Model Output Discussion - 15th April Onwards

[The PIT]

Unsettled cool looking GFS with high pressure only controlling the weather early in the run and then in deep FI. A risk of snow again for Scotland for much of next week impressive and should continue the late ski season. The winds over this weekend are also impressive with gusts up to the mid sixties across Scotland for a time.

[Thundery wintry showers]

GFS 12Z tones down the ridge of high pressure for midweek but also the frontal system that was previously progged to track across the north, so a cool week of sunshine and showers up until Thursday (though many places probably staying dry on Wednesday/Thursday with generally higher pressure) and some snow on northern hills. Friday onwards sees fronts come in from the SW introducing cloudier, wetter and warmer conditions. UKMO looks quite similar to the GFS but with higher pressure come Wednesday/Thursday so probably fewer showers.

Re. the weekend, Sunday looks like staying dry with sunny intervals south and east of a line from Aberystwyth to the Humber, a cloudier zone in N Wales/N England and the rain only really taking off over Scotland, Ireland and Cumbria. Tomorrow still looks like being mostly dry with some sunny intervals and isolated showers- it will be interesting to see if my prediction of widespread afternoon stratocumulus verifies.

[Cheshire Freeze]

Unsettled cool looking GFS with high pressure only controlling the weather early in the run and then in deep FI. A risk of snow again for Scotland for much of next week impressive and should continue the late ski season. The winds over this weekend are also impressive with gusts up to the mid sixties across Scotland for a time.

Yes yes, great weather. The longer we can keep the nasty heat away for the better

The potential for quite a showery week coming up though it should feel pleasant enough given the lack of persistent cloudcover and rain like we have experienced recently.

[Geordiesnow]

I think its fair to say regarding the detail, its very hard to pin down after the NW'ly blast but one is hoping for some consolation for the lack of warm weather that we've been used to in recent years at this time of year is that it will be at least a clean bright convective airflow and no shortwaves will scupper it in any which way possible.

On an Arctic sea ice POV, I hope the ECM is correct as it sets up a reverse Arctic dipole set up which will stop thicker ice leaving through the fram stright, it may even encourage another pattern change if albeit probably not a warm one. Although the ECM has been keen on this for lots of runs, it never seems to get any nearer from 120 hours which is frustrating and this morning run totally backed away from it.

[keithlucky]

Pretty cold weather in UK next week

[Snowy Easterly]

- 5c in the north next week and -2c in the south according to GFS

Goodbye crops

[risk of sleet]

- 5c in the north next week and -2c in the south according to GFS

Goodbye crops

Yeah, Bananas and Ginger are going to be a bit pricey this year! The rain was helpful for everything else I guess.

[Cheshire Freeze]

Quite interesting how the trough has been in situ for weeks on end, allowing the disintegrating vortex to 'leech' its associated cold upper air across the UK. As I've mentioned many times before, patterns seem to be becoming entrenched for weeks on end just lately and I can't really fathom what is causing it. Over winter we had the Azores high parked to our S and SW and now we see it displaced from this position and a trough set up instead. It's like block synoptics i.e weather patterns are coming along in defined blocks.

I can only think that the jet stream is becoming increasingly meridional, buckling in loations for lengthy periods of time.....hence the Russian heatwaves and our cold spells of winter 2009-2010 and December 2010.

Edited May 12, 2012 by CreweCold

[Polar Maritime]

Some cold -4 uppers over the uk early next week, once again frosts a risk. And some big snowfalls over the Highlands

The GFS is still showing a N/E flow throughout the run, cool/cold and unsettled seems to be the continuing theme. ECM seems to agree with this to.

Edited May 12, 2012 by Polar Maritime

[Anthonyb]

Some cold -4 uppers over the uk early next week, once again frosts a risk. And some big snowfalls over the Highlands

The GFS is still showing a N/E flow throughout the run, cool/cold and unsettled seems to be the continuing theme. ECM seems to agree with this to.

Actually don't mind those charts. It will give me in the SE cool but sunny days!

Snow for highlands? No big news really.

[Northernlights]

Actually don't mind those charts. It will give me in the SE cool but sunny days!

Snow for highlands? No big news really.

More or less continuous dry powder snow at Cairngorm above 3000 feet up to a depth of 3 metres for the first 2 weeks in May is probably big news especially when virtually all the snow had melted in March.

[johnholmes]

More or less continuous dry powder snow at Cairngorm above 3000 feet up to a depth of 3 metres for the first 2 weeks in May is probably big news especially when virtually all the snow had melted in March.

erm.. perhaps a touch OTT there-this is the official update this morning and there was not much depth before this last fall?

Last Updated on: 12/05/2012

Top Station Weather, 20 MPH, Westerly, -2.0C

We have had well over a foot of fresh snow over the last 18 - 24 hrs,

but yes another late season in prospect for this area after a poorish spell

[Backtrack]

Just as TWS suggested, the stratocumulus is reaching a cap, and spreading at an impressive rate.

Cloud should soon clear from West coasts up to 10-20 miles inland as the breeze moves any cloud away to leave clearer skies fresh from the sea.

As for the model outlook. Well it's looking poor for those looking for sunshine & warmth.

Whilst the sunshine department isn't looking too bland at least, the warmth part certainly is! A sunshine and showers regime for next week, perhaps with longer spells of rain in the North.

Other than that, it's probably going to be rinse and repeat for some time yet until we can tap into some proper warmth from the South, which doesn't look like happening until the jet stream decides to re-position itself.

The 06z is rolling out now, and I can't see it been much different to the last. The Met Office further outlook suggests uncertainty, but with unsettled weather being the favourite to win at the moment.

Just as in Winter, we play the waiting game.

[Backtrack]

06z a great run in FI. At 7 days out we see a high pressure link up, and although winds will be initially from the North, high pressure IS in charge, so sunshine would be the predominant feature.

Probably an outlier from the ensemble run, but we shall see shortly.

[Gael_Force]

More or less continuous dry powder snow at Cairngorm above 3000 feet up to a depth of 3 metres for the first 2 weeks in May is probably big news especially when virtually all the snow had melted in March.

What might be bigger news is happening in the fields at lower levels! ...and, I don't see much in the way of relief for the farmers in the north. Persistent rain to flood the tramlines and prevent spraying, temperatures struggling to reach double digit maximums, lack of sunshine to provide energy for plant growth.....the list goes on, unfortunately.

[Northernlights]

What might be bigger news is happening in the fields at lower levels! ...and, I don't see much in the way of relief for the farmers in the north. Persistent rain to flood the tramlines and prevent spraying, temperatures struggling to reach double digit maximums, lack of sunshine to provide energy for plant growth.....the list goes on, unfortunately.

Thought I would not be too much of a grumpy old farmer but what you say is the absolute truth after such a magnificent start in March.

[Northernlights]

erm.. perhaps a touch OTT there-this is the official update this morning and there was not much depth before this last fall?

Last Updated on: 12/05/2012

Top Station Weather, 20 MPH, Westerly, -2.0C

We have had well over a foot of fresh snow over the last 18 - 24 hrs,

but yes another late season in prospect for this area after a poorish spell

OOPS AGAIN NORTHERNLIGHTS LACK OF TECHNICAL SKILL!!!

http;//www.winterhighland.info/index.php?resort=cg is where I got the information for the depths of snow on the upper slopes John, sorry if it is a bit OTT but it has been snowing almost every week up there since the begining of April without melting. Even we at our level had a 10 inch fall overnight on the 3rd of April.Also excuse my lack of technical ability in not being able to copy this link.

Edited May 12, 2012 by Northernlights

[johnholmes]

not grumpy at all what is wonderful for the skiing on Cairngorm is hardly likely to fill someone who depends for a living off the land to be anything like as happy. I fully understand how you must feel.

[johnholmes]

Just as TWS suggested, the stratocumulus is reaching a cap, and spreading at an impressive rate.

Cloud should soon clear from West coasts up to 10-20 miles inland as the breeze moves any cloud away to leave clearer skies fresh from the sea.

Its not happening like that here, 6/8 shallow Cu but not spreading out so decent sunny spells are also occurring.

If you look at the Watnall ascent at 00z with tops around 6-7000ft and pretty dry air above one can see why this area at least is doing quite well for sunshine. Looking at the Extra 12-15z predict for Doncaster suggests the tops might get to 8-10,000ft for a time but again with fairly dry air above.

the sat link below shows how most of the UK is faring today

http://saturn.unibe.ch/rsbern/noaa/dw/realtime/current/n1bcurr.jpg

Edited May 12, 2012 by johnholmes

[Thundery wintry showers]

It's a similar story in Tyneside except that some of the cloud patches are thick enough to produce scattered light showers with sunshine in between- to my great surprise there isn't much evidence of the convective cells hitting a cap at the moment despite sea-level pressure around 1035mb. The Met Office satellite images suggest that this is true of most of the country with little evidence of extensive stratocumulus, rather broken clumps of cumulus. The cold upper air and relatively low heights are probably helping to keep the atmosphere relatively unstable, with dry air also raising the condensation level.

It may stay dry and reasonably bright over most of England and Wales tomorrow, where temperatures will be a couple of degrees above today's values, but with cloudier conditions spreading into north Wales and northern England with some rain possibly reaching Cumbria by evening.

[Zenarcher]

Some interesting weather across Scotland on Sunday, strong winds around 30 to 40mph for Western and Northern parts and gusts expected to be 50 to 60mph. Also very heavy rain for Western Scotland into the late afternoon and evening on Sunday which the Met Office have a warning out for. Amazing to see 06z GFS putting very high winds to the far East of Iceland on early Monday morning around 65mph with gusts of 80mph.

Now looking at Wednesday the 16th of May to Saturday the 19th of May during this time high pressure will be mainly in the Atlantic meanwhile low weak pressure will be the main feature over Britain which will keep our weather changeable and also very cold during the nights.

Looking ahead into the last full week of May to see if there are any signs of anything something does appear on both the ensembles of the GFS and ECM they show high pressure building up over our North so possibly staying changeable and cold for the time being.

[mushymanrob]

Pretty cold weather in UK next week

them colours arent temp profiles, the gfs suggests low pressure to our near southwest, thatll advect some warmer continental air....so warmer rain as opposed to cool rain!

[johnholmes]

The colours show whether the heights the computer expects are above(+) or below(-) at 500mb compared to the long term mean for the date shown.

Deep blues generally are fairly coincident with a trough being shown on the upper air pattern, which usually means unsettled weather, the heights , the lines are shown purple=v cold air, blue=the 528 line, green=546 line and the next one shown is the 564 dm line. They are indicative of how cold the air is at 500mb which is a ROUGH guide to what surface temperatures might be.

the above is for anyone not familar with this type of chart-hope it helps?

[bluearmy]

them colours arent temp profiles, the gfs suggests low pressure to our near southwest, thatll advect some warmer continental air....so warmer rain as opposed to cool rain!

and given that its the 6/10 day op mean representation, its actually the week after next !!

[Backtrack]

Its not happening like that here, 6/8 shallow Cu but not spreading out so decent sunny spells are also occurring.

If you look at the Watnall ascent at 00z with tops around 6-7000ft and pretty dry air above one can see why this area at least is doing quite well for sunshine. Looking at the Extra 12-15z predict for Doncaster suggests the tops might get to 8-10,000ft for a time but again with fairly dry air above.

the sat link below shows how most of the UK is faring today

http://saturn.unibe....ent/n1bcurr.jpg

Hi John, just seen this sorry.

Seemed to be strange here. Cloud built, but instead of spreading it gradually moved on, probably due to the constant breeze which made it very cool today, even in the sunshine. Quite annoying really, a sun index of 4 - 5 today, felt almost like winter.