Model Output Discussion 12z 03/04/13

[IanR]

Will we pay for all this spring dryness with another very wet summer

[Frank Trough]

Will we pay for all this spring dryness with another very wet summer

Oh well, that's that then. i'm emigrating.

The ECM has been fairly consistent recently with building pressure from the south as the trough pushes east. I'm happy for that trend to continue. In fact, given that it's quite a dry run later on i think i would "bank" the ECM - there is at least some energy going over the top of the high at 240. Any really nice weather is still a long way out though. It still hasn't got inside t+192 on the ECM.

[Guest pjl20101]

Will we pay for all this spring dryness with another very wet summer

Who knows Ian what this summer will deliver? In the meantime I am going to post the 8-14 day CPC chart and if anything it's very identical to the ECM which is great to see. Its looking much better than it did yesterday:

http://www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php

Promising weather at last and matt Hugo tweeeted something about the SSTs off the north sea having implications for the rest of the spring season. The fact they are cold may have its own ramifications on the rest of the season.

[ANYWEATHER]

ECM FI looks great, this easterly continental influence continues but the bonus is that when we get this far away from winter the continental flow is rather warm and pleasant. Much better than wet and cool eh!

Yep "IF" that chart comes off it would be pretty cloudy I think, away from the lee side of any high ground,ie west wales , but it will be very cool under cloud laden drizzly skies, and lots of fog on the east coast, coming across some record breaking cold North Sea surface temps....

[Man With Beard]

ECM continues with the cold east to SE'ly winds up to Tuesday

That's some turn around from three days ago. Really shocking to have a fifth consecutive week with snow potential in the charts. And now approaching mid-April! I think talk of a warm-up being nailed on is still too far away - that UKMO T144 has continued cold written all over it with a potential north-easterly coming in at T168 / T192. Early days but April CET could come in well below average, second month in a row.

[Frosty.]

Tonight's Ecm 12z is remarkably similar to the 00z with the filling trough slipping southeast by the end of the week and high pressure rapidly filling the void left by the departing trough, the outlook then becomes very benign with intensifying anticyclonic conditions through the middle of april onwards bringing a nationwide fine spell and we begin to warm up, the uppers become much warmer and we join mainland europe in the warming trend so nature can then play catch up after the prolonged cold spell. In the meantime, a fine weekend for most areas with sunny spells and lighter winds for all areas but overnight will continue to be frosty, cold at first next week and the cold will become accentuated by a freshening southeasterly airflow as we get trough disruption developing over the uk, the exact track of the low is still being fine tuned by the models but it looks like the 528 dam line will be pushed gradually north throughout next week, eventually pushing well north of the uk with mild air arriving across southern and central britain by around midweek but then rather colder air pushing the milder air away very briefly if the ecm verifies before pressure rises strongly by the end of next week.

Edited April 5, 2013 by Frosty039

[Gibby]

Good evening folks. Here is tonight's look at the 12z output from GFS, UKMO, GEM and ECM for today Friday April 5th 2013.

All models show a ridge of High pressure crossing the UK over the coming 36-48hrs followed by a fall of pressure from the SW as milder air tries to displace the colder air over the UK early next week. A dry weekend seems likely with frosty nights, quite sharp in rural areas. Later on Sunday and through the early days of next week the weather turns more unsettled while staying rather cold and breezy with some rain and hill snow likely in places, the snow chiefly on the Northern edge of the precipitation slowly moving North early in the week.

GFS then shows the midweek period with milder air pushing NE over the whole of the UK with rain at times in SW winds, heaviest in the NW. Temperatures will rise to normal values for mid April by the end of the week. The changeable pattern then persists through much of FI with rain at times, occasionally for all but other times when just the North and West see any measurable rainfall while the South and East see longer drier spells. This dry theme then extends North across all areas by the end of FI with temperature edging into the warm category with time.

The GFS Ensembles show a huge spread in the pack once the milder air moves in next week. There are some reasonably warm members including the Control run but some much colder ones too with the mean falling on the side of slightly above average conditions with some rain at times as Atlantic fronts cross by.

The Jet Stream tonight shows a sine wave pattern in the flow as we move through next week at a latitude mean close to 50 deg N or Southern Britain.

UKMO for the middle of next week shows the early week Low moving away East leaving Wednesday as a dry if rather cloudy day before a new low and troughs move up from the SW on Thursday with rain spreading steadily NE again across the South and West.

GEM tonight shows a cold and unsettled first half to next week before Low pressure and fronts edge milder and wetter conditions slowly North across the UK later next week.

ECM shows a chilly week to come with rain and a cold wind across the UK at times as Low pressure areas trundle slowly across from the West through the week, clearing away East later as High pressure builds strongly across the UK and eventually Scandinavia by the end of next weekend. Some snow is possible on Northern hills at times through the early part of the week. More settled conditions arrive next weekend with some sunny and pleasant weather for most areas for a time before Eastern areas would become cold and grey as low cloud would feed a long way inland from a very cold North Sea.

In Summary tonight the weather next week will remain somewhat on the cold side of average with some rain at times and a cold wind, especially in the North. Thereafter there are a variety of options on offer from mild and changeable conditions with rain at times such as GFS shows while ECM develops a huge Scandinavian High next weekend which has a lot of warm uppers within it ruined by the feed of surface air crossing a very cold North Sea meaning conditions at the surface would be very cold and raw with extensive low cloud feeding West across England.

[Purga]

Well a surprise from ECM with the huge Scandi HP building at the end.

Certainly is going to give a cold damp grey feel after the transit of air off the N Sea.

Also - Will the HP retrogress to Greenland in due course??

Cold air filtering around the High and approaching from the east again.

Edited April 6, 2013 by Paul

[Guest pjl20101]

Its hard to tell really, but one thing is guaranteed that it will be a set fair pattern.

[Scorcher]

PS: I'm surprised at all the excitement from the mild brigade?

Why is that? I haven't actually seen anyone get that excited anyway. Warmer uppers next week are almost nailed on now which is what we wanted to see- even if we end up with some cloud from the North Sea at least the frosts will stop which is what we need now to get things growing. For people in the west the North Sea cloud is less of a concern anyway.

[Summer Sun]

The ECM ensemble goes for a south to south westerly wind rather than an easterly resulting in less cloud / coastal fog along the east

[soupsurfer7]

Its hard to tell really, but one thing is guaranteed that it will be a set fair pattern.

Because not everyone lives in the East... that chart would be quite good for Wales and Ireland.

[No Balls Like Snow Balls]

If the ECM were to verify my area would see highs of 11c and 12c next weekend. i find it strange that someone such as yourself that craves cold would call that kind of temp cold!.

[Gibby]

If the ECM were to verify my area would see highs of 11c and 12c next weekend. i find it strange that someone such as yourself that craves cold would call that kind of temp cold!.

Personally I think in your area temperatures would be held far lower than that with the feed from the East. The North Sea is just 4C at the moment so any feed of air off it will keep temperatures below 7C in the East and even as far West as me we notoriously often share in this cold raw type weather with low cloud funneling down from the NE and holding temperatures well down. The far West and NW would fair best with some reasonably warm afternoons.

[Snowman.]

Well a surprise from ECM with the huge Scandi HP building at the end.

Certainly is going to give a cold damp grey feel after the transit of air off the N Sea.

Also - Will the HP retrogress to Greenland in due course??

Cold air filtering around the High and approaching from the east again.

PS: I'm surprised at all the excitement from the mild brigade?

I'm also surprised that one is still looking for cold half way through april.

[No Balls Like Snow Balls]

Personally I think in your area temperatures would be held far lower than that with the feed from the East. The North Sea is just 4C at the moment so any feed of air off it will keep temperatures below 7C in the East and even as far West as me we notoriously often share in this cold raw type weather with low cloud funneling down from the NE and holding temperatures well down. The far West and NW would fair best with some reasonably warm afternoons.

You may well be right. The temps i quoted were from yr.no which base there forecasts on the ECM

[reef]

The ECM chart at T+240 would be cloudy almost everywhere. You'd have 850hPa temperatures of 4-5C crossing the North Sea which is also at 4-5C, which is about as stable as you can get. The tight isobars would ensure the cloud would be readily pushed in and remain pretty relentless even in western areas, with perhaps only very extreme sheltered areas getting any brightness. The weather would be much worse than now for most.

It wouldnt be any good for growing either, as 5-6C by day and night with little sunshine or precipitation would be just as useless for that as the current weather.

High pressure doesnt always equal good weather on the ground, especially in spring!

[Captain Shortwave]

Yeah the ECM op keeps showing these yucky north easterly patterns late on. Whilst without ensemble support, these situations have had a habbit of being half right most of the time. The ens southerly looks nice though. We really want the flow south of east from a high pressure cell to keep the flow coming from Holland southward to avoid a large sea track as the north sea would really be a anticyclonic gloom making machine.

[phil nw.]

As Reef has pointed out a Scandi High as shown in the ECM op run would likely keep things on the cold and cloudy side away from the far west and north west with that NE wind across the cold N.Sea.

However mean outputs favour that high locating further south and better orientated which would bring drier air from a more southerly quarter..

http://www.meteociel...01-216.GIF?05-0

as does the CPC forecast Ht anomalies.

http://www.cpc.ncep....y/814day.03.gif

Something along those lines with an increasing chance of some decent temperatures and sunshine would be welcomed by many i am sure.

[mushymanrob]

been there before re the ecm in fi. april 74was dominated by easterlies. yes the mornings were dull cloudy and cool but the sun burned back the stratus and the afternoons were warm in the sun. the west was basking for most of the day in sun, the east coast suffered. but it was pretty normal overall spring weather for most. the west loved it esp west scotland. the southeast got the worst. but either way that scenario was far better then this current regime.

but we have to get there yet, its only one option possible. me, abig moaner, sees nothing to worry about. this cold is finally going. it wont be as cold again until november.

good riddance.

[mushymanrob]

oh, and both the anomaly charts and mjo do not suggest the ecm in fi is likely as things stand atm

Edited April 5, 2013 by mushymanrob

[SP1986]

I wonder if the future few days runs will extend the easterly even further? Or perhaps turn the flow northerly, I think cold is certainly here to stay, and it becomes very confusing because the models pull out a milder synoptic situation, and it's constantly put back.. so you wonder when the situation is actually going to verify, or if it is actually going to verify at all? it must be a fairly tough one for forecasters in a way... the weather certainly makes mugs of us.

[damianslaw]

Whilst the models are suggesting the atlantic will make another attempt to invade the country early next week displacing the very dry settled cold conditions of late, the overall pattern we have been locked in since around 9 January barring the odd shortlived appearance of the atlantic a la late January, doesn't look like changing anytime soon with a preety weak ineffective atlantic, a jet too far south to usher in a mobile westerly pattern, the likely result will either be the trough becoming once again unstuck across the country and forced to eject SE as heights to the north hold it into place, or a renewed albeit milder easterly flow than we have now as heights remain stubbornly strong to our NE. April really isn't the time of year when the atlantic fires into gear, instead blocked dry patterns are more likely to hold sway now than at anytime other time of year, but what is quite remarkable about this year is how such conditions have been in place for nearing on 2 months now.. I do hope we don't see a swift shift in fortunes to the troublesome positioned trough as we did last April after what was also a very locked in dry settled period.

I am enjoying the current calm dry and at times very sunny weather here in the NW, but really could do with a change to milder conditions with no cold wind from the NE or harsh frosts at night.. I also wouldn't mind seeing some decent rain, much rather have unsettled weather now than say in a months time... my fear is things will change come May and we'll be staring once again at another locked in cool wet period as the summer season approaches... lengthy dry periods are often replaced by lengthy wet periods and all of a sudden.. last April being a classic example.

Feb-April is for the NW the driest period of the year mind, its far more difficult to sustain a dry period in the depths of summer.

[SP1986]

The GFS 18z now wants to extend severe frosts to 96 hours... is it over exaggerating, or are we looking at an extention of exceptionally, possibly record breaking cold nights in the west?

[chris55]

Yep "IF" that chart comes off it would be pretty cloudy I think, away from the lee side of any high ground,ie west wales , but it will be very cool under cloud laden drizzly skies, and lots of fog on the east coast, coming across some record breaking cold North Sea surface temps....

I don't think it would be quite as bad as you describe, the winds are V slack and with ever increasing solar strength any low level cloud would probably burn back allowing for some sunny spells. West would be best but not exclusively so.

Although the 240 chart may well bring in more cloud on a much keener easterly wind.