Model Output Discussion 1st Nov.2013

[LomondSnowstorm]

True! normally they're a real pain but in this instance it would help matters, the GFS initially has a flatter pattern because of a shortwave near Greenland which stops more northward ridging of the high, then as the amplified wave runs east it decides then to get rid of the shortwave! When what we wanted to see was that developing and running se. Regardless the GFS 18hrs IMO is the best run of the season so far in terms of trend. I quite like the NAVGEM 18hrs run which is interesting at T144hrs , sadly that model is firmly in the cannon fodder model section in terms of reliability.

It's an intriguing run - while there have been hints of more sustained blocking at times in the output this is the first time we've really seen it develop within the high res part this winter. I'm sure we've had the 'lack of a trigger' issue before - December '09 I believe was one instance where it required a trigger shortwave to drop westwards off Scandinavia to usher in the initial easterly and force the retrogression (although that one seemed much more high stakes than our current situation). It' certainly wouldn't be the worst problem to have though, given the tendency of models to pick up on these features within the reliable.

[Cheshire Freeze]

Looking at the GEFS further into FI, it seems after the initial blast, the perturbations flatten the pattern back out days 9/10 followed by a second bite with a few of the members showing proper Greenland heights.

[weirpig]

Looking at the GEFS further into FI, it seems after the initial blast, the perturbations flatten the pattern back out days 9/10 followed by a second bite with a few of the members showing proper Greenland heights.

yep control looks tasty aswell

[Cheshire Freeze]

yep control looks tasty aswell

 

There's one thing about it, I don't think model watching will be dull over the next few days...

[Frosty.]

Things are looking much better for coldies at last, this would be a huge bonus when you consider that some experts were predicting a mild unsettled november with not even a hint of a cold snap evolving..I'm hooked now. :-)

[Purga]

So another mild run from GFS then.

 

Forget FI  

[Cheshire Freeze]

So another mild run from GFS then.

 

Forget FI  

 

Yes, positively sweltering...

 

 

 

That's why paying attention to warm 850 temps in November is pointless.

Edited November 11, 2013 by CreweCold

[Panayiotis]

Some of you might look at this ensembles and assume its for the north! But actually its for my location in South Wales! I think if any precipitation fell in the night im sure -5C uppers in November can deliver snow?

http://modeles.meteociel.fr/modeles/gens/graphe_ens3.php?x=202&ext=1&y=142&run=18&runpara=0

Edited November 12, 2013 by Panayiotis

[shotski]

Loving FI of the GFS , something is afoot for sure.

Meanwile the CFS is like a dog with a bone and has been showing an easterly

now for several days for the end of the month, before you scoff at the CFS remember

how it performed last March

[lindy2017]

Some of you might look at this ensembles and assume its for the north! But actually its for my location in South Wales! I think if any precipitation fell in the night im sure -5C uppers in November can deliver snow?http://modeles.meteociel.fr/modeles/gens/graphe_ens3.php?x=202&ext=1&y=142&run=18&runpara=0

So i might get it in brynmawr....we are very high up...........

[That ECM]

Interesting output this morning, the best thing for me is that ECM at t192 showing a cool/cold blast. Always good to see the nearer time frames start to reflect the trend of what has been showing in the far FI. T192 is still FI for me but it's edging closer.

[Mark Neal.]

ECM trickling out..

 

144hrs.

 

 

Cold air north of the UK. Middleground UK, neither massively settled or unsettled. 

 

168hrs.

 

 

Colder gets closer, with colder uppers moving into Scotland.

 

192hrs.

 

 

A northerly of sorts, the mid atlantic ridge does look less powerful and a low pressure NW of it,could be a spanner in works?

 

216hrs.

 

 

The high pressure seems to wedge upto towards Iceland as a low pressure system sits SW of Greenland. Colder air slowly sinking southwards across UK, even colder uppers not far away from Scotland.

 

240hrs.

 

 

High pressure moves into Iceland, UK cold air in place still... Cold uppers down into Mid France!

 

 

 

 

 

 

[garbagebags]

Oh dear. Is it just me but is the GFS 00z utterly dire. Refusing to build heights in North Atlantic, cold all but gone in high res

[Radiating Dendrite]

Oh dear. Is it just me but is the GFS 00z utterly dire. Refusing to build heights in North Atlantic, cold all but gone in high res

The cold had never really been present in the hi res. If you analyse every run in this detail it will drive you mad!Just pick a few daily runs and look for trends not specifics.

[garbagebags]

The cold was most definitely present in the high res on the previous 18z, 12z, 06z, and 00z

I would have called that a trend?

[Mark Neal.]

The cold was most definitely present in the high res on the previous 18z, 12z, 06z, and 00zI would have called that a trend?

Yes. Which means that the 00z gfs quite possibly was an outlier? Haven't viewed ensembles secant confirm.

[Snowman.]

Just seen FI on the 0z

 

 

 

PV in a slight mess, Heights extending to the pole, lows undercutting.

 

But all in FI so its going to be gone within a few hours.

[Snowman.]

Big three for T144:

 

ECM:

 

 

UKMO:

 

 

GFS:

 

[Frosty.]

These are the type of charts I love, although this is the end of the Gfs 00z op, I think we have a good chance of something similar next week.

[Severe Siberian icy blast]

Big three for T144:

 

ECM:

 

 

UKMO:

 

 

GFS:

 

I think what we see this morning is a more realistic output from the models , we sort of have agreement there. Low pressure sitting somewhere to the north west of the uk , the cold locked behind the low pressure . It's a watered down version of events , so yes it will get colder , but it's delayed a bit , so from the 20th or so , rather than the 18th . On a plus note the PV comes under stress later with more ridging into the polar regions mainly to the west of Greenland , which is really a great place to see it . Although it suggests a west based -NAO , but you can see the vortex under stress, with very little left over Greenland area.

[bluearmy]

Gem grabs ecm's spoiler low from yesterday. Gfs is diff upstream early on. ECM consistent with the ridge within the semi reliable. Clearly this doesn't fall within the 'count down' scenario!

not worth much at that range but I like ECM re the waa late on west of greeny together with the euro low heights.

[Captain Shortwave]

So from T144 the UKMO/ECM take that low south east towards the UK, you can see the UKMO will follow the ECM by the 500mb pattern as both are showing the trough appear with the high trying to retrogress. GFS simply takes the low east//north east and leaves us in a little bit of no-man's land.

Is the GFS having it's usual issues with this now? Or has it picked something up.

GEM shows the low shown on the ECM last night, the result was not pleasant.

Edited November 12, 2013 by Captain shortwave

[Frosty.]

There are lots of very wintry charts on the GEFS 00z perturbations and lots more which have potential, these are the best, plenty of nice eye candy for all coldies with snow and frost featuring strongly if something similar verifies..ENJOY  

[gottolovethisweather]

The cold was most definitely present in the high res on the previous 18z, 12z, 06z, and 00z

I would have called that a trend?

 

Hi,

 

Try looking at my post from yesterday regarding determining trends. Yes, some folk will analyse the runs in their own ways and jump on every run but I do think overanalysing becomes an ever increasing risk then, even if it's fun to do.

 

http://forum.netweather.tv/topic/78340-model-output-discussion-1st-nov2013/?p=2831215

 

Even then, its not as straight forward as ABC as Mark N suggests you should account for additional data such as ensembles. Also one additional surface feature which suddenly develops in the North Atlantic then alters the whole pattern moving forward.

Edited November 12, 2013 by gottolovethisweather

[johnholmes]

the colder type does look like happening but I doubt any kind of lasting cold. Which is what anyone should expect at this time of the year. The 500mb anomaly charts from ECMWF-GFS this morning give the idea. A rather messy upper air pattern, a coldish flow from north of west but possibly only 2-3 days from about 6 days from now possibly a it earlier?

http://www.meteo.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

 

Not enough agreement between them nor with the NOAA output from last evening, they do look a bit more realistic and may give 5-6 days of the colder 500mb flow from north of west.

Any detail then forget that until we get nearer the weekend for the synoptic models to start to give a clearer and more consistent picture.Will it snow for 'me'=don't even waste energy looking until into the weekend?

http://www.cpc.ncep.noaa.gov/products/predictions/610day/500mb.php

Edited November 12, 2013 by johnholmes