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Short range model discussion - into 2018


Paul

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Posted
  • Location: Camborne
  • Location: Camborne

At midnight, in this transition to a more fluid pattern, the upper trough to the north is stretching down over the UK with a strong north westerly upper flow across the UK

eur_full_500.thumb.gif.3629433c8f3f685967561139f2a39945.gif

This portends a very cool and showery day for all of the UK now that the fronts are clear to the south. The showers will often be heavy with hail and thunder in the mix and initially far more frequent in the north west but spreading south (and inland) during the day so by evening the heavy concentration will be in the south west and south. In comparison with recent temperatures it will feel quite cool with temps below average, significantly so in places.

PPVA89.thumb.gif.952574444a4cfceefba61d4848b7bbac.gifPPVE89.thumb.gif.9e9f6c1195efc32cbb01362889c08675.gifgfs_t2max_c_uk2_4.thumb.png.375e1883edf789f362fe5741908b7d15.png

gfs_z500_vort_eur_3.thumb.png.7b4043fb0f5e48fb4ce233fd8be5929a.pnggfs_z500_vort_eur_4.thumb.png.608add3d47f16e28f2c74698d3597318.png

The heavy showers will slowly clear the south and east during the evening as a ridge builds from the south west overnight and through Saturday. Thus much lighter winds and just a few showers mainly confined to the north west. Temps still below average and with the light winds a possibility of a ground frost in the usual likely spots up north.

PPVG89.thumb.gif.455de62dc889aa623ffb6d5ca93d609c.gifPPVI89.thumb.gif.4ff41ca104c7c204955ccb7cf1f112db.gif

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But the ridge is very transitional and out in mid Atlantic a low pressure system is getting organized and tracking east and cloud and rain from the associated fronts will effect western regions by 0600 on Sunday. The plethora of fronts ( courtesy the senior chappy at Exeter) and the band of moderate rain will then proceed across the country clearing the east coast by midnight.

PPVJ89.thumb.gif.b2541e54c54a329d92c161514bb8ffca.gifPPVK89.thumb.gif.8694631c279d79085796942b18fc301c.gifgfs_t2max_c_uk2_12.thumb.png.5d7c16f896032ba43a72fb1a600025a0.png

overview_057.thumb.jpg.b1f39242bce5c4df119ea1838524f9ca.jpgoverview_063.thumb.jpg.d93d57888e056defd25e41ac6c014e26.jpgoverview_069.thumb.jpg.d87972a472c73463afb7dac0a5d5912d.jpg

By Monday the low is over southern Norway and the, by now, amalgamated fronts well clear to the east, so a relatively quiet day with perhaps a few odd showers in the north west.

PPVM89.thumb.gif.7da5b62edadf0dd823d33da0907ef47b.gifgfs_ptype_slp_uk2_16.thumb.png.9faa071e6fb33c89f75ec1521824ba34.pnggfs_t2max_c_uk2_16.thumb.png.bd12e7d62e1cde598bfb5d09aa2d323c.png

But more changes are afoot and the next approaching upper trough stretches south, assisted by the ridging high pressure in the western Atlantic, and activates the low pressure area west of Iberia.

gfs_z500a_natl_17.thumb.png.d383385e125b21c493cb5b75f42f67bf.png

Thus on the surface a rather complex scenario of a quiet start to Tuesday but later frontal rain will effect the north west and by late evening rain will track into the south, along with some warmer air, courtesy of the activated low moving north east across France

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The NH profile at T120

gfs_z500a_nh_21.thumb.png.b8fbd78c70ddb2d1265552d76837b879.pnggfs_t850a_nh_21.thumb.png.468886d1a8ccec6905ed4206e067ccb3.png

 

 

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Posted
  • Location: Camborne
  • Location: Camborne

The updated fax for Sunday

PPVJ89.thumb.gif.0a6bee1833e0a47804a79b8d32be3422.gif

And the ecm very similar to the above for midweek

1504867771_500a.thumb.png.91ff962b939e448e4f57be4c96b18b28.png1041353019_a120.thumb.png.3bffab3a3e241767f888f1d20b5c2ae7.png

The 0600 sat image with the showery regime already in the NW. Almost total Ci cover with some Sc,Cu down here at the moment.

geo.thumb.JPG.f8289f4fce67669ac7a6dbba0d2038dc.JPG

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Posted
  • Location: Crymych, Pembrokeshire. 150m asl
  • Weather Preferences: Extremes of all kinds...
  • Location: Crymych, Pembrokeshire. 150m asl
12 hours ago, knocker said:

.................

But the ridge is very transitional and out in mid Atlantic a low pressure system is getting organized and tracking east and cloud and rain from the associated fronts will effect western regions by 0600 on Sunday. The plethora of fronts ( courtesy the senior chappy at Exeter) and the band of moderate rain will then proceed across the country clearing the east coast by midnight.

PPVJ89.thumb.gif.b2541e54c54a329d92c161514bb8ffca.gifPPVK89.thumb.gif.8694631c279d79085796942b18fc301c.gifgfs_t2max_c_uk2_12.thumb.png.5d7c16f896032ba43a72fb1a600025a0.png

overview_057.thumb.jpg.b1f39242bce5c4df119ea1838524f9ca.jpgoverview_063.thumb.jpg.d93d57888e056defd25e41ac6c014e26.jpgoverview_069.thumb.jpg.d87972a472c73463afb7dac0a5d5912d.jpg

 

Thanks for the excellent daily summaries, Knocker.  Best forecasts around.  I'm looking at nine hours of uninterrupted rain here on Sunday, by the look of it.  Mustn't grumble, though.

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Posted
  • Location: Camborne
  • Location: Camborne

At 00 Wednesday the ecm still looking at a muted double whammy with a front associated with the low south east of Iceland brining rain to N. Ireland and western Scotland whilst to the south a shallow low tracking north east across France will bring some rain to the south east. The front will weaken on it's travels down the UK as high pressure builds to the west

1667729673_at108.thumb.png.6487946d1a63a7438e248a8341a5d2f2.png36502918_at120.thumb.png.1b580d2a39eb8ac3a639f8079ba0f653.png

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Posted
  • Location: Camborne
  • Location: Camborne

Michael Ventrice msde a comment in a tweet last night:

“The big story this Summer: How ridiculously strong the North Pole Vortex has been (++++AO)”

And this is still the case

Last evening’s EPS short range anomaly is still indicating the vortex over the Arctic with associated trough down through Greenland into the central/east Atlantic but with the Azores attempting to ridge north east over the UK the strong westerly upper flow is forced to veer NW over the UK portending once again a N/S split with temps a little below average. But this does disguise a trend towards the end of the period for stronger ridging in north east Europe, retrogression of the trough and more pronounced ridging by the Azores.

1028592975_500a.thumb.png.3120e5badf95ace74cae1f023aa01640.png571531018_5007.thumb.png.c4223d68d54dfc02495be0f635f8d52c.png

The actual detail is a bit of a mixed bag, particularly this weekend, before a gradual improvement, albeit still changeable for a while.

Overnight most of yesterdays showers have cleared

2018_8_25_300_MSG4_26_S1_grid.thumb.jpeg.d64a454015737be4955136de23dac637.jpeg

and this is essentially the story for today as a transient ridge builds north east. Thus much lighter north westerly winds than yesterday and just a few showers, mainly around north westerly coasts, but some could pop up elsewhere. A cool day after a chilly start but not feeling too bad in the lighter winds.

.PPVE89.thumb.gif.7622d6dce20e25c594430293bad86f1a.gifgfs_t2min_c_uk2_2.thumb.png.7dc7aed43d20b88155e248386788ba82.pnggfs_t2max_c_uk2_4.thumb.png.4b4c6786a0769a90d35633f61f4e760f.png

but as can be seen a depression out in the Atlantic is tracking east and after a clear night on Saturday cloud and rain, along with increasing wind, from the associated fronts will start to impact western coastal regions by 0300 Sunday morning. This belt of rain, that will be interspersed with heavier outbreaks, will traverse the country during Sunday, effecting all regions, before clearing the east coast by evening. So in a nutshell a wet and windy and generally unpleasant day.

PPVG89.thumb.gif.b75afaaa7a0ab770eef3fc80cfb7029b.gifPPVI89.thumb.gif.408eb8da7b1d3966c571a50769f42afd.gifgfs_t2max_c_uk2_8.thumb.png.514e0e15081d2192e7407add8c1c8359.png

overview_027.thumb.jpg.97dfb9b9c53f647dbe8b9302076627a5.jpgoverview_033.thumb.jpg.623d17b63d11e5502c5dd34885dfcdac.jpgoverview_039.thumb.jpg.1f5b4bf0c1c266e08b746e9ca1e752e1.jpg

overview_045.thumb.jpg.04779409c3fe665d8ef4dc399df8adab.jpg

The rain will linger a while over Scotland and N. Ireland overnight Sunday/Monday, as the low drifts further east, but once clear Monday will be a much drier day, with perhaps the odd shower, as another transient ridge makes another brief appearance initiating a light north westerly. Temps around average or a tad below.

PPVJ89.thumb.gif.4cb63c0d4a10e2c4e175b2be56d9caff.gifPPVK89.thumb.gif.0f5835a82481436d24072fcb7fdc3963.gifgfs_t2max_c_uk2_12.thumb.png.27eee3c46ff435e8a5b2cdc613a75399.png

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As mentioned in a previous post by Tuesday the next upper low tracking east  has engaged with the low pressure west of Iberia

gfs_z500a_natl_14.thumb.png.2b920d5abefa100ecd0c7c73c5c84a64.png

and on the surface this initiates a double whammy. On Tuesday cloud and rain from the fronts associated with the surface low south of Iceland will effect north western regions whilst later in the day and overnight into Wednesday showery thundery rain will effect the south east as the activated shallow low tracks north east across France into the North Sea. At the same time the cold front and light patchy rain effecting the north west will move slowly south east.

PPVM89.thumb.gif.2993818d55cf1be07d5d867779592a1f.gifgfs_ptype_slp_uk2_16.thumb.png.ff4c074979dd46fca24faadcb489ca4e.pnggfs_t2max_c_uk2_16.thumb.png.8384a6f77f7be7016685f2276b451af6.png

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And the NH profile at T120 but at this stage keep in mind the opening comments

gfs_z500a_nh_21.thumb.png.6a659aa0bd084180046621214fe67162.pnggfs_t850a_nh_21.thumb.png.72771e0e6654149e88406e0a8128fa58.png

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Posted
  • Location: Camborne
  • Location: Camborne

Apologies if the first part of this post is a tad parochial as I'm off on a early start tomorrow on a coach trip to the South Devon railway and the weather ain't favorable, putting it mildly. But the detail is a tad confusing. The latest fax for 1200 tomorrow has the south west in the warm sector with an upper cold front confusing the issue. Which isn't too bad if the Arome is correct with the rain effecting Cornwall from 0300 but most of the heavy stuff further north and it would appear the cold front is through around 1300 which means it would have to get it's skates on.

PPVE89.thumb.gif.fa64e8ea366aa773c936f150f4044d0c.gifradarrate_015.thumb.jpg.e34d4ed151375a0b485c75a9a3e1119d.jpgradarrate_018.thumb.jpg.a6bbee4ad4bb5569c5bd5ac8bbee8116.jpg

radarrate_021.thumb.jpg.e5b918fde48800897bcbbf3290598964.jpgradarrate_025.thumb.jpg.2aa30dae46be15635ba39818e1183868.jpg

If we now pop forward to 1200 Tuesday and the above low is now in the Baltic with the cold front now waving across France and the new cold front associated with the low south of Iceland brings rain to the north west.

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over the next 48 hours the cold front to the NW tracks south east down the country whilst some convective activity just impacts the south east en route from France to the North sea, before another transient ridge builds.

250129965_aw12.thumb.png.5cf27f6cf7198dd63a9ed852aa885602.png493382139_ath12.thumb.png.c8a694337039d89f3a029ca559b9ec1e.png

Edited by knocker
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Posted
  • Location: Camborne
  • Location: Camborne

The difference between the ECM and gfs starts quite early in the run when the former develops this little low in the baroclinic zone around the North East of NA and runs with it

ecmwf_uv850_vort_atl_4.thumb.png.fe66b02f2265e65afef8c5cf4d3c211b.pngecmwf_uv850_vort_atl_5.thumb.png.9110a41ff18b5060fe20ff26fd57d64d.png

 

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Posted
  • Location: Camborne
  • Location: Camborne

At midnight the surface analysis shows a low 993mb south of Iceland with a plethora of fronts lined up to west about to bring rain and strong winds to virtually all of the UK over the next 24 hours.

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The rain is already into western areas and this will track steadily east during the day but where the more intense rainfall occurs is debatable and at the moment it maybe appears to be a tad further north (perhaps nearer the triple point?) than some model indications. Anyway wet in most areas and quite windy around western coasts. There will be a clearance behind the cold front over N. Ireland Wales and the west country during the afternoon and evening

  PPVE89.thumb.gif.c4713e61ff6453050db0c4ed20c1a64b.gifgfs_t2max_c_uk2_4.thumb.png.0fec82004f267bbe8fa0dbb7a179d7d9.png

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By evening the main rain belt and cold front will be over the North Sea but the filling low and occlusion will be drifting across Scotland thus showery rain will persist for a while  in the north whilst elsewhere has a relatively clear night apart from the odd shower in the west. And this will herald a much brighter and warmer day on Monday as the low continues to drift into southern Norway with just the odd shower around in the north west in the now, much lighter, north westerly breeze.

PPVG89.thumb.gif.f584365f8a120ee5565d95efac8d9682.gifPPVI89.thumb.gif.9bcacf5bd84956b9a7b385d1743391e1.gifgfs_t2max_c_uk2_8.thumb.png.e730d7148542539752e4578512308f2e.png

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As has previously been discussed by 00 Tuesday the next upper low has arrived on the scene SW of Iceland

gfs_z500a_natl_9.thumb.png.b6f8440b035fcc0fdb5d5f8919e082a4.png

and the cold front associated with the surface low will track east and bring rain to north western parts during Tuesday whilst our old cold front is now waving across France, north of a shallow thundery low.

PPVJ89.thumb.gif.e28c24818fb79980ab4ab97145b0efb2.gifPPVK89.thumb.gif.4cd54ea20e1512c5449f92405466c6e6.gif

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During Wednesday the cold front will track south east down the country along with some patchy rain whilst some thundery activity associated with the low over France will move north east and maybe give the south east a glancing blow.

PPVM89.thumb.gif.e213f77f0e5eb2971e2dea0215ea2d3e.gifgfs_ptype_slp_uk2_16.thumb.png.ae39e4714e619331a519885c34ad274d.pnggfs_t2max_c_uk2_16.thumb.png.81ff00ffed91e7ef8a1b559d5038c372.png

With all the fronts out of the way and a ridge building Thursday portends to be a largely fine and pleasant day, albeit the temps no great shakes.

PPVO89.thumb.gif.d0d0acc4f479efbd63d99df5c88333b5.gifgfs_t2max_c_uk2_20.thumb.png.e8d05b40cf0606b2177cb6de5efbbe50.png

And the NH profile at T120

gfs_z500a_nh_21.thumb.png.92da3599aa40c4576f7fcb96597a3aa3.pnggfs_t850a_nh_21.thumb.png.d3e77a85727dc2fcba5e18957777b9c1.png

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Posted
  • Location: Crymych, Pembrokeshire. 150m asl
  • Weather Preferences: Extremes of all kinds...
  • Location: Crymych, Pembrokeshire. 150m asl

An almost completely rain-free UK from dawn on bank holiday Monday until dawn on Tuesday, according to the ICON 7km:-

image.thumb.gif.5ca9d3ff563add673fa2dd6cb57fb08c.gif

Seems optimistic to me but if the country is this dry for the entire day this would have to make 2018 a contender for the best set of Spring and Summer bank holidays on record, surely?

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Posted
  • Location: Camborne
  • Location: Camborne

The 1800 sat image. The clearance was not until late afternoon down here and I've just spent a very wet day at the South Devon Railway.

geo.thumb.JPG.4595aa67d92149360af6a50c3417c44f.JPG

This evening's fax has the low 991mb south east of Iceland with the cold front across southern Scotland tracking south east and a shallow thundery low over France tracking north east. The ecm take on the the weakening rain belt and the thundery activity delivering a glancing blow to the south east through Wednesday

PPVJ89.thumb.gif.fe2ab8a5ade97e80e9c4ca6d6c07476b.gif2122418138_awed00.thumb.png.eb19b066a858d7e4656db2d9cb8f4ce2.png1840709052_awed12.thumb.png.0aaf92eda8bea8cc14cce204a7c047b9.png

Over the next 48 hours as the upper trough moves east the Azores HP ridges strongly north east but there is still a lot of energy exiting NE North America and it soon comes under pressure.

365758574_500thurs12.thumb.png.d2ad5307cd5f2a268e1e5fb7808cc6e7.png1049848767_jet120.thumb.png.ddee13b4cf540b6e3d03b63330da6495.png

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Posted
  • Location: Camborne
  • Location: Camborne

A quick check on last night’s EPS short term anomalies as a context for the det. runs detail. Still the key players the active vortex over the Pole with subsidiary center Greenland/Iceland, ridging in the south east US and particularly in eastern Europe. Thus a continuation of strong W/NW upper flow exiting Canada across the Atlantic which backs south west in the east, courtesy of the east European ridge allowing the Azores HP leeway to ridge north east over the southern half of the UK. Which of course portends a N/S split with temps still on the chilly side

1414642937_500a.thumb.png.595d71c5f9067740b29dbbfa93fdd041.png1276245463_500t.thumb.png.38c8fc068e4670ce7bf104061cc3a041.png

At midnight the upper trough still influential

eur_full_500.thumb.gif.28dadf92603e4d2f43e8b6b39f4fadc6.gif

but this will soon give way to high pressure ridging north east and thus a much drier and less windy day on the cards compared to yesterday. Still some showers in the north and west courtesy of the occlusion as the low moves east.but elsewhere cloudy with sunny intervals and not unpleasant in the sunshine.

PPVA89.thumb.gif.b7c81ffcfe951f9f5894186df2185996.gifPPVE89.thumb.gif.59fe5d7c401c934e8fb8095a1e28e7cf.gifgfs_t2max_c_uk2_4.thumb.png.f1f46dbc8d628698ea5d73e293060c5a.png

Any showers will quickly die out overnight and after a chilly start Tuesday will be clear and sunny just about everywhere but during the afternoon cloud and rain will effect the north west thanks to a cold front associated with a new low that has tracked east south of Iceland.

PPVG89.thumb.gif.935499bce55755f8dfba4b9d4f8601fc.gifPPVI89.thumb.gif.f918e9835ad4294493b64ffff9cd0e4f.gifgfs_t2max_c_uk2_8.thumb.png.e93078130e96fe1d85205f2d31f4341b.png

overview_039.thumb.jpg.927602b94ed6c59510b5288fcd612602.jpgoverview_042.thumb.jpg.953e8563180b7c09f19fc093a31899de.jpgoverview_045.thumb.jpg.c15638efa706847994ad51a5946d5010.jpg

Overnight and through Wednesday the low drifts north to be  east of Iceland whilst the cold front meanders south east down the country and at the same time some thundery outbreaks associated with the shallow low over France that is tracking north east into Holland will deliver a glancing blow to the south east

PPVJ89.thumb.gif.1ef4ccd6592e7d34a6bd0b26e43bd22c.gifPPVK89.thumb.gif.4218e597e2734326ce478c163c74be62.gifgfs_t2max_c_uk2_12.thumb.png.6a8e30fa90b692b0933fdf03dbec4009.png

overview_051.thumb.jpg.3e285965c423dea3e023b932f1cc761d.jpgoverview_054.thumb.jpg.c7bdd77ce9313d2cd7aed742d2662d67.jpgoverview_057.thumb.jpg.809701a4945e1095b1261948d9880b05.jpg

By Thursday the cold front is well clear to the south and high pressure is once more ridging north east, but a quick reminder here of the opening comments vis energy exiting upstream

gfs_uv250_natl_16.thumb.png.34b5901ab05673b5128bfa79be8ca894.png

so essentially over Thursday and Friday high pressure will be in charge with light winds and mainly sunny but also with all the ingredients for some diurnal spread and some chilly nights.

PPVM89.thumb.gif.53cb95010f733eec4544a6bdd8e2eca9.gifgfs_t2max_c_uk2_16.thumb.png.bf2374570f81873539ff8ed45f081972.png

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And the NH profile at T120 that looks vaguely familiar

gfs_z500a_nh_21.thumb.png.b00775707ee97c1950e8d615282f2bc8.pnggfs_uv250_nh_21.thumb.png.87a1f958ddbf4e981d57d5f31ba9ce54.png

 

Edited by knocker
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Posted
  • Location: Camborne
  • Location: Camborne

Perhaps the usual problem with the ridge on Thursday vis the orientation of the high cell and regional variations of temp and cloud. A forecast sounding that would indicate a Sc layer for example

sounding.thumb.jpg.b2e68aa98980748fb5d1f6dd59586848.jpg

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Posted
  • Location: Camborne
  • Location: Camborne

The ecm has the low that is forming around now off the north east coast of North America making inroads into the ridge as the jet splits over the western atlantic.

ecmwf_uv850_vort_atl_3.thumb.png.5c191b55b68b1c5c1d2e240cf346b664.pngecmwf_uv850_vort_atl_4.thumb.png.033f663220c491796653141c18c9620e.pngecmwf_uv850_vort_atl_5.thumb.png.57231cc9781be2985fa5eca6529eb0f3.png

And merely serves to illustrate once more the battle between the east bound energy and the ridging high pressure

jet.thumb.png.06010177e0684c474412566cbb5fb610.png

 

 

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