Model Output Discussion October 2012

[NorthernRab]

Edit:

[BLAST FROM THE PAST]

The only denial is the denial from the people denying the fact that there hasnt been any real warm weather in 6 weeks-

& yet how many times have the models hinted at warmth in the mid term...

The plume may develop it may not- if so we enjoy some late warmth- even if it doesnt im sure the SE has a high prob of getting in on the act of some of that air of corunna origin

Background wise which I AM interested in still remains unchanged- mean zonal wind low V the mean promoting blocking-

S

Steve

Apparently any signs of mild is NAILED ON......haven't you learned yet?

BFTP

[summer blizzard]

A warmer interlude is very likely (assuming surface translation) but it could well turn much colder again.

[shuggee]

Some things never change, and some people never learn, year in, year out...

Back on topic please - shall we discuss the weather?

[phil nw.]

Let`s keep to model discussion please people.

Thankyou.

[IDO]

Its been clear for sometime that there has been great uncertainty beyond T120 with members clusters being split nearly 50:50 for milder/cooler scenarios. It was pointed out yesterday that that the UK is on the battleground of these two air masses and the GFS 12z yesterday favoured milder air edging in, whereas the 0z GFS today has downgraded that, with cooler uppers on average. However the members are still split from around the 19th:

http://cdn.nwstatic.co.uk/ensimages/ens.20121015/00/prmslAberdeenshire.png

Both options are viable and it could be argued that this GFS OP run is showing higher heights than the mean throughout FI. Certainly the GFS ENS is a mild outlier (upper temps):

http://cdn.nwstatic.co.uk/ensimages/ens.20121015/00/t850Aberdeenshire.png

On the GFS 0z we have this Autumnal cool week followed by HP over the North and LP affecting the south, then this mingling of the two on different axis' till the end of the run. So a continuation of the unsettled theme in the last third of October but with closer to average temps. No sign of an Indian Summer bonus or any real cold. The cold has been reserved for Canada:

RyanMaue

Tweet 6000: I may have to add some additional 40°F below normal anomalies to my map color schemes. Geeze. http://t.co/Hspagizn

15/10/2012 06:20

[Gibby]

Good morning. Here's my take on the 00zs from GFS, UKMO and ECM this morning.

All models share the same pattern as we go through the working week with tosay being quiet and chilly as scattered showers move across in the light Westerly flow. Tonight sees a band of strong winds and rain advance NE from SW Britain to all areas overnight, sticking over Scotland. Tomorrow then shows a weak ridge cross East delivering a drier, bright and breezy day as well as milder conditions in the south. Then over Wednesday, Thursday and Friday deep Low pressure near Western Britain will steer strong winds and heavy rain across all areas with intervals of heavy showers in between, heaviest in the SW along with the strongest winds.

GFS then shows the unsettled weather gradually becoming more confined to SW areas as pressure builds to the NE. Early next week High pressure has developed to the North of Scotland with Low pressure to the South keeping rain at times going over Southern England while Northern areas continue to see dry and brighter conditions. Through FI High pressure is shown to maintain a position close to Scandianvia with a lot of dry weather in the North while SE moving disturbances from Atlantic deppressions move close to SW England at times keeping winds from the SE or east with a higher risk of rainfall here while many other areas remain dry if rather cloudy. Temperatures are not expected to be as High as what was programmed from last night's 12z output.

The GFS Ensembles show that the operational is an isolated member in it's dryness for the north with most members going for fairly changeable conditions still with rain at times with any fine weather unremarkable and short-lived indicative of the persistence of an Atlantic Low pressure influence.

The Jet flow currently flowing East or SE close to Southern Britain troughs South over the coming days possibly all the way down to North Africa before returning sharply NE over Europe. Later in the week and over the weekend the flow becomes disorientated and breaks down as it weakens substantially.

UKMO for midnight on Sunday shows Low pressure over mid Atlantic. High pressure lies to the North with a slack ridge South over the UK. There would be a lot of dry and quiet weather about and in any clear skies mist and fog would likely develop. It looks like any prospect of any substantially warmer weather is on hold from this run.

ECM shows low pressure out to the SW of Ireland next Sunday with a light SE flow with the rain risk most likely in the West and SW. As the run progresses into next week the Low transfers slowly NNE to the NW of Britain with winds veering slowly SW. Rainfall would always be most likely in the SW and West at first transferring more to the NW by the end of the run. The output this morning is no where near as warm looking as last night'ss operational from ECM shown.

In Summary the models have had a rethink on how the weather behaves next week. With most of yesterday's programmed warmth expected to stay on the mainland of Europe the UK lies in a South or SW flow with rain at times, chiefly in the West. GFS keeps Northern blocking in place with an East or SE flow though this doesn't look to well supported by its members but it is an option. In general the weather looks like staying rather changeable but less windy than what we're likely to see this week in temperatures close to normal.

[Frosty.]

The latest Gfs 00z ens mean shows a much more benign and milder pattern developing next week with high pressure across europe extending into the uk with a large depression in the azores region, the uk would have winds sourced from southern europe with temps well above average for much of the uk, overnight mist and fog but with warm hazy late october sunshine, the southwest corner of the uk and irish republic could be the exception to the fine and warm picture being closest to the low, eventually the continental high drifts away southeast and atlantic low pressure begins to take control. The Ecm 00z op run shows the much milder weather taking until early next week before it reaches the south and the main core of warmth is then shunted further east but the uk does become somewhat milder but remains unsettled, especially towards the west and north where temps look closer to average, the south and east tending to become drier and brighter and also very mild. So, this week remains unsettled, cool initially, especially in northern britain but tending to become a little milder through the week, windy at times with spells of rain mixed with showers, similar next weekend but then turning milder.

[Summer Sun]

Next week is continuing to look much better from GFS than what this week is likely to be certainly for the northern half with high pressure taking hold for a time

As the week progresses low pressure begins to edge in from the west

ECM is less keen this morning on a pressure rise

[Gavin Hannah]

The HP developing to the North East could bring some very decent high ground snow. The low pressure moving in at the end is an unwelcome sight. Could it shift away to the south east? I hope so, I would quite easily settle for some quieter weather for a couple of weeks after the misery of the this years washout.

[legritter]

Certainly a very interesting week on the way ,all charts show plenty of rain ,and possible flooding issues .towards the end of this week could be very active as different air masses fight it out .but beyond next week end i would not want to put a bet . we even have Post Rafael on the fax chart ,now calling named storms after Tennis players .Here we are Half way through Autumn and its certainly not boring ,bring on the Prozack Charts so we can have some toys being thrown out the prams .as usuall FAX charts will be my most visited charts this week , catch up with you all later Cheers

[Nick F]

One difference I can see opening up between the 00z ECM and GFS operationals into the medium range - is the ECM is less keen than GFS on disrupting the 500mb trough to our west and SW.

GFS disrupts the trough resulting in a cut-off upper low to the west of Iberia and mid-latitude blocking moiving in around the top across the UK and Nern Europe, hence high pressure tendencies shown by the model.

Though the 06z so far doesn't look quite so keen on disrupting the trough. The 00z GEFS for pressure for Aberdeen suggested the operational was at the higher end of the members for pressure compared to the GEFS mean, though the difference was not so great for London.

[Methuselah]

I think that we should keep our toys firmly inside our prams, until New Year...Sort of keep them standby, for rainy day?

Oops! Models are looking uncertain, just now...FI is being FI!

[Gavin Hannah]

Oops! Models are looking uncertain, just now...FI is being FI!

It's that damned low pressure.!! The overall pattern is still there, we just need the models to send it south and east.

06Z

00Z

The 06Z has reverted back to more like the 18Z.

[Frosty.]

A major feature of the Gfs 06z operational is that the very mild air which spreads north next week never really reaches as far north as scotland, temps remain either on the cool side or at best, around average throughout the run but some very warm air flirts with the south and the southern half of the uk becomes generally very mild with max temps of 15-17c range, perhaps closer to 18-20c at times in the far south and southeast, but this is offset by some pretty unsettled looking charts with low pressure generally in control, so the best way of summing up next week on this run would be very mild and unsettled in southern and central areas and unsettled with near average temps for scotland and n.ireland, not all doom and gloom, there would also be some warm sunshine between the downpours but with such saturated ground, the risk of further flooding is ever present, certainly this run is a lot more unsettled than the 00z mean.

[UV-RAY]

It's that damned low pressure.!! The overall pattern is still there, we just need the models to send it south and east.

06Z

00Z

The 06Z has reverted back to more like the 18Z.

Perhaps if we ask them nicely they'll move them for us.

There appears to be a lot of divergence on offer at the moment, more so than usual at this time of year. I think Northern areas look like staying in a cool unsettled regime next week with the South of the country unsettled and milder, How far the dividing line between cool and mild extends North/South remains very much up in the air.

[Gavin Hannah]

Awaiting the 12Z with bated breath now......

[Mark Neal.]

Been watching the models for a while now and are really enjoying watching the models chop and change, we are plenty of time away from winter, interesting to see what we will get as winter slowly gets closer. Interesting times ahead.

[Gavin Hannah]

12Z teasing us with the HP situation. Currently at t.114, HP reaching further north into Greenland than on the 06Z.

[shotski]

This would get me more excited

[Gavin Hannah]

Sorry Hammer but I am not seeing it the same as you, Could you post the chart you are looking at please.

The only high I can see of interest (Northern Blocking) is on the other side of the arctic.

Referring to the HP that was modeled to sit over the northern half of the UK. Migrating from North West Atlantic into Europe. It was looking quite promising on the 00Z chart, but as usual, it's now looking unlikely, with Low pressure persisting through next weekend, and even a hint of Euro High thereafter.

Writing the 12Z off today. It's gone from a promising weekend next weekend, to meh in 3 runs. But, I guess that's what I get for watching individual runs.

[A Winter's Tale]

Evening everyone.

Quite a cool evening out there right now, and a frost should develop in northern Scotland under clear skies and as most showers die away although some showers may still linger around the seas near Shetland and Orkney. A band of rain is moving eastwards from Ireland, clear conditions should be present in the south of Ireland later in the night as the front clears away and rain should clear Wales and most of England before morning but the front may stall somewhat across the north of England and Ireland and the south of Scotland and there could be a touch of brief wintryness on the highest ground here. A cold night for northern Scotland, but typically in towns and cities lows should be at 5-10C. There should be sunshine across much of England and Wales away from the north west and some decent sunny spells across northern Scotland as the front clears out into the north sea although some precipitation leaving Ireland in the morning may hang around northern England for the afternoon. Showers should continue to linger near the northern isles, some cloud cover over Ireland, northern England and southern Scotland for the afternoon but some clear spells may develop in Ireland and southern Scotland. Maximum temperatures at 7 to 10C. Tuesday night, another frosty one for parts of Scotland, showers again will continue in the northern seas, some good clear spells over parts of Scotland, England and Wales and a few in Ireland but cloud will increase from the south west with some rain in southern Ireland as the next front arrives. Lows of 2-10C in cities.

The front should clear England and Wales early on Wednesday as it moves northwards to northern Ireland and Scotland, some sunny spells following behind the front in parts of southern England but showers will persist near the channel coast and some light precipitation will continue around Ireland. Northern Scotland may hang onto some sunshine. Cool in the north with maximum temperatures failing to get above 10C, milder in the south with 16C possible. A largely clear night for England and Wales away from the north west but some cloud cover and precipitation may continue in the south east and showers shouldn't be too far away from the south west. An overcast night for Ireland with some preciptation spread out - more persistent in the north - and persistent rainfall for Scotland, heaviest near the west coast, the south east possibly staying dry. Lows of 6 to 12C.

Thursday at the moment looks like quite a cloudy day with a few sunny spells around northern Scotland and some central parts of England. Some scattered, light precipiation down the western side of England and Wales and few spits and spots of rain in southern Ireland but still a little more persistent and heavier rainfall to the north of Ireland and western parts of Scotland - possibly still lingering across the central belt. Maximum temperatures of 11 to 16C. Largely clear night for England and Wales although at the moment, the south east could hang onto cloud cover related to a feature in the continent. Cloudier for Ireland and Scotland, some precipitation near the west coast of Ireland but persistent and heavy rain in the islands and the northern half of Scotland. Lows of 7 to 12C.

Friday could have some sunshine down the western side of England, Wales, possibly eastern parts of Ireland and eastern parts of Scotland and northern England. Some precipitation and cloud cover further west in Scotland and Ireland and south eastern parts of England may once more remain overcast and possibly wet. Maximum temperatures of 11 to 14C. The night-time period at the moment could be an overcast one for the western parts with some scattered precipitation in the western coasts with clear spells favourable down the eastern side of England and Scotland. Lows of 7 to 10C.

Beyond, at the moment it seems likely that milder conditions assoctiated with southerly winds may persist for a while, but for how long remains to be seen,

[Gavin Hannah]

This would get me more excited

So long as the HP wasn't transitory and made way for the first LP system to come sweeping across the Atlantic, that would be an awesome run up to Xmas.

[BLAST FROM THE PAST]

So long as the HP wasn't transitory and made way for the first LP system to come sweeping across the Atlantic, that would be an awesome run up to Xmas.

It was...

[BLAST FROM THE PAST]

So here we are 15th Oct, 24 hrs from the 25th anniversary of the Great Storm of 1987. I mentioned about week ago that there was model interest in a deep depression around this time. I brought it up as solar and lunar forcing suggests a stormy period. Could we see neartime upgrade, downgrade or is what 12 ECM T48 about right? Worth watching closely IMO. Can't post links on thisa work computer...sorry.

BFTP