Model Output Discussions 18z 31/01/2016

[feb1991blizzard]

An Easterly but no cold uppers, very cold surface air though, the EC32 should be trickling out,  it will be interesting to see what that makes of the current situation.

[Mucka]

4 minutes ago, feb1991blizzard said:

An Easterly but no cold uppers, very cold surface air though, the EC32 should be trickling out,  it will be interesting to see what that makes of the current situation.

Cold pool develops over UK.

[feb1991blizzard]

4 minutes ago, Mucka said:

Cold pool develops over UK.

Yes, very unusual to see it actually intensifying after the point of delivery, too high surface pressure for significant PPN at that point but not worth getting too hung up, a good trend and at least it will kill off any early or late (whichever way you want to look at it) insects!

Edited February 11, 2016 by feb1991blizzard

[damianslaw]

It's far from the tropical SW airflow that has plagued much of the winter so far.. lots of interesting developments, and a messy set up.

Right now we are firmly in trough disruption territory, with heights building to the North, but with no real depth of cold to them - a pity, because on paper the immediate prospect had we a colder pool of air to tap into to the NE would be a very wintry one, with possible ice days in the mix, and snow rather than rain. Alas, its a generally quiet affair for many, some surprise snowfalls for some where we see trough action in the cold east/NE flow, these penetrating into central northern parts over the weekend. The south more a mix of cold rain with some sleet about.

What is catching my eye is the very cold uppers set to invade the north west atlantic next week, any frontal attack looks like having a very very small slither of mild uppers, before a very cold NW feed is pulled in. So either way a stalling atlantic front or a front moving through is likely to deliver a potential significant snow event to some parts, inland Northern parts most favoured with heavy snow showers rattling through on the western flank of the trough - indeed it could end up a snow-rain-snow event!

Edited February 11, 2016 by damianslaw

[nick sussex]

UKMO fax charts:

T96hrs and T120hrs:

 

The occlusion heading sw at T96hrs could give some snow as the colder air undercuts this. At T120hrs quite a strong n/ne flow and some convection likely off the North Sea.

 

 

[Mucka]

A lot of cold solutions within GFS ensembles toward the end of high res' 

[tight isobar]

The tripole effect! 

Ground/mid/upper air conditioning' giving eventual pooling of dense cold incur in a position yet to be established. 

Anyway with the given frame modeled' it's a perfect talk point of even the next +24-72 no pinpoint exacting. Its an elaborate set up and very unstable in all means of 'ways'.

And current modelling has classic possible convective nowcast written ALL over it...

There's more surprise inthis current scenario/scenarios' than even father Christmas could deliver. ....imo!

 

[Banbury]

8 minutes ago, nick sussex said:

UKMO fax charts:

T96hrs and T120hrs:

 

The occlusion heading sw at T96hrs could give some snow as the colder air undercuts this. At T120hrs quite a strong n/ne flow and some convection likely off the North Sea.

 

 

That +96 chart Nick isnt the updated one

[Banbury]

96h

[Nick F]

10 minutes ago, nick sussex said:

UKMO fax charts:

T96hrs and T120hrs:

 

The occlusion heading sw at T96hrs could give some snow as the colder air undercuts this. At T120hrs quite a strong n/ne flow and some convection likely off the North Sea.

 

 

Aren't they yesterday's updates? T+120 would be Tuesday now 

t+96 updated but not 120 

http://weather.noaa.gov/fax/otherfax.shtml

 

[Banbury]

120h fax

Weather fronts on the attack

[karlos1983]

3 minutes ago, Banbury said:

120h fax

Weather fronts on the attack

What confuses me about this fax chart is are we in 528DAM or 546 territory  

Edited February 11, 2016 by karlos1983

[Mucka]

ECM ensembles. Conspicuous warm up in FI.

[Nick F]

2 minutes ago, Banbury said:

120h fax

Weather fronts on the attack

See that twig looking thing over the SE? A covergence zone. Shame it's t+120 from a purely IMBY perspective.

[nick sussex]

11 minutes ago, Banbury said:

That +96 chart Nick isnt the updated one

Oops! lol sorry just noticed.

[karlos1983]

2 minutes ago, Nick F said:

See that twig looking thing over the SE? A covergence zone. Shame it's t+120 from a purely IMBY perspective.

Hi Nick

what is that exactly? Excuse my ignorance. Is it a trough of some sort?

cheers

[fergieweather]

51 minutes ago, feb1991blizzard said:

An Easterly but no cold uppers, very cold surface air though, the EC32 should be trickling out,  it will be interesting to see what that makes of the current situation.

Similar themes to GloSea5. Through to (nearly mid) March, temp anomaly either indistinct from climatology or a tad below. Later Feb sees Atlantic ridging; this followed by a return to zonality (tail-end Feb into 1st week of March) with lows tracking to or across NW/N of UK and resurrection of +ve precipitation anomalies widely nationwide, with ENS suggesting a possible spike in this 'wet phase' circa d15-20 (which could of course include colder Pm or even Am incursions). By 2nd week March, almost indistinct MSLP/PPN/Temp anomalies; slight whiff of lows to N/high pressure to SW, but insignificant signal at that range. Net outcome is predominantly W-NW flow regime throughout, irrespective of cyclonic or anticyclonic bias. However, stamps offer variety of possibilities within this broad idea, as might be expected.

Edited February 11, 2016 by fergieweather

[booferking]

2 minutes ago, karlos1983 said:

Hi Nick

what is that exactly? Excuse my ignorance. Is it a trough of some sort?

cheers

Slow-moving trough quite persistent over many hours or days.

[karlos1983]

Just now, booferking said:

Slow-moving trough quite persistent over many hours or days.

Nice!

[Nick F]

7 minutes ago, karlos1983 said:

What confuses me about this fax chart is are we in 528DAM or 546 territory  

Not particularly clear with my bad eyes either, but the similar UKMO GM, synopticaly, has some pretty cold T850s still at t+120

[booferking]

Just now, karlos1983 said:

Nice!

Very hard to forecast tho but nice to see for you snow starved Southerners 

[fergieweather]

15 minutes ago, Mucka said:

ECM ensembles. Conspicuous warm up in FI.

...but essentially close to (model climate) average...

[Nick F]

25 minutes ago, karlos1983 said:

Hi Nick

what is that exactly? Excuse my ignorance. Is it a trough of some sort?

cheers

Basically where opposing wind/breezes meet or the breeze off the sea meets the discontinuity of land and forces the air upward, hence convergenze zone near or along a coast that can move inland.

Often they form off Pembrokeshire over the Irish Sea in a northerly, or through the Cheshire Gap in a NWly, also the Wash in an easterly, as well as The Thames estuary into Kent/ E Sussex - setting up lines or streamers of showers.

Edited February 12, 2016 by Nick F

[cornish snow]

2 hours ago, Nick F said:

Yep, Wales and West Country waking up to a valentine snowfall according 18z GFS, but may change ... -5C T850s digging further south Sunday on last few runs which is good to see.

 

Take it,when you say "west-country" you dont mean, Devon and Cornwall. ??

[Nick F]

20 minutes ago, cornish snow said:

Take it,when you say "west-country" you dont mean, Devon and Cornwall. ??

Maybe I should have said 'parts of' in hindsight?

On a different note, my quick look at the EC32 control run, and apart from the trough disruption over western UK next THursday, the run looks generally anticyclonic up until day 16 or so, after which a more mobile and cyclonic westerly flow takes over.

Edited February 12, 2016 by Nick F