Model Output Discussion - 31/10/2014 and Beyond

[phil nw.]

It feels much more seasonal with polar air now in the mix.

Much of the this week looks that way too with with only single figure max's for many places until Thursday and our first really widespread frosts likely, especially Tues/Weds.nights.

A snapshot of midweeks picture shows the cold air in place 

 

 

The end of the week sees another low and it's fronts sweeping across in a brisk westerly flow with a brief warm sector before a return to more average temperatures with showers by the weekend. 

Overall the NH modelling continues to show plenty of disruption to the pv with the UK trough looking likely to become slow moving being held insitu by the Euro block further east into next week.

We can see the trough disruption as it comes against the block at T168hrs on both main models.

 

http://modeles.meteociel.fr/modeles/gfsp/runs/2014110312/gfs-0-168.png?12

http://www.meteociel.fr/modeles/ecmwf/runs/2014110312/ECM1-168.GIF?03-0

 

Nothing out of the ordinary weather wise currently but the bigger picture still shows plenty of +ve height anomalies extending towards the pole including signs that we may see further development of those Euro heights further north.

http://www.meteociel.fr/modeles/ecmwf/runs/2014110312/ECH101-144.GIF?03-0

 

a much different pattern to last year that's for sure.

[MR EXTREMES]

A cooler Pm/rPm flow continues with-in the reliable time frame, And the Models continuing to struggle with the complicated background signals in the N/Hemisphere. As I'm dmg says, I would also expect another few days before any strengthening in confidence of recent +144hr out-put, A complicated but altogether a very interesting period of Model watching coming up.

but its getting closer and closer but tbh we seen things get very close then fail at the last hurdle

[MR EXTREMES]

low out of canada moving se and euro high pushing west into greenland could it happen ???/

[bluearmy]

are we still searching for cold in the firat half of november ?  really chaps ???

 

nuri is certainly going to help the aleutian low bomb and this in turn will re inflate the aslaskan ridge. looking at the ecm op NH profile at T0 and T216 shows the vortex weakening significantly at a time when the opposite should be happening. the recipients of this early season consequential cold are in the states. given the lack of ocean to their north, they can certainly take some early season snowfall from it. we on the other hand are better off having the pattern stuffing cold there at this stage and waiting for the feedback mechanisms to ensure it gets stuffed closer to here in a months time when it will count.

[MR EXTREMES]

low out of canada moving se and euro high pushing west into greenland could it happen ???/

yep nice run ecm 

 

[ANYWEATHER]

Hi Folks, nothing on the horizon for anything out of the ordinary in the week ahead with some frost, rain, sunshine, wind and Scottish mountain snow which really is pretty normal for this time of year. As for further afield , a lot of cold air flirting with the Uk, but at the moment ,we will have to wait to see if the second half of November will deliver some Wintry weather

[summer blizzard]

GFS high res has the trough sufficiently far west that it's rather wet.. On the whole, the models have come into further agreement today though regarding the jet trying to dive south.

 

[Captain Shortwave]

ECM ens perhaps showing conditions turning a little drier for the east into week two as low pressure becomes centred slightly further west.

Temperatures look near normal with winds becoming more south/south easterly. 

 

Good split in the tropospheric vortex shown so maybe some interest cold wise further down the line.

[knocker]

D9 GFS, ECM and NOAA 8-14 are in pretty good agreement, Nuri causing disruption in the Pacific. Alaskan ridge through to Scandinavia with another ridge mid Atlantic. Two active troughs eastern seaboard and eastern Atlantic. The ECM actually has the western trough a tad further west along with a weaker Atlantic HP. So still surface low pressure west and east Atlantic with WAA east of the UK as noted by Nick earlier in the day. Question is what next . Well at T336 not a great deal of change apart from the dissipation of the mid Atlantic ridge.

Edited November 3, 2014 by knocker

[radiohead]

Interesting Extended Forecast Discussion from NOAA today

 

DETERMINISTIC MODEL DETAILS CONTINUE TO FAVOR USING A BLEND OF THE3/00Z GFS/ECMWF...WHICH DEPICT A DEEPENING SURFACE WAVE OVER NEWENGLAND AND THE NORTHEAST---BENEATH A SHARP BUT ENERGETICUPPER-LEVEL TROUGH AND JET AXIS. BY DAY 5...THE TRAJECTORY OF THEFLOW ALOFT BETWEEN THE NEW ENGLAND COAST AND ATLANTIC CANADAREPRESENTS A FUNDAMENTAL SHIFT IN THE GUIDANCE AND DOWNSTREAMPATTERN---IE THE POSSIBILITY OF SETTING UP A 'BLOCKY' DOWNSTREAMRIDGE INVOF THE DAVIS STRAIT-GREENLAND. IN OTHER WORDS...APOTENTIAL EARLY-SIGNAL SHIFT IN THE NAO CONFIGURATION...

 

http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdepd

Edited November 3, 2014 by radiohead

[shaky]

Interesting Extended Forecast Discussion from NOAA today

 

 

http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdepd

what do they mean by potential shift in nao signal?In fact in simple English what does all that mean?!I get a little bit of it mind you!!

[Mair Snaw]

Interesting Extended Forecast Discussion from NOAA today

 

 

http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdepd

A block setting up western Greenland and NAO going negetive???? I think.....

[Yarmy]

what do they mean by potential shift in nao signal?In fact in simple English what does all that mean?!I get a little bit of it mind you!!

They think a ridge will extend up the NE North American coast into Greenland leading to a negative NAO. I like the fact they use technical terms like 'Blocky'. Here's to a Blocky winter.

[Mucka]

Interesting Extended Forecast Discussion from NOAA today

 

 

http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdepd

 

 

Seems they are taking this afternoons runs as a genuine signal for a change in the downstream pattern so we may well see this 18z reproduce WAA toward Greenland around  162/168

[bluearmy]

The more I look at that 8/14 day CPC chart the more I see a potential retrogression in tandem with a gradual extension south of the arctic blocking. Maybe the last third of November could hold some interest ?? I would temper this with the observation that the sceuro ridge bringing warmth to Central and Eastern Europe and scandi does fit in with the ECM seasonal model temp profile?

Seems they are taking this afternoons runs as a genuine signal for a change in the downstream pattern so we may well see this 18z reproduce WAA toward Greenland around  162/168

Their discussion based on the 00z runs

[Cloud 10]

A few more hints from the ensembles/NAEFS of things cooling down markedly to our far NE in the longer term,with some sub -15 850's members showing up for Moscow,with what there is of the PV loading up well east of the pole.

 

 

 

[Mucka]

The more I look at that 8/14 day CPC chart the more I see a potential retrogression in tandem with a gradual extension south of the arctic blocking. Maybe the last third of November could hold some interest ?? I would temper this with the observation that the sceuro ridge bringing warmth to Central and Eastern Europe and scandi does fit in with the ECM seasonal model temp profile?

Their discussion based on the 00z runs

 

So it is, I should have twigged with the 5 day comment that they were referring to the earlier ridge anyway.

Shows how the pattern is repeating though.

 

I think we are definitely looking to last 3rd of the month if we are to get lucky.

[phil nw.]

The 18z parallel run showing an impressive amount of warm air heading poleward on the Alaskan side

http://modeles.meteociel.fr/modeles/gfsp/run/gfsnh-0-96.png?18

Which is sending a deep upper trough and cold well south over the eastern side of the NA/Can.

No change for us yet but the buckling of the jet upstream will have the effect of further draining the Atlantic energy,hence the stalling Atlantic trough later in the week.

More changes to come I feel.

[Man With Beard]

What's been really interesting for me these past few weeks is taking more note of the bigger Northern Hemisphere picture and seeing how the building blocks of the overall weather pattern work together - I have to thank the OPI thread for that - and again very interesting to see the PV actually reducing tonight on GFS 18z up to about T216, at a time when it should be advancing - not that all these background signals mean cold for the UK right now - but they do mean a very different story emerging in the long term from the normal zonal winter set-up. All kinds of possibilities there for the next few weeks, it just feels like a matter of time before a colder set-up gets in place whether that's a brief one or longer one.

[radiohead]

18Z GFS(P) ends with a strengthening high over Scandinavia.

 

[damianslaw]

Looking at the trends of recent weeks i,e plenty of warm air advection north into the Poles from mid lattitude climes thanks to the meridional flow, coupled with a polar vortex struggling to gain momentum suggests we are in a different place to this time last year - and very much more akin to where we were in 2008,2009,2010 and 2012 which incidentally all saw a mild first half to November with a change to cold conditions later in the month (less so in 2009 but it did turn chillier by months end). There is a sluggishness to the atlantic at present - the weak build of heights to our NE come Wednesday is noteworthy, and provided the PV stays pretty weak, I wouldn't be surprised to see the pattern become a recurrent theme as we go through the month -with a significant cold block developing to the NE and the trough becoming elongated to the west. ECM and GFS showing hints of this tonight.

[phil nw.]

18Z GFS(P) ends with a strengthening high over Scandinavia.

...and a cold plunge into E.Europe via the backdoor.

The way to a real cold setup with a little more retrogression.

Signs are there but at this range just something to ponder.

Edited November 3, 2014 by phil nw.

[knocker]

For historic levels extratropical transition, hard to beat a Typhoon entering "right-rear" entrance of 200-knot jet pic.twitter.com/7RypKBJ7Lk

[bryan629]

Joe B has just put this on twitter

 

Joe laminate floori â€@BigJoelaminate floori  14 mins14 minutes agoState College, PA

SST analog model continues to support http://Weatherbell.com  idea of nasty US winter with major blocking again!

 

 

That is one heck of a long fetch easterly... surely it cant be right !!  or can it ?  an OPI of -2.12 puts us in a good stead providing blocking favours our neck of the woods. 

 

looks too good to be true TBH , but if something like that came off.....WOw 

Edited November 4, 2014 by bryan629

[summer blizzard]

Another potentially wet run with a slow to clear front from the undercut..

 

 

Tonight's GFS illustrates the scale of our problem. We get the E/NE wind from the undercut but we'd need to keep it for days before we'd get rid of the warm airmass that we drag in.

 

 

We do get a nice inversion in FI though..