Model Output Discussion 12z 03/04/13

[Guest pjl20101]

Very true Frosty39, when I was looking at the average heights for this month on the CFS it was giving hp from the sw to se parts. With whether this retrogression happens or not is anybodys guess.

[Kentspur]

We missed out on the snow all winter/spring apart from one January Sunday-least it looks like we will get a nice warm dry spell to part make up for this so I can go fishing:-))

[Captain Shortwave]

Slightly disappointing turn for Sunday, both models have flattened the pattern and pushed low pressure closer to the UK, also meaning winds are from the South west instead of the South which might make prone areas cloudier than what was modelled earlier.

GFS still looks nice for central/southeastern areas

UKMO would have a moister, cloudier flow with the cold front coming in quicker. I would say that's a big change in one run considering this mornings output.

Edited April 10, 2013 by Captain shortwave

[shaky]

Slightly disappointing turn for Sunday, both models have flattened the pattern and pushed low pressure closer to the UK, also meaning winds are from the South west instead of the South which might make prone areas cloudier than what was modelled earlier.

GFS still looks nice for central/southeastern areas

UKMO would have a moister, cloudier flow with the cold front coming in quicker. I would say that's a big change in one run considering this mornings output.

Yeh i think the ecm is gona have to backtrack this evening its been pretty stubborn in showing the high closer to the uk on sunday but am pretty sure its gona follow the ukmo later!!

[Summer Sun]

GFS continues to give many parts of the south the first 20c of the year given the cold sea temperatures coastal districts are likely to be slightly cooler but inland parts will certainly notice the warmth

For the bulk of the east it should be dry but cloudy with any rain in the west

Monday also has the potential to hit 20c

Next week sees continued indications of a huge area of high pressure building across Europe and this drifts towards the UK with a north south split likely to devlop

Edited April 10, 2013 by Gavin.

[Cheshire Freeze]

Yeh i think the ecm is gona have to backtrack this evening its been pretty stubborn in showing the high closer to the uk on sunday but am pretty sure its gona follow the ukmo later!!

Oh joy, a cloudy, moist SW'ly. You couldn't draw a more boring set up.

[Captain Shortwave]

Oh joy, a cloudy, moist SW'ly. You couldn't draw a more boring set up.

Precisely, the output is moving away from a more directly high pressure dominated pattern. I will stick up for the many here because this output would bring warmth and likely some sun given the strength of the sun to my location. But would bring gloomy weather to many, add to that the unsettled weather is now further south to boot.

The only interesting thing to note is a low forming in the bay of Biscay which could bring some thundery rain to central/southern areas. Oh and giving eastern coasts what the western coasts would have had for a week straight before then

Edited April 10, 2013 by Captain shortwave

[Frosty.]

A real north/south divide next week according to the Gfs 12z op run with a lot of very mild and fine dry weather across the south but with a lot of rain and strong winds at times for nothwestern and northern britain in general, at least it will be mild everywhere and locally warm in the prolonged sunny spells across southern, central and eastern areas.

[chris55]

Oh joy, a cloudy, moist SW'ly. You couldn't draw a more boring set up.

I would normally agree, but with such a long spell of cold easterly winds the classic South-Westerly is rather appealing, and as soon as that sun pops out it will feel quite nice I would think.

Edited April 10, 2013 by chris55

[Frosty.]

I would normally agree, but with such a long spell of cold easterly winds the classic South-Westerly is rather appealing, and as soon as that sun pops out it will feel quite nice I would think.

I agree, although I love cold weather, i've had enough of cold overcast easterlies and am looking forward to the warm southerlies and swlies in the coming days, sunday could get close to 21c in places which would be very nice after such a cold cheerless spell.

[Summer Sun]

ECM has the low ever so slightly further west compared to GFS which enables +8 uppers to cover more places

Edited April 10, 2013 by Gavin.

[weather_it_will]

ECM has the low ever so slightly further west compared to GFS which enables +8 uppers to cover more places

Which is good, if you live in the North Sea.

Edited April 10, 2013 by Deep Freeze

[Summer Sun]

Cooler air heads back to the UK next week according to ECM

Deep Freeze thats why ECM is better +8 uppers cover more of the UK where as GFS is more hit and miss

[Frosty.]

Which is good, if you live in the North Sea.

haha yes but the north sea is about 6c at the moment, so a bit chilly to live in.

The BIG pattern change is almost upon us, very mild air sweeping northeast across the uk on saturday but the sting in the tail will be a very wet and windy spell that comes with it, there is always a price to pay.

[shaky]

There we go ecm has backtracked just what i thought it would do!!more low pressure around than this morning run!!even sunday isnt looking as good as it did this morning!!

[Milhouse]

ENS 12z mean indicating a very high pressure dominated period with pressure at least 1020mb somewhere from 192h out to 384h.

[Milhouse]

After a showery spell midweek, high pressure nudges in from the west to end the week.

[Frosty.]

A lot of mild and fine weather on the Ecm 12z for southern areas next week but unsettled and cooler for more of the uk on this run compared to the Gfs 12z which has half of the uk in very mild and mainly fine weather next week for the majority of the time.

[weather_it_will]

After a showery spell midweek, high pressure nudges in from the west to end the week.

But with a NW breeze it will not be feeling warm at all.

[Guest pjl20101]

It looks like one area of hp over the country is going to merge with another one that I have posted from the CPC 8-14 day forecast which I think is even better really. It does look predominantley dry within that time period:

http://www.cpc.ncep.noaa.gov/products/predictions/814day/814day.03.gif

Positive outlook IMHO.

[Milhouse]

But with a NW breeze it will not be feeling warm at all.

Upers range from -6c in northern Scotland to +6c for SW england. Upper temperatures last Sunday were typically -4c to -7c and we still saw temperatures reach double figures over a wide area.

Edited April 10, 2013 by Milhouse

[Frosty.]

Now this is more like it, the ecm 12z builds high pressure northwards through the uk followed by a very warm SSEly flow from spain/africa by T+216 hours, BBQ time. we would possibly even get a humid, thundery breakdown from the ecm spanish plume type flow.

Edited April 10, 2013 by Frosty039

[Gibby]

Hi folks. Here is the report of the 12z output from GFS, UKMO, GEM and ECM for today Wednesday April 10th 2013.

All models are now confirming the end of the cold spell over the next 24 hours. The last cold rain is currently falling over Southern England and Wales. Overnight this moves Northward as the occlusion bringing drifts slowly north over Britain and weakens. Following on behind will be a more showery SW flow for the South while the far North stays drier and all areas in between sees rather cold and cloudy weather with rain at times and hill snow.

GFS shows the weekend with much milder weather for all as winds settle SW and strengthen markedly, especially in the West and North. Occasional troughs will cross NE in the flow delivering outbreaks of rain at times, heaviest in the North and West. Through the rest of next week and the start of FI a North/South split in the weather looks likely with rain heaviest in the NW with only small amounts reaching the SE at times in rather warm conditions here. High pressure maintains influence for many at the start of FI before a trend to more unsettled and rather warm weather develops late in the run.

The GFS Ensembles show a good deal of milder weather to come over the next two weeks with limited rainfall amounts as weakening troughs pass by. the warm end to the operational was not well supported in isolation but there are plenty of warmish options on the table.

The Jet Stream looks much more favourable now as it migrates North to a position which involves it crossing the UK but allowing many areas to be on the warmer side of Low pressure to the NW of Britain.

UKMO tonight shows an unstable SW airflow over the UK early next week with reasonably mild conditions but with spells of wind and rain at times.

GEM continues to show an unsettled start to next week too in brisk SW winds and occasional troughs spilling NE over the UK with rain at times, heaviest in the West and North in reasonably mild weather.

NAVGEM shows a North/South split developing next week with rain at times, more frequently in the North and less so in the South where much of the time will be bright, dry and reasonably warm.

ECM tonight starts next week unsettled, mild and breezy but continues to show a strong build of pressure North into the UK from midweek with some fine and warm Spring conditions developing with some sunny spells in places in the South spreading to all areas in the latter part of the week and weekend when it could become very warm locally with even the chance of a thundery shower or two as a disturbance runs North next Saturday in the Southerly flow.

In Summary the weather is still on course to warm up markedly over the coming days. There are as always caveats to that general theme in that rain at times will be an issue until towards midweek when there is every sign that the extended runs from the States and European models suggest a build of pressure from the South bringing the chance of some very warm temperatures for April later next week. however, as we say with impending cold weather a week is a long time in weather terms and excitement should be held in check for a few more days to see if the same charts are being shown. Nevertheless gardeners and growers will be pleased to here that after this week frosts will be a thing of the past for the foreseeable future.

[snowking]

Awaiting the ECM ensemble means later, but in terms of the height anomalies, a decent picture being painted for southern areas through next week with the likelihood of high pressure dominating:

Really quite solid agreement on this pattern inter-model and inter-run.

The 11-15 anomalies offer something of interest to me in terms of the May-August projections based around matched QBO/ENSO index values thus far:

Notice the negative height anomalies developing around Scandinavia - a mean Sceuro high is a common theme across both the ENSO and QBO derived composites through many of the summer months, with HP based just to the South-West.

I wonder whether this may be the first signs of such a baseline pattern setting up. Such a scenario would offer mostly near average rainfall but a significant negative departure from the 1981-2010 temperature series.

Before we worry about any of that though some nice settled and pleasantly warm weather to come for our friends in the South, those of you in the North, however, may have to suffer more in the way of cloud and patchy rain into next week.

SK

Edited April 10, 2013 by snowking

[Frosty.]

WOW take a look at the GEFS 12Z mean, a HUGE change since the 00z this morning and now it is much more anticyclonic and warmer, the 00z mean was trending towards a cooler and showery further outlook but now it looks warm and settled for all..beyond the rather mixed fortunes next week with the south doing pretty well for fine and very mild, locally warm spells from sunday onwards.