Model Output Discussions 12z 08/03/17

[Summer Sun]

Saturday and Monday are likely to see some April showers but by Tuesday high pressure builds in and it's likely to last through the week with any rain restricted to the far north

Edited March 31, 2017 by Summer Sun

[Frosty.]

The Gem 12z shows high pressure gradually building in, especially from midweek with the second half of next week becoming warmer too and there should be increasing amounts of sunshine..turns into a beautiful spell, really warming up into the 70's F further south.

Edited March 31, 2017 by Frosty.

[NO LONGER POSTING]

Slightly off topic but has only got records of the last time we had such a long period of high pressure dominated weather. Bar the odd storm and away from the north, it's been on going from the start of winter 

[snowray]

Exceptionally dry period coming up but trending a lot colder and unsettled for the Easter break.

 

London and Manchester ensembles.

[Frosty.]

The GEFS 12z mean shows pleasant looking charts from sunday until the end of next week, decent temperatures generally across southern uk where the best of the sunshine would be, cooler across northern uk and more changeable, especially monday which becomes unsettled and windy further NW but apart from that it looks a quiet benign sort of week but beyond next week trends colder and more unsettled for all..anyway, south is looking best next week. 

Edited March 31, 2017 by Frosty.

[Frosty.]

As snowray pointed out, from around T+240 the run up to Easter is currently looking colder and more unsettled with a large trough to the NE according to the GEFS 12z mean.

Edited March 31, 2017 by Frosty.

[Frosty.]

The Ecm 12z looks largely quiet with high pressure in charge next week, feeling pleasant in the sunshine but chilly overnight and then turning much warmer further south for a time towards the end of next week but then all eyes to the north as Arctic air slowly digs southwards, especially for scotland with some snow on hills and frosty nights later and we get height rises to the NW.

Edited March 31, 2017 by Frosty.

[snowray]

ECM moving towards the GFS idea of things turning colder now, chances of a colder Easter have suddenly gone up a lot, 20% chance of a white Easter for parts of the country now a 30% chance. Skiing in the Cairngorms on Good Friday looking like a 50/50, or an even money punt.

[Summer Sun]

15 minutes ago, snowray said:

ECM moving towards the GFS idea of things turning colder now, chances of a colder Easter have suddenly gone up a lot, 20% chance of a white Easter for parts of the country now a 30% chance. Skiing in the Cairngorms on Good Friday looking like a 50/50, or an even money punt.

 

 

Whilst ECM has moved towards a chillier spell it's still 6 day's off Easter Sunday at its D10 chart

Edited March 31, 2017 by Summer Sun

[Frosty.]

8 hours ago, snowray said:

Well what a difference 12 hours makes with the GFS, Palm Sunday now looking very mild and sunny, and there was me thinking about a Scottish skiing break Easter week too.

Well it's funny how quickly things change on the same day in model output..and the run up to Easter could swing back towards this..but at least next week looks largely settled and pleasant in the sunshine under high pressure..nothing is sorted yet for Easter week.

Edited March 31, 2017 by Frosty.

[snowray]

Indeed, Easter is still a long way off, so although the trend appears to be showing a colder and more unsettled period of weather, both on the GFS and ECM, it could certainly all still change and probably will. I wonder what the 00z runs will come up with, probably show something completely different in another 12 hours time.

[Frosty.]

Tonight's Ecm 12z ensemble mean looks very decent for early April as high pressure builds across the uk, just a hint of something less settled and cooler by day 10 across the north.

Edited March 31, 2017 by Frosty.

[knocker]

The 6-10 anaysis vis the NOAA, GEFS and EPS anomalies has been pretty much nailed on for two or three days now and supported by the det runs, albeit with detail variation which is only to be expected. Thus we have troughs eastern Europe and mid Atlantic with ridging over the UK all portending a pleasant few days next week with the usual caveats regarding anticyclones and cloud and temps. Possibility of a subsidence inversion and Sc layers perhaps. It should be noted that this period heralds the pattern change as the high pressure declines and moves east.

Keeping that in mind all, although obviously not in complete agreement, are on the same page as we move towards Easter. We are looking at a general area of low pressure/trough UK and Scandinavia with positive anomalies and ridging south of Greenland. Thus a north westerly upper flow but precisely how the ridge and trough configure will dictate to some extent the impact of systems moving around the HP and tracking SE in the vicinity of the UK and the spread of the more unsettled and cooler weather.associated with them. Suffice it to say at this stage the percentage play is certainly for more unsettled weather starting the end of next week with temps trending below average and more than likely a N/S split vis some inclement outbreaks.

 

Edited March 31, 2017 by knocker

[snowray]

Here we go, pub run is teasing the coldies again.

[snowray]

Country wide heavy snowfall there.

Funny how its always around D10 though.

Edited March 31, 2017 by snowray

[cheese]

9 minutes ago, snowray said:

Country wide heavy snowfall there.

Funny how its always around D10 though.

And now I'm hoping it stays there.. no interest in snow at all now. Enjoying the lovely warm weather far too much!

Edited March 31, 2017 by cheese

[knocker]

An overview of the GFS in a ten day time frame this morning can safely be kept short and sweet.

Once the decaying trough is out of the way on Tuesday the UK is then under the auspices of the high pressure and by midweek this is centred over southern Ireland.

It remains more or less around here until the weekend and even ridges north west by Saturday and it's only at the end of the ten days that the disrupted Atlantic trough, in the form of the cut off upper low to the south west and some energy running around the top, is the high cell put under any pressure

So in a nutshell a very quiet, not unpleasant spell of weather. The bugbear vis forecasting will be cloud and temp variation both geographically and diurnally

But looking at the GEFS anomaly and keeping in mind last night it's possible that the det. run is hanging on to the high cell a tad long. It will be interesting to see what the ecm comes up with.

Edited April 1, 2017 by knocker

[Frosty.]

Sunday and most of next week shows high pressure as the dominant feature, ergo largely fine with variable amounts of cloud and sunny spells, feeling pleasant in the sun but where skies clear overnight it will be chilly with a touch of frost and some mist / fog patches..generally nice quiet weather for early April across the southern half of the uk, a bit breezier and more changeable for scotland. 

Edited April 1, 2017 by Frosty.

[Frosty.]

The Ecm 00z becomes a bit cooler and more unsettled later and ends generally unsettled but for most of the run its largely settled and pleasant further south by southwest, closest to the high. Scotland, especially further north doesn't look as nice as further south..probably that's being generous.

Edited April 1, 2017 by Frosty.

[knocker]

The ecm is not dissimilar to the GFS up to around T168 when the energy tracking east around the high pressure begins to make inroads squashing the ridge and introducing some wet and quite windy weather in the westerly flow for Scotland. This is merely the hors d'oeuvres before the next trough approaches on Monday heralding the arrival of the expected low pressure, cooler, unsettled spell.

 

[I remember Atlantic 252]

8 hours ago, cheese said:

And now I'm hoping it stays there.. no interest in snow at all now. Enjoying the lovely warm weather far too much!

I'm hoping too, cos the reality is single digits and rain for low levels in the south

[Summer Sun]

If the ECM ens is right it should be mostly settled through next weekend

Cooler air filtering south at the end

[Frosty.]

2 hours ago, I remember Atlantic 252 said:

 cos the reality is single digits and rain for low levels in the south

Agreed, and who really wants that when we have got used to the spring warmth?..in a nutcase, most of the next week or so looks pleasant with sunny spells across central and southern uk.

Edited April 1, 2017 by Frosty.

[Frosty.]

The Gem 00z looks very good, a ridge for tomorrow and then Monday looks fine and pleasantly warm away from the northwest. Tuesday looks a bit iffy but then high pressure builds in strongly from midweek with increasing amounts of sunshine and higher temperatures, the high position shifts around but remains in situ over the uk through to the end although drifting slightly further west but overall it's a very decent run for early April.

Edited April 1, 2017 by Frosty.

[johnholmes]

Taking a look from the anomaly charts persperctive, they are in disagreement! Never a good sign for any relaibility but for what it is worth.

After several days with all 3 (the ones I use) showing ridging as being the main feature with the upper ridge over western Europe/Iberia, ECMWF has gone a different way last evening, see below. NOAA and GFS are quite similar to one another with much as the past few days re positions and depth/intensity of upper troughs and ridges, along with their position.

Usually, NOAA is closer to what actually occurs 6-10 days later but not always. In its 8-14 version it has lost this ridging and shows a more westerly type flow with the trough pretty much over the UK. 

Anyway see for yourselves on each chart in the links below. Looking at any of them and one would not expect any 'cold' weather in the 6-10 day frame and the 8-14 one? Well it does show some signs of the upper flow veering north of west but early days. If it shows it over the next 2-3 days then time to wonder more seriously about temperature levels.

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

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

In the shorter time scale the temperature levels around here are quite pleasant with my monthly data for the whole of March some 2 C above the 20 year average.