Model Output Discussion - 23rd Jan - 12z onwards

[Geordiesnow]

I wouldnt call it a formidable block but I would not like to guess what could happen after that chart but the UKMO again looks a decent run too me.

 

We may have to accept some sort of milder sector coming into play before the upper air could potentially get colder again as some people alluded too, the GFS is slightly better but the further East the trough is the better so we can get more of a NW'ly flow thus any milder sector is reduced.

 

All in all, not a bad start to this afternoon runs. 

[bluearmy]

Anyone find the upper graph for raw dam and slp

Lorenzo posted it the other day.

At the moment, actual thicknesses in the south Midlands are

T72: 520

T96: 526

T120: 526

T144: 520

[Mucka]

Nothing marginal about these 850's 

 

 

Some reasonable improvements in the predicted upstream pattern as far as sustaining UK cold goes this evening thus far. Can ECM keep the theme going?

[nick sussex]

Anyone find the upper graph for raw dam and slp

Lorenzo posted it the other day.

At the moment, actual thicknesses in the south Midlands are

T72: 520

T96: 526

T120: 526

T144: 520

Here you go BA:

 

[Daniel*]

Very very encouraged by 12z reading Kayro's status I thought it was curtains far from the truth...

Cold is hanging on for longer and there is scope for significant snow event(s), little nudge north of heights would take us into a significant cold spell, but what is in front of us is not to be sniffed at.

Some proper Arctic air inbounding @Scotland and far north of England 192hr circa -12C 850s

Trend increased amplification & further 'boost' of the cold spells duration from initial 5-6d to approaching 8d.

Edited January 26, 2015 by Daniel*

[Mucka]

Interesting UKMO, that shortwave south of Greenland is now crucial as to where it would go at T168hrs, to extend the cold that needs to head se with the upstream low amplifying sufficiently to allow some ridging to head north. The GFS has the same shortwave but further east.

 

Hi Nick, I would love to see the 168 chart. 

I think that shortwave West of Iceland slides SE, toward Ireland. The low to the West of the ridge is quite far South and has a nice looking tilt to it and with the showtwave runner helping I think we would see a sharper ridge extending into Greenland.

If we compare to ECM from this morning it is a similar synoptic except UKMO is better in every respect and the shortwave doesn't head SE initially on ECM only because it phases with one over Iceland which is not on UKMO output. 

I hope ECM is similar this evening so we can get an idea of how it might develop.

 

That's my take anyway but it doesn't look like an ordinary toppler.

Edited January 26, 2015 by Mucka

[shaky]

Just brilliant output this afternoon! ! Compared to the morning runs the cold looks like lasting longer now and its more amplified in the atlantic!!

[terrier]

Some great looking charts so far ukmo looks a peach. Hopefully we see the ECM t168 chart showing the cold uppers flooding in. Gfs also looking favourable with widespread snow showers. All In all a great set of charts so far.

[Pennine Ten Foot Drifts]

I know they aren't accurate, however there seems to be much more precip/snow showing on the GFS run upto T84...and on a wider scale.

 

Well, you say that, but for both the recent Yorkshire localised snow events GFS modelled the precip better than the short range NAE/NMM models, (and others e.g. BBC, Meto), which all had the precip stalling further south (as our Midlands friends will no doubt testify). So for me the precip showing on the 12z in the 2-3  day timeframe is not to be disregarded so quickly.

[The Weather Dragon]

I must admit - there's been an improvement for cold

The improvements are based around a seperate blocking HP cell forming around SW Iceland

Will be monitoring this closely over the coming runs

[The Enforcer]

Dewpointwatch update (number of GFS frames above freezing for South Midlands area between Wednesday 3pm and Sunday 9pm:

 

25/1/6z - 10

25/1/12z - 1

25/1/18z - 2

26/1/00z - 7

26/1/06z - 12

26/1/12z - 9

 

The unfavourable dew points appear to be centering on Friday PM and daylight hours Saturday, so could do with precipitation falling outside those periods.

[offerman]

Can someone please give me s link to ukmo charts please . Only use gfs so I would like to look at other sources to. Many thanks

[winterof79]

Although it was nice to look at the GFS 06z op was a significant cold outlier after 3rd Feb

 

Expect changes on the 12z

Well you got what you posted.....

I referenced earlier in the afternoon that I thought the GEFS were sniffing a stronger build to our west,Will post charts upon my return.This is starting to get the heckles up.

[carinthian]

Our special internet portal for winter services gives a weekly update with probability percentages, especially as with regards to snow in the short term high resolution fine mesh model and a 30 day forecast trend . A snowy first week of February for many in Europe including the UK to start with followed by fairly pronounced pressure rise in the vacinity the British Isles , keeping the cold in Central Europe with snow threat continuing. By Mid -month still a good degree of confidence of signs of high level blocking to develop with retrogression of cells likely to feed a source of more Arctic Continent feed into much of Europe and the British Isles ( 40% probability rate ) as opposed to( 30% )probabaility to mobile Atlantic.

So all in all looking good for much of February, possibly with the most potent widespread cold spell of the winter to develop around the 3rd week of the month.

 C

Good Evening, further to the above post from earlier today, the GFS 12z runs looks feasible for the cold high position over the British Isles at 240 hours. Thereafter, retrogression of the cell is more likely poleward to link up with a strong rise of pressure over Greenland  rather than sinking south eastwards . I think the pressure distribution charts do not look correct ( post 240hours ). It does look  good for a snowy spell for many in the British Isles with quite a few polar troughs in the flow. Anywhere could get snow  during the next 7 days or so.

 C

[bluearmy]

Thanks nick - equates to lower than -6c uppers on both timescales where thicknesses are 526.

Should just about support snowfall if there are disturbances

[Liam J]

Nice northerly still there on the 12z with the -10c line right down to the south coast. Some very snowy looking charts on offer this afternoon starting in less than 48hrs time! 

 

 

 

[Summer Sun]

Can someone please give me s link to ukmo charts please . Only use gfs so I would like to look at other sources to. Many thanks

 

http://www.meteociel.fr/modeles/ukmo2.php?ech=6&carte=1021

 

[Turnedoutniceagain]

Nice northerly still there on the 12z with the -10c line right down to the south coast. Some very snowy looking charts on offer this afternoon starting in less than 48hrs time! 

 

gfs279.gif

 

Considering we're 48hrs out, I'd have thought the METO would've upgraded by now??

[Pembroke Dangler]

Nice northerly still there on the 12z with the -10c line right down to the south coast. Some very snowy looking charts on offer this afternoon starting in less than 48hrs time! 

 

gfs279.gif

Just wow is what I can say about that its a thing of beauty ice days and snow anywhere that screams, and all in the semi reliable too! BANK

[Summer Sun]

Whilst GFS, ECM and no doubt UKMO bring sub zero 850's GEM continues to go against them with nothing much lower than -4 I've put a comparison below at t168 and t192 from GFS and GEM to show the differences

 

[LomondSnowstorm]

Whilst GFS, ECM and no doubt UKMO bring sub zero 850's GEM continues to go against them with nothing much lower than -4 I've put a comparison below at t168 and t192 from GFS and GEM to show the differences

 

Seems to be a systematic error with GEM and Polar/Arctic sourced airmasses - e.g. this :

 verified as this:

in spite of the pressure pattern for the GEM being basically the same as what verified. Given that, -6C uppers are actually impressively cold for the GEM to show in a northerly!

[gottolovethisweather]

Just copying a link of mine in here from my own regional, it may be of interest to some, albeit from a CSE & SW England perspective. 

 

https://forum.netweather.tv/topic/82389-south-west-central-southern-england-weather-chat/?p=3140316

Edited January 26, 2015 by gottolovethisweather

[bradymk]

Anyone know what this tweet is about?

 

Ryan Maue â€@RyanMaue  1m1 minute ago

New European global model arrives in 15-20 minutes (1 pm EST)

 

Good upgrades so far this afternoon with a potent northerly early next week on GFS. UKMO good too, but would like to see the +168 chart with the shortwave south of greenland at 144 which isn't there on the GFS.

Edited January 26, 2015 by bradythemole

[Mucka]

Whilst GFS, ECM and no doubt UKMO bring sub zero 850's GEM continues to go against them with nothing much lower than -4 I've put a comparison below at t168 and t192 from GFS and GEM to show the differences

 

 

 

Ignore GEM 850's there is a known fault whereby they are modelled much higher than they should be.

Actually GEM is really a bit of cannon fodder model these days.

 

GFS short ensembles SE England

 

 

NW England

 

 

Ignore that the Op is higher than the mean above - it always is for some reason.

Edited January 26, 2015 by Mucka

[Dean E]

Anyone know what this tweet is about?

 

Ryan Maue â€@RyanMaue  1m1 minute ago

New European global model arrives in 15-20 minutes (1 pm EST)

 

Good upgrades so far this afternoon with a potent northerly early next week on GFS. UKMO good too, but would like to see the +168 chart with the shortwave south of greenland at 144 which isn't there on the GFS.

 

Thats probably just the 12z ECM run. They are, of course, concentrating on their massive Nor'easter!