Jump to content
Sign in to follow this  
Paul

Focussed Model Discussion

Paul

This is the focused model discussion - please only post about the model output. 

For a more laid back, bantery model discussion please use the Cold hunt - models and banter thread.

Message added by Paul

Recommended Posts

26 minutes ago, Catacol said:

It is grim. Clearly the Jedi have returned in force. There are all kinds of theories out there at the moment as to why we have repeatedly failed to see any HLB. They are all interesting, and in the dreadful months of summer heat while we hide from burning, sweating and heat-induced lethargy we can examine them with a sharp eye and clear head (assuming air con....) Right now I’m still looking at a set of signals that should be creating a different hemispheric long wave....but are not. Masiello has admitted to a bit of a bust in the current phase, Furtado looks on shaky ground and GP has disappeared. And underpinning it for me is a frustration - if we cannot develop our handbook with any accuracy and place a degree of trust in the signals we are seeing then we really are only “hope casting” as some describe, and that sticks in the craw. We want to be better than that.

We have an approximate two week window to see whether any hint of the winter forecast can be saved. If we get to mid month with no cold block and no strong suggestion from the ENS of one just around the corner then 2018/19 will have to go down as one almighty bust. Sidney can then leave his nuts in warm storage for another 12 months.

That's a very honest post which I really respect.

Everyone including the MetO has been caught out this winter with such strong background signals delivering so few cold synoptics, but hey its not an exact science but we will learn.

But I do like your openness unlike some others that are either in denial or who have gone into hiding.

Well done you.

Andy

Share this post


Link to post
Share on other sites
33 minutes ago, Catacol said:

It is grim. Clearly the Jedi have returned in force. There are all kinds of theories out there at the moment as to why we have repeatedly failed to see any HLB. They are all interesting, and in the dreadful months of summer heat while we hide from burning, sweating and heat-induced lethargy we can examine them with a sharp eye and clear head (assuming air con....) Right now I’m still looking at a set of signals that should be creating a different hemispheric long wave....but are not. Masiello has admitted to a bit of a bust in the current phase, Furtado looks on shaky ground and GP has disappeared. And underpinning it for me is a frustration - if we cannot develop our handbook with any accuracy and place a degree of trust in the signals we are seeing then we really are only “hope casting” as some describe, and that sticks in the craw. We want to be better than that.

We have an approximate two week window to see whether any hint of the winter forecast can be saved. If we get to mid month with no cold block and no strong suggestion from the ENS of one just around the corner then 2018/19 will have to go down as one almighty bust. Sidney can then leave his nuts in warm storage for another 12 months.

As it's only JANUARY 28th, not FEBRUARY 28th, I don't quite get your frustration.

There's plenty of HP in the EPS and elsewhere but if you're expecting it to be 100% in one location and with one orientation, you don't understand weather models. The signal for the Azores HP to ridge NE has been there for a while - the question is whether it can get a "clean" ridge up into Scandinavia and start bringing the colder air our way.

We may lose put and the northern arm remains so strong HP will be just to the south of us or over Europe and it'll be Bartlett Time but we're nowhere near that. Looking through the GFS 12Z ensemble members the favoured location looks to be to the west with ridging further north but many other options and orientations remain on the table at this time. In a backloaded winter, February was always going to be the month that mattered with everything else (and anything else) a bonus. As 2018 showed, even the first half of March puts many parts of the UK into the game but I suspect this year it's going to be more cold than snow especially if we can get some strong ridging.

Keep the faith.

Share this post


Link to post
Share on other sites

I would like to echo the previous posts and thank you all for such explanatory posts. Never give up.

Share this post


Link to post
Share on other sites

Am I in a parallel universe where February has been cancelled .....we seem to have a collective inquest on the winter with still a third to go ????

Share this post


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

Am I in a parallel universe where February has been cancelled .....we seem to have a collective inquest on the winter with still a third to go ????

I've got your back Blue! 

FWIW I think this is a situation where an Easterly may show up at relatively short notice with the last throws of the Canadian PV sliding under a nascent Scandi block that is being hinted at post days 9/10?

Share this post


Link to post
Share on other sites

The 500mb and surface analysis for midnight

eur_full_500.thumb.gif.14f4666b8a3872140bff6765daffc7e5.gifPPVA89.thumb.gif.141a2241cc25e718f63eed791e171003.gif

Three features to be noted today. Frequent wintry showers, increasingly of snow, in N. Ireland and western Scotland and later further south; some rain early on into south west England and Wales, courtesy of the wave to the west swinging south east into western France; and the main feature, the cold front with a band of rain, sleet and snow tracking south east from NW England, Wales and the south west from around 1100 this morning. It will be over the spine of England by 1800 and not clearing the far south east until the early hours of Wednesday morning. No attempt at any detail here (I'm sure it will be covered elsewhere 😉) but snow will get to low levels in places and ice will be an issue tomorrow morning

PPVE89.thumb.gif.66f76d4a91ff9f1ea608d4ca13c2da59.gifPPVG89.thumb.gif.0fe3d99e8270e80833be58cc4e7cb6a9.gif2005228558_minw.thumb.png.3796d1521cea460cedecce3dc39bc961.png

r08.thumb.png.fc3be4cabfab53af668311a3f01e34a1.pngr11.thumb.png.17853ffaf93b45d9d06d7a054666cec3.pngr14.thumb.png.d48fcd41becd4f9d0149844d16ab474f.png

s18.thumb.png.8d55e6c2f579263e9c688fb7e279076f.pngs21.thumb.png.60fdddb6b5668785a33d5ce3504a9bfd.pngs01.thumb.png.897f013f5b501338a2ca431a71e4e73c.pngs06.thumb.png.32cf194fe814516de15a8a5aa2126d9a.png

After the icy start Wednesday will be a cold but quite sunny day bu still some frequent snow showers in the north west Scotland particularly, but also down western regions of England and Wales. A very cold day.

PPVI89.thumb.gif.9c0978c5f359f9d42d5d25e5e91e6cdd.gifsn12.thumb.png.5d910219cfd56acac0694062416d2a23.pnggfs_t2max_c_uk2_8.thumb.png.d4498cd21309363d8c67597370f145e2.png

Over Wednesday night and through Thursday the upper trough tracks south east and by 1200 Thursday the complex surface low is orientated south west of Ireland with the occlusion southern Ireland > Cornwall with a band of rain, sleet and snow moving across south west England and Wales during the afternoon and evening

gfs_z500_vort_natl_11.thumb.png.a4ac142b39213f86dfef82caba684a01.pngPPVJ89.thumb.gif.60f8fc37a7210c77c0810709a0850e3b.gifPPVK89.thumb.gif.0fff32a82608a8d817d6d20a445095f4.gif

Overnight Thursday and through Friday the low swings south east to be centred over France as the subtropical high amplifies to the west. This movement results in the occlusion and belt of precipitation tracking north through central England and Wales, the details of any snowfall still to be sorted

gfs_z500_vort_natl_15.thumb.png.c34eb0a975a8698812155ccf908f04ef.pngPPVM89.thumb.gif.c7d288b02a4eb8a703d6634fa256b840.gifgfs_t2max_c_uk2_16.thumb.png.141e1c6f55e22c4a2d21e9f08b02e8ba.png

Any rain and snow should clear quite quickly Saturday leaving a mainly sunny, but very cold day with a few wintry showers around.

gfs_z500_vort_natl_19.thumb.png.841c5b037a31d8747c4c3376e412dcc6.pngPPVO89.thumb.gif.bb87aef891ba1ea0b728d4cfc8db0294.gifgfs_t2max_c_uk2_20.thumb.png.7e2e3b1a6f8a239c9f5472ee54061ef1.png

Edited by knocker

Share this post


Link to post
Share on other sites

To continue briefly with the gfs. It's a tad messy but a trough does force itself east to bring another band of rain, sleet or snow late Sunday into Monday. At he same time a trough has tracked north east from the eastern seaboard and undergone explosive cyclogenesis and is south east of Greenland 936mb. A weak front associated with this will effect the UK on Tuesday

gfs_z500_vort_natl_25.thumb.png.cb7ea8488248e9d44ae72bfce4726516.pnggfs_z500_vort_natl_31.thumb.png.b08ef606d476922544af339a4060ee02.png

Share this post


Link to post
Share on other sites
8 hours ago, knocker said:

Comparing the EPS mean anomaly over two days is indicative of a retrograde step vis HLB, And there is not a lot of cold air around

8-13.thumb.png.9a01ab5b7a71557ea3679e8e15ecbfcc.png10-15.thumb.png.ef44689a33fe6a1fcd1e6295e45efcb4.png

I'm I looking at these charts correctly, but does the shades of orange/red mean higher than average pressure anomalies? Looks a lot across the western seaboard of US, up across the north Atlantic, Scandinavia. 

Share this post


Link to post
Share on other sites
9 minutes ago, Weather-history said:

I'm I looking at these charts correctly, but does the shades of orange/red mean higher than average pressure anomalies? Looks a lot across the western seaboard of US, up across the north Atlantic, Scandinavia. 

Yes. Quite a strong ridge in the eastern Pacific

Share this post


Link to post
Share on other sites

At midday Thursday the ecm has the front aligned south west Ireland Cornwall with some heavy rain on it. By midnight it's west Ireland > Wales > East Anglia with dew points hovering around 0C. by midday Friday the front is weakening and now Wales > north of the Humber/

Thereafter the main trough moves away south east and after some transient ridging more fronts arrive on Monday with rain, sleet and snow. Cold over the weekend with widespread frosts

t156.thumb.png.b4e4a6dae9f23e329c99645d32ff2474.png

Edited by knocker

Share this post


Link to post
Share on other sites

Thurs/Frid updated fax charts

PPVJ89.gifPPVK89.thumb.gif.a97fc5d9c22369999782f56c845f6c06.gif

 

Edited by knocker

Share this post


Link to post
Share on other sites

The EPS this morning toys with amplification of the Atlantic trough/Scandinavian ridge in the 5-10 period before reverting once again to the Azores HP pushing north over the UK with an upper flow from the WSW with temps around average.

Share this post


Link to post
Share on other sites

A quick look at the differences between the models at +240hrs as we move into the last full month of the winter:

                                         500s.                                                        850s

ECM      image.thumb.gif.6434af13f4d2c477ebcc3d262b66bae5.gif  image.thumb.gif.630f50d16a375aed555124ff3fc0ad68.gif

GFS       image.thumb.png.37f46d3d7bbf32fc38ca59ab93dd948d.png  image.thumb.png.4aba2e22bfc791b1d6307129066e70b9.png

GFS(p)  image.thumb.png.28cfb434604ad44f6b02ea4a5ba4678d.png  image.thumb.png.1b425854aa64420ade982225b5b9a8f5.png

GEM.     image.thumb.png.232fda0d613b57eb668fdaa71031f6f5.pngimage.thumb.png.e18655c068965dc164df55b701a99fa2.png

The usual diversity between them at this range is apparent but ECM, GFS and GEM all have a deepening low pressure in the North Atlantic tracking east so could this be the feature which has the greatest chance of verifying?  If so, will it move south and allow heights to build over Scandinavia or will it move across the UK bringing probably unsettled, wet and windy conditions.  No point looking further ahead for clues because the models will each have a different solution and in any event l am not nearly knowleable enough to form a meaningful opinion!

Share this post


Link to post
Share on other sites

Quite interesting cloud structure as the wave runs into Biscay

geo.thumb.JPG.574d88c7c94300335afe577c3e4a8493.JPGPPVA89.thumb.gif.ad9829b387a12d8eb5cc918c07ec3a0c.gif

 

Share this post


Link to post
Share on other sites
11 hours ago, bluearmy said:

Am I in a parallel universe where February has been cancelled .....we seem to have a collective inquest on the winter with still a third to go ????

its a game of odds inst it... any longed for deep cold spell needs time to develop. theres nothing in the current models to suggest theres anything tangible regarding a proper cold spell. in all my years of weather watching, its a general, but not fixed, rule that if theres no clear signal of a cold spell showing in the synoptic charts by the end of january....then its highly unlikely (but NOT impossible) that one will develop as we enter february.

the main point is that the models are all suggesting a backing off from any proper colder evolution now.  with that agreement from the 'big two' looking ten days ahead, then this 'game of odds' would suggest a lengthy deep cold spell is now more unlikely then it was a couple of weeks ago.

Share this post


Link to post
Share on other sites

I wouldn't be to pessemistic, cold air is relativly near, for global conditions, this isn't more than a footstep. Those gears just have to shift prob, and easterly cold spells could come real 🙂

 

gfseu-9-240.png

Share this post


Link to post
Share on other sites

Seems like whatever mid-high lat blocking or subtropical ridging trend happens in the 5-8 day range has a strong tendency to persist through the 8-14 day range, which makes the changes by the GFS/GEFS 06z worthy of a raised eyebrow or two.

Edited by Singularity
Clarification

Share this post


Link to post
Share on other sites

As the MJO is mentioned in this and other threads quite frequently this recent open Access paper may be of interest

The Influence of the Madden–Julian Oscillation on Northern Hemisphere Winter Blocking

Quote

ABSTRACT
The persistent and quasi-stationary nature of atmospheric blocking is associated with long-lasting extreme
weather conditions that influence much of the Northern Hemisphere during boreal winter. The Madden–
Julian oscillation (MJO) has been previously shown to influence important factors for blocking, including
Rossby wave breaking and the North Atlantic Oscillation (NAO). However, the extent to which the MJO
influences blocking across the Northern Hemisphere is not yet fully understood.
Utilizing a two-dimensional blocking index, composites of North Pacific, North Atlantic, and European
blocking are generated relative to MJO phase. In the west and central Pacific, all MJO phases demonstrate
significant changes in blocking, particularly at high latitudes.Asignificant decrease in east Pacific and Atlantic
blocking occurs following phase 3 of the MJO, characterized by enhanced convection over the tropical East
Indian Ocean and suppressed convection in the west Pacific. The opposite-signed MJOheating during phase 7
is followed by a significant increase in east Pacific and Atlantic blocking. A significant decrease in European
blocking follows MJO phase 4, with an increase after phase 6. The phase 6 European blocking is hypothesized
to result from two preexisting conditions: 1) an anomalous anticyclone over the Atlantic and 2) a preceding
negative Pacific–North American (PNA) pattern initialized and influenced by MJO heating.

https://journals.ametsoc.org/doi/10.1175/JCLI-D-15-0502.1

Share this post


Link to post
Share on other sites

Brilliant high res. MODIS image at 1130 (courtesy Dundee Satellite Receiving Station)

modis.thumb.JPG.07d7f54171f81d7a5f95901961ba55ae.JPG

Share this post


Link to post
Share on other sites

Afternoon all 🙂

Moving into February plenty still to be resolved.

The GFS 06Z OP tries to build heights from the NE into Scandinavia but it doesn't succeed but there's plenty of northern blocking throughout FI so a definite step forward from yesterday.

The 06Z Parallel is less interested and keeps a strong PV near Canada.

Control looks more interesting - again, the push from the NE fails but the Azores HP ridges NE and then eases back west into a promising position by mid month for a N'ly outbreak.

The Ensembles still show plenty of blocking with the favoured HP locations to the NW.

The 00Z GEM developed a strong Scandinavian HP which even by T+240 was dragging a flow of colder air back in from the SE.

Both the GFS 00Z OP and Parallel ended with plenty of blocking in evidence.

The 00Z ECM OP admittedly rather underwhelming out to T+240.

However, plenty of the ECM 00Z Members interested in developing an intense HP to the NE and more than one gets that far enough west to influence our weather.

It's all a long way off and it's quite conceivable we'll need to go through a much milder spell before we get another crack at cold but there's enough on offer to suggest there's plenty of life in this winter yet !! 

Share this post


Link to post
Share on other sites

This evening and overnight

PPVE89.thumb.gif.acb36b557b79021a1fbb59ebc4d4c2f2.gifmin.thumb.png.b654049a969fa39c7f698bde9c2d7729.pngs16.thumb.png.33400932c9f1658738e005b46bb464aa.pngs19.thumb.png.04e53b97d9b5a11edeb9f6aac09e023b.pngs01.thumb.png.158c723dd4a8018f36f0e7c08e46ac48.pngs04.thumb.png.e3ff4f28f4f29e2a45b5fd9e76541ac7.png

EDIT

And light rain just into the Scilly Isles at 06 Thursday

Edited by knocker

Share this post


Link to post
Share on other sites
1 hour ago, stodge said:

Afternoon all 🙂

However, plenty of the ECM 00Z Members interested in developing an intense HP to the NE and more than one gets that far enough west to influence our weather.

 

Hi,

you got any charts for this? Appreciate! 🙂

Regards

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...