Model Output Discussion 1st Nov.2013

[Cheshire Freeze]

Not entirely shocked the GFS has thrown out a run like this in FI. There was a group of ensembles yesterday which were toying with the idea of retrogressing HP into the N Atlantic/Greenland area with a trough digging into Scandi.

 

Furthermore, vortex disruption in general has been showing up for the past few days within the suite. As Feb1991 knows, I've been very bullish over a 2nd half of November cool down (PM chats), so let's watch over the next few days.

[Barry12]

 

[weatherguy]

+348h, people.  Lets keep things in perspective here...

 

That being said, it's promising to see a more amplified pattern showing up of late in the deeper realms of FI.  Will be interesting if those charts start to make it to within +240.  

[Skullzrulerz]

Lets hope so.

Edited November 6, 2013 by Skulltheruler

[Barry12]

ECM at 144

 

 

ECM 168

 

 

 

Very chilly

 

Edited November 6, 2013 by Barry95

[Tom Jarvis]

ECM at 144

 

 

ECM 168

 

possibility of Greenland height there

[Purga]

Would you kick ECM 192 out of bed?

 

[Barry12]

Scandinavia would be cold at 192 and 216, still remaining chilly for most of us apart from the SW.

 

Edited November 6, 2013 by Barry95

[Summer Sun]

ECM at t216 sees the high building over the UK, with low pressure anchored across Greenland

 

 

Becoming less chilly in the west

 

 

T240 see's ECM ending settled

 

 

Milder air returns

 

Edited November 6, 2013 by Summer Sun

[cooling climate]

The more amplified pattern we are seeing in the longer term is all down to

the strength of the Pacific ridging on the other side of the pole although this

looks to be a troposphere level and not anything to do with the stratosphere.

 

The ECM t240 chart tonight should look very promising from a coldies perspective.

Edited November 6, 2013 by cooling climate

[Purga]

The more amplified pattern we are seeing in the longer term is all down to

the strength of the Pacific ridging on the other side of the pole although this

looks to be a troposphere level and not anything to do with the stratosphere.

 

The ECM t240 chart tonight should look very promising from a coldies perspective.

Really? looks like it's a mild fest for us

 

[swfc]

this evenings ecm not as good as this morning regarding the pv shown at 240hrs on the nh charts.

[Cloud 10]

Some interesting ensemble members on the 12z gfs run this evening in FI, amongst which is this "arctic intrusion"which shows what i would do with the pacific ridge given the power. 

 

[Skullzrulerz]

Scandinavia would be cold at 192 and 216, still remaining chilly for most of us apart from the SW.

 

At least it will help the snow cover go west 

[Cheshire Freeze]

Really? looks like it's a mild fest for us

 

 

Great potential in that 240 hr ECM chart and fits in well with the general timescale of wintry onset on the 18z GFS.......circa 3/4 days on from that 240 chart we'd see amplification across the N Atlantic. People aren't noticing the amplification on the Pacific side, obviously.

[Barry12]

Remaining chilly for the next 9 days (Apart from Monday) only at day 10 does it turn mild, which is unlikely to verify

 

Edited November 6, 2013 by Barry95

[Gaz1985]

 

 

Most notable thing about that is the cold in Eastern USA. Bitter right down to North Carolina.

[Tom Jarvis]

Really? looks like it's a mild fest for us

 

no look at the pacific ridge with heights disrupting the pv not much difference than to the gfs at the same time in that area.

[Barry12]

Most notable thing about that is the cold in Eastern USA. Bitter right down to North Carolina.

 

It certainly wouldn't be T-shirt weather.

[phil nw.]

I don,t wish to be a wet blanket but whilst those purples and deep blues remain solidly modeled over the Arctic any cold incursions will be brief.

The vortex is still cooling and what we are seeing is the ebb and flow of it,s shape as it spirals around the Pole.

As CC inferred in a post earlier we are seeing reactions to the Jet running over the top of the NE Pacific block which is inducing some upstream buckling of the jet.

 

http://modeles.meteociel.fr/modeles/gens/run/gensnh-0-3-144.png?12

 

http://www.meteociel.fr/modeles/ecmwf/runs/2013110612/ECH1-144.GIF?06-0

 

There's no forecasted warmings to slow the zonal winds currently so these ridges will be transient and mid-latitude blocking is more likely at the moment.

The ens graph for C.England says it all.Just your typical mobile November pattern.

http://modeles.meteociel.fr/modeles/gens/graphe_ens3.php?x=262&ext=1&y=97&run=12&runpara=0

 

Not to say we wont see some short bursts of polar air behind the passing rain bands of course.

[mpkio2]

Most notable thing about that is the cold in Eastern USA. Bitter right down to North Carolina.

Its funny you mention that Gaz; it would coinside with what Gavin Partridge and Simn Knealing believe, that the USA would be in for a cold winter.

 

Plus as most mention, on the ECM 12z 240h and GFS 18z 240h, the pacific ridge is almost alike and attacking the PV.

 

At this point, its all about clues and signs. One I notice is the height ridge to the South West of Greenland on the ECM 12z 240h. It won't take much for it to retrogress north to Greenland and then we might get a result of what the GFS 12z 312h offers:

Still early days, but still all to play for.

[Cheshire Freeze]

I don,t wish to be a wet blanket but whilst those purples and deep blues remain solidly modeled over the Arctic any cold incursions will be brief.

The vortex is still cooling and what we are seeing is the ebb and flow of it,s shape as it spirals around the Pole.

As CC inferred in a post earlier we are seeing reactions to the Jet running over the top of the NE Pacific block which is inducing some upstream buckling of the jet.

 

http://modeles.meteociel.fr/modeles/gens/run/gensnh-0-3-144.png?12

 

http://www.meteociel.fr/modeles/ecmwf/runs/2013110612/ECH1-144.GIF?06-0

 

There's no forecasted warmings to slow the zonal winds currently so these ridges will be transient and mid-latitude blocking is more likely at the moment.

The ens graph for C.England says it all.Just your typical mobile November pattern.

http://modeles.meteociel.fr/modeles/gens/graphe_ens3.php?x=262&ext=1&y=97&run=12&runpara=0

 

Not to say we wont see some short bursts of polar air behind the passing rain bands of course.

 

Not a wet blanket at all Phil. Entirely reasonable analysis. However, we have to start somewhere!

[Summer Sun]

Latest from Gibby

 

All models show a Westerly flow across the UK with a front straddling the UK with strong winds, rain and drizzle in very mild conditions in the South and cold and drier conditions to the North with scattered showers in the West. Tomorrow and Friday will see this colder and clearer air extend to all areas with sunshine and showers, prolonged in places. On Saturday a ridge of High pressure crosses the UK with a drier and brighter interlude before a warm front crosses the UK on Sunday with a spell of drizzly rain and milder air flooding NE over all areas. By Monday the mild weather will be well established to start the day before a weakening cold front moves ESE through the day with another spell of drizzly rain followed by clearer and colder air again by evening.

 

GFS then brings a better spell of weather across the UK with a few showers over the North and some mist, fog and frost possible in the clearer South. Soon after midweek the North becomes wet and mild again in strong Westerly winds while things remain more benign over Southern England and Wales. then after a short spell of rain on a cold front crosses all areas another spell of colder NW'lies brings rather cold and bright weather again with some showers in the North as we start the second week with some frost possible overnight. Very late in the run a strong pressure build to the NW brings a plunge in temperatures to cold conditions for all with some sleet or snow showers to the North and East with widespread frosts developing as well as freezing fog possibilities by the term of the run.

 

UKMO closes it's run with a WNW flow over the UK with scattered showers over Northern and Western Britain. Temperatures would be close to average and possibly rather cold in the North where scattered showers could be wintry over high ground. Much of Southern Britain could be mostly dry.

 

GEM keeps High pressure anchored close to SW Britain through next week with WNW winds blowing a lot of cloud and some rain to the North but far less rain than we have been used to of late in the South. Temperatures would be close to average overall with any chill mostly felt in the North.

 

NAVGEM is virtually identical to GEM with a benign and cloudy WNW flow around High pressure to the SW carrying a lot of cloud but little in the way of rain across the UK in average temperatures.

 

ECM tonight also shows a strong build of pressure to the West and SW next week which in essence would bring cold, settled and foggy conditions through next week to the South with some wintry showers for a time in the NE. It's invasion into UK airspace is limited however, as it is quickly squeezed South towards the far South where there may well be some fog patches and cold weather overnight while Northern regions become breezier and mild again with some rain in the far North.

 

The GFS Ensembles look very ordinary this evening with a lot of typical but unexciting weather across the UK over the two weeks. Temperatures look like maintaining average levels throughout the period and maybe a little above in the South at times. It comes as no surprise that the operational I have described above is a cold outlier at the end of the run with no realistic support on offer and is therefore likely to be removed by the morning. What has more support is an increase in precipitation amounts towards the end of the run in the South.

 

The Jet Stream remains focused on blowing across the Atlantic and across the UK for the foreseeable future. It undulates North and south at times and moves North temporarily next week as pressure builds to the SW. Late in the run the flow troughs to the South of the UK which is accountable for the increase of rainfall in the South late in the run.

 

In Summary despite a mouth watering end to a GFS operational run for cold weather fans there is very little else for them to cheer about in an otherwise benign and anticyclonic pattern beyond this weekend. The position of the High is instrumental in determining the air masses over the UK and a mix of tropical maritime air or polar maritime air is likely over the UK with a lot of cloud overall and just limited amounts of fog and perhaps frost in the extreme South due to the refusal of High pressure to move sufficiently North. The further North you travel away from the far South the incidence of rain and mild Westerly winds increases though this could be interrupted at times by rather colder and showery NW winds at times.

 

http://www.norton-ra...is(2859336).htm

 

 

[East_England_Stormchaser91]

Deep in FI, but theres that thing called WAA gathering momentum 

[cooling climate]

One point to remember is you can still have HLB's and an amplified pattern even

with a strong vortex. The amplified pattern in the troposphere if it comes to

fruition can become more pronounced with the vortex moved away from the

north pole. Also any heights ridging into the Arctic can themselves lead to

warmings.

PS I should have said the ECM t240 should look promising for the extended outlook

which in my opinion it does.