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Model output discussion-mid Autumn and beyond


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36 minutes ago, I remember Atlantic 252 said:

which I don't mind living here in early Nov, still too early for proper cold/snow in the south yet, hope for a change in around 3 weeks

Indeed.  Nothing worse than having the perfect pattern  but all it produces is cold rain.  around the latter part  of November   onwards  is where  it becomes interesting 

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Thanks knocker. Useful to come over to this thread for a dose of reality rather than seeing P14 of the 18z GFS run which shows cold weather at 300 hours, when we all know that it's standard wet, windy

Hi Malcolm, I just saw your post after doing mine above. Yes this thread seems under used which is a shame.The idea of this one as you probably know is for any members to post what hopefully

Finally getting time to check how the 500 mb anomaly charts have been over the past week. They have not consistently but generally gone from suggesting trough domination to one that now has ridging as

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The ecm this evening is not hugely different to this morning, At T144 the Bermuda high amplifies in the western Atlantic. in conjunction with the European ridge north west into eastern Greenland., which effectively isolates the huge upper trough in mid Atlantic. This promotes impressive WAA into Europe, with the UK just on the western flank of this and with patchy rain in the the west from fonts struggling against the block.

. t144.thumb.png.e6dd79a67fb2a9fe814bff7cb8e6895f.png

The next 48 hours is essentially a battle between the energy exiting the eastern seaboard and the block to the east with the trough in the middle. As this cannot move east it slowly deconstructs leaving the UK in the 'warm' south westerly and periods of patchy rain as fronts struggle to progress east

t168.thumb.png.993bb05cde6aecb9437826dbead25867.pngt192.thumb.png.e0ec6e98410d9d22b40af689b1b8f5b4.png

Edited by knocker
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The ecm follows a similar path to the gfs and at T120 has a large rough to the west, the block to the east, and a front down the Irish Sea with rain into western regions of the UK

t120v.thumb.png.fcc25cef894878595ce5215ab0380f7f.png

Over the next two days the block to the east remains as solid as a rock and with still a lot of energy exiting N. America the western ridge, and in particular the trough, come under increasing pressure. This results in the latter being forced south and starting to deconstruct but the UK remains in the warmer air and some frontal systems manage to struggle across thus generally unsettled with patchy rain and sunny intervals.

jet.thumb.png.2e587cd1a9d40fb40ffe3c9f55033092.pngt168v.thumb.png.d7ae47777e07b39d1a952c206d5ffcc0.png

Thereafter the battle between the east bound energy and the block begins the next round.

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On 26/10/2018 at 17:49, Summer Sun said:

5th of November & bonfire night daytime temps pushing 17c in one or two isolated spots of the south

GFSOPUK12_240_5.thumb.png.12e6dbd4da1145751cb507f78eb5ac95.pngGFSOPUK12_240_2.png

1 week on and bonfire night still looks rather mild as has become fairly common in recent years

ukmaxtemp.thumb.png.4d824106f3e0f2fda706d31c281fa59f.png186639500_ukmaxtemp(1).thumb.png.22063a975f453edda2b51fb5edd72e0c.png743570268_ukmaxtemp(2).thumb.png.fa9f5fbad48083b59fbaf314ff6aeb46.png

Looking mostly dry bar a bit of rain in the west

ukprec.thumb.png.debb671a9201f51563bc4ae61b88bbbb.png

Should be quite a pleasant evening for most parts

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At T120 the ecm is very similar to this morning with the Bermuda high ridging in the west and the European high, centred south of Finland ridging very strongly north west into NE Greenland and thus trapping the large negatively tilted trough in mid Atlantic stretching west to the UK. This equates to unsettled weather over the latter with patchy rain and temps a tad above average,

t120v.thumb.png.a5a9dafe8e00a2885d46866f0933eae2.png

Subsequent to this some changes from this morning as the energy exiting the eastern seaboard breaks down the western ridge quite rapidly and on this occasion overcomes the resistance of the block to the east and thus systems swing east through the UK bringing some wet and windy weather for the latter part of next week Temps generally a tad above average

t156v.thumb.png.ae2f0ab2746c0cd1f18870fc6a8bc7dd.pngt198v.thumb.png.2c00d71ec8e789fe96d739060e8e5ec2.pngjet.thumb.png.bbd7e45623ed72e1fac012dcbe6c3e49.png

 

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With the negatively tilted trough to the west and the expanding European high into eastern Greenland to the east, the upper flow is SSW over the UK and the latter remains on the western flank of the WAA

5-10.thumb.png.0bd3119010db82c4550494d7e696efb6.png

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The overall picture from the gfs post the short range is not dissimilar to previous runs with just the detail subject to variations. Essentially how the energy exiting  NA interacts with the atlantic sub tropical high as the former hits the buffers of the block to th east. Thus a tendency for troughs to get so far east before disrupting resulting in the unsettled weather again tending to favour the W/NW of the UK and temps above average

gfs_z500_vort_natl_27.thumb.png.09f02089ca3711f7f17c5172d7fa768b.pnggfs_z500_vort_natl_37.thumb.png.4acfdc1e5fa77c1fe34005371d0a1c45.png

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The direction of travel on the extended eps is becoming clearer ....... the vortex is drifting back to nw Greenland (following its holiday on the Asian side) and the semi permanent sceuro block is losing latitude over time as it spreads sw across much of Europe. it did seem as though we could be headed towards a place where the ridge extended west and the Atlantic trough undercut but at the moment, this is looking less probable with each run. 

of course, that could well translate to more wintry surface conditions  for nw Europe as we head through mid month,  depending on placement of the surface blocking. 

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Towards the end of next week the trough hits the block to the east so ducks south east and deconstructs.

gfs_z500_vort_natl_23.thumb.png.86cefc02d7150bfd286256b9dcab6ce2.png

Beginning of next week a repeat of same

gfs_z500_vort_natl_33.thumb.png.668fb25b3d14140ec0a4f93f3e1c0f6d.pnggfs_uv250_natl_33.thumb.png.15ea6e9b1ea89dbad148ee5893d25afc.png

Ergo unsettled over the UK with a marked west/east bias with temps tending above average with the surface wind in the southerly quadrant

 

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12 hours ago, bluearmy said:

The direction of travel on the extended eps is becoming clearer ....... the vortex is drifting back to nw Greenland (following its holiday on the Asian side) and the semi permanent sceuro block is losing latitude over time as it spreads sw across much of Europe. it did seem as though we could be headed towards a place where the ridge extended west and the Atlantic trough undercut but at the moment, this is looking less probable with each run. 

of course, that could well translate to more wintry surface conditions  for nw Europe as we head through mid month,  depending on placement of the surface blocking. 

That continues to be the theme this evening

10-15.thumb.png.a8b3a2c6a3a9a64dda1bae33097b2ea5.png

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The ECMWF seems to be fairly consistent with High Pressure becoming more concentrated over, and/or to the South of, the U.K towards the end of its runs.

Examples of both runs today between 192 to 240 hours:

00Z ECMWF

52B9FA48-2CA4-4308-9BA5-F33F6D345A4B.thumb.png.b87b7761494ed374be8d62d8e6bacd3e.png

A9CCA1EC-235C-45D3-9A86-03FF8A816795.thumb.png.94f3913b6b708212d123205b4a790482.png

DBAB0FC4-B427-4601-8375-489200759AC1.thumb.png.f5c035b36dc06086643c25e7b9a463ac.png

12Z ECMWF

754CA787-1171-4F37-861E-3356CFC68005.thumb.png.639af25740cf588f11339010bb6fe17b.png

7AF8101B-B669-4475-97B3-3EB5C90AF03E.thumb.png.ee5e8e81e77b6f2cf142a2009a452518.png

6744F721-1DA6-40AD-BC03-70DF24CE3BC6.thumb.png.92df78b395b3d40754bdfe69b0fefd83.png

While both runs do exhibit some differences (Low Pressure over Northern and North-Western UK penetrates a little bit further East on the 12Z run), both have Low Pressure that digs South in the Atlantic earlier in there runs lifting away further North allowing High Pressure to build over the U.K/Southern UK. Mostly dry and settled, more so for Southern areas, if something like this was to come off. Something that could become a trend (which a number of cold and snow fans I doubt would like), should the the likes of the ECMWF continue with this sort of idea. 

Still far away and could change - there’s no guarantees that the Atlantic and its Westerlies will break through, particularly for Northern parts of the UK, after this upcoming week. But feel it could be a possibility. (Clearly could as easily see more in the way of undercutting and disruption to those Southerly tracking Atlantic Lows next week with the Eastern UK blocking High being pulled back further West towards Greenland or something. Or perhaps the Eastern UK High may indeed just take a super duper long nap over Europe/Scandinavia. 

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Although obviously varying detail the ecm and gfs are broadly speaking on the same page vis the evolution in the 5-10 day period. Essentially the pattern highly amplified over N. America with a strong jet running up the eastern seaboard and then across the Atlantic. Thus the Atlantic troughs become the major influence and push a tad further east under the strong upper flow,. Ergo unsettled with some wet and windy weather for the UK particularly Friday/Saturday.

gfs_uv250_nh_32.thumb.png.60033a9484b29ccb36b653588a03c0fa.png2131823514_t144surf.thumb.png.9f5dcde37284fab831ec27d782784c9d.png806022616_t204surf.thumb.png.a7dd1b92c3af19485b7302fe54f81c38.png

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3 hours ago, Summer Sun said:

NMM shows parts of the south hitting 17c tomorrow and Tuesday

Unlikely to break any records (21.1c & 19.8c) but it would be feeling very pleasant for the time of year

GEM 12z looking like a decent southerly, here at T48:

image.thumb.jpg.32a806b9d5f2f57e554ad6a7ab1fe518.jpg

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No huge change with the  medium term GEFS mean anomaly, perhaps the Atlantic trough a tad further east.

So still high amplification over N. America with a strong jet running up the eastern seaboard and then across the Atlantic before swinging around the trough and weakening against the block, Portending remaining unsettled with systems pushing slowly east against the block which tends towards a west/east bias, Temps around average.

gefs_z500a_5d_nh_41.thumb.png.f49e4158e58ae7c22b96ff29152c847e.pnggfs_tprecip_uk2_40.thumb.png.e5df2a7fd01bfe9beeb912aad8a11fae.png

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A very typical outlook for the time of year - in a word unsettled, with the atlantic ramping into gear, but coming unstuck somewhat thanks to persistent heights to our east, however, it now looks increasingly likely it will have enough oomph to move the trough further east, which in turn may eventually lead to mid atlantic height rises to our west, which could be the trigger to something colder as we move into the second half of the month.

Alas in the meantime - mmm not very inspiring, many wet dark November days ahead, very mild to begin but temperatures then dropping closer to average and strong winds at times as we move through next week.

Could be looking at some significant rainfall totals in the west.

 

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Looking at the GEFS, EPS and NOAA medium term mean anomalies this evening gives no indication of any significant pattern changes. There are some differences, degree of amplification being one, but overall they are on the same page.

A fairly slack vortex over the Pole with associated troughs eastern Europe, eastern NA and into the Atlantic. with ridging western NA and Europe. So a strong jet running up the eastern flank of the American trough and across the Atlantic resulting in a weakening westerly upper flow, possible backing south westerly depending on the precise trough/ridge orientation, over the UK. This portends unsettled weather with perhaps a NW/SE bias and temps around average which in due course the det. runs will sort out.

eps.thumb.png.35d3a2ef7f33d4d8630168d79cca539d.pnggefs_z500a_5d_nh_53.thumb.png.1da8d780c467ca73c10bb422ef88b6e7.png814day_03.thumb.gif.5cc752c4685e81628ee93d9f18ff27dc.gif

And a certain symmetry with the lower strat

100_nh_stanom_31.thumb.png.0e9dbe4fcdb70488d18fe2efb3946a3c.png50_nh_stanom_31.thumb.png.ae3edbafc210104a948b38ab3b016447.png

Edited by knocker
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As an overview the gfs and ecm pretty much on the same page in the 5-10 day range. A highly amplified upstream  pattern with a strong jet running up the eastern seaboard and exiting across the Atlantic  Leading to some inroads being made against the stubborn block to the east and thus some periods of wet and windy weather for the UK as systems traverse west > east.

1070006014_t156NA.thumb.png.7d3925e9c432712bef68a73aefe4f3d5.pngjet.thumb.png.1d37a542acb09e77c8678bfcb8f22d82.png

ecmwf_uv850_vort_atl_7.thumb.png.e148a4e8ab4cd91f12c2670b45d72022.pngecmwf_uv850_vort_atl_10.thumb.png.4d97b20c38841d95dcb115f48ba3de54.png

The GEFS anomaly rather supports this

gfs-ens_z500aMean_nhem_6.thumb.png.2e01a9967566ab6cb75921f068d07208.png

 

Edited by knocker
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Thanks knocker. Useful to come over to this thread for a dose of reality rather than seeing P14 of the 18z GFS run which shows cold weather at 300 hours, when we all know that it's standard wet, windy and generally mild November weather in the offing for the next 10-14 days at least.

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