General Model Output Discussion

[Optimus Prime]

Kold the GFS always overblows Low Pressure systems in these situation. Upwards 30% exaggeration.

[nick sussex]

The gfs operationals of both the 00hrs and 06hrs have been dumped yet again by NOAA who go with the ecm operational, ecm ensemble mean and the gefs ensemble mean. To be honest i really don't see why anyone is even bothering to give the gfs operational runs any consideration in the further outlook.

Apart from one wobble on one run by the ecm it has been totally consistent for the last few weeks, the same cannot be said for the gfs operationals which IMO at the moment are a complete waste of time.

[Neilsouth]

The gfs last run for the SE not so good!!

The gfs has been way off the plot for the last two days

Stick with the ecm/ukmo this week

[Cheshire Freeze]

The gfs operationals of both the 00hrs and 06hrs have been dumped yet again by NOAA who go with the ecm operational, ecm ensemble mean and the gefs ensemble mean. To be honest i really don't see why anyone is even bothering to give the gfs operational runs any consideration in the further outlook.

Apart from one wobble on one run by the ecm it has been totally consistent for the last few weeks, the same cannot be said for the gfs operationals which IMO at the moment are a complete waste of time.

I completely agree. The GFS, to my eyes, has been nothing short of abysmal since its switch over to the parallel. I think maybe they rushed the change over somewhat? The thing is, it seems to pick up a wrong pattern then stubbornly stick with it right until the last gasp. I don't understand, i think it must be a data problem (or lack of it) that is contributing.

There is a theory going about at the moment that data from the north Atlantic around Greenland is sparser than usual because of a lack of flight data as pilots are flying well to the south to catch the jet stream.

Aaron

Edited January 5, 2010 by CreweCold

[nick sussex]

Must be seriously embarasssing for NOAA to have to disregard what is the premier US model.

They're used to it by now! by and large the model they use most is the ecm and it's ensemble mean, they do also use the gefs ensembles but as for the gfs operational runs these just so often go AWOL especially in the medium term that they don't really have a choice but to stick with the ecm.

The gfs is probably okay with zonal patterns but as soon as European blocking appears in the model output it often implodes and will do everything possible to remove the block prematurely.

Edited January 5, 2010 by nick sussex

[Nick B]

I completely agree. The GFS, to my eyes, has been nothing short of abysmal since its switch over to the parallel. I think maybe they rushed the change over somewhat? The thing is, it seems to pick up a wrong pattern then stubbornly stick with it right until the last gasp. I don't understand, i think it must be a data problem (or lack of it) that is contributing.

There is a theory going about at the moment that data from the north Atlantic around Greenland is sparser than usual because of a lack of flight data as pilots are flying well to the south to catch the jet stream.

Aaron

Makes good sense. Can you imagine the NOAA asking the airlines to please continue using the North Atlantic route despite the lack of jet stream help because their models are suffering?!

[Cloud 10]

The gfs operationals of both the 00hrs and 06hrs have been dumped yet again by NOAA who go with the ecm operational, ecm ensemble mean and the gefs ensemble mean. To be honest i really don't see why anyone is even bothering to give the gfs operational runs any consideration in the further outlook.

Apart from one wobble on one run by the ecm it has been totally consistent for the last few weeks, the same cannot be said for the gfs operationals which IMO at the moment are a complete waste of time.

http://www.hpc.ncep....epd/preepd.html

They also ditch the GEM (canadian model) as it is similar to the gfs op.

[johnholmes]

Makes good sense. Can you imagine the NOAA asking the airlines to please continue using the North Atlantic route despite the lack of jet stream help because their models are suffering?!

I am sure there are lots of such apocryphal stories.

the truth of course is that trans Atlantic jets, although they can change their flight plan to some extent, are pretty unlikely to be doing what is suggested, nor is it going to be making an 'apporth of difference to the models.

[Nick B]

I am sure there are lots of such apocryphal stories. the truth of course is that trans Atlantic jets, although they can change their flight plan to some extent, are pretty unlikely to be doing what is suggested, nor is it going to be making an 'apporth of difference to the models.

Agree! Slight jest. Not having the NW Extra radar I can't be absolutely sure, but are my eyes deceiving me in seeing a slight pep-up of precipitation just beginning NW of Birmingham (on raintoday)? If so, this would tie in with your mention (I read about second -hand) of a separate low pressure area forming further SE over the UK and might explain how and why the precipitation bands were brought to a halt? Also would it have anything to do with the relatively strong 700 hPA vertical winds being forecast (or did I interpret that incorrectly as well?!)? <BR>Hmm... actually I think my eyes were deceiving me after all. It doesn't appear to be happening. Edited January 5, 2010 by Nick B

[johnholmes]

I've just updated my blog but I'd like to see the 12z skew-t's and a later B Isles chart to either confirm or cast doubt on that.

Round here nothing is moving much-8cm so far, the highest I've ever seen in this area and its nearly as heavy again as it was for a time this morning.

I'll use the 15z chart and, by then I hope, the 12z ascents to try and give an idea on what is likely to move where.

By then, mind you, we will have the latest model chuntering out again.

The 06z GFS/Extra is, so far, the nearest to what is happening in terms of precip and intensities it seems to me.

[johnholmes]

For matters affecting the weather further down the line-say the weekend and beyond. There are some rather wide of the mark comments about the 06z GFS, it may or may not have 'gone off on one' but the FULL comments from the NOAA short range team are below

VALID 12Z SAT JAN 09 2010 - 12Z TUE JAN 12 2010

THE GENERAL FLOW PATTERN THIS PERIOD FEATURES AN AMPLIFIED EASTERN

PACIFIC TROUGH/WESTERN NORTH AMERICAN RIDGE/EASTERN NORTH AMERICAN

TROUGH PATTERN. SHORTWAVES/CLIPPER-TYPE SYSTEMS ARE EXPECTED TO

MOVE SOUTHWARD THROUGH THE PLAINS/MIDWEST ON THE BACKSIDE OF THE

EASTERN TROUGH. THE MODELS SHOW BETTER THAN AVERAGE AGREEMENT DUE

TO THE AMPLIFIED FLOW PATTERN EXPECTED. SINCE THE MODEL GUIDANCE

WAS RATHER SIMILAR AND THIS FLOW PATTERN FEATURES HIGH PRESSURE

ACROSS MUCH OF THE LOWER 48...CHOSE TO GO WITH THE BETTER

PERFORMING 00Z ECMWF TO SOME DEGREE THROUGH THE PERIOD...WHICH WAS

ALSO IN BETTER AGREEMENT WITH THE 06Z GEFS MEAN/00Z ECMWF ENSEMBLE

MEAN THAN THE 00Z CANADIAN/06Z GFS SOLUTIONS. A COMPROMISE OF THE

00Z ECMWF/00Z ECMWF ENSEMBLE MEAN WAS USED FOR THE PRESSURES EARLY

NEXT WEEK TO ACCOUNT FOR DETAIL ISSUES. THE UNITED STATES SHOULD

REMAIN RATHER DRY THIS PERIOD...WITH SKIRMISHES OF MODERATE/HEAVY

RAIN ALONG THE COAST OF THE PACIFIC NORTHWEST AS A WEAK PACIFIC

SYSTEM MOVES THROUGH AND ACROSS FLORIDA ON THE 9TH AS GULF OF

MEXICO MOISTURE REMAINS SUPPRESSED DUE TO THE GENERAL OFFSHORE

WIND FLOW EAST OF THE ROCKIES.

As all of you know I do like things to be properly balanced!

[full_frontal_occlusion]

As all of you know I do like things to be properly balanced!

And long may that balance continue John.

Judging from the Meteogroup radar ppn images, it looks very much like a fast moving closed circulation is forming just SW of Aberporth out in Cardigan Bay.

ffO.

[casparjack]

I am sure there are lots of such apocryphal stories.

the truth of course is that trans Atlantic jets, although they can change their flight plan to some extent, are pretty unlikely to be doing what is suggested, nor is it going to be making an 'apporth of difference to the models.

Looking at the radar, there appears to be some development off the Welsh coast near Fishguard, it really seems to have wrapped around in the last hour or so.

This doesn't appear to accord with the latest FAX chart, the 12z analysis, as this has a centre more to the NE of this.

In Herefordshire we are now in virtually still air with 50% cloud cover. Last snow was around 12pm, temp now falling again from a high of 0.9c.

As you say everything appears to have stalled at the moment - fascinating!!

[Neilsouth]

Looking at the radar, there appears to be some development off the Welsh coast near Fishguard, it really seems to have wrapped around in the last hour or so.

As you say everything appears to have stalled at the moment - fascinating!!

Looking at that fax the cold front is actually in the wrong place , it's currently moving across the south and the center is over west wales!

[derrylynne]

It really is fascinating watching the radar, i have been for a while now, this fast moving development off in Cardigan bay. That is no doubt why everything is stalled. Seems that is where the formation is taking place. Waiting now for an update from the Meto for warnings...

[casparjack]

Looking at that fax the cold front is actually in the wrong place , it's currently moving across the south and the center is over west wales!

Not if you look at the latest radar on NW, I would say they had it nailed three hours ago, it currently runs up from the Bay of Biscay, makes land fall at Bournemouth and tails off mid way between Hereford and Oxford.

The feature off the coast of Wales is the 'one to watch' now I suspect...

[derrylynne]

What does this mean? Could it travel across Wales eventually?

West Wales could get some heavy falls along with South Wales and parts of South West England. There is already snow in North Wales. Waiting to see what updates appear now from the Meto. I am sure this has taken many by surprise. Seems the depression is forming much further West than expected. It is where it goes from here that is interesting....

[full_frontal_occlusion]

Waiting now for an update from the Meto for warnings...

Indeed. The main ppn proged for this afternoon and into tonight looks to consequently shift WSW by 75 miles or so.

ffO

[KTtom]

Well, im in Aberporth and its just constant snow shower after snow shower comming in off the sea....as soon as it clears its going to freeze solid and although looking at the models its then going to remain dry for the foreseeable here this covering won't be going anywhere !

Interesting that the Aberporth Met are going for 5 -8 cm overnight, this is not backed up by BBC???

[casparjack]

What does this mean? Could it travel across Wales eventually?

...not sure yet, the Satellite image appears to have it moving SW at the moment, that can't be correct...

However, if one looks again at the 12z analysis chart and then compares the latest radar and satellite images, maybe the centre has moved/transferred SW?

Edited January 5, 2010 by casparjack

[Bobby]

Lol the latest NAE now has just 2-5cm of snow for the supposed Met Office "Red Zone" that on the 06z NAE showed 20-35cm of snow. There is huge uncertainty still over what is going to happen - BIG surprises and BIG dissapointments to come.

[Frosty.]

I thought the 6z GFS was a slight upgrade on previous runs to mid-range, the block continues with a slight easterly by this time next week there after we see more of a push from the Atlantic, will be interesting to see if the GFS gently heads in the direction of the ECM.

More mobile towards the final third of the run really although before then looked fairly anticyclonic but not the bitter easterly the ecm is currently showing to develop next week. I just hope the ecm doesn't downgrade from the 00z but on the other hand, how could it possibly upgrade on perfection.

Edited January 5, 2010 by Frosty039

[Neilsouth]

http://www.wzkarten3.de/pics/Rtavn1021.png

Bitter in the east and south east , well into saturday aswell!

I'd expect warnings for this come wednesday late

[JoeShmoe]

12z UKMO 120-144 and GFS 120-144 are very different

UKMO follows ECM this morning to a degree. GFS doesnt retrogress the HP NW and has it sat over the UK

What will ECM do

[Cheshire Freeze]

i think hp over the uk has been the general idear and most likely the outcome from what i can see.

there also seems to be slight signs of a less cold outlook.

The only signs are from the GFS which i suspect greatly. UKMO and ECM have both been very consistent and I personally wouldn't back against them.

Signs tonight of the GFS backing ever so slightly away from earlier, I would expect this to continue on the 18z if the ECM keeps its trend tonight

Aaron