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phil nw.

Model Output Discussion 1200 hrs 15/11/14

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The GEFS anomaly has definite west to east dance this morning although definite is a no no these days.

 

 

post-12275-0-78013300-1416383790_thumb.p

post-12275-0-68294900-1416383801_thumb.p

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There are differences between the 3 anomaly charts I use, NOAA is much more progressive than either EC or GFS. One output is also a bit suspect but it is unusual for NOAA to be much out. Will see how the output is this evening and for EC-GFS for tomorrow before deciding if they are altering the main wavelength. If they are then it would suggest that mobility 'may' become the watchword for a time?

links below

http://www.cpc.noaa.gov/products/predictions/814day/814day.03.gif

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

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HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY WEDNESDAY NOVEMBER 19TH 2014.

NEXT UPDATE THURSDAY NOVEMBER 20TH 08:00

THE CURRENT GENERAL SITUATION A weakening front will kove slowly NE across England and Wales later today and tonight.

MODELS-2 WEEK HEADLINE
Slowly becoming windier and more changeable next week and beyond with rain or showers and strong winds at times moving down from the NW.

THE JET STREAM ENSEMBLE FORECAST The GFS Jet Stream Ensemble forecast continues to show the large High pressure block over Europe continuing to divert the Jet Stream both North and South of the UK over the next 5-7 days. Very gradually the flow becomes more direct to lie over or near to the South or North of the UK late in Week 2.

GFS OPERATIONAL The GFS operational this morning continues to show High pressure over Eastern Europe continuing to affect the UK in one form or another over the next few weeks. For the most parts the attacks from the Atlantic are half hearted or thwarted as fronts come up against the block and while delivering some rain for all at times there will be some drier spells too with average temperatures as a result. For a period though through the start of Week 2 a more powerful Low pressure area is shown to pull SE across the UK with rain and gales for all as well as some snow on hills in the North as a temporary wedge of colder air accompanies the Low.

THE GFS PARALLEL RUN The GFS Parallel run is broadly similar to the operational this morning with much Low pressure disruption near the British Isles through Week 2 delivering a lot of rain and showers for all in temperatures turning rather chilly at times with snow on northern hills. The High pressure over NE Europe does become more favourable in position at times to deliver the chance of colder air from the East too.

THE GFS ENSEMBLES The GFS Ensembles also shares the view of the above model runs with a trend to a more deeply unsettled spell in Week 2 before it shows a rise of pressure from the SW late in the period with cold and frosty plus foggy conditions possible towards the end of the period.

UKMO UKMO today shows High pressure developing in 4-5 days across the UK with dry and bright weather with frost and fog at night the most likely scenario towards the beginning and middle of next week following some rain over the start of the weekend.

THE FAX CHARTS The Fax Charts show a complex frontal system towards the weekend becoming slow moving across SE Britain while pressure rises strongly over the North and West. Occasional rain crossing the UK looks like becoming slow moving near the SE at the weekend before the quiet, colder and perhaps frosty weather develops by the start of the new week.

GEM GEM too shows the High pressure across the UK early next week before it become displaced to the East and allows Low pressure to sink down and develop as a complex system around the UK later delivering spells of rain and showers in temperatures close to or a little below average with some snow possible on Northern hills.

NAVGEM NAVGEM this morning shows the rain at the weekend disappearing as High pressure ridges up from the SW. The rest of the run shows a mild period with basically SW winds and some rain in the NW while many others become dry and rather cloudy.

ECM ECM this morning takes the road towards a slow decline in conditions from the NW through next week and the weekend as the rain clears this weekend to give a drier and colder period with some frosts likely before cloud, wind and rain become more dominant from the NW from midweek with a wet and windy spell looking most likely by the end of the run and beyond. Temperatures look like being close to or maybe a little below average at times and some snow on Northern hills is possible at times later as a result.

THE ECM ENSEMBLES The Ensemble run continues to show an ever deepening trough aross the UK by Day 10 powered by a deep Low likely to lie somewhere close to the NW of the UK at that point with spells of wind and rain or showers as a result in average temperatures.

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trend seems to be for a slow decline in conditions across the UK towards more Atlantic driven weather under Low pressure later next week and beyond.

MY THOUGHTS Today's output continues to show a slow decline into more unsettled conditions later next week as the benign and stagnant weather of present mostly due to a High pressure block to the East recedes. The models though still show some resistance from the block to the East even then and as a result steers deep and developing Low pressure down across the UK from the NW. This of course means plenty of wind and rain at times for the UK and with some polar maritime air getting into the mix at times later temperatures would likely be average at best and perhaps a little below at times with some snow on higher elevations of the North. There is still little evidence shown of any major dip into cold weather with the most likely option shown currently that Low pressure to the NW is likely to remain dominant until at least the end of this morning's outlook period with wind and rain at times for all as a result. I will note that although this is the consensus shown this morning High pressure remains over Eastern Europe even at the extremities of the run and at some point in the future it may position itself more favourably to deliver cold to the UK on an Easterly flow but patience is going to have to be administered until later in the season and other building blocks align in better positions than shown at present.

Edited by Gibby

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This mornings models seem to all show that the jet stream will be digging south in a week or so, this could indicate the start of stratospheric warming taking place. Of course nothing may come of this, but don't be surprised if a flip to colder weather charts around the turn of the month.

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Morning, again the latest offering from ECM is to progressive. The Russian high is showing signs of entrenchment and will not decay at that rate shown. I expect the UKMO post 144 hours will hold the block longer into early next week. Beyond that the zonal flow coming out of Canada, I have an increasing feeling will start to align more NW to SE . Potential for cold in 10 days time.

C

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An increasing signal for a spell of stormy weather towards the end of November if the NAEFS and ECM ensemble means are near the mark.

 

naefs..  ecm..

 

An example from the gfs ensembles.

 

 

 

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So the ECM drops last nights progressive run and return to its earlier idea. you can see its return is allied to a more amplified upstream pattern and better interaction with the PV chunk of the deep low which pulls some of those low heights further nw.

 

Last nights run flattened the pattern out and hence we saw everything pushed eastwards.

 

Just a chance that there might be some more interesting changes between the 144 and 168hrs timeframe but only if the upstream pattern keeps that deep low and more amplified setup.

 

Apart from that small risk there overall it looks like the Atlantic does make a return, the uncertainty really in the form that takes.

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Morning all,
 
Looking odds on for a return of a more mobile flow for the UK.All  models showing the retreat of the Scandi/Russian block allowing progression of fronts into the uk,angle of entry looks good as others have stated with a constant spew of low pressure sytems from the Baffin Island vortex,N/W S/E angled as highlighted below,
 
ECM ECH1-216.GIF?19-12
GFS,gfsnh-0-228.png?0

Temperaturs also dropping as wind swings into the N/W and taps into colder air,
 
MT8_London_ens.png

Jet stream also picking up sum intensity,
gfsnh-5-192.png?0




Looks like after this weekend nothing mild on offer but plenty of cold wet and windy weather as we head into December.

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This mornings models seem to all show that the jet stream will be digging south in a week or so, this could indicate the start of stratospheric warming taking place. Of course nothing may come of this, but don't be surprised if a flip to colder weather charts around the turn of the month.

 

There's a post in the 'winter hopes/chat thread with MJO composites for December which show a very sharp southerly trajectory for the jet being a response to the phase forecast in the next week or so.

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Well no shocks on the GFS 06z, and it looks like we are having some consistency. The Atlantic fuels up next week sending a LP system to the UK. It warms out, the Azores does its repeating party trick and cuts off that upper level low towards the Med:

 

post-14819-0-77364200-1416393949_thumb.p post-14819-0-52386000-1416393961_thumb.p

 

And  by D16 we are back where we started: post-14819-0-15536100-1416393985_thumb.p

 

So trending towards average to slightly below temps with bouts of rain before we are transported back to no mans land.

 

D10 means from the big three:

 

post-14819-0-73434500-1416394259_thumb.p post-14819-0-80507200-1416394269_thumb.g post-14819-0-06399400-1416394339_thumb.p

Edited by i'm dreaming of...

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Morning carinthin , I have never bought into the Atlantic taking charge , although that really is what we all should expect given the time of year , but it just goes to show how different the set up is this year , to have a Scandi high so powerful so early having this much influence on brittish weather is quite unusual for November/December , I think we all should expect maybe a week or so the Scandi high easing its grip somewhat (wanning) as Tamara explained , but looking at the output this morning we can see the strength of the blocking isn't really going anywhere , looking at 2 charts

attachicon.gifimage.jpgattachicon.gifimage.jpg

It's easy to see , firstly we have WWA straight into the Artic , the high really is very strong , we have the low pressure systems grinding to halt and really trying there best to dig south , then looking at the jet steam , it splits in 2 pieces , the small arm going direct North and the other main arm going South infact almost been forced back on itself . You would expect once the low pressure systems goes south the high to the north East will strengthen , and exert more influence on us , particuarly with the continued warm air into polar regions , it looks very interesting to say the least and feel December may well trend cold very quickly .

Yes Siberian, I agree the Russian Block is not going to disintegrate that easily. Just look at the amount of extensive snow cover in Northern Asia, that will enhance high surface pressure. Also the amount of snow cover in North America is phenomenal for this time of year. I think a trend to cold is now beginning to take place with some cold pm air mass starting to dig into the block with the UK and Western Europe in the firing line for some tasty depressions.

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If this se running troughing sets up then its a case of how long this lasts for and whether you head towards the GFS P trend of eventually more trough disruption and a splitting of that trough energy as pressure builds to the ne.

 

Before that though theres still uncertainty with the amplitude of the pattern over in the USA and the type of interaction that takes place between that deep low and the PV chunk near Greenland.

 

You can see how complicated the whole affair is by looking at the GFS P , this manages to develop the jet running se inspite of that shortwave to the north phasing with the troughing to the west which pulls this east, then as that low interacts with the PV some of the low heights are pulled nw.

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the extended ecm ens increase the potential for scandi blocking compared to yesterdays 12z and also of euro falls in slp. also noticing for a trend in the gefs members to become very amplified later in week 2 and for some proper HLB.  both of these had been a bit absent over the past week when looking late on in the runs.

 

also, a lot more ridging in the aleutian region now showing - perhaps in conjunction with the siberian vortex heading a bit further east.

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Certain posters have claimed that the Atlantic will win out for weeks now, by analyzing day 10-16 charts supposedly supporting there claims, it was the exact same with the Polar Vortex apparently getting stronger and more organized. It does confuse me that certain posters still seem to be unable to understand the fact that what the models are showing outside the unreliable time frame is not certain to happen, whether it be an Atlantic flow or an Easterly flow.   

 

Agree. And of course looking at it from the other way round, since late October far more posters have been suggesting that cold is on the horizon, yet we are in one of the warmest Novembers for sometime. Nuri was the reset that stopped the Atlantic/PV going closer to its normal state; it amplified the NH. I think not spotting this tropical storm is forgiveable as many of us are only amateurs.

 

I can promise you that we will get 5-7 days (maybe longer) of quazi-Atlantic weather next week.

 

Anyway with regard to Saturday-Monday surface setup (temp-rain) this remains unresolved. ECM's ensembles are all over the place. The ECM 0z op forecasts a high of 5c for Sunday, the GFS op 13c!!

 

post-14819-0-36060700-1416411019_thumb.g

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Interesting developments on the GME at T132hrs, shame its hardly known for its reliability. We only wheel it out when we need some better news in terms of a more positive output for coldies!

 

post-1206-0-88640500-1416411855_thumb.pn

 

Its more amplified upstream and has managed to develop some higher pressure to the ne, theres still some shortwave phasing issues but not a bad output really.

Edited by nick sussex

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Slightly stronger heights on the gfs parallel run at 72 hours going into greenland!!

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There's a post in the 'winter hopes/chat thread with MJO composites for December which show a very sharp southerly trajectory for the jet being a response to the phase forecast in the next week or so.

but in all fairness this is in december and unlikely to happen in reality after all we are not even sure what and where the models are heading.

and with the vortex set to strengthen and set up shop in and around its normal home this would suggest that the likely trend would be a uk aimed jet stream.

 

with our block to the east reclining futher east allowing the zonal flat flow in.

and alot has been suggested that the wave warmings have split the vortex but its not been enough to sustain a great impact of the polar vortex which is gaining strength and starting to to control of the hemispheric weather.

 

gfs as seen is about the same as the last few runs and pretty much close to most of the other model outputs.

gfs-0-120.png?12

 

if you look at the overall hemispheric amon 500z charts and run through then you can see there is really not alot of hemispheric blocking or strong sustained blocking,

gfsnh-12-192.png?6

the block to our ne slowly loses strength and zonal flow starts to take control still not a steam rolling zonal yet but low pressure systems starting to build up and start lining up for the uk onslaught.

 

gfsnh-12-132.png?12

as you can see the gfs has moved blocking slightly futher east in the latest gfs outputs.

id be inclined to say nothing to interesting for sometime.

 

UW144-21.GIF?19-05

the ukmo from this morning and last night are most certainly flattening the whole pattern.

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Could be more drama tonight, the GFS P doesn't phase the shortwave to the north which means that troughing to the west doesn't get pulled eastwards and a big dig in the jet southwards in the mid Atlantic.

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Interesting developments on the GME at T132hrs, shame its hardly known for its reliability. We only wheel it out when we need some better news in terms of a more positive output for coldies!

 

attachicon.gifgme-0-132.png

 

Its more amplified upstream and has managed to develop some higher pressure to the ne, theres still some shortwave phasing issues but not a bad output really.

I think the GFS 12z is nudging that way

 

gfs-0-150.png?12

 

 

 

Run on to t174

 

gfs-0-174.png?12

 

And this was the 6z at t180

 

gfs-0-180.png?6

 

 

I know which one I fancy

BFTP

Edited by BLAST FROM THE PAST

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Ive gota say i knew the gfs runs were onto something right from as early as 72 hours! ! At 168 hours low pressure is disrupting and going even further south in the atlantic! ! Higher heights across scandy aswell!!

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A better ukmo aswell! ! Low disrupting in the atlantic and heights trying to build across the uk into scandy!! Compare it too yesterday's 12z run and it's a big improvement! !

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