Model Output Discussion - 8th - 14th January

[Radiating Dendrite]

More good news from NOAA this morning:

TELECONNECTIONS WITH STRONG POSITIVE AND NEGATIVE MID-LEVEL HEIGHT

ANOMALIES OVER THE BERING SEA AND BRITISH COLUMBIA RESPECTIVELY

TOWARD THE END OF THE MEDIUM RANGE PERIOD FAVOR A MEAN LONGWAVE

TROUGH OVER THE PACIFIC NORTHWEST AND A MEAN LONGWAVE RIDGE OVER

THE SOUTHEAST DAYS 3-7. THE DETAILS OF THE TELECONNECTS VARY

SLIGHTLY HOWEVER...WITH THE NEGATIVE ANOMALY TELECONNECTING MORE

STRONGLY WITH ABOVE NORMAL TEMPERATURES FROM THE SOUTHERN PLAINS

NORTHEASTWARD TOWARD THE GREAT LAKES...WHILE BOTH ANOMALIES

SUGGEST BELOW NORMAL TEMPERATURES WILL PREVAIL ACROSS THE PACIFIC

NORTHWEST/NORTHERN ROCKIES/NORTHERN-CENTRAL PLAINS...WITH ABOVE

NORMAL PRECIPITATION ALONG THE PACIFIC NORTHWEST AND CALIFORNIA

COASTS. DETERMINISTIC MODEL AGREEMENT IS QUITE GOOD EVEN THROUGH

DAYS 6/7...AND CORRESPOND BETTER WITH THE SECOND SCENARIO OF

GENERALLY BELOW NORMAL TEMPERATURES ACROSS THE NORTHWEST.

HOWEVER...THE ENSEMBLE MEMBER SPREAD REMAINS QUITE HIGH...WHICH

SUGGESTS SOME CAUTION IN FOCUSING TOO MUCH ON THEIR

DETAILS...ESPECIALLY LATER IN THE PERIOD. NEVERTHELESS...THE

GLOBAL ENSEMBLE MEANS ARE SUPPORTIVE ENOUGH OF BOTH THE

OPERATIONAL 00Z GFS/ECMWF TO WARRANT EQUAL USE OF THEIR SOLUTIONS

IN CONSTRUCTING THE PRELIMINARY PRESSURES/FRONTS FOR ALL DAYS

Is this basically saying that the models are now starting to converge together on the same idea?

[phil nw.]

The background signals suggested limpet high being displaced with high pressure to the ne, thats been the case for a week now, the big variable was that PV and thats still the case today.

But I agree don't take this run as gospel, detail isn't important at this stage and none of those interesting synoptics can come about if we don't get a strong enough ridge to the ne within 144hrs, this isn't about looking well into FI for signs of change, once you get low pressure developing in the northern Med and a ridge to the ne thats a good sign.

If you get an undercut at 168hrs then you're 90% of the way there.

The trend as we say Nick is the thing,compared to previous output.

That area around Svalbard the area to watch.Remember yesterday i highlighted how the 12z UKMO was more keen than the others on keeping the vortex back from there delaying the erosion of our block.

Compare these 2 UKMO charts.The one on the left is yesterdays 00z(T144) and the one on the right todays 00z(T120) for the same period.

The vortex looks to be weakening up there where it matters.

If this trend continues then we will looking at much colder charts in later runs as more energy drains south allowing those heights to become stronger to our North East.

Edited January 11, 2012 by phil n.warks.

[Frosty.]

The Arctic High is a sight for sore eyes, it finally looks like the uk has a good chance of a cold or very cold spell within the next few weeks, the shape of the jet on the Ecm 00z is perfect for undercutting lows and enabling the bitterly cold air to the east/northeast to be sucked into the uk, actually the day 10 chart suggests heavy snow for the uk with much more to come. We also have the ukmo and gfs onboard and we have a much colder weekend to look forward to with widespread frosts and fog once the current very mild air over the uk is chased away southwards by friday, colder and brighter weather pushing south to all areas by friday...for everyone on here who is thoroughly fed up with this mild springlike weather which also ruined christmas, a change is afoot.

[nick sussex]

Is this basically saying that the models are now starting to converge together on the same idea?

That suggests that the PV is on the move westwards, and thats the best news of the day so far.

Of course they are concentrating on the USA but that main negative height anomaly is not near Greenland, you might stll keep some residual energy there but this is certainly much better for colder prospects.

And yes both models agree on the overall pattern, regardless of the more local detail.

Edited January 11, 2012 by nick sussex

[SMU]

http://www.knmi.nl/exp/pluim/vijftiendaagse/index.html

That is almost worth a mini rampede-

the ECM mean for debilt at 1c now...

Someone contact SATSIGS.... S

Edited January 11, 2012 by Steve Murr

[nick sussex]

Looking at the De Bilt ensembles the operational run does become a cold outlier towards the end but the main clustering shows a big dip since yesterday.

This is probably in relation to where the troughing sets up over Europe, the control run looks nice.

I think we should stick to within 144hrs to see if we get that strong ridge to the ne and some lower heights towards the Med.

Edited January 11, 2012 by nick sussex

[MisfitDog3]

Oh Lordy! First time I've actually seen some material you can hang your hat on with regard to the cold! Very, very interesting overnight developments which actually seem to nail down a few loose ends. Perhaps I will go and get one of those reduced price snow shovels from Sainsburys before the word gets out....

[VillagePlank]

Agree, Nick.

A cursory analysis of GEFS shows that FI begins on the 25th forecast period (16th Jan, 12z) FI is defined when the trends of the maximum and minimum first diverge.

All of the interest, apart from a cold Sun/Mon is beyond that marker, That said, around the 40th time period (20th Jan, 6z) the trends appear to be doing the same thing but with up to 14C spread between maximum and minimum. The mean is unremarkable for this time of year throughout.

I'd say that the period of interest, then, is the four days between 16th and 20th Jan, where, it seems to me, the critical pieces will fall into place, particularly at the beginning of that period, which will determine whether we blow hot or cold.

Edited January 11, 2012 by Boar Wrinklestorm

[Methuselah]

Signs are there, that the inevitable pattern-change could at last be about to occur. Interesting model-watch indeed!

[kold weather]

GFS is actually quite a cold run on its 12z run, whilst we never really get a direct cold feed, thicknesses are fairly low and there is a slight drift from Europe so temps are quite low.

As for the ECM...wow that really is a tasty run!!

[TEITS]

Chart of the day for me is this.

http://www.knmi.nl/exp/pluim/vijftiendaagse/Data/15DAAGSE_06260_NWT.png

The 2m temp mean has dropped a whooping 4C and the control follows the OP.

What a fantastic start to the day.

[Cecil Hogmanay Melchett]

Well big changes in the output this morning as the models wrestle with the teleconnection changes, particularly from the ECM which has done a complete volte face.

I’m not sure that I agree with Steve M that a T264 or T268 ECM would be ‘epic’, as with the height anomaly where it is, we would only be in a battleground situation and there would be no floodgates from the East.

However, this is all a long way off, and I would remind newer members that when similar set-ups have been at this range in the past, prior to 2008, then failure (for cold) was nearly always the outcome.

Its certainly been an interesting few days as the models try to come to terms with the emerging -AO.

I suspect quite a few more twists and turns but at the very least there is scope for something much more seasonal.

I disagree about the ECM by the way it looks a stunner to me.

[cooling climate]

It was always doubtful that we would see the easterly with the first bite of the cherry but with pressure

modeled to build over Russia and then extending west and north into the Svalbard and Scandinavian

area which I am convinced is due to previous and ongoing down welling from stratosphere warmings

the PV to our north is being eroded and pushed back west.

The chances of seeing a very cold pattern setting up for the UK in the next 10 days has greatly

increased this morning I think. The beast is poised ready to pounce.

[john mac]

WOW!! -5 almost into crete at t117 that will be a shock to the system for them lol.

[rich1]

http://www.wetterzentrale.de/pics/MT8_London_ens.png

These have been fairly consistent with a dipping of the mean after the 19th for a while now. ECM also looks interesting. Not actually in the UK now but feel a colder last few weeks of winter may avoid the potential 'pairing' of mild horrors i.e. 1988-9/1989-90 or 2006-7/2007-8 for when I am back in December of this year so am quite keen to see the pattern evolve even if I am not there to experience it. I wonder if a 2004-5 scenario could be in the offing of some sort, though it was a bit frustrating in some ways with warm ground temperatures stopped settling snow for quite a few places, february and march did kind of rescue the winter as a whole. Perhaps it 'could' be a similar scenario in the long run

do seem to be some changes afoot with the fierce PV which ruined the festive period looking less entrenched than it has been

[Cecil Hogmanay Melchett]

I think i see trough distruption at 120h.

Is GFS going to join the party??

[nick sussex]

The GFS and the Euros still disagree with regards a shortwave heading se into Scandi. They agree on the overall NH pattern but not this more local European detail, the GFS would probably be the quickest route to much colder conditions but a bit more risky given our history with shortwaves!

[Cecil Hogmanay Melchett]

Really is on a knife edge at 144h with a big anticyclone building to the NE but the jet looks to be powering up,(when doesn't it)?

[nick sussex]

Really is on a knife edge at 144h with a big anticyclone building to the NE but the jet looks to be powering up,(when doesn't it)?

The jets not the problem as long as the energy splits towards Iberia, thats the key, if that happens then its good bye prolonged Autumn and hello Winter!

[TEITS]

Really is on a knife edge at 144h with a big anticyclone building to the NE but the jet looks to be powering up,(when doesn't it)?

Hopefully though when you have such blocking to the NE then undercutting will eventually occur.

Based on my experience of these situations I still feel the +144/+168 has potential to upgrade i.e the blocking is further W. You sometimes see this upgrade once inside the +72/+96 timeframe.

[KTtom]

Seems to be some consistancy finaly showing up, not sure I can remember the last time 2 succesive runs at +174 were so similar.

[SMU]

Well big changes in the output this morning as the models wrestle with the teleconnection changes, particularly from the ECM which has done a complete volte face.

I’m not sure that I agree with Steve M that a T264 or T268 ECM would be ‘epic’, as with the height anomaly where it is, we would only be in a battleground situation and there would be no floodgates from the East.

However, this is all a long way off, and I would remind newer members that when similar set-ups have been at this range in the past, prior to 2008, then failure (for cold) was nearly always the outcome.

Hi Ian- the ECm control follows the OP- look at the surface temps that follow -5c...

The svalbard high ridging into Greenland will be enough to secure the easterly- its almost a case of cant miss once that happens

Anyway onto the 06z better than the 00z

t180 sees a wave in the atlantic ( note what I said about a ridge towards greenland)

http://176.31.229.228/modeles/gfs/runs/gfsnh-2012011106-5-186.png?6

Is it enough to get a shortwave under the block...

the berlin ensembles will be interesting at 1145am

S

[Cecil Hogmanay Melchett]

GFS Is going to say YES!!!!

But it really is proving a struggle!!

Edited January 11, 2012 by happy days

[shedhead]

Irrespective of your desires/wants/needs, there is no denying the GFS runs are becoming increasingly consistant in the 96-168hr range, indeed there's barely a Rizla between the 00 and the 06. It remains to be seen whether or not we ultimately see the blocking set up a little farther west as Eye has alluded too, allowing more energy to slide SE towards Iberia/Biscay and preventing a temporary milder SW flow around the middle of next week, but to my mind this has now become rather more likely than not. As is always the case more runs are needed, but as long as the general trend continues I'll remain happy to ignore the odd bad run or two.

Edited January 11, 2012 by shedhead

[SMU]

http://176.31.229.228/modeles/gfs/runs/gfs-2012011106-9-288.png?6

Subzero maxima almost a certain with that air...

S