Jump to content
Sign in to follow this  
phil nw.

Model Output Discussions 06z 04/11/16

Recommended Posts

I suspect temperatures will be much lower than shown below in rural parts tomorrow morning -6 or -7 certainly possible midlands south and in the Scottish highlands

27-778UK.GIF?28-0

Share this post


Link to post
Share on other sites

 

GFS 0z showing from the weekend some increasingly cold nights across many parts of the UK. :cold:

126-778UK.GIF?28-0150-778UK.GIF?28-0174-778UK.GIF?28-0192-778UK.GIF?28-0

Share this post


Link to post
Share on other sites
27 minutes ago, bluearmy said:

T210 on the mean and we're getting pretty close to undercutting over Iberia .............

The tipping point will come blue, i think its reasonable to say the first week of Dec will generally be dry and chilly, esp given the time of year, thereafter its either retrogression or a sinker, we badly need undercutting as thr Atlantic has moved into 4th gear...

Share this post


Link to post
Share on other sites
3 minutes ago, Summer Sun said:

I suspect temperatures will be much lower than shown below in rural parts tomorrow morning -6 or -7 certainly possible midlands south and in the Scottish highlands

27-778UK.GIF?28-0

Nice to see people looking to the nearer term, as opposed to what is lurking after 10 days. GFS keeping the UK below average for the next 10 days or so. Not a bad place to be going into December, I think.

Share this post


Link to post
Share on other sites

The longer range outlook seems to be getting drier with each run

gefsens850London0.png

Temps struggle under the high

gefstmp2mmaxLondon.png

Colder still the further north you go whilst we are not seeing snow it certainly ain't going to be warm over the next few weeks with more frosts than some had in the past 3 winters combined

Share this post


Link to post
Share on other sites
5 minutes ago, MattHugo said:

Just for the record but after inspection of the 00Z EC Clusters there is a large population of 37 members which supports the blocked, high pressure regime over the UK right through to the Thursday 8th of December, remarkably 10 days away. Clearly I'm not saying this is a certainty, it isn't, but when looking for some signal and consistency then, overall, the likelihood of this weeks blocked pattern continuing well into next week is increasing. Out of interest the other 14 ensemble members support the high pressure declining into the Continent and with a mild SW'ly flow becoming established, as per the GEM of late for example.

I wouldn't even bother looking beyond that because what happens after that is anyones guess and clearly D10 is 240hrs as it is.

The other thing to highlight that is 850mb temperatures, at times, won't tell the whole story in terms of boundary layer conditions and temperatures. Clearly cloud amounts and distribution moving forward will be key, but as an example the 00Z EC has 850mb temps rising above +5C through the middle of next week, towards the end of the run, but surface temperatures are particularly depressed from the ECMWF with still overnight frosts and highs no more than +3C to +6C as a very general guide across the UK.

Far from a 'proper' cold and snowy spell, but in-keeping with the autumn as a whole this blocked regime we now find ourselves within this week isn't going anywhere soon at all, again where we go from there I wouldn't even like to say.

Regards, Matt.

Thanks for the heads up matt, backs up what a few of us were saying yesterday, beats wind and rain and mild gunk everytime! Will be a much more seasonal set up than 12 months ago...:cold:

Share this post


Link to post
Share on other sites
10 minutes ago, MattHugo said:

Just for the record but after inspection of the 00Z EC Clusters there is a large population of 37 members which supports the blocked, high pressure regime over the UK right through to the Thursday 8th of December, remarkably 10 days away. Clearly I'm not saying this is a certainty, it isn't, but when looking for some signal and consistency then, overall, the likelihood of this weeks blocked pattern continuing well into next week is increasing. Out of interest the other 14 ensemble members support the high pressure declining into the Continent and with a mild SW'ly flow becoming established, as per the GEM of late for example.

I wouldn't even bother looking beyond that because what happens after that is anyones guess and clearly D10 is 240hrs as it is.

The other thing to highlight that is 850mb temperatures, at times, won't tell the whole story in terms of boundary layer conditions and temperatures. Clearly cloud amounts and distribution moving forward will be key, but as an example the 00Z EC has 850mb temps rising above +5C through the middle of next week, towards the end of the run, but surface temperatures are particularly depressed from the ECMWF with still overnight frosts and highs no more than +3C to +6C as a very general guide across the UK.

Far from a 'proper' cold and snowy spell, but in-keeping with the autumn as a whole this blocked regime we now find ourselves within this week isn't going anywhere soon at all, again where we go from there I wouldn't even like to say.

Regards, Matt.

Thank you Matt for your fab input - true professional

Share this post


Link to post
Share on other sites

The spread on the GEFS at just 5 days showing the continued uncertainty in the 2 key areas that we have been watching for a week now. Can we get the High to ridge towards Greenland and can we get a Low (more energy) in a position to undercut the High and move towards Iberia.

GEFS Spread oz 28Nov for 3Dec.jpg

Looking at ECM and GFS runs this morning, ECM is still showing this possibility by Day 8, but GFS (Op) is moving away from this option and now thinking about ridging towards Scandinavia. So we continue to watch these key areas. But at least we're in the position where either option could be good news (if your preference is cold).

Day 8 GFS GFS 0z NH 28Nov for 06Dec.png Day 8 ECM ECM 0z NH 28Nov for 06Dec.GIF

Share this post


Link to post
Share on other sites
25 minutes ago, Summer Sun said:

Update from Ian

59522475-0a6b-4e82-bcdd-9ab3133eb171.png

No talk of anything particularly wintery at the minute, a block over us would be nice but I'm sure many want it to our North as per some seasonal models...Lets hope we get the block in place first then it migrates into a weakened PV towards the pole!!

Share this post


Link to post
Share on other sites

The height rises in the vicinity of the Aleutians by days 9-10 are impressive on the 00z runs - progress being made there. The resultant (intermittent) vortex split and cross-polar ridge could easily have allowed HP to the NE of the UK to fend off the Atlantic troughs. Not bad considering most of the period in question is still prior to the period of greatest potential indicated by that extended EPS/ECM update last Friday.

 

Much shorter term, I'm very interested to see how the next few nights turn out down here versus model projections. I've seen some shockers in the past under calm, clear conditions with relatively high 850hPa temps; lows of -5 or -6 between 6 and 9 am when the models had temps barely below freezing (and I'm sure there was one time later last winter or during the one before when GFS went for +2 or +3*C and the reality turned out to be -4*C!).

Share this post


Link to post
Share on other sites
28 minutes ago, Summer Sun said:

Update from Ian

59522475-0a6b-4e82-bcdd-9ab3133eb171.png

Finely balanced against more changeable weather? Having looked at the GEFS and all the various det. runs, I'm very surprised not to see settled reported as a strong favourite! Just what are the Met's models seeing I wonder... :unsure2:

Share this post


Link to post
Share on other sites
4 minutes ago, Singularity said:

Finely balanced against more changeable weather? Having looked at the GEFS and all the various det. runs, I'm very surprised not to see settled reported as a strong favourite! Just what are the Met's models seeing I wonder... :unsure2:

rose tinted maybe! but changeable might not mean mild if the high moves North although I guess the form horse is drift south, just my thoughts.

Share this post


Link to post
Share on other sites
14 minutes ago, Singularity said:

The height rises in the vicinity of the Aleutians by days 9-10 are impressive on the 00z runs - progress being made there. The resultant (intermittent) vortex split and cross-polar ridge could easily have allowed HP to the NE of the UK to fend off the Atlantic troughs. Not bad considering most of the period in question is still prior to the period of greatest potential indicated by that extended EPS/ECM update last Friday.

 

Much shorter term, I'm very interested to see how the next few nights turn out down here versus model projections. I've seen some shockers in the past under calm, clear conditions with relatively high 850hPa temps; lows of -5 or -6 between 6 and 9 am when the models had temps barely below freezing (and I'm sure there was one time later last winter or during the one before when GFS went for +2 or +3*C and the reality turned out to be -4*C!).

I don't find this particularly odd. You only need some relative slight changes in boundary layer conditions to bring this about. Unexpected cloud clearance, wind dropping out brings the radiation inversion into play.  and the reverse can also happen of course

Edited by knocker

Share this post


Link to post
Share on other sites
Just now, knocker said:

I don't find this particularly odd. You only need some relative slight changes in boundary layer conditions to bring this about, and the reverse.

Not sure if it is a regional thing or not. I usually find the GFS will often go a few degrees higher even for runs during the days than is reached. This is for the day time highs, I should add. At night time it appears to underestimate the low by a few degrees as well. Never seen it widely out, though, not more than by a few degrees.

Share this post


Link to post
Share on other sites
2 minutes ago, TSNWK said:

rose tinted maybe! but changeable might not mean mild if the high moves North although I guess the form horse is drift south, just my thoughts.

Oh yes, I agree that it may not mean mild :)

Fergie's update would be less surprising if he'd said 'week 2 of Dec' instead of 'early'. Perhaps that's what he meant but kept the terminology simpler/snappier for his wide audience.

 

@knocker I just find it remarkable that those boundary conditions can still be modelled so insufficiently in this day and age. Perhaps it's a matter of needing to allocate processing power elsewhere, because after all, specialist services can provide adjusted output to customers where needed :cold:

Share this post


Link to post
Share on other sites

Ok so it would appear to me that the cold plunge forecast by the GFS last Thursday, (remember that epic 06Z run.... :drunk-emoji:) is back on? The prospect of snow I think is gone but if i'm not mistaken, from that epic 06z run last thursday? The GFS backed down towards the ECM and now we've had successive runs lean more towards an upcoming frosty weekend? Looking at the 06Z so far, at t.96, the LP in the Atlantic is further south (thats good), the HP  over is is more favorably aligned (that's also good). I think we could see a few upgrades in terms of cold as we get closer to this weekend.

:D

Share this post


Link to post
Share on other sites
11 minutes ago, Singularity said:

Oh yes, I agree that it may not mean mild :)

Fergie's update would be less surprising if he'd said 'week 2 of Dec' instead of 'early'. Perhaps that's what he meant but kept the terminology simpler/snappier for his wide audience.

 

@knocker I just find it remarkable that those boundary conditions can still be modelled so insufficiently in this day and age. Perhaps it's a matter of needing to allocate processing power elsewhere, because after all, specialist services can provide adjusted output to customers where needed :cold:

I take your point but specialist services can concentrate on a specific locale, which is quite important with an anticyclonic/temp forecast as regional, and even smaller , variations, can be quite large.

Share this post


Link to post
Share on other sites
5 minutes ago, carinthian said:

The latest t168 chart from UKMO shows a developing low out from Iberia. This is more of a feature than shown on ECM and GFS this morning. If this develops , it should tighten the baro-clinic zone over the Southern Med and induce lower heights into Southern Europe and I would expect a developing low circulation in the Western Med (cira 7-10 days ) Of course lower heights , whether, be  over Iberia or further east into the Med Basin will be good for maintaining heights further north. The UK block shows no sign of subsidence, it rarely stays put  for long, so a retrogression should start to show later this week. My bet is to move NE , partly due to the enhanced lower heights develop over Europe. Possibly too much SWly energy over the top to send it NW. Great chart watching continues to this very interesting start to winter season. Meanwhile , here in the Eastern Alps, colder air mass arrived last night and temps of -8c at 2000m  with snow flurries as I type ( my favourite kind of weather ) . Enjoy your seasonal weather !

 C

ukm2.2016120500.168.lant.troplant.prp.fcst.gentracker.png

Pretty sure the METO 0zoutput was roundly disliked going by this mornings comments. This puts a different spin on it.

Share this post


Link to post
Share on other sites

Hmmm each run seems to increase heights around scandi and pull that colder air ever slightly westwards each time!!think some places are gona be in the freezer by the end of the week even though there wont be any snow!!

Share this post


Link to post
Share on other sites

HP is looking to hold out more and more with each run.  No snow prospects yet, but it is keeping the Atlantic at bay.

Share this post


Link to post
Share on other sites

Gfs6z trending colder as we import continental air, short days, low sun, splendid stuff for coldies!! :cold::D

Share this post


Link to post
Share on other sites
Guest
This topic is now closed to further replies.
Sign in to follow this  

×
×
  • Create New...