Model Output Discussion:

[cheeky_monkey]

morning its 10pm here..so looking a little drier but still cold on the gfs...becomes a bit messy in the middle of the run as the high retrogresses back to greenland..and becomes a bit of a dogs dinner towards the end.

[David-kig]

morning its 10pm here..so looking a little drier but still cold on the gfs...becomes a bit messy in the middle of the run as the high retrogresses back to greenland..and becomes a bit of a dogs dinner towards the end.

hey gd morning am i reading the ukmo correctly showing the same as gfs????

GEFS esm are very good. there is slight disagreement with the exact start of the spell and also the end showing like the gfs very messing and don't know what it wants to do. control run at times was cold and some support of being colder then gfs op. very very good gefs has to be said the a gd cold spell dry or not. better then mild and rain

Edited February 5, 2010 by David-kig

[KTtom]

It seems every morning the models are picking up on a new trend. Yesterday the channel low evaporated and this morning the Scandi trough which was going to give the east a foot of snow has pretty much gone AWOL!

Still solid agreement between the GFS and UKMO for a sustaind cold spell but both have the high sinking to sit on Brittain for a time before the GFS sends it back to Greenland and introduces the snow from the south, but thats at +192 ish.

Wonder what tomorrows trend will be

[Iceberg]

These are still very good cold charts by all the models, we can't look at snow detail(particularly convective) this far in advance.

The potentcy of the easterly has probably gone down, but I do think that was very likely. The High at 144Z cannot sink south, the only real direction for it is NW, this is supported by all of ensemble evidence and the ECM EPS members are frankly incredible with the cold sticking around for many days 18/19th of Feb, ditto really on the GFS ENS.

When looking at the EPS London ensembles on meteogroup remember that 2M temps will be higher than the begining of Jan, simply because of the angle of the sun and time of year, we are probably 2C higher for max temps under the same conditions now than in the first week of Jan.

Any way a fantastic GFS run, which does seem very messy, but IMO is likely to be a good stab at what is likely to occur, once the high starts the retrogression to GH, the fronts and low pressure will start to flood in from various angles, this won't be a killing blow from the atlantic bringing in the mild, but a death for the cold weather from a thousand cuts, which might be very interesitng.

All good models this morning.

Edited February 5, 2010 by Iceberg

[NorthNorfolkWeather]

It seems every morning the models are picking up on a new trend. Yesterday the channel low evaporated and this morning the Scandi trough which was going to give the east a foot of snow has pretty much gone AWOL!

Still solid agreement between the GFS and UKMO for a sustaind cold spell but both have the high sinking to sit on Brittain for a time before the GFS sends it back to Greenland and introduces the snow from the south, but thats at +192 ish.

Wonder what tomorrows trend will be

Today's FI on the GFS is a total reversal of what it was showing yesterday, so is a great example of why we shouldn't talk ANYTHING in the low resolution far end of GFS.

TEITS made some very good comments about accuracy late last night, and I think he was very accurate in his assessments.

As for this run, France looks cold, so Nick S will be happy, more of the cold slips south of us, but the Atlantic certainly doesn't make a comeback. So looks like Cold, snowy in places, but details? Come back in 3 days

[KTtom]

http://www.wetterzentrale.de/pics/Rngp1441.gif

If in doubt....bring out the NOGAPS

[Frosty.]

Next week now looks very anticyclonic, still a few snow showers in the southeast but the bulk of the uk should be fine and sunny but with frosty nights according to the gfs, ecm and ukmo, at this range it can't really change much more I wouldn't have thought so the snow threat has decreased to almost nothing, just as the daily newspapers are warning us of arctic blizzards next week

[LomondSnowstorm]

Yes, well done to the GFS 18Z for a change for picking up on a new trend, although the ECM last night wasn't too wide of the mark either. I think the models are making a wrong call in FI by transferring heights towards Greenland.

Why? GP mentioned the pattern eventually returning to a west based NAO, and surely this is just another way of doing that.

[pureasthedriven]

I think everyone is paying to much attention to detail. The Cold will come . Were in a situation with the charts at the moment where upgrades are likely , could appear anytime and would be plausable .

I logged in, had a quick flick through previous posts, checked the 00z, expected to see disaster and saw ... a sustained and cold run with bags of potential.

Bizarre.

[LomondSnowstorm]

I think everyone is paying to much attention to detail. The Cold will come . Were in a situation with the charts at the moment where upgrades are likely , could appear anytime and would be plausable .

I certainly don't think the position of the shortwave is settled yet - perhaps it will end up cold and mainly dry, but as these things move closer the models tend to pick up shortwaves/undercuts a bit better, so I don't think this morning's output will neccesarily verify with such small details impacting on precipitation levels.

[Iceberg]

Yes, well done to the GFS 18Z for a change for picking up on a new trend, although the ECM last night wasn't too wide of the mark either. I think the models are making a wrong call in FI by transferring heights towards Greenland.

There is nothing else the high can realistically do surely ?

It's hardly a big shift either, both GFS and ECM yesterday brought the high over the northern UK, the models have just settled on the timeframe and reduced the easterly a bit. when looking at 144Z its really a very small shift, the problem being that some people were looking at convective situations 5 days out !.

As JH was so found of saying you need the cold and then the snow. The charts are solidly cold.

[Duane S.]

http://www.wetterzentrale.de/pics/Rngp1441.gif

If in doubt....bring out the NOGAPS

I think this particular idea is going to be played around with by the models for a few days. It would be marginal for some (me) but the notion of it elongating over Northern France as the high pressure tries to sink (but won't be able to)certainly is a very tantalising one.

The models are going to chop and change for the foresseable future unfortunately. However I really don't see how anybody can complain

[Glacier Point]

Why? GP mentioned the pattern eventually returning to a west based NAO, and surely this is just another way of doing that.

But, there is also a signal from GWO composites for high pressure to our west / NW transfering towards the UK over time. The trumping factor in all of this is the influence of downwelling zonal wind anomalies from the high troposphere - models are lurching all over the place w/r/t the polar field - symptomatic of poor modelling of the upper atmosphere.

As was suggested, the most safe assumption for downwelling to drive the Artic Oscillation negative is for this to happen from mid month. Before that, we see a relative angular momentum reaching its greatest anomaly of the winter and a strong phase 5 projection. This augers for height rises to our north and north west.

My guess is that mid term modelling is picking up the signal for phase 6-7 type progression which is for the ridge to become more orienated to our west and trough becoming re-established to our east with enough flow over the top to keep it as a mid latitude feature.

The movement of the high back towards Greenland programmed t216+ can only be accredited to stratospheric downwelling. Possible but given the way models have failed to cope with this, unwise to place too much faith in this.

Either way, cold becoming established and not going anywhere fast. Precipitation, hmmm, that's the thing.

[Duane S.]

Yes, well done to the GFS 18Z for a change for picking up on a new trend, although the ECM last night wasn't too wide of the mark either. I think the models are making a wrong call in FI by transferring heights towards Greenland.

That is a serious case of premature backslapping there.

And, IMO, retrogression to GL is still the most likely outcome.

[Nick F]

I wouldn't be so resigned to what will happen next week is what the GFS is showing this morning!! The models may not have nailed detail of the position and strength of the high to the NW and the movement of the cold pool dropping down from Scandinavia, still time for movements.

However, very good agreement on the upper pattern into the medium range, looking at the 00z ECM/GFS 8-10 day mean H500 comparisons:

A good upper pattern to lock in the cold for a while, and a look at the GEFS shows a cold outlook with the mean ridge staying to the NW and most of the upper flow energy going into the southern stream across southern Europe, though as GP mentions, this ridge may sink back towards the UK with time.

[Frosty.]

Good news from the GEM 00z, the high is further NW and the Scandi Trough impacts with a very snowy bitterly cold spell gripping the uk next week, nogaps 00z also ticks the correct boxes.

[Geordiesnow]

Yep, a little premature to be congratulating certain models but the 12Z runs we have seen yesterday by both the GFS and UKMO looks unlikely to occur now but weather patterns can be fickle so i still would not rule out a fairly decent easterly.

I will probably admit to defeat if by this afternoon, the easterly is still being predicted as a short lived affair with high pressure toppling over us after a brief showery airflow. Our hope from then would be hoping the high can retrogress to Greenland somehow.

[Frosty.]

Add the GME 00z to the snowfest camp, amazing charts from the gem, nogaps and now the gme 00z with a severe wintry spell next week but the big 3 look benign in comparison although the gfs 00z does have a snowy FI and the ecm shows late retrogression so it's 50/50 as to whether next week will deliver the snow we want.

[nick sussex]

Yep, a little premature to be congratulating certain models but the 12Z runs we have seen yesterday by both the GFS and UKMO looks unlikely to occur now but weather patterns can be fickle so i still would not rule out a fairly decent easterly.

I will probably admit to defeat if by this afternoon, the easterly is still being predicted as a short lived affair with high pressure toppling over us after a brief showery airflow. Our hope from then would be hoping the high can retrogress to Greenland somehow.

People will either view the model output from a glass half full or empty perspective, given these charts a few days back there would have been great relief, however today there might be disappointment by some members who followed yesterdays GFS 12hrs.

At least we can count on the GFS to help with prozac orders or stress medication because the way people follow that model they certainly will be needed!

[nick sussex]

Does anyone know when UKMO update there last two FAX charts. Be intresting to see them, as the last two are not updated from last night so still based on yesterdays runs

You'll have to wait till tonight around 10.30pm UK time for the new 96 and 120hrs charts. They used to a few years back have a 108 and 132 hrs done during the day but for some reason this was stopped.

[cooling climate]

Why? GP mentioned the pattern eventually returning to a west based NAO, and surely this is just another way of doing that.

Unfortunately IB has not made one good call this winter so make of that what you will.

The reason as I see it of weaker heights to the north is a portion of energy running over the

top of Greenland. below are the 400k isentropic charts to show this.

At five days out this could still be modeled incorrectly which would change the strength of

blocking to the north and have a knock on effect of what happens to the troughing over

Scandinavia.

Below is the 400k isentropic chart for 5 days out and you can see the residual vortex

energy over Greenland helping to lower heights.

http://strat-www.met.fu-berlin.de/cgi-bin/ecmwfpv?alert=1&level=400&forecast=f120

This next chart shows the vortex out to day 8 and with the residual energy gone heights

can build once again as there is plenty of blocking over the Arctic to the west and east.

http://strat-www.met.fu-berlin.de/cgi-bin/ecmwfpv?alert=1&level=400&forecast=f192

Over the next few days depending on whether this area of the stratosphere is being

modeled correctly or not, we could see better heights once again to the north,or not

as the case may be.

[MisfitDog3]

Well the models are suggesting a scenario much more appealing than rain, wind and all that stuff but they also say to me cold nights, cool/cold days with some sunshine. Nice enough but not particularly exciting. Probably more to come but each consecutive runs seem to be moderating any extreme temps.

[Duane S.]

A bit doom and gloom in here. Not as extreme a forecast in terms as cold and snow as yesterday but that will change, many times.

This doesn't look good though...

If we were in 1989 that is.

A world of difference from the likes of that fortunately and any future 'downgrades' are still likely to lead to a cold (although relatively uneventful) scenario.

[mountain shadow]

The models have really struggled with the Atlantic/Block battle and a difference of 100 miles east or west makes a massive difference to our small island.

Who knows, the Atlantic may hold back west a little bit more allowing for the WAA to get further north and there by setting up a better easterly. At the snd of the day it's still going to be cold.

[Lewis]

Given the appalling way that the models have been handling the ongoing developments, how about we stop looking so far ahead and stick to the short term charts up to, say, t+48 or 72 hours ? Take anything past that with a pinch of salt. Once again people are looking too far ahead, hence the usual miserable and silly posts cropping up.

Totally agree with you there.

After looking at the 00z, the colder air starts to dig in tomorrow! with -5 850's about. So everything is coming forward, with the coldest weather pushed back in FI. Yes it's looking likely that we are going to see a Brief Northerly, possibly switching to a ENE'rly.

I don't know if this helps anyone but the miss's watch's GMTV (i hate it personally). Anyhow the weather forecaster showed snow right down the east coast, she went out to Tuesday. She also said that there is a lot of uncertainity to whether we hit a strong easterly, so stay tuned.

So expect a huge change on the FAX charts to show this, it will probably be sat on the fence, somewhere in between. 06z rolling out, let's see where this goes.