Winter Model Discussion - 12/01/13 06z Onwards

[TEITS]

This is really fasinating to watch. At first glance the 06Z was poor compared to the 0Z but then at +144 with see a splitting of LP with this going under and over our HP. Remember you will always need some energy going underneath because if all goes over the top the forcing sinks HP.

For now im happy to settle for an inbetween solution between the UKMO/ECM and that is the 06Z GFS. Amazing that when we aren't seeing our normal weather pattern and this is coming from the E instead, weather forecasting remains as uncertain as it did back in the 1980s in my opinion.

[bradymk]

The GFS 6z is a good run imo, cold lasting too end of next weekend with some real cold days/nights. The ECM gets mild too quickly in my opinion but you can't disregard it. A strong jet exiting eastern seaboard is strong but heads SEwards on the GFS when it first hits the block and thats if the GFS is even correct regarding any jet speed. A difference in the speed of the jet can bring about huge changes. This run is probably what I think will happen, cold until the weekend before coming slightly milder for a time but still probably average to below average.

[Jason M]

look at that pv over greenland,what gives?????

I'll wager it won't be the heights over scandi that give. At that range its all about trends rather than specific. Other than the ECM this morning the medium term outlook is starting to trend strongly towards an easterly. I'd also suspect that in terms of uppers this is on the milder side of the ensemble pack by the time we get to 186.

Jason

[WhiteFox]

you mean like the way the jet/depression runs into the weak scandi block tomorrow and heads sse !! will the jet be that strong come verfication ? i wouldnt bother over analysing post the point that the atlantic tries to get in. the entrenched cold will give the uk a 'continental type locale' at that point in time.

If the scandi high was a bit stronger I'd agree. In situations where we've seen the cold push back the pressure has been stronger. It may take a couple of pushes, but I'd expect the Atlantic to push through based on what the 6z shows.

It's a moot point anyway because I don't believe for a minute that we will end up in that situarion in the timeframe shown! Either there will be an undercut and easterly or the high will sink. I'll wait for more reliable 12z output before considering the removal of my bottom from this comfortable fence post.

[Nick F]

A look at the 06z jet charts, it still takes the jet SE into SW Europe, so the ridge holding to our NE. If the main jet energy was going NE over the ridge, then I'd be worried about a return to a more mobile Atlantic regime. But for now, the Atlantic struggling to make inroads on the operational.

Edited January 12, 2013 by Nick F

[Great Plum]

http://www.wetterzentrale.de/pics/Rtavn2162.png

-5 finally leaving the uk after 9 days! Could be an interesting low res section...

http://www.wetterzentrale.de/pics/Rtavn2401.png

FI snowmaggedon for some!

Edited January 12, 2013 by Great Plum

[Severe Siberian icy blast]

Another fantastic gfs run , very blocked into fi , once snow cover takes hold will only fuel this cold block.

Also take a look at the northern h charts all the way though , we have a brilliantly split vortex there and heights will only keep renewing there strength so long as there's that split.

If your looking for trends , I would say its to stay cold.

[BLAST FROM THE PAST]

06Z shows that even going down the ECM route it doesn;t have to coallpse the block and back the cold away. There is a strong signal for pressure to rise, and sharply to our north say from 22nd Jan so IMO if we head towards this

then we'll go on to GFS route rather than ECM. Too much credence is given to the jet 'powering' through. The hemidpheric set up we are in won't see a jet 'powering' through.

06z is an awesome run.

So UKMO v ECM. GFS sees a touch of ECM but then thinks 'hang on UKMO is not budging, back I go'

BFTP

Edited January 12, 2013 by BLAST FROM THE PAST

[ChartViewer]

Good Morning,

PS When at work yesterday (flying from Luton to Barcelona) the tropopause was 36000ft, we were at 38-39000ft and temp was -56. That is considerably warmer than a week ago when it was -69.. Maybe talking rubbish (again) but thought it maybe of interest.

Maybe Best place to observe a strat warming

Edited January 12, 2013 by ChartViewer

[chionomaniac]

It's not really to do with the Scandi high pushing back - it is to do with the split vortices. Crossing the bridge from one to tother requires a big jump and that is why I suspect the ECM is wrong. As soon as the jet reaches mid Atlantic it loses the potential vorticity element of the Canadian sector and strong thermal gradient that this brings and will lose power immediately - hence the block appears to hold.

[Severe Siberian icy blast]

It's not really to do with the Scandi high pushing back - it is to do with the split vortices. Crossing the bridge from one to tother requires a big jump and that is why I suspect the ECM is wrong. As soon as the jet reaches mid Atlantic it loses the potential vorticity element of the Canadian sector and strong thermal gradient that this brings and will lose power immediately - hence the block appears to hold.

You need to make this appear in every thread every day I think as it gets lost so quickly and people either don't listen , forget, or miss it !! I agree entirely and what a fascinating spell we have !!

[Southern Storm]

I'll wager it won't be the heights over scandi that give. At that range its all about trends rather than specific. Other than the ECM this morning the medium term outlook is starting to trend strongly towards an easterly. I'd also suspect that in terms of uppers this is on the milder side of the ensemble pack by the time we get to 186.

Jason

Yes I'm thinking along the same lines, and expect this uncertain outlook to continue for at least another 3 days, by which time the effects of the stratospheric down-welling

will be modelled much better and I wouldn't be surprised to see very decant near-time upgrades as we approach the 15th and 16th of this month.

[TEITS]

Just to digress from the model output for the UK but I hope nobody is planning a trip to Canada.

http://www.wetterzentrale.de/pics/Rnamavn1802.png

Those americans who are looking for a noreaster in the NE are going to be disappointed. If you think we moan about the model output you should hear those in the NE of the US!

Just shows how difficult orecasting can be. I recently remember Joe B talking about a severe cold spell plunging S across many states even into Florida and now it only affects the far northern states.

[MR EXTREMES]

well its the ecms turn haha.

right gfs brillant ukmo good gem super not looked at any of the others cold spell is now on.

will the ecm relocated the heights in coming day possibly but all the others are game on happy today.

[Captain Shortwave]

GFS really starting to show the effects of the ssw, the atlantic train has turned more into a broken down car. Whilst heights are not that strong over Scandinavia, the lows just cannot get all the way across the Atlantic. During mid range, we have a low heading towards us, it literally gets crushed by the high to the north east and renewed lows coming in from the west. Real promising signs. Plus in this run Eastern areas would have snow showers all the way until Saturday night.

[Snowfan50]

Is their snow potential tuesday aswell as the low drops south? it seems to be still in the Uk on tuesday.

[Mrlucky1]

It's absolutely fascinating to watch unfold and seen how the models change and then come together. What are the best estimates for how long the cold spell looks likely to last?

[BLAST FROM THE PAST]

http://www.wetterzen...s/Rtavn2162.png

-5 finally leaving the uk after 9 days! Could be an interesting low res section...

http://www.wetterzen...s/Rtavn2401.png

FI snowmaggedon for some!

Indeed but I suspect surface temps will be rather on the low side

BFTP

[Methuselah]

It's often been said just how wonderful a model-run the GFS 06Z truly is...Today's model-of-choice?

[TEITS]

It's absolutely fascinating to watch unfold and seen how the models change and then come together. What are the best estimates for how long the cold spell looks likely to last?

Well the ECM suggests the end of the week but in my opinion that's too soon. However im not dismissing the ECM though and we may see a brief less cold spell next weekend. However this could easily change and if it does then because its likely to come from the E any snowfall potential is more likely to come from showers into E areas.

When the Met O update their 6-15 forecast I suspect the outlook will be cold ,suggesting snow showers in E areas but they might suggest it turning milder into W areas. That way if the ECM is right they cover themselves by saying the milder weather spread further E than they were expecting. Thats what I would write anyway.

[Jason M]

It's often been said just how wonderful a model-run the GFS 06Z truly is...Today's model-of-choice?

At least today it's in line with the 00z ensemble suite :-), albeit a little on the warm side!

Jason

[Lynxus]

It's often been said just how wonderful a model-run the GFS 06Z truly is...Today's model-of-choice?

I personally feel that the 06z can only really be used for trending and giving some idea as to how the next run will unfold.

With its missing balloon data, its obviously not the full bag of spanners, but its certainly handy to get some "idea" of what the next runs can be like.

I always take the 06 with a pinch of salt. If it manages to get to grips and output similar to other models that evidently there is a strong signal hidden in the data somewhere.

[Met4Cast]

GFS 06z seems to be similar to the UKMO with regards to the Scandi High

Cracking chart, undercut time!

[MR EXTREMES]

i really cant understand why people are not talking about the ukmo it looks lush less messy and a possible.

[BLAST FROM THE PAST]

[quote

name=Rybris Ponce' timestamp='1357987809' post='2483063]

It's often been said just how wonderful a model-run the GFS 06Z truly is...Today's model-of-choice?

Edited January 12, 2013 by BLAST FROM THE PAST