighty. Seems like everyone is worried about the continental 850 temps, but look the other way!

http://weather.unisys.com/surface/sfc_daily.php?plot=ssa&inv=0&t=cur

[Cumulonimbus Tower]

Judging by the mood in here tonight i'd have thought there was a blowtorch Bartlett showing up and everything was lost... Looking at the latest from Exeter i'd say all to play for personally.

Edited January 25, 2014 by Cumulonimbus Tower

[Joe Levy]

Without wanting to make a prediction, the one consistent theme is how cold the 850s are coming from the WEST despite the Atlantic modification. The SSTs off labrador are miles below average and there is a below average SST corridor all the way to Blighty. Seems like everyone is worried about the continental 850 temps, but look the other way!http://weather.unisys.com/surface/sfc_daily.php?plot=ssa&inv=0&t=cur

Hence IF's mention of wintry showers moving across South-West England and penetrating inland on Sunday night into Monday as the cold air wraps around the low. Perhaps this is one of the few instances where a cold PV over Canada can be favourable for wintry weather in parts of Britain

[Timmytour]

 

And for those doubters there is less than 5 months to go before the nights start drawing in for the next round on the NW forum.

Small point of order....actually the nights don't start drawing in till late June so your use of the phrase "less than" might be inappropriate in this instance. The days start getting shorter from the 21st onwards because the mornings are getting darker

[kumquat]

Tells the story for midweek. Sadly. Heavy rain south of M4 corridor. Snow showers into the extreme NE. PPN  more wintry for the midlands up.

Edit: I call 50/50 toss for Kent/South East Anglia.

Edited January 25, 2014 by kumquat

[draztik]

Draztik, you've been using these charts to show the atlantic coming through for the past three weeks. Where is it? As steve has posted, you are not using them properly. Slp mean charts are almost useless by the time you are into week 2 and the heights are heights, not wind direction.some very strange late evening stuff on here. i suggest you all go to bed and awake to more decent wintry nwp fayre in the morning.

im not highlighting the slp mean, nor to my knowledge is my reference to a westerly favoured flow based on the heights 'incorrect'. I cant see the postage stamps, so I use the mean; which indicates a majority of members support a zonal flow into day 10/15! A cold zonal flow, based on the position of the troughing, a possibility! But, amazing how you can be so blasé;

Edited January 25, 2014 by draztik

[kumquat]

im not highlighting the slp mean, nor to my knowledge is my reference to a westerly favoured flow based on the heights 'incorrect'.

Lots of misinterpretation going on here. Offering the best (IMO) alternative view seems to have bought you some friends lol.

[draztik]

Lots of misinterpretation going on here. Offering the best (IMO) alternative view seems to have bought you some friends lol.

or none! I would love to see a sustained cold spell, but I'm not seeing it right now! I enjoy being told I'm wrong though; if i had a penny for everytime I've heard that id be a rich man Edited January 25, 2014 by draztik

[geordiekev]

For those folk looking too far ahead, I would like to point out some uncertainties within the next 72 to 84 hour timeframe.240114 MetO Fax Chart - t+84 original.png240114 MetO Fax Chart - t+96.png The surface features for Monday are far from nailed as indicated above and to my eyes, there are signs that the all important 528DAM line could be showing down by the South Coast even by then. Ask yourself, WHERE IS FI NOW?

As I said days ago when the JMA done a stellar job of picking up the trend. FI is when the low actually hits the block to the east as everything beyond that point is open to change.

The models struggle to forecast how they will interact because they ARE only predictions and is the reason we have the odd flip flop but now there are less flip flops as there are less options for mild, but it's not nailed on yet.

However signs are that the PV is disrupting allowing heights to rise in favorable positions. The cold is to our north, east and west so we would be very unlucky note not to tap into something special cold wise.

Edited January 25, 2014 by geordiekev

[Ali1977]

UKMO still looks excellent, and GFS is looking better than the 18Z. Positive steps this morning, lets hope ECM follows the trend.

Edited January 25, 2014 by Ali1977

[Mucka]

UKMO still looks excellent, and GFS is looking better than the 18Z. Positive steps this morning, lets hope ECM follows the trend.

 

Good morning.

Yes UKMO rock solid again.

 

 

GFS same old same old and another poor run. I'm not sure how good GME is as a model but that supports GFS rather UKMO

 

 

What would be nice would be for UKMO to have the upstream pattern nailed and GFS have the Arctic modelled correctly because imagine that strong Arctic ridge on the GFS 144 chart still being intact on the UKMO 144 chart, yum.

 

Decent GEM run as well this morning.

 

Edited January 25, 2014 by Mucka

[Man With Beard]

UKMO rock solidly sticks with its easterly and a held back Atlantic, and brings it forward to T120. Consistency. Scandi upper block looks like strengthening by T144, though a risk it might sink shortly after.

If the UKMO is right, the ideas of Atlantic domination - again - will have been rubbished.

GFS looks like it might follow at T120 but in its usual fashion it pushes the block away with ease at T144, however, not before injecting some colder uppers into the mix. Even when it brings in westerlies at T168, it still looks cold enough for some snow.

[Mucka]

JMA only goes out to 84h on the 00z but looks very nice.

 

 

Looks like a stronger Arctic ridge than previously, low clearing South effitciently with cold uppers just on their way in from the NE. Reasonably amplified upstream as well so would expect that to be a lot more like UKMO than GFS by 120/144 if it went that far.

[shaky]

What a brilliant start to the day!!I have woken up specially to see the models and I have not been disappointed!!ukmo rock solid again and gfs going the same way!!jma out to 84 hours and same as last night!!

[KTtom]

Amazing differences between UKMO and GFS at day 6.....UKMO has the Scandinavian high ruling the roost with the Atlantic trough nowhere to be seen...

 

 

GFS has it slap bang over the UK, probably a more wintry chart than the UKMO although I would have thought most will prefer the UKMO's chart......

 

Its not surprising the met are non committal.

[london-snow]

Morning all..

Glad that none of us has had to call Dr Sussex out of hours emergency prozac line this morning.

UKMO solid as she goes a continuation of the broader pattern from previous output up to +120 which is where i am looking up to.

GFS was looking good and looking nailed on to side with the UKMO but in typical fashion goes off on one (It really does love sending energy east).

Big ECM coming up soon. It's been up and down recently but it's now approaching crunch time let's hope it sides with the UKMO and the GFS will come crawling back in line eventually (Regular as clockwork).

Great start to this morning let's hope support grows.

[Mucka]

GFS ensembles are not great but it's all relative really.

 

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=250&y=62

 

Here is the UKMO 144 chart

 

 

ECM now out to 120 and closer to GFS than the UKMO

 

 

Either the UKMO is putting the other models to shame or it will start backtracking this evening I would imagine.

 

ECM 144 pretty poor it has to be said, completely opposite wind direction to UKMO, hmm.

 

Edited January 25, 2014 by Mucka